Primary Gear Removal

[belldane]

Hi all.

I need help/ideas on how to remove the primary gear on a Cota 247. I have used the four letter word many many times but it just will not come off. I have attached a gear puller to it, tightened it as hard as I could, heated the gear with oxy, belted the shaft on the puller with the biggest hammer I could find and it still will not come off. The thing is still in the shed with the puller on and plenty of tension on it. Failing that the gear may pop off by some miracle, I will have no choice but to get a grinder to it and cut it off. That is unless someone out there has any better idea.

Thanks for any help you may be able to give me. Belldane

[feetupfun]

I had to take that gear off my 348 and I'm assuming your 247 has the same sort of taper. I found that a gear puller with fingers couldn't put enough force on so I made a tubular puller that has a full circle shoulder that goes behind the gear. It is made in two halves so it can be fitted over the gear, then the two halves are held together for the pull. It worked. I think that sort of puller is available from Montesa specialist Jared Bates or can be made with a welder and lathe.

Edited December 6, 2008 by feetupfun

[belldane]

Thanks for the reply Feetupfun

Yes the primary gear is the same as the 348. I rebuilt my 348 a couple of years ago and there was no drama getting the gear off. I actually made a puller very similar to the one you sent me photos of. No problems it just popped off. This time, however, when I applied the pressure the welding came undone ( no doubt my sh welding job) I think I will get in touch with Jared. he is very helpful and have had dealings with him over the years. I think the angle grinder is looking really good at the moment as I have other primary gears the same. Will keep in touch and let you know how I finally get this b-----d off in case you ever come accross the same problem.

Thanks for your help mate. See ya. Belldane

[peterb]

Hi feetupfun,

What an excellent set of photos you posted on the puller - well done. Was good of you to do that.

Belldane, I guess you have tried all sorts to break the taper, no doubt with the puller in tension and tapping the gear. I don't suppose that Loctite spray-on freezing coolant would help, on the crankshaft while the gear is under puller tension.

Good luck.

Bye, PeterB.

[belldane]

Hi feetupfun,

What an excellent set of photos you posted on the puller - well done. Was good of you to do that.

Belldane, I guess you have tried all sorts to break the taper, no doubt with the puller in tension and tapping the gear. I don't suppose that Loctite spray-on freezing coolant would help, on the crankshaft while the gear is under puller tension.

Good luck.

Bye, PeterB.

[belldane]

Hi all

Thanks for all your help with this. I actually managed to get the gear off without the need of the angle grinder.

PeterB - I used the freeze in a can on the crankshaft, got the primary gear so hot it nearly started to glow( while all the tension was on the puller) and it just popped off. There were no marks on the crankshaft or gear to suggest why it had not come off easier. I suspect it may have been tightened in excess of the specs in the first place. Thanks again