Bob is the creator of the "Magnaceptor" a Honda Magna with an Interceptor motor. He recently had it professionally tuned, and wrote this report:
I can't believe I rode 750 miles to have a bike dyno'd.
My reasoning was - it's a Honda dealer and they have a Factory Pro dyno which is supposedly very precise. In the end - it was a long, hard ride, 250+ miles of hard, windy thunderstorm rain (and hail), but worth it! The T bar and forward peg ape position is more comfortable than stock, but after 6 continuous hours of riding leaves the wrists and legs begging for redemption or even a mere shred of mercy. I'm still hurting.
Back to the dyno. Initial runs showed about 73hp and 44ft lbs. I had two cylinders lean (one extremely so) and the other two close. The horsepower curve was sad. It climbed, peaked out, then sloped down past 10,000. The typical VFR will climb past 12,000 on its way to 100hp. Not too bad for a blind tune.
The bike would run on the dyno at idle in 6th gear, and would pull, but given time the motor would have burnt up from being too lean.
It took the guys 6 hours, yes, 6 long hours to tune this mother bumper. Turns out a previous owner of the donor VFR had installed a dyno jet kit. The dyno jet kit required drilling carb components, thus making it a permanent fixture, or at least one would think.
At some time this kit was replaced with original parts - rendering the carbs ineffective until a dyno jet kit was reinstalled. At this time I would like to point out that the person who replaced those parts is a son of a bitch. The bike ran, but didn't perform well, and didn't respond correctly to tuning.
The mechanics cracked open the carbs, noticed it had been drilled, and figured this out. Luckily on their clearance rack, marked way down to cost was....one lone dyno jet jet kit for the vf750c 1994-2003 magna. Granted, this is VFR interceptor equipment, but we all know it's basically the same stuff. They used it, and it worked (thank god). In the end the whole process was $250 more expensive because of this.
After 5 hours of dyno jet drama and fiddling, the afternoon heat had set in. The temperature in the dyno room (combined with heat from tuning the bike) was nearing 100 degrees. Relative humidity was super high due to thunderstorms in the area. Under these conditions the final dyno runs were numeric failures. I don't have reliable power numbers, but I do have reliable power graphs. The graphs show increasing horsepower throughout the entire rpm range, and a torque peak right in the middle.
Where horsepower used to drop off it slopes upward. The tuner estimated that it might dyno very close to, or even over 90hp under better conditions. The best it would do Tuesday was 3hp over what I brought in - a paltry 78. Stock horsepower on the magna is....78. This was my first dyno experience, and I was very displeased to leave with such poor numbers. I had mixed feelings though because the motor sounded very strong both on the dyno and on the street when the mechanic test rode it.
The weather didn't cooperate, but they did dial the bike in. I didn't lay into it much on the return trip because of rain, and fatigue - and I didn't want the bike to explode (the dyno is a pretty rough place). I noticed a substantial decrease in fuel economy - low 30's on the first few tanks afterward, which was annoying.
On the way home from work today I gave it a test. The bike tells a different story. It pulls and Pulls and PULLS!! It's a riot in the high rpm range. I mean, it's not slow on acceleration down low, but it hits 9,000ish and wakes up in a way that lifts the front end (not in a wheelie) if you don't miss second gear! It IS really strong - stronger than I've ever experienced!
So I'm excited - plus, barring mathematical error, this last tank netted 37mpg.
Sometime this fall, on a cooler day, I'll take it in for a dyno run and share some numbers. Until then...it's a certifiable sleeper. Go ahead...take it for a ride!
I can't believe I rode 750 miles to have a bike dyno'd.
My reasoning was - it's a Honda dealer and they have a Factory Pro dyno which is supposedly very precise. In the end - it was a long, hard ride, 250+ miles of hard, windy thunderstorm rain (and hail), but worth it! The T bar and forward peg ape position is more comfortable than stock, but after 6 continuous hours of riding leaves the wrists and legs begging for redemption or even a mere shred of mercy. I'm still hurting.
Back to the dyno. Initial runs showed about 73hp and 44ft lbs. I had two cylinders lean (one extremely so) and the other two close. The horsepower curve was sad. It climbed, peaked out, then sloped down past 10,000. The typical VFR will climb past 12,000 on its way to 100hp. Not too bad for a blind tune.
The bike would run on the dyno at idle in 6th gear, and would pull, but given time the motor would have burnt up from being too lean.
It took the guys 6 hours, yes, 6 long hours to tune this mother bumper. Turns out a previous owner of the donor VFR had installed a dyno jet kit. The dyno jet kit required drilling carb components, thus making it a permanent fixture, or at least one would think.
At some time this kit was replaced with original parts - rendering the carbs ineffective until a dyno jet kit was reinstalled. At this time I would like to point out that the person who replaced those parts is a son of a bitch. The bike ran, but didn't perform well, and didn't respond correctly to tuning.
The mechanics cracked open the carbs, noticed it had been drilled, and figured this out. Luckily on their clearance rack, marked way down to cost was....one lone dyno jet jet kit for the vf750c 1994-2003 magna. Granted, this is VFR interceptor equipment, but we all know it's basically the same stuff. They used it, and it worked (thank god). In the end the whole process was $250 more expensive because of this.
After 5 hours of dyno jet drama and fiddling, the afternoon heat had set in. The temperature in the dyno room (combined with heat from tuning the bike) was nearing 100 degrees. Relative humidity was super high due to thunderstorms in the area. Under these conditions the final dyno runs were numeric failures. I don't have reliable power numbers, but I do have reliable power graphs. The graphs show increasing horsepower throughout the entire rpm range, and a torque peak right in the middle.
Where horsepower used to drop off it slopes upward. The tuner estimated that it might dyno very close to, or even over 90hp under better conditions. The best it would do Tuesday was 3hp over what I brought in - a paltry 78. Stock horsepower on the magna is....78. This was my first dyno experience, and I was very displeased to leave with such poor numbers. I had mixed feelings though because the motor sounded very strong both on the dyno and on the street when the mechanic test rode it.
The weather didn't cooperate, but they did dial the bike in. I didn't lay into it much on the return trip because of rain, and fatigue - and I didn't want the bike to explode (the dyno is a pretty rough place). I noticed a substantial decrease in fuel economy - low 30's on the first few tanks afterward, which was annoying.
On the way home from work today I gave it a test. The bike tells a different story. It pulls and Pulls and PULLS!! It's a riot in the high rpm range. I mean, it's not slow on acceleration down low, but it hits 9,000ish and wakes up in a way that lifts the front end (not in a wheelie) if you don't miss second gear! It IS really strong - stronger than I've ever experienced!
So I'm excited - plus, barring mathematical error, this last tank netted 37mpg.
Sometime this fall, on a cooler day, I'll take it in for a dyno run and share some numbers. Until then...it's a certifiable sleeper. Go ahead...take it for a ride!
| About The Author | |
|---|---|
| Bob has been riding, fixing, and modifying motorcycles since his youth. His latest project "The Magnaceptor"... which has the body of a 1996 Honda Magna and the engine from a VFR Interceptor. |  |
More about the Magnaceptor...
No comments:
Post a Comment