VBB Engine Compression (Won't Start).

[tranquilitybase]

Hi,

I've been trying to start my '64 Sportique without success. I'm restoring it and whether it ran or not before rebuild is unknown as some parts had been removed when I bought it.

What looks to me like a good spark is there and I took my time with the timing when I reassembled. I triple checked this.

I have tried some easy start with no sign of firing.

I have done a compression test (cold obviously) and can't see a reading over 4 bar/50psi. This is a bit annoying as a new piston/rings has been fitted and the cylinder has been honed.

Any advice would be welcome.....Thanks

[alan34]

I don't know if this will help but worth a try are the piston rings the flat or concave type some bikes have concave ones which must fade the right way up and down.best of luck alan.

[tranquilitybase]

Good point Alan.

I'm thinking I'll probably have to take the power unit out again. At least it's much easier than a car to do.

I've been reading about "squish" which I've never met before. I'm new to two stroke engines.

I believe also that you can use grinding paste on the head/cylinder mating faces to ensure a good seal. I'll try oil in the bore to eliminate the seal between the piston rings and bore tomorrow.

Thanks for your reply.