Lack of GO

[phunkynova]

Okay the engine 1.4 NV with big valve ported head, new Newmann 288 camshaft, Kawasaki 600cc bike carbs. new rebuilt.
The engine runs good up to 4000 RPM and just when it should start singing, the power falls off and it slowly climbs through the rest of the revs like I've just added 3 ton to the car or backed right off the gas.
Plug new, good spark in all 4, good compression in all 4,
Any one got any ideas why it's doing this ?.

[Southie]

Any air leaks from your bike carbs to the manifold?
is your timing advanced enough?
You might need to enlarging the jets on the carbs.

Edit: also have you got a fuel pressure regulator like a filter King as the carbs will need to be set a 3psi.

On my old SR 1.4 I had R1 bike carbs and they had to be redrilled 3 times to get the jets fueling spot on but once they were my old engine was revving up to 7500k easily;)

My old lump, I miss that engine... Did have £2500 in it though :eek:
http://i345.photobucket.com/albums/p379/SOUTHIE01/MINE/IMG_0029-1.jpg (http://s345.photobucket.com/user/SOUTHIE01/media/MINE/IMG_0029-1.jpg.html)

[Jonesfach]

Fuelling issue?

[phunkynova]

Thanks for the advice guys I'll take a look at it next week when I'm back in Plzen and let you know how it turns out.

Southie what was the final size of the drilled out main jets on your carbs ?.

[millworm]

Fueling or ignition probably fuel

[garyc]

I'd check the cam belt timing too.