Dynoed the Vmax today

[Constantinos]

Completely stock no mods whatsoever. 100 hp even on the rear wheel. Vboost kicked in at 5300 rpms. The expression on the guy's face (who was running the test) was priceless. Just when he was expecting it to even out at 85 hp then wooooshhhhh...He aborted the test the first time because he thought that something was wrong :rofl_200:. Anyways how do these numbers sound? Seems ok to me for the old #105.

 

[jfeagins]

Low.

Completely stock OEM 85 here, and I still turn 115hp. My bike has around 32K miles on the odometer.

 

[m-cman]

Wonder if it is one of those European market bikes with 100 hp limit?

 

[Constantinos]

Nope...US bike with vboost. I do not trust the equipment to be quite accurate as on both occasions the wheel spinned freely when the vboost kicked in so no contact with the roller...could that have affected hp report?

 

[Tex85]

Nope...US bike with vboost. I do not trust the equipment to be quite accurate as on both occasions the wheel spinned freely when the vboost kicked in so no contact with the roller...could that have affected hp report?

Yes, since the speed that roller turns is how it measures HP. You are pushing more to the rear than it states, you will need to try it on better equipment if you want a proper reading.

Sent from my Nexus 5 using Tapatalk

 

[Itgoes]

If the tire spins the reading is not accurate. Tie down straps should be used from the passenger pegs to the dyno to keep that from happening.

 

[jfeagins]

Nope...US bike with vboost. I do not trust the equipment to be quite accurate as on both occasions the wheel spinned freely when the vboost kicked in so no contact with the roller...could that have affected hp report?

If the tire spins the reading is not accurate. Tie down straps should be used from the passenger pegs to the dyno to keep that from happening.

Yes, that would for sure affect the dyno outcome. Hard to believe that dyno operator didn't recognise, and correct, the problem. Can you get a freebee do-over?

 

[Biker Dash]

If the tire spins the reading is not accurate. Tie down straps should be used from the passenger pegs to the dyno to keep that from happening.

Thats how I've seen it done at the two shops I've seen that do dyno runs here in Maine.

 

[Constantinos]

If the tire spins the reading is not accurate. Tie down straps should be used from the passenger pegs to the dyno to keep that from happening.

No down straps on the passenger pegs. Actually he used no down straps anywhere on the rear of the bike. Hey it was free to begin with but inaccurate to say the least...

 

[one2dmax]

You should not need straps but it is common for the tire to spin a few times until the rubber warms up and grips the roller. IF the bike was making big HP or an older smaller dyno drum then you can strap if needed. You want back to back pulls until the HP quits climbing. This can take 7-10 pulls.

 

[Rusty McNeil]

I'd want a strap period to keep it stabilized and from "getting away" from the dyno operator.

 

[Biker Dash]

I'd want a strap period to keep it stabilized and from "getting away" from the dyno operator.

When done properly, that bike aint goin ANYWHERE

 

[one2dmax]

Exactly. The front locks it in. Only a catastrophic machine failure is going to make it come loose and even then a pair of straps isn't going to save it.

 

[Rusty McNeil]

When done properly, that bike aint goin ANYWHERE

Yes, I speak from ignorance on this subject no doubt. Not being sarcastic either.

I realize fully the front wheel doesn't go anywhere, and can't. That the front wheel is locked in a taking the full force things. Failure up there is not what I meant by "getting away"

But if no strap is on the back what keeps it from drifting left to right?

Of course while I'm typing this I realize that it would be no different than all the burn outs I've done and controlling side to side movement was not difficult at all while performing a burnout.

But it was not something that could be totally ignored either.

 

[Constantinos]

Well from what I could see yesterday we had 2 pulls. Aborted the first one because the rear wheel was spinning freely on the roller. The second one, exactly the same story but got the reading. If there were rear straps attached things would have been different.

 

[Rusty McNeil]

Well from what I could see yesterday we had 2 pulls. Aborted the first one because the rear wheel was spinning freely on the roller. The second one, exactly the same story but got the reading. If there were rear straps attached things would have been different.

The 184 page dynojet manual clearly states it should be strapped down. Says the straps should not put extra weight on the rear, but then goes on to say that the operator should sit on the bike and pull additional tension on the straps, so kind of conflicts itself.

 

[one2dmax]

The bike will find center as you do the pull so it should not walk side to side.

The operator needed to repeat the pulls and let the tire heat up. The combustion chamber will also heat up and make more power. I bet he left you 10hp not on paper.

 

[Biker Dash]

The bike will find center as you do the pull so it should not walk side to side.

The operator needed to repeat the pulls and let the tire heat up. The combustion chamber will also heat up and make more power. I bet he left you 10hp not on paper.

The tire not being heated, could that be another reason the tire would slip when the V-boost kicks in?

 

[one2dmax]

Yes, it could be. Also make sure you're air pressure is good. The older a tire is and the more worn it is the less traction it will give.

 

[CaptainKyle]

When I was taught to use the dyno we were always drilled to check air pressure and to sit on the bike and grab the rear straps and pull them secure