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Re: Tool for checking crankshaft is true
Posted: Sat Aug 04, 2018 11:23 am
by Muppet
take a look at the inner race on the crank look for an even or uneven running mark where the rollers run against it if it's even it's in if it's uneven and undulating then its out of true
Re: Tool for checking crankshaft is true
Posted: Sat Aug 04, 2018 7:43 pm
by holty
ive fitted one of the 62mm gt cranks for a mate of mine, and it fitted without having to machine the case at all, it was a spanish case and had not been altered in any way.
Re: Tool for checking crankshaft is true
Posted: Sun Aug 05, 2018 2:45 pm
by johnny650
Strummer10 wrote: ↑Wed Aug 01, 2018 6:19 pm
. The only reason I'm thinking crank 'might' be out of true is because the oil seal has failed after only 3000 miles and I'm a pedantic bugger when I draw the crank through the seal and bearing so I'm sure it went it without damaging the seal and on dismantling the seal looks ok ?
I just had the same problem on my recent build . When i stripped the block I found the brand new oil seal looked fine but it was one of those highly recommended double lipped seals ....supposed to give a superior seal ................well that is complete and utter bunkam in my opinion.
having 2x oil seal lips in such a small space of 6mm means the rubber lips are very thin and weak and one of the lips are positioned extremely close to the edge of the crankshaft shoulder .
I've gone back with a good quality single lipped drive side oil seal with a strong seal lip as per standard spec cos I really really don't want to have to go and strip all that lot for a third time
Re: Tool for checking crankshaft is true
Posted: Wed Aug 08, 2018 9:30 pm
by Strummer10
johnny650 wrote: ↑Sun Aug 05, 2018 2:45 pm
Strummer10 wrote: ↑Wed Aug 01, 2018 6:19 pm
. The only reason I'm thinking crank 'might' be out of true is because the oil seal has failed after only 3000 miles and I'm a pedantic bugger when I draw the crank through the seal and bearing so I'm sure it went it without damaging the seal and on dismantling the seal looks ok ?
I just had the same problem on my recent build . When i stripped the block I found the brand new oil seal looked fine but it was one of those highly recommended double lipped seals ....supposed to give a superior seal ................well that is complete and utter bunkam in my opinion.
having 2x oil seal lips in such a small space of 6mm means the rubber lips are very thin and weak and one of the lips are positioned extremely close to the edge of the crankshaft shoulder .
I've gone back with a good quality single lipped drive side oil seal with a strong seal lip as per standard spec cos I really really don't want to have to go and strip all that lot for a third time
Will do some checks, but yes I recall seals did have just the single lip. I also have the additional seal on the inner face of the bearing. Scoots only done 2,200 miles since build so wondering if bearings should be replaced, but all looks good.
Re: Tool for checking crankshaft is true
Posted: Thu Aug 09, 2018 3:28 pm
by johnny650
Bearings will be fine surely ? unless your crank was out of true sufficiently to cause rumble and vibration then those bearings should be good for many thousands of miles .
Did you do a leak down test to establish the drive seals leaking or did you just do a strip down and visual inspection ?
Re: Tool for checking crankshaft is true
Posted: Thu Aug 09, 2018 6:22 pm
by Strummer10
Did a leak down test and two major air leaks....1. Was on inlet manifold, resolved with threebond sealant....2. Around the spark plug, resolved with hermitite red......then acceptable levels of pressure loss. Bearings do seem ok tbh, visually and under a tug, slight wave mark on the collar to the mag side on the flywheel, but when I arrived the timing, no discernible movement on flywheel
Re: Tool for checking crankshaft is true
Posted: Thu Aug 09, 2018 6:33 pm
by Muppet
slight wave mark on the collar to the mag side that's a pointer to the crank being out of true ; mabee next time it's out have it checked
Re: Tool for checking crankshaft is true
Posted: Fri Aug 10, 2018 5:56 pm
by Strummer10
Its still out the bike i could pop to JB Tuning in the morning and see if they have a device to check it.........was thinking of maybe going for a 62 / 116 and pack it out etc. Does that interfere with the exhaust fitting ? I'm either going back with a JL3 or Version 3 BGM Clubman ...Thanks