Dyno run showed bike was too rich.

[TommyTheGun]

I took my nc30 to do a dyno run on Friday as ive been having problems with it running rich. It was running 115f 118r jets with pilots out 2 turns, standard air filter but aftermarket end can. It was confirmed by the dyno that it was far too rich, so we put in 112 jets all round which improved it, but the main problem was the mid range being far to rich still. Took the snorkel off the air box and it was a bit better again but still rich in the midrange. Sliders hole drilled to 2.5mm also but hasnt cured it. Rick O is sending me out some of his road needles to see if that sorts it. The bike is running well in low rpm and high rpm too, the last dyno it got 61hp, it just bogs down a bit in the midrange which is strange as usually these bikes are too lean in that part.

[CMSMJ1]

Where you based dude?

I see your other post about needles - you need to tune what you have as it does work and can be made to work.

are you at altitude?



*edit* > your note about the slider hole drilling not affecting it makes me wonder if you understand how the carbs work and so what you want to do to sort them? Drilling that hole larger is all about affecting the speed of response of the slider - it does feck all for the fuelling really and is not really a benefit to all bikes.

You want to lower your needles - so check how many washers you have.

[TommyTheGun]

No not at altitude. They are standard needles and only have the one 0.5mm washer under them. The guy at the dyno told me removing the washer probably wouldn't be enough to sort it and I would need longer ones.. Rick Oliver is sending me out some of his "road needles" to try. Im reasonably new to all this and only learning how exactly the carbs are working as I go.

[CMSMJ1]

cool, you have a plan at least :)

No bugger knew about carbs before they had to start messing with their NC!!

Can you scan the graph up?

[b1hrider]

I'm watching this with interest as I sound to have exactly the same problem. Tried RO road needles, tried removing washer, tried turning low end screw in, but still well rich on part throttle. Gonna raise floats 1mm to lower the carb fuel level tonight, as the only time it runs bang on is just as it's running out of juice. If I turn fuel off, once the carb level starts to drop it revs perfectly.

[TommyTheGun]

Didn't get a print out of the graph but saw it on the screen. I was hoping the needles would improve it being a bit longer. I will compare them against the standard when I get them to see if there is much difference. My mate found adjustable needles in his but doesn't know what make they are.
Float heights are all 6.8mm standard setting. If float heights were the problem though would it effect it across all the rpm range? If not then I would try it if no success with the needles.

[philfingers]

Basics- but is your air filter clean. I thought mine was, but the bike ran rich. Then I removed it and did a few 100 miles and fuel economy went from 43 to about 50mpg, ran much better too. Still a little rich. i used the 'K&N filter from the chrysler' mod
Just try removing the filter and giving it a run.

[TommyTheGun]

Airfilter was new in December genuine Honda one. We removed the snorkel on the Airbox which did help matters its running well top and low end, it just struggles midrange.
Whats the Chrysler mod?

[b1hrider]

My airfilter looks clean, but haven't tried it without it, worth a go i guess!

[CMSMJ1]

put the snorkel back on - have you got the rubber flaps too? They sit across the frame spar and you might imagine they would block the airflow..

a fully standard airbox setup is far easier to diagnose..