I've been looking at building a big bore engine or putting a big bore kit on my '88 250R. It currently has a 300cc LRD using a standard cylinder (no case machining required I don't believe). I know there are several options out there. Can I get some opinions on which one I should go with. I want something around 350cc as I've heard that 350cc is still fairly reliable whereas 370cc-425cc isn't so much.

The list as I have so far is:
1. ESR (Eddie Sanders Racing): 350cc or 350cc powervalve
2. CT Racing- 350cc
3. Duncan Racing- PC 2000 340cc- a bit much $$ though

Anyone have any parts (engine, cylinder or machined cases, etc.) for sale so I could get started? Thanks!!

Get in touch with jlbierig450r. He has a lot of knowledge and 250 parts.

Surely someone has one of these and has an opinion on them!

do a CPI Puma. you can go up to a 431cc motor and they are made by the same company that builds the cheetah cylinders.

Do you have a website or phone number for them? Where are they located? Thanks!!