RS125/Rotax 122 crank oil seal pushed too far in? and more!

[andy_uk]

The saga of the rebuild continues...
I've finally put the crank case back together.
Before I fitted the gearbox side oil seal, the crank turned fine.
When I pushed the seal in, I think I've pushed it in too far because there is now quite a bit of resistance when turning the crank.
Should I have left it flush with the case? ( I guess it's now rubbing against the crank bearing)

2nd question...
In the gasket set, there were 3 different thicknesses of cylinder base gaskets. I know they're to get optimum squish, but let's face it... the engine is in my Classic 125... so I wouldn't have thought it was that critical?
I have actually fitted the medium size one, but if the answer to my first question is "yes noob, pull the seal out and fit it properly!" then the cylinder etc will be coming back off so I can swap the gasket if need be.
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Aprilia Classic 125, GS500E, ER5-A1, ER5-C4, ER6 & an XJ6 project frame...

[Kickstart]

[andy_uk]

[Kickstart]

Hi

Suspect yours would be OK with this. The old ones were very high compression and needed high octane fuel as standard.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Mikey CB500]

Since fitting the crank back int the casings and fitting tha casing back together have you, trued up the crank to make sure its centeral? That would be the first thing id suspect with it being hard to turn that its seated further one side than the other.

[andy_uk]

[Mikey CB500]

No its nothing about the bearings being seated properly. If you havent trued you crank up (which you obviously havent as you dont know what I mean) I would get on with it and do it as this could be whats most likely causing the rubbing. Plus if you try to run it without the crank trued up then ther is possibility of a damaged top end and bent con rod and youd be lucky to not bugger the crank up also.

[andy_uk]

Do you mean the axial clearance?
I did check that and put a .3mm shim on the magneto side.
Although I haven't measured the gaps between each side of the crank the the case (they do look even to the eye, but I'll check it with feeler gauges when I go back down to the lockup).

If you didn't mean the above, then please explain...as I haven't seen anything else regarding trueing up the crank.
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Aprilia Classic 125, GS500E, ER5-A1, ER5-C4, ER6 & an XJ6 project frame...

[Pete.]

It can't help but be central - enough so it makes no odds anyway.

The bloody crank is a tight fit in these, tight on the bearings and the bearings are tight in the case - personally, I think it's excessive and I can find no good reason for it.

Try putting a snug-fitting packer in between the crank webs opposite the big end pin (which you really should have done before pressing it in) and then giving each end of the crank a stout crack with a plastic hammer. turn it to see if it's improved and if it has give it another clout each way until it frees up. If it doesn't improve don't continue and don't whatever you do use a steel hammer.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Mikey CB500]

[andy_uk]

Thanks Pete / Mikey,
It's certainly not catching against the casing and like I said, it spun with no friction after I had torqued up the crankcase bolts. I was a little heavy handed with the oil seal...
Having said that, I'll check the clearances when I get down to the lockup.
What tolerance is allowed between the 2 measurements? (if any)
____________________
Aprilia Classic 125, GS500E, ER5-A1, ER5-C4, ER6 & an XJ6 project frame...

[Mikey CB500]

You really want it to be as equal each side as possible, and it should roll perfectly freely. Another thing is the seal too small and causing friction?

[Pete.]

If it turned freely before fitting the seal, then the seal is the fault so leave the crank alone. You're faced with either splitting the cases or pulling out the seal by destroying it and fitting a new one. I know which I would rather do.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[andy_uk]