HMF engineering slip-on

Is it any good? It recomends you use a 160-170 main jet and like 2 or 3 turns out on air mixture( i think). What kind of performence increases does will it give me?

[Guy400]

The HMF recommends that jetting using the DynoJet jets. They use a unique numbering system which is higher than standard Keihin jets. Do a search on "HMF pipe" and you'll see what I've said about it in the past. Performance increases are great for low/mid and you gain some top end power but it begins to trail off. You can't beat it for the money.

This is the story I just bought the 400 from a friend of mine. He bought the pipe last year but never put it on. I wont be doing it for a few weeks yet no real big hurry wont be riding fro a while any ways.

What I am thinking about doing is putting the pipe on and getting it jetted correctly and cutting some holes in the air box lid if
I have to and maybe adding a K&N filter w/outerwear. HMF's site says to use 160-170 main jet. Is that Dyno jet or just a regular jet(from what Ive read I think the are differnt)? Also what about the needle clip and air screw? I dont know much about this sruff but have a buddy that knows how to do this. thanks for your guys help...



Stunz, I ve never ridden in Sanford. Is the a track there or you ride there or something? maybe we can get togther and ride sometime.

[Guy400]

HMF recommendations are for the DynoJet kit. We did this with my cousin's 400EX using the DynoJet kit. We used the 170 main, no air box lid, a K&N filter with pre-filter, the 3rd or 4th lowest clip setting and I think 2-1/2 turns out on the air screw. If you buy the DynoJet kit it'll have all the instructions you need.

[Live2Ride300]

Whats better HMF or Pro Circuit T-4??

Should I buy the Dyno jey kit? Is it worth the money? and i dont plan on removing my air box lid completely but will cut some holes in it and put some screens in the holes if it is worth.

Anyone else have any ideas for me?