OzVMX Forum
Clubroom => Tech Talk => Topic started by: Toolboy on August 09, 2011, 02:40:16 pm
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Gday all,
A few months ago and apparently for no known reason my RM400N started fouling plugs, so i replaced the crankseal and o ring, pieced the bike back together it still fouled.
Last week i split the engine and replaced the crankcase gasket. Whislt apart i could not see where to gasket was at fault with the cases??
The bike seemed to run fine once assembled and was pushed pretty hard at Connondale on the weekend.
Today i have taken off the barrel to have a look inside and here are the pic:
Everything looks fine
(http://img.photobucket.com/albums/v318/Airfireman/P8090002.jpg)
Rotate the crank:
(http://img.photobucket.com/albums/v318/Airfireman/P8090001.jpg)
(http://img.photobucket.com/albums/v318/Airfireman/P8090003.jpg)
The top of the piston:
(http://img.photobucket.com/albums/v318/Airfireman/P8090005.jpg)
Breather holes in crankcases:
(http://img.photobucket.com/albums/v318/Airfireman/P8090006.jpg)
(http://img.photobucket.com/albums/v318/Airfireman/P8090008.jpg)
It defiently looks like the left breather holes is where the oil is coming from ???
Any help or suggestions??
Tim
???
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Perfectly normal Tim. The oil holes are for lubrication of the main bearings, some engines only have the hole on the left as the right side is lubed by the tranny oil. The oil at the bottom of the cases is residue from the mix. There is even a special tech name for this residual oil but it eludes me at present. Might look like gearbox oil but it isn't ;)
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I am at a loss to explain how it could come from the left [ignition] side breather as there is no possible access to the gearbox oil from that side.
But, I had a faulty petcock once. There was a small amount of fuel left in the tank and the slow leak eventually partially filled the crankcases. The fuel evaporated and left behind a pool of pre-mix oil. It wasn't that dissimilar to what you have described.
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on a side note, 1 thing to be wary of when reassembling any old Suzuki 2 smoker is the over use of the black aviation type gasket goo. It's preferable not to use a sealant at all. If you do need to use anything then go for a thin smear of silicon type sealer. You'll find if the gasket and mating surfaces are good then all you'll need is to smear the gasket with oil and assemble it like that. The oil swells the gasket and should not leak. This includes crankcase gasket, base gasket, reed gasket and clutch cover gasket. Have seen motors wrecked from over use of gasket sealant, especially the the gooey black type ;)
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You haven't started running 100 octane have you, that may make it run rich and foul plugs... Not advice from an expert but it did happen to me on my 250.. leaned out main jet and now is all ok.
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We've had this one before I think.
All two strokes have oil floating around in the crankcase.
Nature of the beast. :)
Put it back together and ride it.
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I recently restored a PE250 Z (82 model) which had the EXACT same symptoms.
It wasn't "good" fuel lubrication in my case - it was ever so slightly drawing it from between the case halves out of the gearbox and fouling plugs instantly.
My fix: I split the cases, lightly and ever-so-gently "decked" the case halves on a large sheet of flat wet and dry (and found them to actually be not quite true and level!!) replaced the centre gasket, with the smallest smear of yamabond, whacked it all back together and it fixed the issue.
I know you said you had it split before, but in my recent experiences you just may need to do what I did mate.
Hope that helps..... Bloody Suzuki's hey.... :-\
Hardo
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What bothers me a little in the photo's of the crank is how the top halves of the crank look so dry after the bike had only been ridden a couple of days ago. Hopefully you may have simply wiped the crank with a rag and then spun it which then picked up the oil from the bottom of cases. The cases where the oil feed holes are look to be coated with an oil film so I'm assuming you probably wiped around the crank/rod area. It isn't overly common to have the cases draw tranny oil but not saying it doesn't happen as Hardo pointed out with his recent experience. Yamabond or Threebond sealers are fine but as a general rule..less is best. I don't remember ever pulling apart any early Suzuki engine to find gasket sealant used from the factory. (excepting engines where no centre case gaskets are fitted)
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There should indeed be a little oil on the floor of the cases if it's all running right, however in this case two things stand out to me (tho I am no expert).
1. The oil in the pic is dirty. Typically the residue I see in my engines is pretty clean.
2. There seems to be some scoring on the piston.
Now, I don't know quite what to make of that and perhaps I'm just imagining things. Any thoughts? I like the sound of Hardo's suggestion.
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Gday all,
The bike seemed to run fine once assembled and was pushed pretty hard at Connondale on the weekend.
Today i have taken off the barrel to have a look inside and here are the pic:
Rotate the crank:
(http://img.photobucket.com/albums/v318/Airfireman/P8090001.jpg)
(http://img.photobucket.com/albums/v318/Airfireman/P8090003.jpg)
The top of the piston:
(http://img.photobucket.com/albums/v318/Airfireman/P8090005.jpg)
Any help or suggestions??
Tim
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How I read it " had a problem , split cases ,new gasket , ran good at connondale, took top off and this is what I found".
No mention of plug fouling now.
No mention of any problem except the oil which is normal.
Other than the piston/bore coming to it's use by date I'me sorry but I can't see the problem.
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My thoughts on the dark amber colour of the oil maybe due to the gasket goo washing off around the reed valve area or in the actual cases surrounding the crank. I'm a little fussy in this regard but I've always kept the internals of my engines and air filter scrupulously (almost surgically) clean. If infact there is any grit in the residue pictured I'd be looking at my air filter as the major probable source. There does appear some scuffing to the piston as Graeme noticed and the lower edge does indicate some piston rock. If the bore/ring is getting a little worn the drop in compression could also lead to the fuel mixture not burning as cleanly as it should thus leaving slightly increased oil deposits. Coulda woulda shoulda..could be a number of things that can't really be 'measured' by pictures alone, if the bike was going well, ring gap is fine (hard to see if there is any blow by under the ring) if everything else seemed normal I'd leave well and good enough alone excepting the air filter which should be cleaned regularly. Removing the top end off to simply inspect 'too often' can cause it's own issues with head studs and such pulling. Waiting for Lozza comments ;)
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There is not a quality oil being used (the 'striations' Ithink they are called) or lots of verticle lines left on the piston, your jetting is to lean your on the very edge of a seizure(grey death ash and the pock marks).
RM 400 pistons(PE as well) suffer badly from excess expansion on all 4 'corners', right where the cutaway is. Happens on stock and aftermarket pistons
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I'd agree that there may be some issue with the centre case gasket surfaces, also is it possible the right hank crank seal is in the wrong way around? These seals are double lipped and will seal either way around but maybe it's let some oil from the transmission to pass if in the wrong way. Also inspect the seal area on the crank itself, may be some imperfections.
Good to see Doc's back.
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I always assemble the center gaskets with Threebond grey 1215, Loctite 515 for base (sometimes Threebond though) and Hylomar/Aero blue for the head gasket (unless it is the type where the manufacture says to use no sealant).Threebond is what the Japanese factories use and i have never had a problem with it. I can not afford rebuild an engine and then have to tear it down again because of a leak so the Threebond is piece of mind. The whole idea is to not use heaps of it so you block up oil galleries or whatever, i have pulled apart many engines that have be stuck together with way too much sealant by other people. It is very rare you pull apart an old engine that has got perfect gasket surfaces. Theres always little nicks etc.
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When i pull my 2t bikes top ends off there is always oil on the crank,the fuel evaporates & leaves the oil behind,the oil I use is blue so its easily identifiable,what brand & colour oil do you use & what ratio?
If its the same as whats on your crank then thats all it is,If that is the oil you are using then i agree with lozza it looks like a crappy brand of oil ;)
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Thanks for your input guys, i will try to answer the questions:
Smed.. i use Mobil 2T Racing oil, 32:1 mix
PMC..The crank seal is fitted the right way around, as per workshop manual
Lozza..The piston is Weiseco
Doc..I sanded the cases with wet/dry 800 used a smear of aviation sealant. I was thinking of not using any but did so lightly and only on the cases. No other gaskets.. The oil matches the colour of the gearbox oil i drained.. and to answer your earlier question the pics taken were as i pulled the barrel of the piston so there is a pool of oil in crank. When i have checked this before i had the same situation, with a gheavy amount of gearbox oil in the crank.
Mike..I fouled a plug on the test run after the rebuild but before Connondale and switched to a B7ES plug...it was a bit of a gamble not too burn a hole in the piston.
Hardo.. As per the answer to Doc
Slawsley... I use 96 Octane with Mobil 2T Racing oil 32:1
What is a big give away is the blackness on top off the piston, i have never had this before
Thanks guys...looks like i need to split again???
Tim
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Ahhhhhh.
Check the left side seal " again ". :)
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Yeah Mike i will do that...I have the engine out of the frame and in the next few days i will look at the seal and oring,,, i did clean and lightly sand the surfaces of the crank and used rubber grease so as not to damage the lip of the seals... I will add pic's
Tim
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Just to add that the bike did run fine and that i reved it pretty hard at Connondale, so much so that the pipe split from vibration. I was going to pull the engine out to fix the mounting bolt holes being out of shape causing the bad vibration and checked out the barrel to see if i had fixed the leak.. :-\
Tim
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32 to 1 errrr, get some more oil in there. 20 to 1 will improve things. I would go to a 8 or 9 on the plug (400T uses 9EGV as std) and also swap the ES for the original spec EV or EGV or iridium. ES are the most bottom grade basic plug you can get. I can easily see why things look hot and skuffed now. Very close to seizure thats for sure. Remember, the original specs by suzuki for 20 to 1 are to provide good cooling and lubrication and the bikes were designed to be ridden and reved hard. Try and use the highest octane fuel you can get/afford but you may still find you need lean off the needle and mixture screw (new fuels/lower octane dont burn as well at lower temps to get complete combustion and the fuel companies have admitted this) but it will depend on how you ride it. A lot of people ride like grampas in fear of breaking their bike but all this does is cause fouling problems requiring jetting tweeks or just simply changing riding style and giving it some more revs (eg rev it right out through the gears and dont labour it) I do understand this can be hard to do for road use with all the 50km zones we have though ::)
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G`day Toolboy,
just adding my 2 cents worth. I would have a close look at the length of the bolts that hold the cases together and make sure you haven`t got too much thread length going into the other crankcase half, they may feel like they have tightened up but may be bottoming out in the case first.
It would only take 1 or 2 of the screws to not clamp the cases together and you will have a small leak, if this isn`t the problem you may need to look for a small fracture somewhere in the cases. Hope you solve it. Peter.
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I'me trying to remember a discussion somewhere , PE forum I think , where the guy had the bearings loose in the c/case letting the shaft wobble and the seal leak.
Sounded like a rare sort of problem.
He ended up putting a sleeve in it.
Might pay to check. :)
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looks normal docs right and some of the residue is from
sealer
b7es is not a problem if jetting is ok
looks lean like lozza said
20 to 1 is ok for original standard jetting
32 to 1 is fine but you would have to rejet
also a fouled plug can be as simple as a oversize pilot by 5
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My RM250X had a vaccum at the gearbox vent tube. It kept fouling plugs. Thought it was crank seals or centre gasket too. However when I pulled it down it was the inserts in the cases for the main bearings that were loose causing it to suck gearbox oil. I had a look at another set of engine cases from another engine I had and it had new inserts that had been machined up which suggests it may be a common problem. The original inserts are dowled but they had come loose just enough to cause the problem. Might be worth checking
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Bikeaholic... Yes i have considered this, and will look into it more
Holeshot.. My fuel mixture and carby settings have never changed since first rebuilt, the problem with the fouling plug is only recent.
Mike..I did consider putting speedy sleeves on the crank to ensure a perfect seal. Maybe i need to do this??
Billet...Yes i will check this for sure when i pull the covers off...but when i did split the bike i could not see no sign of where the oil was getting past the gasket..
LWC...When i had the cylinder rebored i was told by the Serco/Wieseco machinist that 20:1 is old school oil and with the advances in technology of oils 32:1 was fine. I have had this discussion with people before who say the same thing that you dont need 20:1 and others that say you do???.
Thanks guys
Tim
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Start playing with fuel oil ratios and you'll need to start looking at plug chops and jetting changes. 20:1 isn't old school if you use regular oil like Castrol SuperTT, it's been around just as long as the RM and besides, while the new oils now may not be oldschool the engine still is. You'll find the more oil in the mix the cooler it will run ;)
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LWC...When i had the cylinder rebored i was told by the Serco/Wieseco machinist that 20:1 is old school oil and with the advances in technology of oils 32:1 was fine. I have had this discussion with people before who say the same thing that you dont need 20:1 and others that say you do???.
Thanks guys
Tim
With advice like that i would be seeking another reborer.There has been no advances in oils.
Tim it's running lean and a cold day will have that seizing solid. The piston does not lie.
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the best way to check if you are sucking gearbox oil into the engine is to use castrol r30 in the gearbox take it for a good run then get behind the bike with some one giving it a rev.your nose will tell you due to the smell of the r30.if you can smell the r30 its sucking oil.
jim
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Have the same problems with my RM125X. Thought it may be the crank seals,but have left well enough alone for the moment. Running motul 800 at 32:1 and have had no problems and piston crown looks great. Plug is a little dirty. It could not leak that much past the seal while the motor is stationary could it ???
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Toolboy I was talking about the same thing as Bikeaholic not speedy sleeves. :)
Bearings or bearing housing loose in c/case. :o
Ps. Talking about oils , didn't Maico invent or at least promote the first use of synthetic oils ?
My memory is shyte but the figures 50/1 and 100/1 ring a bell.
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LWC...When i had the cylinder rebored i was told by the Serco/Wieseco machinist that 20:1 is old school oil and with the advances in technology of oils 32:1 was fine. I have had this discussion with people before who say the same thing that you dont need 20:1 and others that say you do???.
Thanks guys
Tim
Well i strongly disagree with that, certainly not for old air cooled engines. I will never understand why some people want to use or are told to use less oil.
'Its cheaper to use less oil' and 'my bike smokes less' are not valid reasons.
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If i am running the bike so lean then why is the top of the piston black, also the plug???
When i havent changed my fuel mix or jetting in the 10 years i have owned the bike??
LWC..I am yet to sieze an engine but i am willing to try the 20:1 mix once i resolve this issue
Im guessing that with the barrel off and i refill the gear box oil i maybe i will able to see if the gearbox oil is seeping through to the crank when standing??? If not then it must be sucking it through???
Thanks all
Tim
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I first heard of the 20:1 thing here on OzVMX, and also about how a certain amount of oil on the floor of the cases is a sign of a well tuned engine running the correct oil ratio. I later read much the same from Eric Gorr. I had been using 35 or 40:1 as a result of being led to believe modern oils allow that. Since I've gone to 20:1 on the RM125, I have found it to run cleaner and cooler and whenever I open it up everything looks just fine inside. I am a convert. I am no expert and won't say that I know what's best as it's a complicated subject, but 20:1 works for me.
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Tim, what exactly is the issue? fouled plugs? the oil in the crankcase? You state on the last ride at Conondale it went well with no mention of fouling. If it's the oil in the cases that's bothering there isn't a thing to worry about. All my 2 smokers have the same thing and it is quite normal. I've owned my 400 since new in '78 and I too still run the original jetting, only time it has ever fouled a plug in 33 years was when I inadvertently mixed fuels, one synthetic premix and the other had a mineral based oil. The 2 simply don't mix and this combination will foul plugs everytime. If it was all going well, not fouling plugs and not pinging up top then I'd say leave well and good enough alone ;)
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Yes thats right, you want to see oil in your crankcase. The big end and left main actually need lubrication so as Doc says its perfectly normal. Have you noticed a mysterious drop in gear box oil?
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We could talk about oil ratios till the cows come home, and I once had a cow get out and it never came home.
20-1, 30-1, 40-1, people run all different ratios without problems
Any leaking into the crankcase has nothing to do with oil ratios.
And like has been said already, oil in the crank case is normal, it’s most likely from the oil you mix in your petrol, that’s why we put it there. If you want to fix a problem first you must make sure you have a problem,” if it ain’t broke don’t fix it”
If it was running fine then I would concentrate on the jetting, and if you increase the oil to 20-1 will make it run leaner.
I don’t know where I got the idea but I have been under the impression that the oil separates under pressure which is how small amount stays in the crankcase
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There is no real pressure in the crankcase. while running it is mixed , swirled and 'turbulated' (I pinched that one ;D ) by the spinning crank. Each cycle happens at a rapid rate, even though 1 fuel/oil particle takes 20 cycles to go through the engine, that at a moderate 6000 rpm is 1/5th of a second.
Tim a tell tale sign of a leaky crank seal is the presence of white(not blue) smoke and lots of it from the exhaust, and the disappearing gearbox oil.
With oil ratios I will defer to a brilliant tuner Jan Thiel who led the developement on the single most successful 2T racing engine, spanning 20 years. The Aprilia RSW/RSA they have and always will use between 4-5% oil as Jan explained (20-25:1).
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Tim a tell tale sign of a leaky crank seal is the presence of white(not blue) smoke and lots of it from the exhaust, and the disappearing gearbox oil.
Yeah thats right, its all basic stuff, ive read that in many manuals 'troubleshooting sections' that most people just ignore. Sometimes it pays to just go back to basics. It should be obvious if your loosing gear oil. Going to 20 to 1 wont necessarily make it leaner or too lean with the standard sort of jetting which was set up for 20 to 1 front the factory. It depends on what jetting you have with the 32 to 1 currently. It will get things to about where they were originally. Suzuki was not in the habbit of shipping bikes jetted on the lean side in std trim. You need to work out if the plug is oil or fuel fouled.
One last thing are you sure you put the RHS seal in the right way?
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One last thing are you sure you put the RHS seal in the right way?
You are so right LW , the gearbox oil is on the right , I was looking at the photos and the black stuff is on the left side oiler/transfer area which is the flywheel side .
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Ok,,,,more pics added. Looking more like the new crank seal i fitted.
Doc...I know you talk about residue in the crank from the fuel/oil mix but i think the pics show a bit much.
(http://img.photobucket.com/albums/v318/Airfireman/P8110001.jpg)
(http://img.photobucket.com/albums/v318/Airfireman/P8110002.jpg)
(http://img.photobucket.com/albums/v318/Airfireman/P8110020.jpg)
(http://img.photobucket.com/albums/v318/Airfireman/P8110023.jpg)
(http://img.photobucket.com/albums/v318/Airfireman/P8110024.jpg)
I am sure the B7ES plug burnt hotter stopping the bike from fouling up.
Tim
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Pic taken of crankside of seal and o ring..
Is this oil bypassing seal/o"ring...or coming down breather tube into bearing????
(http://img.photobucket.com/albums/v318/Airfireman/P8110008.jpg)
(http://img.photobucket.com/albums/v318/Airfireman/P8110007.jpg)
Tim
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Drain some oil out of your gearbox and compare colours would be my first choice
How old is that crank seal pictured ( shows signs of rust ??? ) Might be a case of the rust mixing with your oil ??? giving it that brown colour.
A guess and a wild one at that.... is that the motor has got water in it at some stage creating scale on your crank webs and seals .If this is the case you need to replace your main bearings ....get the webs pressed apart and bead blasted.
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Tim, the amount doesn't bother me or appear out of the normal. My RM has always had much the same. It doesn't take much to pick up that amount of oil on the crank due to the close association between the crank and cases. The colour doesn't look pretty and there is some contamination but you have to remember the location of where it resides and how it gets there. It might seem like a lot on the crank but looking down the cases in the picture there doesn't appear to be much sitting on the bottom.
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The oil's pulling in from somewhere and it can only come from either the R/h seal area or the centre case gasket area.
Is the R/H seal and the O-ring genuine Suzuki parts? If not, go genuine if at all possible.
There appears to be an imperfection (at about 2 oclock) where the seal fits in the r/h case. Do you use a light smear of sealer on the OD of your seals? I do and don't have any problems with leakin seals on their OD.
The o-ring is there to stop oil from sucking through the clearence between the crank shaft and the primary drive pinion gear. If the o-ring is non-standard it may not be quite the right section diameter and not doing it's job by sealing the crank shaft and the bush that fits behind the primary drive pinion.
That plug looks ugly
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Interestingly the gear box side seal on my RMX250 goes the other way round to the seal shown and the manual showed a parts breakdown with the seal round the WRONG way but later in the manual a detail showed it correctly! Different model obviously but something to watch.
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Oldfart...Yes the colour matches the gearbox oil and the crank seal is genuine and brand new as well as the o ring. The extra colour you can see is possibly the red rubber grease i put on the seal lip so as not to damage it when first started.
Doc...yes i did notice that there was no oil in the bottom of the cases, if i run 20:1 mix wont that foul the plug quicker with that much oil in the crank area??
PMC.. genuine Suzuki parts fitted with the gasket, seal and o ring.
WMC...the seal is double lipped so it should seal and is fitted as per manual???
Thanks
Tim
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If your manual says thats how it's fitted then no probs, I just think it's strange the seal on my bike is the other way round (spring side out) and it's double lipped as well.
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Yes the spring side is out no matter which way you fit the double lip seal.
Tim
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Ahh I had another look your seal is completely different to the RMX seal ( it has double lips but has a spring on one side only) that explains it.
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Looking at this again, that seal is in the wrong way around, vmc83 is right.
Seals are always supposed to be installed so the dirty side, or the side where you want to stop the oil coming from, is the cavity side of the seal. Even if the seal has two springs (double lipped), one spring is normally more dominant and it's normally the cavity side.
The intention with the seals is these models is to stop the oil getting from the transmission into the combustion area, therefore the transmission side is the dirty side. The main bearings are lubed only by the two stroke oil mixed in with your fuel, hense the two lube bypass holes either side leading into the bearings. A correction to earlier descriptions, these are not vent holes, they are there to allow oil enriched fuel to pass through the bearings during the fuel transfer phase from case to combustion chamber of a two stroke.Earlier model RM's had the r/h bearing outside of the seal where they were lubricated by the transmission oil. In these models the seals had the cavity side facing inwards toward the crank case.I'd suggest replacing that seal the other way around and try again.
And to answer your question about going to 20:1 fouling quicker? What actually happens when you add more oil, you decrease the amount of fuel in the fuel/air mix, so in effect you're leaning your mixture. This is why people who think fouling plugs is fixed by using less oil. It only makes the matter worse by causing a richer mix. This I think is also your problem with the lean look on the piston crown. More oil (too much coming in from the r/h crank seal) = less fuel. Less fuel = lean mix.
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that is gold. Frame that.
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I think the confusion stems from the fact it can have a rich fuel/oil mix being rich in oil, you can have a rich fuel/air mixture being rich in fuel and visa versa or a combination of both. Sometimes even the brand of fuel used is an issue. One thing we haven't mentioned is fouling plugs on a regular basis may be sourced to an ignition issue. The thlot plickens! ;D I must admit, my plugs have always looked somewhat cleaner than the one in Tim's picture.
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And to answer your question about going to 20:1 fouling quicker? What actually happens when you add more oil, you decrease the amount of fuel in the fuel/air mix, so in effect you're leaning your mixture. This is why people who think fouling plugs is fixed by using less oil. It only makes the matter worse by causing a richer mix. This I think is also your problem with the lean look on the piston crown. More oil (too much coming in from the r/h crank seal) = less fuel. Less fuel = lean mix.
And to confuse the issue you can foul a plug by running your fuel too lean [ jet wise ].
It is called bridging but some call it fouling.
Ahhhhhhhhhhhhhh.
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Ive just had a sinking feeling as I have just replaced the seals on my RM465Z with the lips facing inwards - the same as Toolboys 400N
I just checked the climber and Suzuki manual and it looks for all the world like I have put it in correctly but as they are just line drawings and dodgy photos it could be either way
I haven't started it as yet as I am waiting on suspension work to be completed
Sorry to hijack the thread but can someone definatively tell me if the 465Z should look like Toolboys photo or have I stuffed up as well!!
Cheers
JB
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Well i would have thought the seal is in right.
Now it still could be leaking past the seal if the gear box has a blocked vent and is pressurising it and pushing it past the seal.
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Huskys have the spring facing in and NO double lip. :)
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another simple test is to fill the crank case with petrol or similiar thin viscosity fluid.
if there is a leak the level will drop and you would do this with the clutch cover off to see if the seal or the gasket is leaking.
If it leaks one way it will leak the other as well.
Very first test for blown seal or gasket would be to remove the oil filler cap and run the motor.
Dont mistake oil flying off the clutch or gears for a positive. hold you thumb or fingers over the hole and feel for pressure changes.
sorry this advice may be a bit late now that you have pulled it apart a couple of times but I have resisted this post as suzukis dont really apeal to me.
You are right in being suspicious of the oil you can see it does look like gear oil.
One last thing I would do is use atf as gear oil, it is clearly identifiable in the crank due to red colour.
Hope this helps
David
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The vent holes are clear, so is the seal fitted the wrong way???
Ok here is the full history of the fouled plugs.. the bike was rebuilt in Alice Springs...ran like a dream,,i moved to Sunny Coast and went to CD7 at Connondale.
On the saturday after lunch whilst riding the RM it suddenly stopped..when i kicked the bike over it felt like i had seized a piston,,so i pushed the RM back to the trailer, took the bike home where i took the head off, no problems there, removed the barrel with ease,,, no probs with piston or crank, remove the clutch ass, no probs there, in the end i removed the stator cover and saw that the only 2 screws i had not lock-tighted, holding the stator had come loose and had been spinning around and eventually jammed in the stator and the rotor.
i cleaned up the rotor, the stator looked fine, refitted everything and then the bike started fouling plugs, i hadnt noticed the oil in the crank the first time just assumed the stator had been damaged by the screws floating around. I bought a new stator, (from ebay, said they were better than original, better spark) and still the bike fouled plugs, it was then i took note of the oil in the crank and replaced the seal, o ring and then finally the crankcase gasket after a box of spark plugs. I even tried different jetting and needle clip position but the bike always died after 5 min of riding.
Tim
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Dok...would it better to fill the clutch side and see if the oil is coming in that way rather than fill the crank??
Direction of oil flow??
Thanks
Tim
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Tim, I think I met you at CD7 while the legends/sidecars were doing some laps. I was talking to a guy trackside with a nice RM400N who'd just moved down from Alice Springs. 'I think' it had lost an engine mount bolt at the time. Parked back a little from drunks hill on the main road in to the 'B' camping area.
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I think a proper pressure test is the best way to determine if there is a leak from the crankcase into the gearbox or ignition.
Filling everything with oil or petrol might work, but the viscosity of the liquid, by its very nature, will probably just hide a small leak - which may well be the problem.
Pressure testing is much easier, cleaner and more definitive. It can be simply done at home with some scrap materials, a schrader valve, a bicycle pump and a spray bottle of soapy liquid. It take minutes and will give you an answer one way or the other.
If you don't want to go down that path then most bikes shops will do it for you for a nominal sum.
P.S. don't overpressurise with the pump. A few psi is all that is needed.
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Hi Tim
Yeah you could do that but its a little difficult to see where the fuel would leak in from (crank in the rode and you would just see a puddle in the middle.
The other way around you would see the fluid around the seal and if its the gasket it would flow from the gearbox to the clutch housing.
Another thing to consider is a compression test when its assembled it was mentioned earlier in this thread I think. If you have low compression the fuel combustion is not complete the volitile fuel will burn and leave the oil to pools in the crankcase.
Check your ring gap should be equal to .05mm/25mm of bore ( the old Tech days .002th/in ) also use a feeler gauge between the skirt of the piston and the bore.
put the feeler gauge into the bore and slide the piston in start with .05mm and increase in size by .05 until the piston can be held in place by its own wheight this should tell you piston to bore clearance check with w/s manual that its within spec.
David
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Again I know this is a different model but just be careful how you interpert shop manuals I got caught out buy this when doing a rebuild
(http://i833.photobucket.com/albums/zz260/wsclarke/image-2.jpg)
note the orientation of the transmission side seal
and two pages later
(http://i833.photobucket.com/albums/zz260/wsclarke/image-3.jpg)
The first image is wrong I found this out by the puffs of white smoke wafting out the exaust, I'm not saying your seal is in wrong but I'd get some one who knows his suff to check it out first.
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The vent holes are clear, so is the seal fitted the wrong way???
You say the vent holes are clear. What i was meaning is that you need to check the vent hole to the gear box housing. Some where there will be a vent from atmosphere to the gear box. If that is blocked with mud or something you will have problems of gear oil getting pressurized and be forced out of areas its not ment to. This can particularly a issue on race bikes and bikes with poor gear box venting such as many english bikes and to fix this additional gearbox venting may be required if the std vent is too restrictive.
I have thought about this all day and nothing is making sense. If what PMC says is correct then all bikes with the cavity towards the crank would leak. I have always done it like that and never had leaks ???.
I am looking in my RM400 manual right now and it shows a photo, not a drawing, showing the oil seal fitted in the case with the cavity towards the crank like Toolboy has it. I also checked with a RM400 owner and he agrees thats the right way.
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LWC...Yep i understand what you saying now, I will check the breather tube. Yes i too am confused about the seal fitment.
WMC.. I will recheck my manual...its confusing.
DOK.. Brand new rings and rebore, everything is well within spec. I though is was compression at one point, when it first happened.
DOC... Yes Doc that was me and my RM's first outing on the track, i do remember chatting to you and having a good discussion about engine vibration..hahaha,,,,i had so many people came to me to talk about my shiny new lookin RM400N,,all them said "damn i had one of these and should never have sold it". I never realised how popular they were. :) This is how it looked on the day:
(http://img.photobucket.com/albums/v318/Airfireman/P6120276.jpg)
Tim
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With all the confusion going on for you Tim.
This is a pic out of the RM400N manual (compliments to Luke)
(http://i199.photobucket.com/albums/aa250/hjcoupe/rm400crank.png)
Then you put the RM250N into it and get this ::)
(http://i199.photobucket.com/albums/aa250/hjcoupe/rm250n.png)
cheers...Mario
Great to have Doc back too ;)
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I have a photo of the RM400 similar to that top one Mario and you can see its a RM400 case with the seal that way. It actually says its RM400 too.
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and here's a PE400 being pulled apart shot, (Dan on the PE list), just to sorta help confirm.
(https://byfiles.storage.live.com/y1pshaPEdAklqrrmCBAzYegIkvsc-nW-GAWcRqojUiVqECmuMb5sxD_2s5RDkRnjsmAj0FOpy-w8VU/PE400_Seal.jpg)
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Monaro...yes it is all confusing, there are so many conflicting pic's in the manual and parts list.
I will try to pressurise the crank and check the seal fitted both ways???
Tim
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leak down test is the best way to go remove carbi and pipe and seal mannnifold and inlet manifold pressurise to 6 psi spray with soppy water ,a loss of 1 psi per minute is acceptable
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I have thought about this all day and nothing is making sense. If what PMC says is correct then all bikes with the cavity towards the crank would leak. I have always done it like that and never had leaks .
LWC82PE, I'm sure you're right in the true sence about he direction of the seal, but i think it has more to do with the length of the sleeve behind the primary drive gear that fits inside this seal. When the seal's installed cavity side out and the seal is installed only as far in as flush with the r/h housing, this should allow the inner lip to be just short of the bearing inner race. If installed the other way around (cavity in) there is a risk the seal is installed too far in (so it matches the sleeve) and runs the risk of blocking or partially blocking off the r/h lube transfer hole with the outer cage of the seal.
I haven't done this model for a while now, but I'm sure when I did one last, i had a think about this and took a few length measurements to confirm where the seal sat in relation to the sleeve. Also my Clymer manual shows a few pics of 400 N or T cases with the seal cavity side out.
I still think there's a leak from somewhere else with this one, maybe when the screws got jammed in the rotor it gave the crank shaft a big shunt and disturbed the centre case gasket or maybe cracked a case. Needs further investigating I think.
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Pete on the T the flat sides face out and are flush with casings( no more than 9mm in) end of story.
I will explain why.
Next time you have your cases apart, pay particular attention to the mag side inner case as it has a 9mm area to take your seal and a 1mm step on the bearing housing. This is there to allow some oil to feed the bearing via the crank oiler hole.
Now if you where to put the seal around the other way ( flat side in ) and it was pressed in too far and rest against the bearing your liable to have bearing failure.
check it out next time ;)
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Stewy,
Yes your mention of the mag side seal position is correct, but I still think the r/h side has more to do with the dimensional position of the seal in relation to the sleeve hense the way it faces. If you read my thread again, I say the inner lip (I say inner because I'm presuming the flat side of seal is facing in) of the seal fixed with cavity side facing transmission, should just clear the bearing inner race if the seal is pressed in so it's flush with the casing, no contact of the inner lip on bearing and no chance of bearing failure because of seal contact.
I still think it's a dimensional thing that dictates the way this seal faces as well as the sealing quality, check the lengths of the sleeve and how the seal positions itself with it. The seal will do it's job either way around, but what we don't want is the r/h lube hole being obstructed.
There's still a problem with this 400, whether the oil's coming through the seal or somewhere else, it's still coming in and the challenge is to find out where from.
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Toolboy,
Any update on the oil leak in the 400? What did you find or do to fix the problem?
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Gday PMC,
I have been busy at work so not much to tell you at this time, i tried the leak down test without much success (no oil in the crank no matter what i did) so i have resorted to flipping the seal around and test run the bike... i also had issues with engine vibration/cracking the pipe so i have drilled the frame to engine bolt holes and welded the cracked pipe. So on my days off work this week i will be able to get the bike finished and out for a run... ohhh and I will also try the 20:1 fuel mix.
Cheers
Tim
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Tim
Keep us all informed on the outcome and how things turn out, it's a very interesting problem.
I noted your comment about engine vibration which caused me to have a thought (some may say a rare thing), maybe your crank shaft is not aligned within tolerance which is causing the vibs and this may be effecting the seals ability to do their job.
I'd be interested to hear others point of view on this.
Pete
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Pete,
Yes i will all informed,,i was thinkin the other day that i had not mentioned anything in a while...
The engine bolt holes pretty flogged out so i am hoping drilling them out will stop the vibrations.
Tim