Saturday, 15 March 2014

Hunt for the Missing Compression

Last time I was out on the 1954 Velocette MAC it was pitifully slow, and uphill it really struggled. Being overtaken by Welch on an MZ 150 was the last straw.

A compression test revealed all of 50psi. Valve clearances aren't tight, so apart it came.

Taking this bike to bits is easy. I have stripped it so many times when I was having main bearing problems that I can have it down in no time.

Popped the valves out of the head.

No real signs of damage. Valve guides are good too. Probably need lapping in but thats easy enough.

Need to pop the piston off the conrod and check wear and ring gaps in the barrel

Other than some carbon the piston looks OK. No burning or seize marks. Barrel is unmarked too.

So I reckon a top end tidy up and some new rings and we'll be back in MZ beating business.

No comments:

Post a Comment