NTV650 well down on power

[john493]

Guys,
I've got an NTV650T, 1996, it's only done 8000 miles since new.  When I bought it in April this year, it ran OK but misfired at about 60 mph.  Since then, I've strugged to fix it.
I sent the carbs off to a specialist for ultrasonic cleaning and checking.  Since then, it does not misfire but is still gutless - just about gets to 60 mph.  Only the first 25% of throttle movement seems to make a difference.  The cables are adjusted correctly.
Also done:
New plugs
New fuel filter & fuel pump eliminated
Sub air filter changed
Air filter temporarily removed, no difference.
Valve clearances checked OK.
Compression tested, 150 psi on both cylinders.
Now I'm at the point of wanting to change out the carbs complete - I'm out of other ideas.  The ignition timing is not adjustable on these bikes.
So - any ideas ?
Will Deauville 650 carbs fit straight on my bike ?

Thanks
John

[odie]

check inlet manifolds for cracks, (under the mounting clips)
balance the carbs.

[ben]

may all so be the coil packs playing up is it worse when it gets warm

[john493]

Thanks guys
Don't think it's the coils, it's not misfiring.
I'm going to check the float levels then the carb balance next.
Carb to head rubber connectors are perfect.

[odie]

you can borrow my spare set of carbs if you want try to find the problem that way.
Just out of curiosity you dont have 33bhp restrictors built into you inlet manifolds do you?

[john493]

Thanks Rick - appreciated - will try to check float levels tomorrow.

[john493]

I bought some carbs from a breaker, now the bike pulls like a train so it's definitely a carb problem, although the new carbs must need a clean out as it doesn't idle properly.

[AllRider]

I am having a very similer problem, but I'd say the first 10% of throttle/1 16th a turn seems to be fine with is next to nothing, did you ever work out what the issue with the carbs was.