nc35 struggles after 11k

[skinnydog0_0]

Hi All,
I have put the nc30 engine back together with the nc35 heads. The bike runs great in 1st and 2nd pulls right through the rev range, no dip. 3rd gear onwards it starts to struggle at the top of the revs. and by the time i get to 5th and 6th it struggles from 10k. It will get there no problem then kind of chokes up/runs out of power.
The carb has 110 jets, extra 0.5 washer. the air box has a freeer flowing foam filter and 2 of the squars cut of the top. Before i changed the engine, the bike ran fine. I have polished the ports so it will be a little free'er flowing.
I am thinking i may need to use a slightly bigger jet, go from 110 to 115.
Any thoughts much appreciated
Cheers

[Drunkn Munky]

is the rubber flap under the headstock in place?

[skinnydog0_0]

No the rubber flap has been left off. This was on prior to the engine going back in, do you think the turbulance is affecting the air intake?

[CMSMJ1]

I'm thinking you need more fuel in there so at least 118/120 jets. 110 is far too lean and 115 might be too lean too.

The flap is essential, unless you have a HRC air tray. also, the airbox can be a funny thing - chopping bits out of it causes more trouble that it saves,

My race bike runs a DIY ported motor, full system, NC30 carbs with 120 jets in and a totally standard airbox system.

It runs like a dream!!

If you have a whole airbox lid, try it back to back against your chopped one.

[skinnydog0_0]

Okay thanks, will put the flap back in and try 120 jets.
The modded air box and 110 jets were set on a dyno before i had the bike, and they seemed to be running perfectly. Thanks CMSMJ1 about the flap. i will put it back in tonight, and go for a run tomorrow. I will also use the standard airbox lid, and go from there.
Will let you know
Cheers

[CMSMJ1]

wasn't 110 jets in rvf carbs?

You'll crack it mate..where you racing on this moto or is it trackdays gahoy?

[skinnydog0_0]

Sorry over type was on,
Thanks CMSMJ1 and Dunken Munkey about the flap

Yes it's for racing, but it's been a very long drawn out saga. In short, i have to use a push button gear change system as my left foot don't work very well after a bike spill. and i had to get a medical report done to say i could race. Cost a small fortune, but i had that in Feb, then blew the engine up, so have not been able to get in at the start of the season. I am going to do a few races with NGRRC and perhaps 1 or 2 with BEMSEE if i have funds.
I was hoping to go in the street stocks, but with the engine rvf/vfr combination, i am going to be forced into the F400. still it's a learning curve and i dont expect to win any pots Who are you guys racing with?

[skinnydog0_0]

wasn't 110 jets in rvf carbs?

You'll crack it mate..where you racing on this moto or is it trackdays gahoy?

Yer 110 jets with the modded airbox, when i got it. seemed to be running fine. The plugs always seemed biscuit brown and never missed a beat.
I have noticed that the neutral light flickers some times, so i am thinking i might have an earth fault too. Could this affect the top end revs do you think?

[Old Painless]

Neutral light flickering might just be the connector on the engine being a touch loose.

[skinnydog0_0]

Neutral light flickering might just be the connector on the engine being a touch loose.

Will have a look Old Painless, thanks