AJS & Matchless Owners Club

You have the head steady bolted down tight as well I presume? If that is the case, then yes I think you ought to be delving into the cases. Both my 56 CS models are almost vibe free and certainly don't numb the bum or get anywhere near to it.

ajscomboman wrote:You have the head steady bolted down tight as well I presume? If that is the case, then yes I think you ought to be delving into the cases. Both my 56 CS models are almost vibe free and certainly don't numb the bum or get anywhere near to it.

Well, I haven't yet checked the head bolts, but i am supecting flywheel imbalance. When it idles, the engine wobbles(occilates) for and aft in the frame. I can only sumise that this may be due to flywheel imbalance?

Pitty... engine doesn't leak a drop.

Anyways... looks like some delving needs to be done. Perhaps I might take the opportunity to get the flywheels balanced and polished at the same time

Matchymarty wrote:
Well, I haven't yet checked the head bolts,.....

To avoid any confusion, Rob was referring to the heady steady bolts which secure the steady plate from the cyl head to the under-tank top tube of the frame. You do have one I suppose?

Don't think the head steady would cause a great deal more vibration if it was loose. Unless exaggerated , I think there's something else at fault to cause vibration you appear to have.

SPRIDDLER wrote:

Matchymarty wrote:
Well, I haven't yet checked the head bolts,.....

To avoid any confusion, Rob was referring to the heady steady bolts which secure the steady plate from the cyl head to the under-tank top tube of the frame. You do have one I suppose?

aahh... sorry Spriddler.. .My mistake. Yes, Mis-interpreted that. I have checked the 'head steady' bolts when I ran over the engine/frame bolts the last night.

I haven't checked the clutch, though, it is operating well, (strangely, very lightly) although, perhaps the nut could be loose causing clutch wobble? No shudder or anything though....

Won't be the clutch and being Burman it will be very light. The fore and aft movement of the engine in the frame really does indicate a serious flywheel alignment issue or a bloody great 12-1 high comp piston being fitted. Either way looks like you'll be having to take the motor down.

ajscomboman wrote:Won't be the clutch and being Burman it will be very light. The fore and aft movement of the engine in the frame really does indicate a serious flywheel alignment issue or a bloody great 12-1 high comp piston being fitted. Either way looks like you'll be having to take the motor down.

Bugger.
The peril of buying a 'restored' bike once again bites me. 3 bikes bought over 12 months, all 3 with major redo issues. sigh....
At least I'm learning a lot!

Sounds like an overweight piston to me. I weighed an original piston with rings & original taper bore gudgeon pin at 21.3oz/602gr. Cheers! Don

Don Madden wrote:Sounds like an overweight piston to me. I weighed an original piston with rings & original taper bore gudgeon pin at 21.3oz/602gr. Cheers! Don

Thanks Don. That's the Short stroke piston?

I'll be putting the bike up on the table this weekend to start the pull down.

Yes, the figures I gave were for the factory original G80CS, short stroke engine. They apply for years 1956-59. Cheers! Don.