Hi all,
Over the next few months ,I intend to re sleeve a dead Pinasco 177cc cylinder and fit a Yamaha DT 175 piston ( 66mm). Worb 5 have one on their site and it’s inspired me to do lthe same. My Thai version won’t be costing 800+ Euros, I hope.
I’ll be sticking on a reed valve, modified from a Yamaha TZR 150 and a 28mm Jap carb. Also a PM Tuning / ScootRS / Thai copied exhaust.
I know the cylinder will need plenty of alloy welding so I can open up the transfer and boost ports. I’m not too sure what to do with the head for compression etc.
Will a rebuilt and modified crank be strong enough? Using Japanese bearings.
Does anybody have any thoughts or experiance with this conversion?
I try to give some advise for the head, but I think Diablo might be the right man to do so.
You should make clearance in the head for the bigger pistons crown, + 2 mm for miss alignment.
Make a squish band 1,5 mm to follow the contour of the pistons crown.
Measure the volume of the head with oil when it is mounted and piston in top, and rework the head to a suitable compression ratio.
Hi Leif,
My local bike shop does alot of work an small cc ( 100-220cc ) automatics. I’ve seen their work at it looks good. At the moment I intend to have the crank the same as Polini’s or Malossi’s fitting instructions. I think I’ll try this first. Maybe later get a Worb5 full circle crank,but I don’t know.