Kick start plunger dragging on 1st Gear

[paulnobodyimportant]

I have a TS1 within a SIL 200 engine, in otherwords, at least a SIL kick start, plunger and GP end plate. However, the kick start plunger has always dragged on the first gear creating that whirring sound. So about a year ago, I replaced the 1st gear, plunger and reference pin with a new SIL one and made sure that the kick start was well shimmed up, with a MB circlip, to give no movement at all in the longitudinal direction. Despite all of this, the plunger is still dragging, but not as much as before. Now I know that I could do several mods to really cure this, such as:
• Cut away the GP ramp and fit a Series 3 kick start guide.
• Weld a bit more metal onto the ramp to make sure that the plunger is well out of the way.
• Putting on one of the new cork caskets, because I have a feeling that I probably only need a further 1-2mm of clearance.
However, I’ve 2 other SIL based GP engines and I don’t have the same problem, so in my mind, the solution must be in the parts. Now I have 3 spare GP end plates (2 Italian and 1 SIL) and the ramps in all instances, including the one in the engine above are the same, so it can’t be the ramp???
The other variable can only be the plunger or the kick start shaft. Now I know from reading through the threads that others have had issue and Adam W noticed differences in plunger height vs position of reference pin.
Any thoughts on this issue, i.e. anyone have any measurement for the plunger. I know that I could check on another engine, but it means another partial strip down. I know that MB doe a well engineered plunger, but if the relative dimensions are the same as SIL, then I will still have the same problem.
Or, are there differences in kick start shaft lengths.

Now I could try the above 2 mods, but I seem to have an aversion to going down this route, don't ask me why though, its just one of those things

Cheers

Paul

[bizzly]

Have you thought about removing the kickstart lever and moving it around the splines by a notch or 2. It could work. I had to do that when I built a new chain case side with all the grubbings etc.

[ForemanBob]

Are you sure that the plunger is fully up the ramp when on the bump stop, otherwise you could move the kickstart lever one tooth round on the shaft.

I've also had kickstart shafts that were just wrongly manfactured and too long :freak: , if it's just rubbing you could use a thicker chaincase gasket to give you that 1mm or so you are looking for...

Good luck

[Adam_Winstone]

There is a HUGE variety in all of these parts, which makes it difficult to know if changing any one of them will resolve your issue. Fitting a thicker chaincase gasket (or multiples) is the only way that you can be sure that the teeth will move away from 1st. You could modify the side casing so that the shaft sits further away (as per early/late shaft and side casing modification) and then take up the difference on the outside with additional shims, however, this is less than ideal as modifies it for ever more... only for fixing a problem caused by other factors.

The introduction of the Cyclone gearbox has highlighted the vast differences in components out there, many of which can cause such an issue, so there is plenty of discussion on line.

Adam

[paulnobodyimportant]

Thanks for the replies.

This engine is out of the frame and on the bench. So first thing that I will do is put chain case back on, but pack away with washers to give a 1mm gap between cover and main engine case. Then spin round flywheel and see if I can hear plunger dragging across 1st gear. If this works, then I will put on the cork gasket that I have just ordered, that compresses down to 1mm.

But if this just fails by a cock hair, then I will also try moving the kick start around one notch, then bolt back on chain case.

If that fails, I’ll buy a GTS

[rosscla]

If that fails, I’ll buy a GTS

At least you'll be used to a whirring noise already...

[scottwally]

Moving the kickstart lever 1 notch moves the 'foot' end a significant amount - I've been dealing with that on my newly S3 engined S1 chassis. Finding and adjusting (bending, fitting to motor, etc.) a kickstart lever that works with both, doesn't hit the footboards AND doesn't engage the plunger is a pain without shimming the case cover or messing with the internals.

I was still able to use the original, unmolested Italian S1 kickstart lever on the S3 engine, but had to trim the bump/stop rubber on the case. Moving the position on the splines did not achieve good results: the lever either 'drooped' too much towards the ground and looked like crap, or engaged the plunger and ground inside the case with the horrible sounds it makes. I understand a loud enough exhaust will take care of that though

Good luck finding what works for your situation man and keep us posted.

SW
Denver

[Toddy]

If that fails, I’ll buy a GTS

At least you'll be used to a whirring noise already...