6 replies to this topic

[mad4classics]

At some point someone has fitted a duplex chain set without a tensioner and it's now very slack to the point where the crank will move 5deg without moving the cam.

 

Had a job to get the crank pulley off - had to resort to a puller; at which point I realised someone had used green bearing fit on it - chipping this off reveals the pulley to be a fairly loose fit when pushed back onto the crank.

 

Unfortunately I think either the bearing fit has seeped into the crankshaft gear OR worse that's been fitted with bearing fit as well (surely not)!!!

 

Being duplex it's difficult to get leverage behind it.

 

Getting a bit frustrated and toying with the idea of cutting the chain off and trying a small puller - I've come in out of the cold for a cup of coffee and a grumble.

 

Any suggestions?

[Spider]

I find I can get a tyre lever (which I seem to use for everything but levering tyres) under the sprockets to get them started. Just be mindful that you aren't levering against the plate that's unsupported and bend the plate. Once it gets too far off for the lever, I then go over to a puller.

[mad4classics]

I find I can get a tyre lever (which I seem to use for everything but levering tyres) under the sprockets to get them started. Just be mindful that you aren't levering against the plate that's unsupported and bend the plate. Once it gets too far off for the lever, I then go over to a puller.

Ok, tried a long pry bar on it,but that kept slipping out because I can't get enough purchase. I've got a handful of car tyre levers, so I'll give that a try tomorrow and let you know how I get on. People seem to use excessive amounts of bearing fit and thread lock.

[weef]

From your post I presume the object of removing the chain/sprockets is to replace the chain, so just cut it off to get access. Due to their nature locking compounds are hard to remove.

With the chain removed, work out what will be the best approach to remove the sprocket, my preference is the use of a puller but if not use two heel bars either side of it. Once established the best method you have, get a good hot air blower an heat up the sprocket, the heat will tend to "soften" the retaining compound and make removal easier, being a big lump of metal it might take a bit of time to get it up to temperature. When hot fit your puller/heel bars and "crack" the sprocket off. Once "cracked" removal should be straightforward.

[mad4classics]

From your post I presume the object of removing the chain/sprockets is to replace the chain, so just cut it off to get access. Due to their nature locking compounds are hard to remove.

With the chain removed, work out what will be the best approach to remove the sprocket, my preference is the use of a puller but if not use two heel bars either side of it. Once established the best method you have, get a good hot air blower an heat up the sprocket, the heat will tend to "soften" the retaining compound and make removal easier, being a big lump of metal it might take a bit of time to get it up to temperature. When hot fit your puller/heel bars and "crack" the sprocket off. Once "cracked" removal should be straightforward.

Yep, trying to replace chain - I've got an ordinary paint stripping heat gun and a 2kw electricians gun for heatshrink or a gas blowlamp; it's a lot of metal to heat up!

 

I've got another pulley that's a good snug fit so it's not the crank that's at fault.

Edited by mad4classics, 20 December 2021 - 08:00 PM.

[weef]

I would prefer to use either/both of the hot air guns. If you think it might help fit the puller first to save time of things cooling  and will save burning the fingers.

[mad4classics]

Used a Melco car tyre lever the curved end of which gives really good leverage; in fact so good I just kept stacking scrap steel bar stock in increments under the lever to gradually work it right off the crankshaft in stages.

 

With the gear off I can see the bearing fit on the shaft; looks like it seeped into the gear and settled at the lowest half at the time because it wasn't all the way round just covering ~180deg of the shaft.

 

With it all cleaned up the crankshaft gear slides on nicely and another pulley I've found is a nice snug fit.

 

Thanks for all the suggestions...

Edited by mad4classics, 21 December 2021 - 01:40 PM.