Well I picked up my bike from HMF, they installed my pipe and dyno tuned it. Scans of the dyno runs are below, let me know what you think and if they are good numbers. The torque curve looks crazy!

HP SCAN
TORQUE SCAN

-Josh

 

Thats a great pickup of torque, especialy for a slip on and jetting. I assume you are running the stock air box with the lid on? Did the HMF have a spark arrestor or noise reducer in at the time of dyno?

This is great if you are a trail rider, low rpm type of ridding. Not great if you are a drag racer or hill shooter who likes to be up in the red line.

 

Yes it was with everything else stock, except for a no toil air filter. No sparky or quiet core installed.

I ride mainly trails and sometimes head up to Silver Lake so hopefully I will like where the power comes in. I rode it around my yard for a half hour and the one thing I hated about the DS has been resolved. With the stock pipe I had to work pretty hard to get the front end up and if I blipped the throttle barely rolling it would stumble, now a slight blip and the tires are skyward very easily. I notice it also runs out of revs fairly quickly, where does the stock rev limiter kick in? Looking at the numbers I should be shifting alot sooner because it don't make any power after 650

 

I have had my HMF slip on for 7 months and really like it. I live in Florida and mostly trail ride, and it does have noticable power to it. The only thing that I don't like about it is that my pipe is already ready for a rebuild. Thats a little to soon to be repacking a pipe in my opinion.

 

Those are pretty realistic runs. I'm guessing that they dyno'ed on knobby tires, thus the power is down about 6hp and the torque curve does it's little crazy thing because the knobbies slipped big time at peak torque (peak torque is where the power and torque will be the most inaccurate when dynoing on knobbies), which would have been at 35mph if the tires hadn't broke loose.
If, by chance, that was on hoosier or amer racer tires, then jetting is way way off to make that kind of curve.
You'll love the bottom end and mid range of the HMF.
222

 

Thanks for the explanation, it was dyno'd with 22" Razr2 knobbies. So your saying with slicks I would be around 46 hp?

-Josh

 

As far as I know I bought the first HMF on this forum. I bought my first one way back. Great pipe, great bargain.

 

It was a bargain, since I am only 40 minutes away I paid $250 cash for the pipe, black powdercoat, quiet core, install and dyno-tune. Dropped it off at 7:30 in the AM and picked it up at 5pm the same day. Great guys up there.

 

I have a DG slip on, It works good butt i wanted a full system so big gun is making a full exhaust for the ds, I orded it about a week a go. I had HMF pipe on my vforce and they worked well.

 

I will give you some input about me average findings on DS dyno output.

I looked for a bike that had similar mods to yours. This DS was a Baja-X with Yoshi slip-on, dynojet kit and bigger intakes to the airbox. Airbox lid was on and the ATV had maxxis 22” razr 2's on the rear while it was doing the run.

My dyno is at 5000 ft above sea level and the run was done on a very hot summers day. Power output on a colder day and at sea level should be higher than the numbers I list. Dyno tyres should also show more output power, but since it is the same tyres as what you had on, we can compare the output power.

I will start with HP. I will start with RPM, followed by my average HP numbers.

2500 RPM, 16.
3000 RPM, 20.
3500 RPM, 24.
4000 RPM, 29.
4500 RPM, 32.
5000 RPM, 36.
5500 RPM, 39.
6000 RPM, 41.
6500 RPM, 41.
7000 RPM, 40.

Torque. I will start with RPM, followed by my average Torque numbers.

2500 RPM, 32.
3000 RPM, 34.
3500 RPM, 34.
4000 RPM, 36.
4500 RPM, 37.
5000 RPM, 39.
5500 RPM, 37.
6000 RPM, 36.
6500 RPM, 33.
7000 RPM, 30.

Your bikes low down power is good, but it is running out of steam at the top end. It seems to have a breathing or fuel supply problem at the top RPM's. Try running without the stock intake tubes to the airbox. Remove the fittings that hold the air intake tubes to the airbox. If you can, try and find bigger pipes that will fit the holes in the airbox and run them instead of the stock hoses. The pipe thickness must be very thin. I found a plastic tube that is very thin, about 1mm thick. It has a metal coil like a spring inside it to hold the shape of the pipe. They work great and give you nearly double the intake flow to the airbox.

Running a slightly lean main jet can also cause top RPM power loss, but I assume they have jetted it right.

I hate it when the guys post speed instead of RPM. What the hell is speed going to tell you since there are no air resistance on a dyno? Please ask them to post the Power and the RPM on the same dyno. If they can, also try and find out what the Air/Fuel ration was across the RPM range. If they know their stuff, they should try and get it around 13:1 across the RPM range.