Anyone have any knowledge of these they could share with me? I saw these on ebay and I'm looking to squeeze a few more HP out of my NC30.

I tried a search and nothing came up.

Have been considering this option. Only reservation IMO is the cylinder liner thickness remaining after the re-bore or the risk that the cylinder liners are off-centre and a re-bore will break through. For street use probably little risk but not a racing option as pistons are quite heavy.

RO has one, he reports mostly increased mid-range. Stock valving, ports and cams will limit top-end performance. Maybe drop him a line.

Mike Norman (G-Force Performance USA) started with this kit but changed to longer stroke and smaller re-bore engine with custom Cosworth pistons to avoid the cylinder liner thickness and piston weight issues.

Hi JC - if you are in Socal..then you need to get hold of Mike Norman at G force for a chat.

Have a look at his blog - mngforce and you will get all you need to know

Welcome to the site

Thank you. I'll contact him. Hopefully he's got some time to give me some tips.

I've actually been on this site for a little while but forgot my last screen name and couldn't retrieve it. I'm done with my RSV4 project and am itching to get back to my VFR400. The suspension is all good so the only thing left that I want is more HP. Mine's got 53 rwhp on the dyno right now and I was reading that Gforce got ~72hp out of their motor for around $7500USD. 20 more hp would great!

This is a dream bike of mine and I want to deck it out and make it that much more special even if costs me a pretty penny. Lots of people around here love seeing this bike. They take out their camera's all the time to snap pictures of it. It's not a bike you see too often on the road if ever in the States.

Mike Normal appears very contactable, Had an e-mail conversation with him very recently about this very subject.

My rough figuring suggests 66-68 at most. G force engines are more than just oversize. Race exhaust, cam changes, head flow and other things that are only practical on a race bike. IMO mid-range torque increase should be more noticeable and is the view expressed by Rick Oliver.

If you are really keen, Rick Oliver has a 490 cc engine which proves it is possible however the parts are no longer available. So far my research into currently available alternatives has proven unsuccessful.

490cc is still available, this is what TTS performance tol me

"We do a 429 and 440 rebore options and 490 is a reliner, piston kits are £500 + vat, the liner kit is £500+ vat for the piston kit and £600+ vat for the liners and £500 to fit the liners to a bare case/ head gaskets are £80+ vat each. A rebore is just £160+vat for the 429 and 440 kits"

Interesting DM, when I last contacted TTS Performance, six months ago, they told me that the 490cc kit was no longer available. I need to contact them again.

Thats was when i spoke to them on 21/09/2011. From speaking with rick o i get the impression TTS dont want to do the 490 kits anymore due to comlexity of it, im sure there do it if you waved pound notes in their direction.

If you're planning to go to those extremes, why not just fit a 600 lump?

Cos no IL4 600 is going to fit between the frame spars