[zx10rsandrail]

Newbie here, looking for help.

I have a 2 seat sandrail that had an old 91 Katana engine it it, but I have repowered it with a 2005 zx10 out of a wrecked bike.

The problem I am having is it wont rev past 11,000, and from what I can find it's supposed to come in at 12,700. I thought maybe it was the ecm, so I found another Gen 1 ecm, plugged it in and it made no difference. It just makes a sort of rhythmic popping/stuttering at 11K.

I have the complete engine harness, tach/meter and think I have everything wired up correctly. Is there possibly some sensor I've overlooked, or is there a chance my tach isn't correct?

I do have it running on a bypass type fuel system, but I have the regulator set at 45 lbs, and it's not dropping off that when it hits 11k.

I'm looking for ideas. Thanks!

 

[badassjake]

it can be either over fueling, or under fueling at those rpms........the top end is fueled rich. so if you can adjust the fuel pressure, higher at first and trouble shoot that way to see if the issue is resolvable that way.

 

[zx10rsandrail]

I tried that last night, ran the idle fuel pressure from 44 lbs to 58 lbs and revved it and it didn't make any difference. I did notice that when it bangs out at 11k the fuel pressure drops a little.

With the regulator set at 58 at idle, it will drop back to about 45 lbs at 11k and with it set at 44 at idle it will drop to about 38 lbs at 11k. Both setting don't seem to make any difference in max rpm or the way it sounds when it bangs.

Also the way I have it set up is the rh end of the fuel rail is drilled out connected to the regulator, so the rail is seeing actual pressure.

I haven't tried it this time rolling and in gear, but several months ago when I working on it, I did it rolling in gear and it didn't make any difference. Still banged at 11k.

One thing I probably need to look at is the valve clearances. I havent had the cam cover off. Thats next.

Appreciate the input and reply.