TheOz,

I think you made an excellent choice on the HMF, I always thought it was a pretty good pipe, then some dyno testing proved it. However, you might want to see if you can cencel the order on the #165 main jet - you already have one from the factory. You'll probably want to run the #170, but you might want to get the #175 just in case. If you buy more jets, buy only whole sizes, like 170, 175, 180 etc. I don't suggest bothing with a 172.5 unless you need to get your jetting down to a gnats ***, and most people don't.

When you start to work on the carburetor for the first time, (I'm assuming you've never pulled it off or replaced the jets) do yourself a favor and pull the carburetor off of the ATV. This will save you a lot of hassle and time. Then you can try and unscrew the bowl screws, if you are lucky - they'll come off. Otherwise, use a drill bit that is -very- close to 10mm and drill the head off of the screw taking care not to drill into the carburetor bowl itself. Even taking your time and never having done it before I'd bet you can get it pulled and re-installed in an hour or less depending on how mechanical you are.

The screws you'll need for the float bowl are (3) 4x10mm and (1) 4x12mm hex head stainless steel screws. Unfortunately I do not know the size of the screws on top of the carburetor, I believe they are 5 or 6mm x 10mm or so (you had better check though!)

Jdub260,

Your HMF looks SWEEEEEEEEEEEEEEEEEEET! Congratulations! I'm sure TheOz's HMF will look about the same as well.

 

you can buy a 180 but it is way to big for my quad with HMF. I run a 170, I might try my 172.5. The 175 is too heavy.
I'm at 700 ft. & I run a 45 pilot jet

 

Man...you guy's have got me wondering about my jetting now... I've got a WB slip on with open end, not discs. I've got a K/N, with lid on. The guy I picked my DS up from said it's jetted with a 200 Dynojet. I don't know what the needle is set at. I'm at 2548', and will get a serious burble if I go too much higher in elevation. Does anyone have any suggestions on what I might try for alittle more power, and to clear up the way it runs up to 4500'?
Justin

 

200 dynojet sounds high to me with those mods. But who knows.

I'd guess you'd be better with a 185 dynojet. check & set the needle at 4th or 5th from the top. See what happens.

 

Yup, you are too rich if the burble gets worse with increasing altitude.

 

Yup, I figured as much. I was told that going back to the stock needle, set at the 4th position from the top, and a regular 175 mikuni jet would be the best starting point. When setting the needle up, does 4th from the top mean the 4th position down from the top of the needle? I'm carb illiterate, so if someone could clarify this for me, I would appreciate it!!! Does anyone know what the dyno jet is that's equivalent to the 175 mikuni? I might just try that 1st, since I have a ride planned for Sunday, and won't have alot of time to mess with the needle until next week.
Thanks for the help.
Justin

 

yep 4th postion from the top being #1.

175 is like a 190 maybe. I think my 185 dynojet was like a 172 Mikuni.

 

Thanks for the needle info. I just went out to do the jets, and possibley the needle, and found the carb bowl screws have been destroyed. The guy I got it from tore the he!! out of them when he put it back together. Looks like I'll have to take the carb completely off, and deal with them...this sucks... I'm going to go pick up some 10mm allen head bolts tomorrow.

 

Personally, I don't think it is necessary to take the carb off to get those screws off. I used some small, needle-nose vice-grips on all six bolts (2 top-4 bottom) and they came off without too much of a problem. It might be a little easier to get the main jet out with the carb off (easier to see what you are doing) but it is doable without taking it off. Just my $.02.

 

Here you go guys, maybe this will help.