Help with carb prob???

[jimirobinson0]

Any tips / experience greatly appreciated........

I have put together an NC35 from a crashed bike that I needed the engine from. I refurbed my engine and replaced. I have the bike back together and I have an issue revving past 6-8k and when pulling away.....

To eliminate I took the carbs from my other bike and there is no issue when using the known carbs with the same air box etc....

Before rebuilding I cleaned up carbs

set float height
pilot screw set at just under 2 turns out
standard jets cleaned and installed
The bike idles ok and I have balanced with vacuum gauges

Seems like fuel starvation but I'm a bit lost after checking the needle valves and float heights over and over. I can replace carbs in < 2mins now

Any input welcome!!!

[Neosophist]

Are any of your sliders in the carbs sticking? push them up and watch them return back down.. sometimes you can get a stiff slider if there worn or dirty, this will certainly stop your bike revvin up.

[superlite]

If all the internals (including pilot jets, emulsion tubes) are standard and set at factory settings, there shouldn't be a problem. I don't think a sticking slide would give you those symptoms. Are your carb (inlet) rubbers in good condition and sealing properly? Have you checked for fueling issues - vacuum hose, fuel tap?

It may be an aside, but have you checked that it's not restricted after swapping engines (looms?).

[Neosophist]

One of my bikes wouldn't rev up when the fuel sliders were stiff as they wouldn't open far enough to allow fuel / air into the carbs.

At least you've isolated it to carbs.

It's got to be something :)

Check fuel height, blocked jets / passageways / emulsion tubes / carb rubbers / sliders / even jet sizes may be different

[jimirobinson0]

Many thanks for the input

It's not tank/vacuum or carb rubbers (or restricted) as I used the same when testing with the other carbs. I'll check again and let you know.

Thanks again