thedktor Posted February 13, 2009 Report Share Posted February 13, 2009 I need to remove the primary drive on my 1980 349 and found this thread, any other tips as it's sure on there tight! http://www.trialscentral.com/forums/index....y+drive+montesa seems freezer spray on the crank and heat on the gear is the way to go? Thanks Steve Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 13, 2009 Report Share Posted February 13, 2009 The only other thing I thought of after looking at the photos again was to make sure your puller contacts the back of the gear evenly so you don't damage the ends of the teeth. Quote Link to comment Share on other sites More sharing options...
thedktor Posted February 14, 2009 Author Report Share Posted February 14, 2009 The only other thing I thought of after looking at the photos again was to make sure your puller contacts the back of the gear evenly so you don't damage the ends of the teeth. Yes, agreed! And when using a finger type puller I always clamp the gripping ends so they cannot open up and damage the item being pulled, and/or you Quote Link to comment Share on other sites More sharing options...
thedktor Posted February 22, 2009 Author Report Share Posted February 22, 2009 Ah fun and games. First attempt with moderate heat and the gear refused to budge. Second attempt today with a LOT more heat, plus freezer spray and the goddam thing still refuses to move! Frustrating to say the least - I have everything else off ready to split the cases. I have paused for now, not really sure what to do, but got a couple of engineering friends to seek opinions from. I have been using a 3-legged puller, with legs strapped together so they can't open up, and done the thing up as tight as possible. Heated the gear, cooled the crank, tapped with hammer on the puller, all the things that would normally move a flywheel.... Steve Quote Link to comment Share on other sites More sharing options...
spokerider Posted February 22, 2009 Report Share Posted February 22, 2009 Sounds like you're covering the bases..........dunno. I haven't tried mine yet, but I sure hope it comes off easier than yours! I think I read that someone heated the gear hot enought that it was almost glowing? Hummm, wouldn't that take the temper out of the steel? I'll be fabbing up a puller myself, Sounds like it ought to be a big-ass strong puller to do the job. Do you have the means to fab a puller that'll allow more torque and thus pulling power? Quote Link to comment Share on other sites More sharing options...
thedktor Posted February 22, 2009 Author Report Share Posted February 22, 2009 Sounds like you're covering the bases..........dunno. I haven't tried mine yet, but I sure hope it comes off easier than yours! I think I read that someone heated the gear hot enought that it was almost glowing? Hummm, wouldn't that take the temper out of the steel? I'll be fabbing up a puller myself, Sounds like it ought to be a big-ass strong puller to do the job. Do you have the means to fab a puller that'll allow more torque and thus pulling power? Yes I wouldn't put too much heat into the gear. I'm using a hot air gun so doubt it would get it glowing! I cannot make a puller myself, but the friend I bought the bike off can! so that is the final option.... Steve Quote Link to comment Share on other sites More sharing options...
oldplugger Posted February 22, 2009 Report Share Posted February 22, 2009 OK Guys, oldie here..I split my first 348 in '76 to repair a cracked big end roller. AT THE TIME all I used was a 3-legged puller, carefully, evenly and gently applied - but I guess the that was then, this is now. Quote Link to comment Share on other sites More sharing options...
toofasttim Posted February 23, 2009 Report Share Posted February 23, 2009 BANG! Omygodwherethef%$$didthatgo! Quote Link to comment Share on other sites More sharing options...
thedktor Posted February 23, 2009 Author Report Share Posted February 23, 2009 FINALLY !!!!!!!!!!!!!!!! Yes the gear came off at last, 3rd attempt. Here's my setup: Note chain clamped round the puller to stop the legs opening, and I used some foil from a pie(!) to shield the crank from the hot-air gun to try and stop it heating up as much as the gear. The puller was as tight-as, creaking alarmingly, and then just kept tapping the end with a hammer, loosening again so the legs could clamp up tight again, as even with the chain clamped tight they were moving out a little with the knocks, then tapping some more. And off she pops, after some time! Blimey, that was hard work 1 Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 23, 2009 Report Share Posted February 23, 2009 I see you have a special left-handed Cota 349 there with the primary drive and gearshift on the left side. That must be a rare one! Congratulations by the way. Good to see you are getting closer to getting it running right. I can feel for you as I went through similar on my 348. Quote Link to comment Share on other sites More sharing options...
thedktor Posted February 25, 2009 Author Report Share Posted February 25, 2009 Congratulations by the way. Good to see you are getting closer to getting it running right. I can feel for you as I went through similar on my 348. Thanks! Yeah it was very frustrating for a while. Next difficult task needs a new thread... Steve Quote Link to comment Share on other sites More sharing options...
tael Posted February 26, 2009 Report Share Posted February 26, 2009 BANG! Omygodwherethef%$$didthatgo! +1 hehe, yup i was there last month. used a three-legged puller with the legs chained up. In the end went for the get it as tight as you can, then using the longest bar you can, carefully approach and give it 1/4 turn, sweating - usually with eyes shut. retire to safe distance, wait 5 mins and repeat. On the 4th or 5th 'turn' the aforementioned BANG, jebus where the " Quote Link to comment Share on other sites More sharing options...
thedktor Posted March 13, 2009 Author Report Share Posted March 13, 2009 I have just picked up a s/h 349 bottom end, which hopefully has better gears than mine. The only problem is............. the flywheel and tapered gear are still attached, which means having to go through this trauma again!!!!!!! I have been advised that the way to get the bleeders off is a hard hit on the end of the puller. Not a tap, but a bl@@dy hard wallop with a big hammer. I did hit mine quite sharply last time to pop it off and I'll stick with the normal hammer and see what happens.... Steve Quote Link to comment Share on other sites More sharing options...
wayne_weedon Posted March 13, 2009 Report Share Posted March 13, 2009 Thats a score! Gears ought be be less damaged than your others! Soon you may work out a patent procedure for getting that primary gear off. Wayne.... Quote Link to comment Share on other sites More sharing options...
dave dix Posted March 13, 2009 Report Share Posted March 13, 2009 No, use a big heavy hammer as its the jolt that gets the gear off . I have just removed the same gear off of my 247, i just used two long tyre leavers , one being pushed by my knee and the other by hand and i walloped the crank end with a thor copper and hide hammer once and it came off Dave Quote Link to comment Share on other sites More sharing options...
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