Originally Posted by
Do-Over
Hey Lance,
I'm not out to steal any secrets but I'm very curious about the pinching process. I've sent you a PM before on resizing a B5 my buddy was gonna loan me but it kinda fell thru... I'm just curious as to how these sleeves could be pinched without crinkling the metal. Again, it's not like I would do it for myself but wanted to know about it, just to know really... Send me a PM if you prefer, or don't respond if it is some sort of secret, I'm just curious about it as I'm mesmerized on how these small 2 strokes operate at such extreme RPM's and I'm trying to learn about them. Just to learn really. I feel the more I understand them the better tuner I will be. We need some good tuners in my circle of friends so I'm trying to learn.
Thanks,
Rich
Well Rich, Basically the tolerances we are dealing with here are very very small, down to .00001" . These engines have very close tolerances between the piston and sleeve. Because there are no rings like a conventional engine that are spring loaded and constantly wear in and keep the cylinder to piston seal. These engine rely only on the actual fitment of the piston and sleeve to do the sealing. Thus the reason you hear about people resizing sleeves that are way too tight, or making them out of round, or just not running correctly.
The piston/sleeve tolerances are EVERYTHING with these engines.
There are no secrets to resizing, but just like everything, everyone has a different way of doing things, and different opinions on what the best way is.
Basically there are some guys using clamps, that just clamps the sleeve. Or there is tooling, which Rayaracing(ray is a great guy and has a great service) and Rcrenew use. The tooling and equipment does not do the work for you, I think this is where people find out the hard way that its not easy for everyone to get this down to an art.
On tuning, it just takes practice, But if you look on werksracing.com they have a really easy way of tuning and understanding tuning posted under tech tip's. I Have told many people about Ron's (werks) tuning method and they all were very pleased with how it helped them.
Hope this helps a bit,
Take care,
Lance
Rcrenew.com