How to remove engine sprocket. - drive sprocket - pic

[arkives1]

How to remove drive sprocket

Hi Woody. I'll assume that you have a puller as supplied with most kits.
Generally, when using that type of puller, tighten the 14mm bolt as far as you can, then tap the head with a steel, (not rubber, as suggested), hammer. Tighten more, tap more, etc.
Don't give up. Like dropping a ball joint in a car, it'll loosen eventually. Usually just when you think it'll never come loose and aren't expecting it.
Don't hit too hard, either.
I also used water-pipe on the 14mm socket's wrench handle, when removing the clutch using the supplied tool, to increase leverage.

... Steve

Hi Steve, I've tried all the above tactics and that thing still refused to come off, a friend of mine came over and he applied pressure on the wrench as I slipped a thick flat screwdriver behind the sprocket at the hub and tapped in inward with a hammer, still no good. We then used an air driven die grinder and a small carbide burr running as slow as we could get it to go. We ground a bit of the aluminum casing behind the gear away, just a tiny bit. We couldn't get all the way around the sprocket but apparently we hit the right spots, a bit of polishing there and on the nub where the engine mounting screws are along with a generous dab of high viscosity grease and now it's quiet and smooth. Not sure if it will last or not but for now it seems to have worked. One word of advice to any one else using that last method, be sure to use plenty of cutting oil or grease on the carbide burr. The metal is soft and will gum up the burr quickly and is nearly impossible to remove. I learned that lesson long ago in my pattern making work. I still have another engine that has a small gear that needs to come out, we had the same problem with it, it wouldn't budge. We decided that after our weather warms up in late spring we will strip both engines down to parts and re-work what ever needs attention. Thanks Steve, the pipe helped, it didn't get the sprocket off but it did get his big hands out of the way. Woody

 

[AussieSteve]

I used really cheap carbide bits to smooth out after port-matching, then ran a file over the bit to remove the aluminium.
Next time I'll try grease. It should be easy to wash off in solvent afterwards.
I keep forgetting that it's Winter over there. We've been roasting in 40C+.
Penetrating oil might help with that sprocket when you tackle it again.
Otherwise, my favourite, pull out the oxy acetylene or similar, try to shield everything, then give the sprocket a blast of heat to expand it and then re-try the puller while the sprocket is hot. That usually does it.

... Steve

 

[arkives1]

how to remove engine sprocket

I used really cheap carbide bits to smooth out after port-matching, then ran a file over the bit to remove the aluminium.
Next time I'll try grease. It should be easy to wash off in solvent afterwards.
I keep forgetting that it's Winter over there. We've been roasting in 40C+.
Penetrating oil might help with that sprocket when you tackle it again.
Otherwise, my favourite, pull out the oxy acetylene or similar, try to shield everything, then give the sprocket a blast of heat to expand it and then re-try the puller while the sprocket is hot. That usually does it.

... Steve

Yikes! 40C is about 104F, man that's a lot hotter than I like it. Currently about -4 C here. Expecting freezing rain and light snow showers tonight.
Steve, we did consider the torch, very briefly. We remembered that we were working in the basement of my home. (The engine has never been run or even fueled) Somehow a torch and two big men in that rather small area doesn't seem a good idea. When we decide to rebuild these engines in spring we'll work in my garage.
As for the sprocket itself, I suspect a key that's undersized and pinched sideways. We found one on another engine when removing the small gear to install a centrifugal clutch. That engine had not been run or we probably would have had to crack the gear to remove it, it came out very hard as it was.
If you use grease or cutting oil with the die grinder, wear old clothes and a face shield if possible... With all the cast off, I looked like I had black measles when we finished. My son said I looked like a Dalmation and offered me a Milkbone. Kid get's that wit from his mother. Woody