KH primary chain alignment

[will_curry]

I need some help with my recently-acquired KH which is a bitsa
with a 1953 engine in a 1955 swinging arm frame.

I dismantled the primary drive to investigate the action of the
engine shaft shock absorber and discovered that the engine sprocket
and the clutch sprocket are some 1/8" or more out of line with the
engine sprocket being further out than the clutch. As best I can
tell the shafts are parallel.

The primary chaincases are the earlier, pre-FERC cases as I would
expect and the gearbox mainshaft is also the appropriate short shaft.
The clutch centre and chainwheel are also what I would expect.

This leads me to suspect the issue is somewhere within the shock absorber,
twin shock absorbers being something that I have no real experience of.

The sleeve is 55.3mm long and seems to butt up against the inner of the
main bearing while the outer end overhangs the end of the crankshaft
by 1.5mm. The outer face of the sprocket, a pattern part, is 15.7mm from
the crankcase wall measured at the root of the teeth.

Suggestions anyone?

[Mick D]

Hi

That shock absorber spring looks to be very compressed, are you sure the sprocket is correct for your engine?

Regards Mick

[Roger Gwynn]

As far as I know sprockets for the KH have never been re-manufactured and what you probably have is one from an FH or A10, which are almost the same and may require modification to get the chain to line up. Note the warning against the item 10471-54 on this page https://draganfly.co.uk/product-categor ... ottom-end/ so out with the angle grinder or the shims!

[will_curry]

Mick,
That was the reason for dismantling in the first place. The ride was dreadful.
An original spring and slider seemed to have sorted that problem but I then
found the chain alignment issue.

Roger,
The sprocket came from Draganfly recently and was ordered as K98-48.
It is obviously a pattern part and I didn't see the note attached to
part 10471-54. Oh well, more spares for the FH when I get round to it.

Anybody got a spare K98-48 (21 tooth engine sprocket for a 500 twin)?

[Roger Gwynn]

I don't have any sprockets but I do have a sleeve that measures the same as yours. It measures 11/32 from the back face to where the back of the sprocket sits, which is the critical dimension for sprocket alignment. I know from trying to sort out boxes of assorted shock absorber bits that there are a lot of very similar sleeves, sprockets and cams.

[will_curry]

Thanks for the measurement Roger. My sleeve is the same.

I'm not convinced the sleeve is fitting as far down the crankshaft as it should either.

[paul.jameson]

I have a 21 T KH engine sprocket which I can measure for you or send it down to you for trial purposes although I want it back. Both my KH and KHA use 23 T Square Four sprockets with a minor mod which I can never remember but can work it out when fitting the sprocket.

The sleeves are many and various but look alike until you have a few different ones to hand. Again, I should have a correct one for checking purposes.

Either PM me or give me a ring on the number in Cheval to let me know what, if anything, you would like me to do.

[paul.jameson]

I have a 21 T KH engine sprocket which I can measure for you or send it down to you for trial purposes although I want it back. Both my KH and KHA use 23 T Square Four sprockets with a minor mod which I can never remember but can work it out when fitting the sprocket.

The sleeves are many and various but look alike until you have a few different ones to hand. Again, I should have a correct one for checking purposes.

Either PM me or give me a ring on the number in Cheval to let me know what, if anything, you would like me to do.

[will_curry]

Thanks Paul.

PM sent.

[will_curry]

The arrival of an engine sprocket from the club's spares - thanks Rob - confirmed my suspicions
that, contrary to what others may have me believe, FH sprockets are not the same as KH sprockets.

KH sprocket on top - note recess in face and smaller flange

The new sprocket and a more suitable slider from my collection of parts - thanks for the hint Simon -
have sorted both the primary chain alignment problem and the almost-coilbound shock absorber spring.

With the shock absorber set up as it was there was a maximum movement of three teeth. With the new
parts this is now eight teeth. Moreover, the sprocket which was at least 3/16" too far out is now
where it should be and lines up properly with the clutch chainwheel.

The new arrangement

With a new primary chain and replacing the six chainwheel set bolts that were there with the proper
bolts with a suitable shank to engage with the rebates in the chainwheel - thanks Acme Stainless -
I should be 'good to go'.

Thanks to all who offered advice.