Advise on which engine

[Dean Dickinson 1970]

Hello all,

I’m just starting to think about converting my Shelbourne to Pre-Injection but really not sure which motor to use, it will be doing the 600cc class , if that helps, all advice would be greatly appreciated,

Cheers Dean

[Tibs]

Hi
You can use any engine as long as the engine was originally manufactured with carburettors. If you would like to know more come and see and have a chat at our next round, Mallory Park 21/22 of September, Cheers

[Big Tim]

If you want to do the 600 class, your best option is probably a Thundercat (Yamaha YZF 600R or the earlier FZR 600R - which was known at the time as the "shortstroke". The original FZR 600 motor appeared on the road bike market in 1989/90 - that being the "longstroke" motor which was cosmetically different but used the same bottom engine mountings - it didn't produce as much bhp / top end speed but offered superior torque, and is still a viable option). You will also need a set of correctly spaced Keihin flatslide carburetors.

The Thundercat has proven reliabilty and results in sidecar racing, and motors are less scarce than the later R6. In fact, the F2 lap record at Croft is still held 20 years on by Tom Hanks & Steve Wilson on one!

[little chud]

I'd have to agree with Tim. Thundercat engines are a lot easier to pick up and are therefore cheaper. I like the R6 5EB but these are harder to find good ones.

CBR600 PC 25 would also be worth looking at.

Jc