I just got off of the phone with a guy at HMF. We spoke for several minutes about their Raptor pipe and although I didn't plan to buy one today, he was very helpful and seemed to be incredibly honest about their product.

The details:

Their headpipe is a stepped stainless steel design. It uses factory Yamaha doughnut gaskets and comes out of the head measuring 1.5" in diameter, then steps up to 1.75" before going into a handmade collector where it ends up being 2" after both pipes are merged. The silencer is 2.125" in diameter where it connects to the headpipe and goes into the muffler which is an aluminum, turn down end design.

His sound readings were 90dB at idle and 99dB at 1/2 throttle, measured 20" at a 45 degree angle from the tip.

Also, I was very straight forward when I asked why their dyno readings were not as high as the one shown by CT Racing. I was amazed to get such a straight answer back when he said, "I don't have a clever comment to give back to you on that one, we don't know." He went on to say that their dyno reading was taken by/at DynoJet when they used the HMF pipe to develope a jet kit for a piped Raptor. He said that he's had several conversations with the folks at DynoJet who have developed, designed jet kits and tested literally thosands of different engines and they don't have a credible answer as to why CT shows so much more power and how they can raise the peak RPM so much without a cam change.

During my conversation, I mentioned that CT does use a special pair of dyno tires when testing. He wasn't aware of this and said that just changing tire pressure can affect the dyno readings.

Anyway, from what I gathered on the phone, they seem like great people to do business with, I would just like to find out more about the reasons for the differences in HP readings. It seems strange that even DynoJet wouldn't know where the CT's extra HP is coming from (if it's real).

Oh well, just thought I'd share this with you all.

 

Bash,
That's great info and I appreciate your efforts! Hmf sounds like they have realistic knowledge and a fair amount of professionalism. Those qualities can be hard to come by, when speaking with some of these companies out there.

By chance, have you had any discussions with "Sparks Racing"? Their web-site doesn't show a graph, nor do they explain the amount and where their pipe exceeds. It seems as if they have done a considerable amount of testing on different products for the Raptor.

After speaking with other mfg, It seems almost to good to believe CT's graph. What do you think?

Again, great effort Bash. Look forward to further input from ya!

 

The HMF pipes comes in at 102db's at full throttle the only way they can bring that down is to put more packing in which in turn produces less hp. Also a spark arrester is sold seperately at $25. and the xtra packing is $30. and the anodized colors are an xtra $25-$30. Add it all up and the white bros and also the factory GYRT are excellent values. GYRT is loud also but comes w/ spark arr. and produces a very nice wallup>>>>>>