Kickstart piston not engaging

[denisiw]

I have a problem on a TV175 which I have not experienced before.

When kicking the scooter over, the kickstart piston does not engage with the gear teeth in one place.

It engages for about 5 kicks, but then the kickstart lever goes down without engagement, it might just catch but when pressure is applied it slips. If I carry on pressing the lever down it will eventually catch enough to turn the engine over until it's working fine again. Carry on kicking and it seems to reach the same spot and it happens again.

A GP side cover is fitted to this engine but it has been tapped M6 to accept a Series 3 ramp. It has a modified GP end plate too, the ramp has been removed.

I thought I'd sorted out this problem a month or so ago when I replaced the Li kickstart shaft, which was fitted, with a GP one. I transferred the piston etc to the new shaft. The piston pin was rubbing on the casting so I ground the pin down to clear.

I've taken the side cover off, the piston moves freely. I've inspected the gear teeth on the side of fourth gear; they are perfect. I've replaced the old piston with a new one.

It's as if something is stopping the piston from moving all the way out in one place per revolution of fourth gear. I've ground the kickstart shaft slot a couple of millimetres longer to ensure that the piston goes out far enough, but it made no difference.

I'm going to make up another side cover, the correct one for the scooter and see if that solves the problem.

If anyone can help with this it would be much appreciated.

Denis

[coaster]

I had a similar problem with mine and suspected that it was due to worn teeth on the side of the gear (it's 1st gear by the way) as some of them were chipped. I sourced a replacement 1st gear (thanks Demitrios) and also had a replacement shaft and new piston just in case. When I took the cover off I could see that both teeth on the piston were badly chipped so I took a chance and just replaced the piston which I'm happy to say had completely cured the problem

Thinking about your situation, have a really good look to check that none of the teeth on the 1st gear are damaged or rounded. Also check that there isn't too much play in the layshaft or that the end plate isn't loose.

When I changed the shaft I my other scoot recently I used a Tino Satchi one and noticed that the circlip that retains the disc that the piston spring rests on is about 10mm further up the bore which has the effect of increasing the spring pressure. Are you sure your spring is as strong as it needs to be?

Colin

[denisiw]

Cheers Coaster.

My mistake, of course it's first!

As I said I've looked at the teeth and they all appear to be in the same condition, not worse in one area, however I shall have another look. I'll check the spring too.

I asked the owner how long he'd had this problem and he told me it had been happening since he had the engine rebuilt! I've no idea why he didn't take it back and get it sorted, he's only recently come to live on the Island from Bristol way.

Denis

[denisiw]

On closer inspection of the teeth on the side of first gear, I can see that there are a number of consecutive teeth that are worn so that the piston teeth will not engage, they will just slide over them.

I think that it's the smaller of the two 50 toothed gears that Innocenti used but luckily I've got a spare of both diameters.

Thanks for the pointer coaster.

Denis