Help me get my Air/Fuel mixture right! PLEASE!

[vfrman]

So today I took my track bike into PJ's Motorcycles to get a baseline done on the dyno. I am running very rich, and I have that nasty dip at 5k.

I'm running 118 front 120 rear on the mains, 35 pilot all around, 4 hole emulsion tubes front and 5 hole rear, stock airbox with K&N element, and an aftermarket exhaust. I also looked at the needles and I'm running something aftermarket. It is the gold one in pic set at the third position. I also have a set of the silver needles in the pic, but I'm thinking that with the bike running as rich as it is, maybe I don't want to put those in just yet. I'd like to get the fueling spot on, then later on put the HRC setup in from Rick O and see what difference it makes.

Anyways, on to the pics of the needles and dyno sheets...








Also, WTF is happening at the top end of the rev range?

[johnnie5]

i reckon you have a issue with missfiring at the high RPM

bad plugs or something else

[vfrman]

Those plugs are pretty new...but with it running that rich they are probably fouled.

[krisztian_andre]

Does it burn oil, what was the altitude, temperature and humidity, do you have a strong spark, were the carbs cleaned, float levels set and float needle valves checked?

Other than that it's probably a good idea to get a set of road needles from rick and start with those and standard sized jets.

I forgot the pilot screw check.

[magg]

IMHO a needle change would not make much difference, the top end mixture is a main jet function. Restrictive air filter will cause over-rich mixture that could be significant at the top end of the rpm range, are K&N filters as good as OEM (you can get OEM filters from PowerSportsPlus, bought two last week). May be remove the K&N filter and see if the mixture become leaner, might still not be perfect but could head you in the right direction.

[hunter]

IMHO a needle change would not make much difference, the top end mixture is a main jet function. Restrictive air filter will cause over-rich mixture that could be significant at the top end of the rpm range, are K&N filters as good as OEM (you can get OEM filters from PowerSportsPlus, bought two last week). May be remove the K&N filter and see if the mixture become leaner, might still not be perfect but could head you in the right direction.

[Yakama]

Those needles look like factory pro ones

[vfrman]

Does it burn oil, what was the altitude, temperature and humidity, do you have a strong spark, were the carbs cleaned, float levels set and float needle valves checked?

Other than that it's probably a good idea to get a set of road needles from rick and start with those and standard sized jets.

I forgot the pilot screw check.

Doesn't burn oil, altitude is 5300 feet ASL, temp was 71 F (21.6 C), 13% humidity. Spark should be strong, but with the bike running that rich, the plugs may be F-ed. Carbs were clean, floats were a touch high...maybe 7-8mm instead of 6.8mm, float needles were good, and pilot screws set properly.

I know this doesn't do anything for fuel metering, but I think the hole in the slides is still std. What diameter do we drill those out to again?

[Morespeedvicar]

I'd try n put it back to standard jetting and see what happens, i wouldnt of thought the filter would make it go rich.
Cheers
Ian

[vfrman]

It IS set to standard jetting!