Crf 100 carb settings

I have a 2007 crf 100 as a mini moto and I'm struggling with my carb settings. Due to a leaky petcock and prob bad gas from storage for winter which I plan to fix.

Current setting
Stock main jet 98 3 notches out
38 pilot idle jet at 2 3/8 out
2 turns out on air fuel screw
1000 feet elevation

It's still not running right and everything is stock. It's actually increasing the throttle and idle speeds without me moving the throttle. I'm hopping some one has a good setting I can start from or recommend me to try different jets.

Thanks

 

Don't know how the 1000' of elevation will change things but at sea level a 40 pilot and 100 main worked well with the airbox for me.

What are you talking about notches out on the pilot and main jet?

 

my crf doesnt have a mixture screw. And Im positive there are no adjustments on the jets or exterior of mine. At sea level I run a 105 main. I run the needle in the middle position.

 

Check to see if you have an air leak at the manifold. Spay some carb cleaner on the manifold while it is running and see if the idle goes up. If it does then replace the gaskets. Rule of thumb is reduce the main jet by one point for every 1000 foot above sea level. Your 98 is prob pretty close.

 

Notches on the main jet And turns on the pilot. What do u currently have your set at?

 

Ok i think you're talking about the Needle, not the main jet.

Main Jet


Needle


Mine worked out in the center.

As for what you call the "Pilot", start at 2 turns out and follow the idle drop procedure in the manual and you'll get it pretty close.

 

If you are looking at your carb bowl (ie holding carb upside down), you'll see a flat head screw that isn't holding the bowl on. That's what I refer to as the mixture screw. It may actually be called the pilot screw, but I don't have a manual handy.

 

If your adjusting the main jet that is your problem! You change it not adjust it! Its not adjustable like a mixture screw.

If its revving on its own you may have a air leak some where near the carb like the boot.

 

only screw I have on the bottom is the float drain screw. No adjusting that unless you want to leak gas. My 80 and 70 have mixture screws... but the 100 is "jet it and forget it"

 

im thinking you have an 80 carb on your bike. They are pretty close in size but the 80 has the mixture screw.

 

The 100 has one also, its one the bottom of the carb , all the way forward.

 

My 2005 CRF100 had the stock carb on it and the 2005-2007 Honda service manual gives instructions on doing a idle drop procedure for tuning. The service manual gives those instructions for both the 80 and 100, which are both addressed in the same service manual. Yeah I know, who buys a factory service manual for a mini bike

You sure you don't have the wrong carb on yours?

 

See pic. This is a screen grab from a service manual. Mixture screw circled in red...

 

looked last night...mines epoxied over for some reason.

 

Weird. Did it come that way from the factory or are you not the first owner?

 

Im assuming the previous owner did it. They bought it new in 2008.

 

I think that's my problem. I dont have a screw where you circled. It looks like its plugged though. Does the screw go on top of where you circled because I don't have any grooves or anything where it looks like something is suppose to screw in.

 

2005 and up CRF100's DO NOT have a mixture screw.
Plugged at the factory.
We now re-join our regular scheduled broadcasting.

 

Hmmm, my 2005 was open. I can't say for certain the po didn't open it up but there were no scratches or scuffs to indicate it was opened up.

 

reference diagram page 5-12 of Honda OEM Service manual:
"After '05" (I don't have .jpg to share, sorry)

I couldn't tell if that included 2005 or they made the change in 2006.
So you might have confirmed that 2005 did in fact still have it.
I have a 2007 and definetly no pilot screw.
Should also mention that they changed the needle to only a single clip so there's no adjustment.