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View Full Version : jetting for HMF slip on + K & N Filter?



nakedfrijoles
10-05-2007, 09:57 PM
What is the best jetting option for this setup? If anyone would be willing to share their setup or have any advice i would appreciate it:D

matt1106
10-05-2007, 10:19 PM
You should put the filter and slip-on on ur quad first and see how it runs, because i put a white bros slip-on on and a K&N filter, and mine runs great. And i never touched the jetting. The guys at my local shop told me that if i didnt re-jet my quad it would run like crap, and I couldnt even notice a differance how it ran at all, it was just a lot faster. But that just may be my conditions, too, but you never kno its worth a try. you mite be able to save yourself some work

nakedfrijoles
10-05-2007, 10:34 PM
ok thanks ill give it a shot

oleboy87
10-05-2007, 10:39 PM
well i have the hmf slip on with a k&n filter and an open air box im running a 170 jet in mine... runs great!

matt1106
10-05-2007, 10:45 PM
if you do try just the filter and the pipe, keep the lid on, if you take it off, it will definatly run lean.

oleboy87
10-06-2007, 06:45 AM
i called hmf when i installed the pipe and asked for the jetting specs for my set up and he said put a 170 with an open box and he was right.. its dead on!

WFO400
10-06-2007, 10:09 AM
I have an HMF with a uni. I just went one size bigger on the main to a 155 I believe it was (it's been a while). It runs great and I didn't touch any other jets. It didn't run bad at all with the stock specs, but it's definitely better with a bigger main.

Pipeless416
10-06-2007, 11:07 AM
im running an hmf s/p with a k&n without a lid. im running a 160k main, 42 pilot, needle is one clip lower than stock, and the air/fuel screw is 2-1/2 turns out.

hornetgod13
10-06-2007, 01:49 PM
I'm running a 155K in the summer and 158K main in the winter and the plug check is paper bag tan. I have a HMF Slip on, UNI filter and EHS Racing lid. A 170 sounds rich. Are you running Keihin or DynoJet jets?

Wheelie
10-06-2007, 01:57 PM
I agree, 170 sounds rich. A 155-160 is about right with a slip on, filter and no lid. Most pipe manufacturers recommend jetting on the rich side.

400exrapes
10-06-2007, 04:40 PM
well i have a stock filter with lid on and i run a 150 main and 40 pilot, runs perfect in about high 80's and low to mid 90's never tried it in the snow but im pretty sure its perfect, im about 400 feet about sea level. My guess is that you will be anywhere between a 150-155 main and a 40-42 pilot will both work for you. thats depending on your elevation and temperature as ive learned from members of this great site.

tanner 222
10-06-2007, 06:53 PM
i got the same pipe and filter and i run 165 main and 42 jet and i noticed a huge difference in power so im guessing its good. i can also run it either with the lid on or without.

nakedfrijoles
10-06-2007, 08:40 PM
THANKS guys for the help...i live at about 700 ft above sea level..all i know is that i am running the main that came with my hmf slip on.. i cant remember what it was...but other than that i didnt change anything

oleboy87
10-06-2007, 10:21 PM
well im right at sea level and the main that comes with the hmf is a 165. but im running an open air box soo hmf specs calls for a 170 and im running dyno jets...

hornetgod13
10-07-2007, 10:54 AM
Originally posted by oleboy87
hmf specs calls for a 170 and im running dyno jets...

Dynojet, that explains it. You didn't mention that in your other post. I assume stock keihin jets unless otherwise mentioned.

oleboy87
10-07-2007, 11:01 AM
sorry for the confusion... i didnt know between the two diff kinds of jets that there was that much difference

hornetgod13
10-07-2007, 11:58 AM
Originally posted by oleboy87
sorry for the confusion... i didnt know between the two diff kinds of jets that there was that much difference

Dynojet and Keihin jet sizes (numbers) are completely different.