ham2 Posted October 4, 2009 Report Share Posted October 4, 2009 (edited) I think the crankcase centre-gasket is the culprit according to your rev:pressure findings?...got to be,surely? Has the engine taken a bit of a knock recently? Just for sheer laziness,if it were me , I would take the fly-wheel off and tighten all the engine case bolts as tight as I dare just to see if it made any difference ( I never said I worked for NASA now did I?). Just for the record ,I've only ever found Viton seals in brown, in the UK and I have discovered a partially seated crank-seal before (from the factory!). Edited October 4, 2009 by HAM2 Quote Link to comment Share on other sites More sharing options...
zippy Posted October 4, 2009 Report Share Posted October 4, 2009 In my opinion, if somebody is going to all the trouble of pulling engine out of bike and splitting the cases to replace the center gasket, then you might as well freshen everything else up. I know money can be a bit of an issue, but if you can afford it, do the rings, bearings, seals etc..... it will save the time and frustration of pulling it apart to do those things a little later. Quote Link to comment Share on other sites More sharing options...
shercoman2k8 Posted October 4, 2009 Author Report Share Posted October 4, 2009 Did the trial today, blocked off my breather, she survived and didn't miss a beat, well... she went from lean to rich a few times but nothing a dab of choke wouldnt fix. Now then, what should I do, remove flywheel & stator, replace that one seal without splitting everything, or split it, change both seals, and reassemble with a new center gasket? Quote Link to comment Share on other sites More sharing options...
copemech Posted October 5, 2009 Report Share Posted October 5, 2009 Had a quick read through these past few posts, Cope... The bike only seems to do it after the fans cycled in and out a few times, so she's definately warmed up, and it's too long for it to just be the expansion during warm up.I held the breather pipe vertical for a minute or so, and kept the engine at a high idle... This pipe is about bar height and the oil still managed to work it's way to the top. Blocked off the breather for todays trial then we shall be doing the seals straight after. If this does not cure the issue, im guessing I should change the centre case gasket, yes? I'm guessing that it's almost definately a leak from the crank case, the higher the revs, the faster, and with more pressure the flow. The lower, no flow atall. I have no noticeable loss of compression atall. I use either proper motorcycle oil, or atf occasionaly... IIRC it's 15w40 ATF at the moment, but not cheap stuff. Around Quote Link to comment Share on other sites More sharing options...
shercoman2k8 Posted October 5, 2009 Author Report Share Posted October 5, 2009 Right, No play flywheel side, guessing the bearings fine, seal may not be however, but if the bearings fine wear shouldn't be excessive on the seal. Clutch side, rattle slightly when running, definately main bearing, so chances are, clutch side seal is shot. Agreed? So, any way I can remove this seal and bearing without splitting the cases, or is it bad news? left side casing off again, or is it a case of, well.. splitting her down the middle? Any tips to keep in mind, and will definately do both sides as theres no rush to be getting out riding soon again. Might whip the top end off and check clearances, freshen her up. Cheers, Jamie Quote Link to comment Share on other sites More sharing options...
copemech Posted October 5, 2009 Report Share Posted October 5, 2009 (edited) Just remove the gear off the clutch(drive) side of the crank! Clutch basket probably has to come off for clearance! Bearings stay put! Seal pops out! Edited October 6, 2009 by copemech Quote Link to comment Share on other sites More sharing options...
tony27 Posted October 6, 2009 Report Share Posted October 6, 2009 Shot mains rumble not rattle, normally its the flywheel side that goes first due to leaking seal allowing entry of dirt. The clutch side one would cop extra lube if the seal went. As Cope says you can do the seals without removing the motor but bearings need the cases split. I'd just replace the seals & see if that fixes the problem before trying anything else to eliminate them as the cause, if you do end up doing the bearings as well it pays to not fit the clutch side seal until the cases are back together as the crank can catch the seal & turn it inside out Quote Link to comment Share on other sites More sharing options...
shercoman2k8 Posted October 8, 2009 Author Report Share Posted October 8, 2009 So, Clutch side casing is off, was pretty lose really, but that gasket was fine. All centre case bolts nipped right up tight. New crank seals are here, brown, definately viton. Will remove old seals once I get hold of a clutch basket holder and flywheel puller, will check the colour and if black possibly do a bit of research. Will note back. Quote Link to comment Share on other sites More sharing options...
copemech Posted October 9, 2009 Report Share Posted October 9, 2009 (edited) So, Clutch side casing is off, was pretty lose really, but that gasket was fine. All centre case bolts nipped right up tight.New crank seals are here, brown, definately viton. Will remove old seals once I get hold of a clutch basket holder and flywheel puller, will check the colour and if black possibly do a bit of research. Will note back. Ok, once again I will explain to you the EASY way! Firstly, you must use a dremel tool or something similar to scribe proper torque alignment lines into the clutch and crank shafts and nuts so that you have a reference before removal. Then you can zip them off usually with a proper 3/8 drive air(pistol) gun, do your job, then zip them back to the same position or just slightly beyond to obtain proper torque. Large 1/2 in drive guns are not recommended due to easy overdrive! Your flywheel side will still require a proper puller, yet the nut can be treated the same way. This side is not your current main objective, though. Specs on the clutch and crank are listed at 45 and 72 ft/lb as I recall, then you get into all that wet/ dry thread stuff. Basically you need to put them back to where they came if there were no issues! Still safe! Be gentile on it all! Edited October 9, 2009 by copemech Quote Link to comment Share on other sites More sharing options...
shercoman2k8 Posted October 12, 2009 Author Report Share Posted October 12, 2009 So, I stripped off the case today, to see something scary... Very scary. Inner casings broken, on the sticky out bit that goes between clutch basket and main drive gear... Whats this for, can i trim up the new gasket and live without it or is it a case of trying to get it welded/remachined.. or new case if required? Will get pictures tommorow, not in the mood tonight. Quote Link to comment Share on other sites More sharing options...
trialsnutterman Posted October 12, 2009 Report Share Posted October 12, 2009 I'd think that piece is just there to control the oil flow if it's the bit I think your talking about, it might explain why your losing oil out of the breather. Quote Link to comment Share on other sites More sharing options...
copemech Posted October 13, 2009 Report Share Posted October 13, 2009 The plot thickens! Need pics! Quote Link to comment Share on other sites More sharing options...
tony27 Posted October 13, 2009 Report Share Posted October 13, 2009 Is this the bike you had the problem with the clutch coming loose? Sounds like the piece I thought you'd broken off then has come off now, any idea what has been flying around in there? Look forward to seeing the pics to get better idea Quote Link to comment Share on other sites More sharing options...
ham2 Posted October 13, 2009 Report Share Posted October 13, 2009 Are we talking about the outcrop at 11/12 o'clock high? Quote Link to comment Share on other sites More sharing options...
shercoman2k8 Posted October 13, 2009 Author Report Share Posted October 13, 2009 Tony - Yeah, It is the bike which the retaining nut came loose on... But the basket was removed and everything was checked for damage, no sign of anything flying around in there. Ham2 - No, the bit at about 2 o'clock, above the crankshaft gear... only the end broken off, maybe a 1cm peice? im reckoning I can get away with filing it smooth and trimming up the gasket, I'm guessing its so oil drips right onto the gear itself? Shall get pictures in an hour or so. Quote Link to comment Share on other sites More sharing options...
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