[JDracer]

Hey fellas!

I need to know what you guys are running for a 20 mm Keihn carb on an Ultra head set-up.

I've got this awful bog at mid rpm's.

Carb has 85 main with clip on needle at the highest setting.

Gets worse if clip set lower.

Pilot is perfect, starts first kick & no off idle hiccup.

I'm confused that if I install a better flowing head (than stock), that I would need to lean it out more???

I would expect it to need a bigger main.

I am up to my usuall last minutes mods before my race tonight.

Any help would be great!

JD

 

[manwhore]

85 main i am running a stock ported head with a 98 main and the clip in the middle

 

[JDracer]

Is it a 85 or 98 main?

 

[NoBars]

I'm running a stock ported head, s stage 88, pipe,

needle on bottom slot (all the way up) everyone told me to go to an 85, from my 92. cuts out at hi revs. 85 made it worse. go bigger. shop is closed otherwise i would have a 95, 98, 100 to play with.



guess that ported head flows a little more air!

 

[JDracer]

I ordered smaller & bigger mains to experiment with.

The weird thing is that, when the clip on the needle is set to the highest position (leaner) it runs better.

So I guess I will try to run a one smaller main (82?) & see what that does.

I will still be puzzled, because once I get passed the "burbs" it screams!

I was advised to check my timing also, it may be a tooth off.

We'll see...

Still, any help/advise would be great!

JD

 

[OLDSCHOOL]

Hey JD,

What are you running for a CAM, AIR FILTER and PIPE..? Will go from there........



OLDSCHOOL

 

[JDracer]

Ultra big pipe with Uni foam filter.

Turns out I may have been stuck with a racing cam in my Ultra head.

It was supposed to ship with a touring cam, but some "slipped" out of Kitaco to Classic with racing cams.

Shane @ Classic is pretty sure it may be a racing cam causing my probs.

Touring cam on the way, fingers crossed.

 

[p3racer]

it could be the float level is too low :?:

 

[JDracer]

Well, got the cam in.

What a huge difference!

I cannot believe anybody would even use the race cam.

It has no balls! It could not get out of the corners for sh--.

I'll admit, once you get out in a clearing and let the motor chug up to speed it screams!

Almost like a 2 smoker hitting the "pipe".

Maybe a clutch equipt fiddy could use one, but I have an auto clutch and need all the torque I can get.

I still have a small bog that I will try to work around by changing my gearing.

Currently run 13/30 sprockets, I will try 15/37.

Later!

JD

 

[OLDSCHOOL]

Im trying to figure out that bottom end BOG but can't till the weather gets better. I think what has to be done is get it to where your on the edge a little lean. My plug is perfect light brown and I still get that BOG even with my Inner Rotor Ign..... I'm building a new Power Plant now that I will pay attention to the power delivery. And carburation is a big part...







Later ...OLDSCHOOL

 

[JDracer]

I am curious if an 18mm (instead of my 20mm) carb would help?

I tried all kinds of carb settings (mains, pilots, clip positions) before the touring cam came in.

None of those changes made a difference with the bog.

Only a different cam helped.

JD