Hawk 250 tuning

[Chris44050]

i just recently purchased my hawk 250 just had a few questions about jetting. I have put a k&n cone air filter on it right off the carb and I put an exhaust on it I changed the stock jet (88) to a 100 I did not change the pilot jet at night the pipe gets glowing red hot not sure if its because the exhaust is cheap or there is a problem .

What jets should I put in?

[Ariel Red Hunter]

i just recently purchased my hawk 250 just had a few questions about jetting. I have put a k&n cone air filter on it right off the carb and I put an exhaust on it I changed the stock jet (88) to a 100 I did not change the pilot jet at night the pipe gets glowing red hot not sure if its because the exhaust is cheap or there is a problem .

What jets should I put in?With the exhaust and intake mods you described, I would start with a 115 Mikuni main jet. It should screw right in, even though the thread pitch is slightly different. If this is a new Hawk, the carburetor they now use has a non replaceable pilot jet which is not easy (or cheap) to replace. Many people who have done the mods you have done change to a Mikuni carburetor because of its ease of tuning....ARH

[JerryHawk250]

I'm with ARH. Start with at least a 115 main. You are running way to lean.

[Chris44050]

I will try that later.. I was looking at other forums and they say that changing the main jet will only affect it at wot but others say they work toget her I bought a kit so I also have 115 120 125 and 130 jets.. I had the dremel the bolts on the carb to be able to take the bowl off to change the jet I also had to do the same with the idle air screw the only problem is you cant adjust the idle screw while the carb is on the bike because it is too close to the engine.

[JerryHawk250]

I will try that later.. I was looking at other forums and they say that changing the main jet will only affect it at wot but others say they work toget her I bought a kit so I also have 115 120 125 and 130 jets.. I had the dremel the bolts on the carb to be able to take the bowl off to change the jet I also had to do the same with the idle air screw the only problem is you cant adjust the idle screw while the carb is on the bike because it is too close to the engine.
Start with 1 1/2 turns out on the idle mixer. Mine was dead on at that setting. also shim the needle with a couple of small thin washers.

[Chris44050]

what needle do I shim and where do I put the shims, also do you have any advice on adjusting the idle screw while the carb is on the bike.

[pcspecialist]

https://www.youtube.com/watch?v=34yYWSolKc0

[pcspecialist]

btw, a nail and hammer is another way to remove the tamper screws, they tap out pretty easily.

[JerryHawk250]

what needle do I shim and where do I put the shims, also do you have any advice on adjusting the idle screw while the carb is on the bike.
Motocheez's YouTube is a good guide to go by. I never had to adjust the idle mixture while on the bike so i'm no help there. I just got lucky and got it right the 1st time. I used a drywall screw to remove the cap for the idle mixture screw. I just drilled the screw right into the cap and it popped right out. Here's a video I did after tuning.
https://www.youtube.com/watch?v=EzeiiRjdeis

[Megadan]

I think you may have misread or they poorly stamped your stock main jet. It should have been a 98. So by stepping up to a 100 you really didn't change much in the way of fueling.

As others have said, a 115 Mikuni jet is a good starting point for the main. I can't stress the Mikuni part of that enough, because there are Keihin jets that are almost identical to the Mikuni jets, but the numbers represent a much different fuel orifice in the jet. The Equivalent for a 115 Mikuni jet is a 130 Keihin jet.

As far as tuning the idle mixture screw on the bike. If you are willing to spend the money, this tool is perfect.... but not cheap. https://www.motionpro.com/product/08-0229

If you aren't willing to spend the money, then I have had luck with using a bit driver ratchet. They can be had for about 8 to 10 bucks and use any normal bit driver bits. The downside is that it can be very tedious doing it this way.