RM400N Oil in Crank...Help!!!

[Toolboy]

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

[wmc83]

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.

[Toolboy]

Yes the spring side is out no matter which way you fit the double lip seal.

Tim

[wmc83]

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.

[pmc57]

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.

[lukeb1961]

that is gold. Frame that.

[Doc]

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! I must admit, my plugs have always looked somewhat cleaner than the one in Tim's picture.   

[Mike52]

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.

[Bitten]

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

[LWC82PE]

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.

[Mike52]

Huskys have the spring facing in and NO double lip.

[DOK]

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

[Toolboy]

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

[Toolboy]

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

[Doc]

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.