Guys,
I thought I saw a sig or two listing a HMF pipe as one of the mods on a Raptor. If so, how do you guys like the HMF?
I saw they now make a slip-on for the DS. The price isn't too bad. Just wondering what your opinions were ?
How was the power output? What about fit & finish ?
What is the noise like?
Thanks,

 

yeah i would like to know also

 

I have the full system on my Raptor. It is definately much stronger than stock in the low and midrange but upon furthar investigation ( drag racing some 2002 stock Craptors) it seems to lack soem top end. I didn't lose any but didn't gain a lot. I have heard it is a good pipe for the DS650. Sounds killer too!



Wait a second... this is one heck of an old post!

 

I myself don't have an HMF, but I know alot of guys on Raptors with the HMF tips and they love them. Not to mention their fairly cheap $. So yes I would reccomend them[img]i/expressions/face-icon-small-cool.gif[/img]

 

I like the HMF, fit was superb, manufacture quality good also. Power gain was strongest on the bottom to mid with the stock airfilter. Excellent power gains on top once the airbox lid was biffed and a proflow added and the jetting dailed in. KILLER sound........ all my riding buddies comment on the grunty 4 stroke bark, but it is loud...........

Gearing on the 2002 seems to help alot in drag races, a 2002 with pipe etc will be really quick off the line...........

kiwi

 

Xplor,
I thought the same thing... old post!
I bought the HMF. It is great for a DS because of the DS's lack of low end power. Sometimes I think I lost top end, but it seems that way I think because of the flatter power curve. Now I can yank the wheels into 3rd gear with my DS. It is kinda loud, but the sound is big & deep. People say it's Harley like. Not that loud though....

 

Kiwi, I tried her out without the lid last weekend and did gain a lot of top end. Being scared to run lean... I was considering removing the lid and going up a notch on the main jets but then I read somewhere that I would need to go up on the pilot jets too. Right now I am running a DynoJet kit with 146/148 mains. Would just going to 148/150 and keeping the same pilots and needle configuration be enough?

I want more top end but really hate fiddling around with needle jets and pilot jets.

Thanks!

 

where is the best place to purchase the dyno jet kit? ihave a uni air filter and a trimmed snorkel would i be better off getting the k and n jet kit? if so which stage? thanks for the help.

 

I found the jetting to be a real pain, when we dyno'd it the needles where one notch lean and the top end to rich, what we found was that the dyno jet instructions where spot on. I'd leaned the needles one notch trying to clean up the midrange, all this did was kill the torque, what was wrong was that i'd over jetted the mains, they have as strong infulence down as low as 1/2 throttle it would appear. The dyno jet needles flow more fuel too so don't over do it. Mine runs strong with the stock idle jets at about 2 1/2 to 2 3/4 turns, we found these to be very touchy, the "recommended' 3 turns out was to rich...........

Flipside a friend of mine has gone up one size on the pilots and reported a noticeable boost inlow end ?? He runs a sparks pipe , proflow and no lid.

If you are worried then get it to a dyno, it's really worth the effort.

I can run with the lid on in muddy conditions ok, the throttle response isn't as good and the top end flattens off due to the lack of airflow, lid off it breathes so much better but I don't think you need to up the jets, it just getting more airfuel so it revs higher ????

have you got a small K&N on the crankcase breather hose since your running with the lid off.

Kiwi

 

Bad660,

The K&N jet kit and Dyno jet kit are one and the same. Rockymountain ATV, Parts direct.com. These are two good places to buy online or you can get the kit from dynojet.com for 83 bucks. parts direct has them for 65 bucks. Rockymountainatv.com has them for 59 bucks.