nc30 complete but now has as an hesitation...

[powerbio]

...i completed the doing up of my bike yesterday and took it out for a little spin...it now has an hesistation around 5500rpm and then clears about 6000rpm, after that it carries on pulling very well.... the bike hasnt been ridden since last october, problem wasnt there last time i rode it.

im sure it is a carb problem, though i didnt touch the carbs during the work i did...i did drain the fuel out of them whilst i was doing the work on the bike.

im hoping a good run will clear it?!

any ideas welcome

thanks
duncan

[1990nc30]

When i bought my bike the same sort of thing happened at 5-6000 revs, i just kept riding and tried to work around it and a couple of weeks later it had cleared up completely. Now it revs cleanly all throught the rev range. I'd just keep riding it and see if it clears up. Oh forgot to mention my bike had been siting in the ex owners garage for a year.

[Sligeach]

i use my bike every day and ride it to a resaonable standard, not gunning it everytime from the lights, but i do light all cylinders on occasion.
i have stripped and blew out the carbs with an airline, but the hesitation is still there.
its not that big of a deal to me

[powerbio]

well ive just been for a short ride, around 30miles...it pulls alot better in 1st, 2nd and 3rd gear without hardly any hesistation.

in 4th,5th,6th it hesitates.....the problem is more apparant if i short shift fron 2nd to 5th and open up the throttle in 5th gear at low revs...its quiet bad. it also hesitates worse in 4th gear etc at the top end of the revs.


im throwing some ideas around....

rectifier?

coils...if i put the 2 small wires that connect to the coils the wrong way round?

ive shortened the exhaust by 3"..possible affect?

(this is hard to explain so bear with me!)...when the air box is removed, there is a piece of plastic attached to the inside of the main frame that goes upto the area below the main headstock..im assuming this is where the main airflow comes in for the airbox....i cut some of the plastic back to allow more air to flow to the airbox....im wondering if this would of created a problem? though i cant see that being much different to an ram-air tray really?

i feel disappointed at the moment to be honest.

thanks
duncan

[CMSMJ1]

Messing with the std airbox is about the best way to introduce fuelling issues in the rev range.

Eiher leave it std or go crazy!

Have you got a lower tray to put the flap back?

Ram air and extra cool air are different things.

[powerbio]

its the tray that the airbox sits on and then heads towards the front of the bike and sits in the 'v' part of the frame,allowing a small gap just under the headstock.

ive cut this back about an inch...would that really make much differnece?? sorry to be dumb!

thanks

[CMSMJ1]

Yes - exactly that part. It does make a lot of difference.

I removed the one on mine and it seemed to hit a bit of a wall as would not pull so strongly through it.

Your bike wants still cold air to breathe - the flap will reduce turbulence I think and this is why removing it causes issues.

[powerbio]

havent the time to do it today, but on sunday im going to take the tank off and make a new plate up to re-create the original gap for the air...does anybody have a picture of the tray and gap?

many thanks
duncan

[powerbio]

hmm, just food for thought....on web page that has been wrote rick oliver, he states you can cut that piece of plastic away to increase air-flow...now it does say that along with a race/half exhaust system, an K&N airfilter and that mod that ive done, requires the carbs being done. but is the carbs needing to be done primarily due to the new exhaust sytem or because of the of the mod ive done aswell?

[tanuki]

ive shortened the exhaust by 3"..


its the tray that the airbox sits on and then heads towards the front of the bike and sits in the 'v' part of the frame,allowing a small gap just under the headstock.

ive cut this back about an inch...would that really make much differnece?? sorry to be dumb!

thanks

Both of these thing will make a huge diference to the fueling of the bike. A few people will advise that you now put washers under the needles and mess around with the jetting (this is the issue you now have) but the only advise I will give is take it to a decent dyno operator and get the carbs set up properly it the only way you will get the most from your bike and the best £150 you will ever spend...