Cannot Remove Engine Sprocket

[Sean M]

Hello.

Bought a Bob Newbie clutch…as a comment, beautifully made piece.

Everything was going smooth - had the clutch removed and then was moving onto removing the engine sprocket so I can remove both as an assembly.

No such luck.

Sprayed a combination of acetone and ATF daily for about a week, while trying to remove with a gear puller. As a comment, I screwed two threaded bolts into the two threaded holes as located on the sprocket. Cranked hard enough to start bending the threaded bolts - better judgement told me to cease and desist.

Anyone have any suggestions? Similar experience?

Appreciate.

Sean

[ducati2242]

I think the holes in the sprocket are for a puller to be fitted not for jacking it off the casings . something along the lines of this would probably do it .

[cdsdorset]

Put the puller on , put it under some load, leave it overnight. See if you can wind it up some more the next day.
Try a bit of heat , not too much.

[Sean M]

Thanks men…used a gear puller with bolts threaded into the sprocket - applied the acetone/ATF combination for a week, all under pressure of the gear puller.

It’s not budging - applied heat also, coupled with a fairly solid tap with a ball-peen hammer - nothing.

Open to any/all suggestions.

Appreciate.

Sean

[cdsdorset]

Do you have access to a rattle/air gun?

[Spaceman]

The only thing that holds the sprocket on is its tight fit on the splines - if the sprocket is very rusty then that could make it difficult to remove. All you can really do is to tighten up the pulley as much as possible, apply a bit of heat to hit and perhaps tap it hard with a hammer to try to shock it into coming loose. I'm not sure how much clearance there is through the hole in the back of the chaincase but I would try to use a conventional 3-legged puller if you can if the screw in puller is not up to the job.

[tige]

Looking at what you have tried, and not wanting to cause any damage to other parts, i would be tempted to use a die grinder on the sprocket and get close to the shaft, not touching it, this will weaken it and cause it to split and come off, yes it will destroy the sprocket but allow you to get the job done, i do it on bearing shells when they are stuck on shafts, keep spraying coolant on it so as not to transfer heat.

[Mike Farmer]

 

It sounds very much as if you may/will have to do a destruction job on the sprocket.

Do you have access to a mig welder or arc welder. If so

Put a puller on the sprocket and tighten as much as humanly possible. Wrap a really wet cloth around the crank end, and belt a high energy mig weld on it for two three seconds. Thats power turned well up. in two places 90 deg apart. Should give you a radical instand heating. With a lot of luck your sprocket will pop and survive and you'll juct need to grind the weld off. If it doesnt work, you've lost nothin.

Luck to you. Sometimes these illigitimate babies really are the pits.

Mike  

[Sean M]

Hello.

Sincerely appreciate all the reply’s/guidance/taking the time to help.

I ended up cutting down into the gear to provide a relief cut figured easier to install new gear…finally came off. It was my gut thought, but a few of you confirmed it!

Again, thanks, sure I’ll be back on looking for some more insight.

Bye for now.

Sean
Hudson Valley of NY/USA

[Spaceman]

I've never come across the need to do this before with a BSA gearbox sprocket. Any idea why it was stuck so fast?