MK1 - Possible Rear Crank Gear Play

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Re: MK1 - Possible Rear Crank Gear Play

Post by allan.walker »

Great news, Cam.
It's always satisfying when a problem has been solved. The new keys arrived yesterday so I'll trim two of them in readiness for rebuilding the engine. The head and barrels are off and the bottom end is now sitting on the bench ready for stripping.
I wonder what the 'few noises from the primary side' are. A good chance that it is 'normal' for these engines. Roger's advice to wear earplugs is very sensible for lots of reasons!

When my engine is fully stripped I'll post the findings in a new thread.

Allan.
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Re: MK1 - Possible Rear Crank Gear Play

Post by Roger Gwynn »

Unfortunately those centres are very hard so you won't be reaming the holes out, and sometimes the pins are a really tight fit and an odd size to boot. I don't know why there are six tight fitting pins, when there are 6 bolts holding the plot together as well, a couple would do just to hold it together whilst it is assembled on the bike. Did your fitter support the centre while applying 50 tons?
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Re: MK1 - Possible Rear Crank Gear Play

Post by camstevens »

john.whiting wrote: Fri Jul 30, 2021 11:43 pm Its rather obvious that the key transmits drive...to have a cylindrical surface transmit drive ,the interference fit would be in the order of 10-15 tons push on/off......The simplest way to fix the fit would be with a thin deposit of electroless nickle in the gear bore ....which you can do yourself.......Its unwise to plate crankshafts ,due to hydrogen embrittlement,however with a bit of ingenuity ,you could deposit electroless nickle on the worn part of the crank. without dismantling the motor.
Hi John
I'm liking the idea of electroplating nickel. I need to.measure my gear inner first to see it is worth saving, but assuming it is, the nickeling sounds very feasible. I take it this would not be a case of building up the nickel and re-machining, but one of simply regaining some interference?

Regards
Cam
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Re: MK1 - Possible Rear Crank Gear Play

Post by Simon.Gardiner »

Cam
I did some research on using plating to build up shafts several years ago - although I was going to use copper, not nickel.
For copper, thin coatings (up to 1 thou if I remember correctly) go on uniformly and don't need any machining afterwards (which was the attraction).
I must have made some notes about various alternatives at the time but I can't find them now - I do seem to remember that nickel might have had a similar property.
I've just done a bit of internet 'digging' and can't find anything definitive on this, although to me this site suggests that nickel might go up to +030" uniformly:
https://hcsplating.com/finishes/compari ... l-plating/
I did buy a kit from Caswell at the time (https://www.caswelleurope.co.uk/) - they seem to have grown a bit since 2017!
I think you'll need to do some research on your own account but that electroless nickel process does seem very promising for what you want to do.
Sorry I can't be more help.

SG
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Re: MK1 - Possible Rear Crank Gear Play

Post by camstevens »

Hi All
I have done a first pass of the gear centre nickeling, and fitted to the shaft as test (without key). I have to say the results are really pleasing and I feel I'm on the way to a successful outcome. The gear was markedly more snug than before and required a moderate amount of force to fit. A massive improvement.

I have a question which I guess has no "correct answer", but more based on judgement; should I be happy with what I have and fit with Loctite (I suspect this would be OK), or plate some more nickel on to get a much tighter fit, and possible do away with the Loctite alltogether?
I guess part of the answer is how tight are the gears supposed to be in the first instance.........my intuition is to plate some more an be sure.

Regards
Cam
Electrolyte.mp4
(1.71 MiB) Downloaded 29 times
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Re: MK1 - Possible Rear Crank Gear Play

Post by camstevens »

With file
Electrolyte.mp4
Electrolyte solution -home made!
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Re: MK1 - Possible Rear Crank Gear Play

Post by nevhunter »

It relies on the tight press fit. It can't be just the key doing it. Nev
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Re: MK1 - Possible Rear Crank Gear Play

Post by allan.walker »

I think I would go for the tightest fit achievable, so that the proper pinion fitting pusher is just capable of fitting the gear. If the plating depth is too great, fine emery cloth would reduce it.
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Re: MK1 - Possible Rear Crank Gear Play

Post by allan.walker »

Out of interest, Cam, how do you plate the centre bore of the pinion, but not the rest of it?
(showing my ignorance again...... :oops: )
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Re: MK1 - Possible Rear Crank Gear Play

Post by simon.holyfield »

camstevens wrote: Tue Jun 20, 2023 11:56 am Hi All
I have done a first pass of the gear centre nickeling, and fitted to the shaft as test (without key). I have to say the results are really pleasing and I feel I'm on the way to a successful outcome. The gear was markedly more snug than before and required a moderate amount of force to fit. A massive improvement.

I have a question which I guess has no "correct answer", but more based on judgement; should I be happy with what I have and fit with Loctite (I suspect this would be OK), or plate some more nickel on to get a much tighter fit, and possible do away with the Loctite alltogether?
I guess part of the answer is how tight are the gears supposed to be in the first instance.........my intuition is to plate some more an be sure.

Regards
CamElectrolyte.mp4
If it helps your decision, my gears were very tight and needed a lot of force on the wrench I used to operate the pusher/puller.
cheers

Simes

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