Cush drive

[Steve.Smith]

I am slowly working through the problems with my 1939 VG. I found that the wrong size of spacer was fitted between the bearing and drive sprocket and confirmed that the engine sprocket and clutch sprocket aligned once the correct spacer was fitted. I thought that would cut down the noise which seemed to be coming from the bottom end. On start-up the noise was even greater and truly horrible! On investigation I found that I could move the engine sprocket slightly (by hand) even when the cush drive was clamped up tight. The later type sliding member (1272-41) is fitted as is the later spring retaining plate (1315-41). Are these components the cause of my lack of spring compression? The retaining nuts can be screwed up tight without much effort. Any help would be gratefully received as I would like to get the bike out in this good weather.
Thanks, Steve

[Simon.Gardiner]

The issue is whether the sprocket can actually rotate regardless of how tight/loose the spring might be - it needs to have something that will mechanically stop it slipping, whether by the spring becoming coil bound or the lobes of the sprocket and retainer locking together without being able to pass each other.
(I once made some adaptations to the engine shock absorber on the 650 that relied on the strength of the spring to stop any slipping - needless to say when you got to an incline and asked it to pull in top it seemed to lose poser and rattled like fury.)
In my opinion the fact that you can turn the sprocket slightly by hand isn't necessarily fatal - but how much is slightly? I'd say ride it while the sun shines (provided it can't actually slip) and see if the transmission feels slack and clonky. If you think it does just be more gentle on the throttle and get at it again when the rain comes and when you've maybe got more of a feel for how it's behaving!

HTH

SG

[Steve.Smith]

Hi Simon,
thanks for the reply. I can rotate the sprocket by about 10 deg without moving the crank. I started the investigation into a noisy bottom end before I replaced the drive side spacer with the smaller one. The noise is now much worse and even at tick over it is very loud. As the bike has obviously been built out of a selection of bits I am trying to find out what should be fitted and if there is a difference between the parts fitted and the correct parts.
Steve

[simon.holyfield]

Are you in a position to take it apart and post some close-up pictures of all the bits? Hopefully then some experts can confirm which bits are right and which bits are wrong...

[Steve.Smith]

Hi Simon,
Hopefully I will have managed to download the photos of the current set up.
When the components are just placed on the driveshaft there is approx 0.28" from the collar to the end of the shaft.