Racebike Only Thread.

jerry · Post by **jerry** » Thu Jan 27, 2011 2:44 pm

Teazer, All round the cranks work out about 1000 miles then a rebuild then a bin job. 350 and 500 both use same cages and rollers. Nothing lasts forever and no engine is bullet proof. Com chains last 2 race meetings. Gearboxes last 3 seasons. Engines are stripped after every race meeting . Jerry

G-Man · Post by **G-Man** » Thu Jan 27, 2011 3:16 pm

Jerry

Thanks for sharing your experience with us, it's really fascinating. Are you managing to get NOS Honda parts for your cranks or are they built up to your own design? Did I hear that the basis for your cranks is CB350 or CB 450?

I'm trying to build up a 350 motor for a fun trackday bike as a technical exercise. I'm going to build a lightweight crank for it but the bike won't be stressed anything like your machines. Even 1000 miles would last me a long time, so I shall probably start with a CL77 part.

Looking forward to hearing more about your exploits.

G

jerry · Post by **jerry** » Thu Jan 27, 2011 3:39 pm

G-Man,CB450 for the 500 and a combination of CB360 and CB250G for the 350. I run the same big end assys. on both. It is a combination of NOS and second hand rebuilt. New parts can need extra care because they have not been run in. LoudMouse has been a great help to me and continues to be. Without his help things would be a lot more difficult If you are looking for top speed do not go too light on the crank and keep those pistons as light as possible. Jerry

Hotshoe · Post by **Hotshoe** » Thu Jan 27, 2011 4:31 pm

This has been a great read, thanks for sharing the info.
If it's something you can share Jerry, how do you lighten your pistons?
I had very good results with porting my head and raising the compression a little (thanks again LM) on my current 305 rider but I'm building another engine out of my left over parts and I'd love to try lightening the pistons if it's practical for an experienced home mechanic that is.
I've seen several racing engines over the years with drilled out piston skirts, is that kosher?

jerry · Post by **jerry** » Thu Jan 27, 2011 5:35 pm

Hotshoe. Keep the piston pin bosses strong and remove material from all areas possible. I have been known to go as thin as .100" on the piston crown but you DO need to have the mixtures right otherwise the inevitable hole in the piston can take place. LoudMouse may actually be able to give you a more unbiased and accurate description of what I do as he has had a good look inside the motors and I will not be against him talking about it. Jerry

Hotshoe · Post by **Hotshoe** » Thu Jan 27, 2011 8:08 pm

Thanks Jerry, I'm not sure Ed would want to expand on this topic but we'll see.
Regards, Chuck

jerry · Post by **jerry** » Thu Jan 27, 2011 8:40 pm

Chuck, Ed and I have very similar views regarding the Hondas. I prefer to see them as they came from the factory . With what I am doing it is not really tuning or abit of hot rodding. The bikes have been built for one purpose only and to achieve that aim they have been re engineered. Apart from the castings and a few other components there is not that much Superhawk in them although I hope that the character has not been totally lost. The bikes are a mountain of work to maintain but I do get a lot of personal satisfaction playing the game. Unfortunately my bikes have been a bit disheartening for some of the Honda riders especially and I think Teazer can attest to that. In many ways what I am doing is a mugs game but I do enjoy it . 95% hard work and 5% joy. A bit like an addiction I imagine. Jerry