Just after some mild tuning ideas please guys, the bike is running @58hp on a dyno pro, it's got standard air box with no filter but retaining the snorkel,, full hrc "ish" exhaust and some unknown adjustable needles,,
I want the bike to be running as close as 64hp as possible,,,
Any thoughts?

On the cheap or not?

You could get the heads off and get all the casting flash removed and lap the valves in. remove the backlash gears, remove the flywheel...

All basically free - just takes some time, and suppose some headgaskets!


Edit to add - you could also get it dyno'd somewhere else - or on the Bemsee dyno asap - to make sure you have a decent figure..no point tuning the nuts off it if it then reads high on other dynos..

bean wrote:Just after some mild tuning ideas please guys, the bike is running @58hp on a dyno pro, it's got standard air box with no filter but retaining the snorkel,, full hrc "ish" exhaust and some unknown adjustable needles,,
I want the bike to be running as close as 64hp as possible,,,
Any thoughts?

Is it a road or track bike? An NC30?

some more details like jetting for that kind of setup.

Where did you pick 64hp from?

Without some HRC bits I dont think youll see much over 60. 58 is very respectable figure.

Chain tension, binding brakes and rough hub bearings can all rob some horsepower.

Most good 30s whose graphs ive seen make between 58-62hp depending on dyno / condition. I dont think 2hp is either here nor there though and I wouldnt be loosing much sleep over it.

If its a race bike and money is no object and you really want to stick with a 400 you can hunt out some rare old HRC stuff.

How is your brakes / suspension and tyres? With 58hp more often than not upgrades to the brakes / suspension will improve times more than 2 - 3hp will.

CMSMJ1 wrote:on the Bemsee dyno asap .

I was told the bemsee dyno is very conservative lol,,
The geny and flywheel have been ditched already, you think the quieting gears would make much odds?

And neo it's my race bike, the 64hp is the limit for the bemsee f4 class I'm in,,
Suspension is sorted to a fashion and the breaks upgraded and lovely

I reckon that a head refresh will make some difference for sure. My race bike was pretty fast though I never did dyno it. I had the heads off and removed and cleaned up all the casting shit out of it. Lapped the valves in, cleaned piston tops and so on.

ballache..but I could see that the bike was going to like me for doing it....

ref 64bhp class - the point was to remove the rocketships by RMKD and so on - I've raced against 80bhp ZXRs and they are awesome.. I reckon Richie Welsh's FZR was getting on for 75+ too...but at the end of the day, kids on RS125s used to beat me...so power is not all that!

Yes I know mate,, but the v4 needs some breathing on to be competitive in the sub 64 class,, I really do fancy going all out over the winter and see what can be squeezed from the rvf without going bang, ready for the full fat hp 2013 season,, I think I'll get the dremmel on the ports and remove a few bits see where im at before brands, to be fair I did somewhat part companie with the track last race on Sunday, so yes the engine isn't the only thing in need of improvement :)

Nc30 HRC carbs will see another 4-5 hp I reckon, easiest bolt on power.

I've been looking into this myself and talking to a couple people who work on the Honda V4's. Mike Norman at G-force uses NC30 carbs on all their NC35 race bikes. Maybe that with some tuning could get you there, however some good porting work would definitely do the job.

I had hrc 30 carbs on my race rvf engine, was a great combo combined with other work.