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Re: TLR Engine Reassembly

Posted: Sat Aug 04, 2012 6:05 pm
by keychange
This is the area the problem tooth is middle of picture

Image

Re: TLR Engine Reassembly

Posted: Sat Aug 04, 2012 6:30 pm
by TriCub
Is it the tooth that lines up the end of your finger? Bit hard to see in a photo.
It could possible be a bit bent at the end of that tooth.
If it was mine I would use a very small dremil type grider and remove the high spot. If you cover the tooth that you think is the problem with nikko pen then assemble and rotate it through a few times you should see the high area were the ink has been removed.

Re: TLR Engine Reassembly

Posted: Sat Aug 04, 2012 10:16 pm
by FM350
If you can see that the tooth is damaged, that will be the problem certainly, and its something that used to affect new Beta's, and was caused by swarf not being cleaned out properly during production, and getting picked up in the clutch drum teeth.

Way to deal with this is to use a slip stone on the damaged tooth (or teeth), until the clutch and crank pinions mesh without noise or any perceptible rough feeling.

Re: TLR Engine Reassembly

Posted: Sun Aug 05, 2012 5:32 pm
by keychange
The problem is there is no visible problem with the tooth - it simply doesn't mesh properly. I have tried emery paper and even lapping compound using the primary drive to try and work the problem out but to no avail. What can I expect if I just use it as it is?

Re: TLR Engine Reassembly

Posted: Sun Aug 05, 2012 7:38 pm
by FM350
I would imagine that if the noise is bad, that a tooth breaking off is a possibility. You have 2 choices, the first is replace damaged part (or parts) and the second to find out the exact cause of the problem and see if it can be sorted out.

Re: TLR Engine Reassembly

Posted: Sun Aug 05, 2012 9:33 pm
by David Lahey
There may not be a problem with a single tooth per se, it may be that one of the shafts that the gears run on is bent. I have seen this effect with TY175 primary drive gears (bent gearbox shaft) and Cota 348 primary drive gears (bent crankshaft)

Re: TLR Engine Reassembly

Posted: Sun Aug 05, 2012 10:32 pm
by TriCub
With the 2 gears in your hand off the engine can you turn them together to feel the tight spot?
From the sound of it running , I still think it's a single tooth causing the problem.
If you put the gears back on a different spline on the gear shaft and the crank is the tight spot still in the same place on the gear? If it is that would eliminate bent shafts.
Have you tried inking the gears as I sugested?
If it is a bruised tooth it should be possible to grind the effected area down without risk of the tooth braking off. If the tooth is cracked at the root, which should be visible with a magnifing glass then you would need to change the gear.

Re: TLR Engine Reassembly

Posted: Sun Aug 05, 2012 11:54 pm
by FM350
If there is no visual damage on the clutch drum or crank pinion teeth, then I would imagine the noise is coming from inside the cases. Very easy to check this by simply removing the clutch drum, and turning the gear shafts and crank without the drum fitted. If the noise is still there you need to strip the motor, if not check whether anything is bent using a DTI.

Re: TLR Engine Reassembly

Posted: Mon Aug 06, 2012 10:01 am
by TriCub
By the sound from your audio it's not a crank problem as it is way to slow a frequency. If when it was running and you put it in gear with the clutch in the gearbox would not be rotating and therefore not causing the problem. Did you try that when it was still together?
The only gears that turn all the time are the clutch, oil pump and kick start gears all the rest stop when the clutch is disengaged.
Put a big pen cross on the clutch basket and notice were it is when it catches and the take the cltuch off and rotate it 180deg put it back on and if it catches in the same spot it can only be the clutch gear itself.

Re: TLR Engine Reassembly

Posted: Mon Aug 06, 2012 10:37 am
by keychange
Sorry I must have not spelled it out clearly enough.

The problem is definitely - absolutely without doubt the ring gear - one tooth is not meshing properly - with both parts in my hand it is clearly catching on one tooth and one tooth only. There is no obvious damage to the tooth but it must have been bent very slightly when I used a washer to lock the clutch in order to remove the bolts on the oil filter.

So there is no bent shaft - the noise is caused by the tooth catching - it is only a click when in my hand but translates to the clunk when installed.

Apart from the obvious damage if a tooth was to break, do you think it will cause other damage by running the engine in this state eg: will the clunk cause wear on the primary gear or on the main bearing.