Topic: How do you stop an engine from turning? Done - 2/26/08

[KB02]

SO, I have finally gotten down to my cases and getting things ready on the bottom end. As I ordered and waited patiently for special tools to arrive from motion pro to remove that special clutch nut and and the flywheel puller. This is where I run into a bit of a problem. I can't seem to get the engine to stop spinning. After sitting behind the PO's shed  for God knows how many years with the pistons stuck in thee bores, the bottom end, now free of its upper end restraint wants to do nothing but spin and spin and spin... (Which is a good sign, I guess)

Anyway, Without getting the engine to stop moving I can't get either the clutch nut or the flywheel off. Now, I have already split the cases. It was necessary to get the jugs off to remove the connection rods from the crank, so I know I can take the cases apart with removing either of these parts, it just seems like it might be easier to take them off prior. What would you all suggest?

Here are a couple of pictures of my engine's current state:

[mark]

Air tools. One little zap from the ol' impact and those stubborn little bolts are history.


 

[bryanj]

Either put a bar through the two outer small ends at the same time and let them jam on wooden blocks placed on the crackcase base gasket surface,
OR put a copper coin in between the gear on the clutch and its mate

[MRieck]

Air tools. One little zap from the ol' impact and those stubborn little bolts are history.


 

I'll second that. You can put the engine in gear and hold the countersprocket with a motion pro clutch basket tool too. It looks like large vice grips with 90 degree fingers at the end

[kghost]

I thread a piece of rope down the spark plug hole.

Kinda shade tree...I know   

[mark]

I thread a piece of rope down the spark plug hole.

Kinda shade tree...I know   

I've done that trick to keep the valves up to replace stem seals with the head on. cheap barsteds....

I don't think I'd try to lock up a motor that way. I'd be concerned about a rod bending if that bolt really didn't want to let go.

.... besides.... the head and jugs are already off the engine in question.


howzabout waddin' up a rag an' stuffin' it in the primary chain?

 

[mattcb350f]

I use a tool that looks like a Vise-Grip with a roller chain attached to it. I wraped a strip of rubber around the inner part of the rotor and then clamped the vise grip tool around the rotor, using the rubber as a cushion. Didn't have to clamp it too tight since the rubber griped well.

That's how I took my rotor off.

Just gotta' make sure that you clamp the chain vise grip as close to the "cases" as posible. That part of the rotor is solid all the way around where as in the middle, it's cut in that zig-zag pattern.

Pic attached of the tool:

[TwoTired]

Has anyone tried a big strap wrench on the rotor?

I haven't done it, but, I'd probably try it given the circumstances.

Cheers,

[KB02]

okay, well, I managed to get the clutch apart. I made a make shift clutch holder out of some aluminum that I have lying around:



The clutch bolts were too short to hook on, but they're the same thread as the all the side covers and everything, so I just borrowed a couple of the longer ones and I had a way to hold my clutch while I undid the nut.   

The fly wheel is another story. Looks like my local shop might get a wack at it...    

[Raul CB750K1]

Screwdriver between the slots - nope. Extractor clamp - nope. Strap and rear axle as extractor - Eureka!

[KB02]

Well, turns out it was so hard after all. Just a short little drive to the local shop with the whole crank in a box and they took care of it. Didn't even charge me for it. I'll have to take back some of the mean things that I have said about them in the past. 

[Superbiker_uk]

Screwdriver between the slots - nope. Extractor clamp - nope. Strap and rear axle as extractor - Eureka!

Thanks Raul - just been fixing my starter clutch - used your method for holding the engine to get the alternator bolt out. Worked perfectly. Used the Honda special tool for the pulling the rotor. This forum is the best - cheers. Hopefully have the Dunstall up and running again pretty soon 

[crazypj]

I thread a piece of rope down the spark plug hole.

Kinda shade tree...I know   

If you do this to remove clutch or generator nut there is a real good chance of pressing through oil film and damaging big end shells. I watched it being done on a GSX-R750 motor thats now knocking pretty good
PJ

[CBJoe]

Has anyone tried a big strap wrench on the rotor?

I haven't done it, but, I'd probably try it given the circumstances.

Cheers,

This worked great for me.  My 650 engine was in the same state and I pulled the rotor off by using a strap wrench around the rotor to keep it from turning.

Joe

[MRieck]

I thread a piece of rope down the spark plug hole.

Kinda shade tree...I know   

If you do this to remove clutch or generator nut there is a real good chance of pressing through oil film and damaging big end shells. I watched it being done on a GSX-R750 motor thats now knocking pretty good
PJ

I'd say grab the crank end or the countersprocket.

[754]

KB02

 if you keep using the tool in your pic, you run a pretty good chance of brealing those threaded towers off..

[KB02]

Well, it was pretty much a one time thing. Putting the engine back together will be a different story. Things will be done properly.