OzVMX Forum
Marque Remarks => Suzuki => Topic started by: Tony Two Times on September 01, 2010, 11:32:47 am
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Hi all,
Got meself a VMXer after a long time standing on the outside looking in. Yeah yeah I know it's pre-90 but I'm in Qld and the likelihood of convincing a bloke to sell me his race ready 250N for the $2000 I paid for this one are pretty slim. So pre-90 I is for a little while.
Anyway the bike runs pretty good and is generally in good nick. It came out of the US and had a pod on the carby. I rode one meeting with it like that beforee finding and fitting an original air box and filter. I took it out for a practice run on the weekend and now there is a solid film of oil on the right hand side of the rear tire. The engine has no leaks so I'm scratching my head wondering where it's coming from.
Obvious guess is the exhaust. But why ?
Is it running way to rich because jetting was set for the pod ?
Has it sucked oil up from somewhere and blown it out the exhuast ?
The exhaust had a spark arrestor that I removed. Is it the crap that has been building up in there for who knows how many years ?
It's running fine but are the rings rooted ?
Anyway I do most of the spanner work on my bikes myelf but it's my first 2 stroke in many years so I'm on a steep learning curve. Any advice would be appreciated.
T2X
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11 hours and no answer thats a record ::)
could be oil fuel mixture excessive oil amount
and gunging out exhaust
or maybe crank seal pumping oil out of gearbox
check gearbox oil level
or gearbox could be overfull and coming out breather
what ratio oil mix are you running
cheers rusty ;D
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Thanks Rusty. Figured the slow reply might have been because it's not a real VMXer ;D
I was on a similar track last night..........
Fuel is mixed at 33:1.
Dropped the gearbox oil. Motor says there should be 800ml in there. Looks about right when measured with the Mk 1 uncalibrated eyeball.
Figure I'll wash the bike, repack the exhaust, refill the gearbox oil and see if it happens again. If it does maybe I am looking at a crank seal.
A bit over a week to my 2nd VMX meeting. Gotta get it sorted !!
T2X
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Maybe the rear shock ::)
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You callin' me fat? :o :)
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A quick check of the conditon of your gearbox side crankseal is while it is idling gently unscrew the gearbox plug, normally if the seal is leaking when you remove the plug the engine will rev up as it sucks air in. Not fool proof but a pretty fair indication.
Stan
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Or...... get a vacuum gauge like the cheap ones you get from Autobarn and hook it up to your gearbox breather hose (most pop straight on). If it's suckin' it'll show it on the vac gauge. :)
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Well I bit the bullett yesterday. Rang the Suzuki dealer. They said they could have a crank seal in for me today. Pulled it apart last night. All good so far.
Went to the dealer to pick up my bit today at the allocated time. No go. On a truck somewhere apparently. ??? Have to wait till next week.
Just once I'd like to be pleasaently surprised by a bike dealer and not disapointed.
T2X
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so did you diagnose the crank seal to be the issue or just decide to do it anyway? hope your putting in new seals both sides while your there ( and even consider a set of main bearings as well).
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…hope your putting in new seals both sides while your there ( and even consider a set of main bearings as well).
Come on Hoony, it's not a Honda!!!
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Come on Hoony, it's not a Honda!!!
My point Exactly Keeno, its a Zook, therefore better to ensure of reliability where possible ;)
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…hope your putting in new seals both sides while your there ( and even consider a set of main bearings as well).
Come on Hoony, it's not a Honda!!!
Yeah Hoony, what were you thinking. If it was a certain Honda you would need to throw a crank in it as well, just in case you know. ;D ;D
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While you have it apart, lock the evac system shut.They had a problem of bouncing open & shut over rough ground,giving a weird power feeling.From what ive been told,most riders did this with the '86.Apprantly the '82 model head fits and gives a way better powerband...
Thats what ive been told,hope it helps...
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Did you try refitting the pod first and see if that changed anything?
Going from a pod to an airbox would certainly make a huge difference to your air/fuel mixture ie richer.
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Good point. No I didn't. But I should have the crank seal today and fitted tonight. It would be a Homer moment if I fit the seal and still have the problem. But I read this and was pretty well sold on the diagnosis.........
http://dirtbikedoctor.com/page/2
T2X
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Well it's been an interesting couple of days.
Got the seal. Fitted it no dramas. Put it all back together. Same problem - oil out of the exhaust.
Pulled it all apart again to check the seal. (Lots of) coolant in the oil. Checked the seals on the water pump and they were hard as nails and cracked. I figure removing and fitting the case cover moved one of the (24yr?) old seals enough for it to give way. Get new seals from BSC for $5 each (so much for going to Suzuki), chuck 'em in, button her up, and give her the boot.
Same problem - oil our of the exhaust. Remove the oil filler plug while she's running per earlier suggestion and she revs like a zirtec suggesting she is sucking air (and oil) through the new seal !!
So all I can surmise now is that the crank shaft is worn or grooved and not forming a tight fit with the new seal. Don't remember seeing any obvious wear when fitting the new seal but I've got the whole dissasembly process down to a 20min exercise by now, so it will all come apart again for another look.
Pressure is off now though as this weekends VMX meet is a goner as I won't have time to sort it by then.
Old bikes hey ? Gotta love 'em ;) :)
T2X
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G,day Tony,have you looked at a Suzuki parts diagram to see if anything is missing,some bikes run a thin oring on one end or the other of the collar that goes on the crank before the primary drive gear,also is the collar the correct one or bodgy?or as you said grooved?, no main bearing movement?worst case scenario cracked or porous cases?
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in regards to the seal you can tweak them a little by slipping out the spring and twisting it a few more turns before refitting. Obviously don't go winding it in too much or it will be overtight on the shaft and it'll wear the seal rapidly ;)
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Couple of things worth checking. I don't know about the 86, but up until 84 you will need the new ceramic washer on the water pump shaft as well as the seals. If it is leaking here ,and it is a common problem, the main seals on both sides might not seal due to corrosion/rust/pitting etc on the crankshafts.I have had to have 2 125's crankshafts replaced(resurfacing is an option) due to this.
If they are leaking here you can also get oily build-up in the stator/rotor area due to it blowing through, as well as the "milky oil" etc. Probably worth getting the chamber de-coked and re-pack the muffler.
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Hmm sounds similar to what happened on my RM250X (81) Fouled plugs running like a dog, oil dribbling out the header pipe. Suspected crank seals but ok. Then thought perhaps the centre case gasket had gone and sucking gearbox oil via there. Split engine and found steel inserts in cases for the mains loose on clutch side. Oil was getting sucked in past the insert. The originals have dowls that locate the inserts to stop any movements. Mine had copped the center punch treament at some time to tighten them up. Apparently a common problem with the RM's. I used another spare set of cases that had aready been modified with new inserts and fixed the problem. Still have to do the mod to the originals. Don't know if the 86 has the same inserts but worth checking all the same. No noticable loss in gearbox oil while this was going on either.
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Well last minute change of heart on Saturday morning. Pulled her apart to check and reassemble her one more time. In my frustration I *may* have had the sleeve behind the cog on the crank back to front. :-[ ::)
Checked the parts diagram. Turned the sleeve around and put it back together. Still blowing some oil but not too bad. Decided to go and ride the QVMX round anyway and bugger me if she didn't all but stop the problem during the course of the day. I figure there may have a little oil left in the zorst and header but as the day wore on she was all good.
Thanks to everyone for the tips and advice. It's been a frustrating but educational couple of weeks. All worth it !!
Big tip - never understimate the stupidity of the bloke with the spanner in his hand !!
T2X
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Hey Tony, was that you I seen go A.O.T near the top of the hill on Saturday? Sounded like it had A stuck throttle too...Was nice to meet you on Saturday, catch up soon.
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Nah man I managed to stay in the saddle all weekend. Had a couple of brown trousers moments yesterday when I got my ambitions and ability confused but held it together thank christ.
Yeah good times mate. See you at the next one on a 250 maybe!!
T
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I'll be there, caboolture isn't it?
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Good to hear its sorted but you should never get coolant in the gearbox.
The coolant should come out the relief hole under the pump.
Has someone blocked it up ?