TLR Engine Reassembly

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TriCub
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Re: TLR Engine Reassembly

Postby TriCub » Mon Aug 06, 2012 1:13 pm

I thought the clutch gear was what you had told us but I just wanted to double check.
Without seeing the degree of the mesh problem first hand it's a bit hard to know how bad it is. The worst damage I would think would be to the bearings as they don't realy like impacting loads. I don't think that the tooth will break but I have seen 4 cyl bike engines split the cases when a gearbox gear lost a couple of teeth.
If you lived close I'd offer to take a look at the gear for you , I'm quite sure it would be possible to carefully grid that tooth by hand to fix your problem.



pop
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Re: TLR Engine Reassembly

Postby pop » Mon Aug 06, 2012 1:38 pm

I think ,like tricub suggested earlier, is to get a dremmel tool with a small grinding disc and clean up the tooth that is binding, and while you are in there do the whole lot , so every cog meshes nicely. Keychange did you get a mechanical stetoscope yet? :-k



keychange
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Re: TLR Engine Reassembly

Postby keychange » Mon Aug 06, 2012 2:10 pm

"did you get a mechanical stetoscope yet" - Yes I have the stethoscope - not that it really helped with this issue as the clunk is widely transmitted - even with case off it was difficult to pick up where the noise came from as it coincided with piston on TDC - but not every stroke.

As for grinding - all of the other teeth mesh perfectly, the primary gear runs smoothly and silently (by hand) over the entire clutch gear except for the bad tooth. There are no burs, no dents, no chips - the bad tooth looks identical to the rest (with my eyes) but the primary gear tooth catches about half way up the clutch tooth on the release - suggesting the pitch is just slightly out. I thought that working the primary gear teeth back and forward across the face of the tooth (alternating the primary so as to not wear any one tooth down) with liberal amount of course valve grinding paste would match it up but it made no difference - even after 10 minutes. I am worried that with a dremmel I could make it worse then again what have I got to lose.

With the engine assembled the clunk is only really noticeable at idle. I am tempted to take if for a good run and see if with some heat build up it might bed down. Or I just buy a replacement of ebay



FM350
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Re: TLR Engine Reassembly

Postby FM350 » Mon Aug 06, 2012 2:41 pm

If you know what tooth is causing the problem, rather then rather than risking more damage by riding as is, would it not be an idea to get a slip stone as I suggested earlier and rectify the problem?



TriCub
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Re: TLR Engine Reassembly

Postby TriCub » Mon Aug 06, 2012 4:30 pm

Can you post a photo of the tooth from the end looking inline with the shaft? The teeth on those gears are case hardened, which will not ware down in a hurry so just riding it will not work. The slip stone if you could find one small enough would work if you had a month of Sundays and it was only a small high spot. I had to do a hole 2nd gear for a Maico engine once as the only one available was a repo from USA and it didn't mesh at all with the original gear. Got to it with the dremil and took every tooth down a bit and it's been in there for about 5 years and still working.



keychange
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Re: TLR Engine Reassembly

Postby keychange » Mon Aug 06, 2012 4:59 pm

Here is the gear - back and front
Attachments
P1060563.jpg
P1060563.jpg (168.74 KiB) Viewed 3516 times
P1060560.jpg
P1060560.jpg (104.56 KiB) Viewed 3516 times



FM350
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Re: TLR Engine Reassembly

Postby FM350 » Mon Aug 06, 2012 5:10 pm

If you are 100% certain the clutch drum is the problem, and are not confident of repairing the damaged tooth, then why not just get a used replacement part?



TriCub
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Re: TLR Engine Reassembly

Postby TriCub » Mon Aug 06, 2012 5:33 pm

Looks like on the second photo that the right hand corner of the tooth is bruised a bit. Is that the case?

Looking some more and using a ruler it looks like the distance between the tops of the marked tooth and the ones either side is different. Grab a ruler and have a measure.



keychange
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Re: TLR Engine Reassembly

Postby keychange » Mon Aug 06, 2012 5:56 pm

TriCub wrote:Looks like on the second photo that the right hand corner of the tooth is bruised a bit. Is that the case?

Looking some more and using a ruler it looks like the distance between the tops of the marked tooth and the ones either side is different. Grab a ruler and have a measure.


TriCub - I am not sure what you mean by bruised but as I have said even under magnification I cannot see any obvious flaw. There is every possibility that the distances are different although even under magnification it is hard to measure accurately but yes I think that is the issue ie: the pitch on that tooth is slightly too large and causes the opposing gear to catch.
Attachments
P1060562.jpg



keychange
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Re: TLR Engine Reassembly

Postby keychange » Mon Aug 06, 2012 6:25 pm

Just paid for a replacement $50 delivered from Alaska :) Guy has good reputation on ebay so worth the risk.




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