Fatholley, Welcome.

The best way to determin if you need jetting is like this. The carb delivers fuel depending on the throttle position: 0 to about 1/8 throttle is controlled by the Pilot jet size, and fine tuned by the airscrews 1/4 to 3/4 throttle is controlled by the needle taper & length, fine tuned by the clip position 3/4 to WOT is controlled by the main jet size Once you know which circuit or circuits are rich or lean, you can begin to dial in the jetting. Anytime you make a change that effects either something going into or out of the motor, jetting is effected.

Best thing to do is if you really want to get fanatical about it is get yourself three sets of new plugs. First start the quad and let it idle and chop the throttle to 1/8th throttle for 10 minutes. kill it and pull the plugs when cool enough. You wont need to mess with your pilot jet more than likely. Adjust your air screw accordingly but generaly 2-2.5 turns out from being all the way in is usually just right.

You can do the same with 1/2 throttle and full throttle by running them a decent distance at those positions. Remember though, kill the motor at those RPM's, Dont let it go back to idle then kill it or you will get a false reading. Remember to pull in the clutch too when you kill it.

This is a bit or work but it pays off huge. When you hear stories of some guys with the same mods that others have but are alot faster, this is why. They have taken the time to tune the bike in 100%. When I had mine I spent an entire weekend doing this and gained 8 quad lengths over my brothers Raptor. Thats how you put "magic" into your carb!

I must give props to BansheeHQ.c0m for the best describes write up on how to properly jet. I have always done this but didn't have the best explination.

 

I just spoke to Randall and he said to try a 200 main with the needle in the 5th position. Does anone know where to get real Mikuni jets in the San Diego area.

 

a 200 with needle in the fifth?? WOW

 

Well if your running a stock carb I would say as Randall said. If you are running a TM45 then I'd run a 162.5 based on your elevation.

 

ILivSD, My friends are going to Glamis Oct 7-10. I'm sure they'll be camping at roadrunner. I'll probably wait until the next trip before I head out there. I'd like to try Ocotillo one of these days, but not right now. Let me know when your next trip will be.

 

The purpose of a Race ported intake is to accelerate the air into the cumbustion chamber right? Well if thier is faster air through the carb then it will pull more fuel. So if anything you may have to jet down.

Check out the thread by oldmanracing about the stock carb settings, all of your questions will be anwsered, But you WILL have to do your own testing. All these suggestions are just best Guesses. If you take a WHOLE day and play with your carb settings, you will find improvements.





Bigger.

 

04DS650,

Next trip ... will do.

I think we will be up for a Dunes trip after Ocotillo Wells.

I'll drop you a line then this will give me some time to get my Carb jetting set up better.

See ya.

 

Is there that big of a difference with the ported intake?

 

A 200 Mikuni main should work good with no air box and snorkel in place.