50cc to 70cc question

[orrible-64]

Time for exhaust and headwork. The bike Joseph set that record with was not running at its best. . It is a good record to aim at. Once I have finnished moving my workshop we will play seriously with your bike


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[Volksy1]

OK, stripped it back down and there's good news and bad news!

Good news is I haven't broken anything, or installed anything 'wrong'.

Bad news is ooracing sent the wrong head gasket with the kit. When I took it back if and laid it out with the old one its exactly the same size

So now I'm stuck until tuesday, when hopefully I'll receive the proper one.

IMG_6653 by sagalout, on Flickr

I just rebuilt the top end of my 50cc. Ported the head, unshrouded the valves, increased the valve pockets on the piston and removed the base gasket. Compression now 11:1. Huge difference! Easily gets to 73km/hr with a straight through muffler. I would keep the head gasket though. Unless you do a valve to piston clearance check (using putty) I think you may have a valve to piston clearance issue.

 

[Streetfighterkz]

Just a FYI:

This thread is 10yrs old and the user you quoted hasn’t been on here since 2015…

Later, Doug