DYNO Numbers for Baggers???

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Oct 7, 2011 | 08:06 AM

#2841

grbrown

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Joined: Jun 2007

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From: Bedford UK

Quote:

Originally Posted by MNPGRider

My speedo/rpm chart shows an rpm of 4950 to achieve 120 mph.

That's closely in line with the numbers I gave above.

Quote:

My 75 T150 Triumph is only 60 hp, weighs 510 lbs if I remember correctly, and easily does 120 (red line is 7250). Cycle World tested it way back in the early 70's and top speed was 124, which was extremely fast at the time.

Velocette claimed their 1960s 34HP Venom would do 100mph. They are of course very slim compared with any of the other bikes we've mentioned! Their Thruxton model needed its extra 7HP to reach 108mph, so we shouldn't be surprised that our much more modern and obese bikes need a hell of a lot more power to go a little faster.

Oct 7, 2011 | 08:11 AM

#2842

harleytuner

Outstanding HDF Member

Joined: Mar 2009

Posts: 3,253

Likes: 222

From: Fredericksburg, Va.

Quote:

Originally Posted by coolerman69

Ok since i cant get my videos to load i'll ask this. My 88ci, stock headed bike will hit the rev limiter in 4th gear so how fast am i actually going? The gearing commander is working on it but its way too slow.

If you have all stock gearing etc, etc. In 4th gear at 6250 RPM's your theoretical speed would be 122.1 MPH. Red line in 5th gear would be 149.7 MPH assuming your bike could get to 6250 RPM's in top gear. Keep in mind that these numbers are NOT accounting for Cd, friction and all that other crap. In 5th gear your bike would hit 121 MPH at 5000 RPM's

Oct 7, 2011 | 08:13 AM

#2843

grbrown

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Joined: Jun 2007

Posts: 45,429

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From: Bedford UK

Quote:

Originally Posted by Heatwave

The newer 96's do have the advantage of being a 6sp versus the 88's that were 5sp.

In this debate having an extra gear is no advantage! Both TC engines are likely to give of their best at speed in 4th gear.

Quote:

If you have a desire to hit 120mph on a Harley, you're going to need a minimum of 100hp and probably abit more.

Back in the days when Evos were new an English Harley owner went to great lengths to tune his Glide to give 125HP at the rear wheel. It would just do 125mph flat out.

Oct 7, 2011 | 10:09 AM

#2844

muccimr

Cruiser

Joined: Jul 2010

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2010 Limited 103
BUB True Duals
Stage 1 Air
SE Super Tuner
SE 255 Cams

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Max Power 83.79 Torque 105.47

Oct 7, 2011 | 11:33 AM

#2845

Heatwave

Member

Joined: Jul 2009

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Quote:

Originally Posted by coolerman69

But where do the rpms stall in 5th gear? That will likely be the top speed of the bike.

Oct 7, 2011 | 11:35 AM

#2846

Heatwave

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Joined: Jul 2009

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Quote:

Originally Posted by harleytuner

Here we go again. Round 2 ding ding. LMFAO

Gotta love the video evidence. Hard to refute!

Oct 7, 2011 | 11:41 AM

#2847

Heatwave

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Quote:

Originally Posted by grbrown

In this debate having an extra gear is no advantage! Both TC engines are likely to give of their best at speed in 4th gear.

Not necessarily. If your engine can hit the revlimiter in both 4 & 5th gear. You will definitely be going faster at the revlimiter in 5th gear than you will in 4th. Once again, the math of the higher gear ratio will undoubtedly generate a higher speed for any given rpm, therefore if the motor can reach a higher rpm in 5th gear than it can in 4th, you'll absolutely be going faster.

Oct 7, 2011 | 12:17 PM

#2848

harleytuner

Outstanding HDF Member

Joined: Mar 2009

Posts: 3,253

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From: Fredericksburg, Va.

delete

Last edited by harleytuner; Oct 7, 2011 at 12:21 PM. Reason: repost

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Oct 7, 2011 | 12:20 PM

#2849

harleytuner

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Joined: Mar 2009

Posts: 3,253

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From: Fredericksburg, Va.

Quote:

Originally Posted by Heatwave

Gotta love the video evidence. Hard to refute!

That is video evidence for a bike with his HP. My arguement is that you don't nesisarily have to have 100HP to reach 120MPH. The video is proof that he can't acheive 120 MPH, but his HP is nowhere near 100

Oct 7, 2011 | 01:24 PM

#2850

Heatwave

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Quote:

Originally Posted by harleytuner

The video evidence is that an Ultra in mostly stock form with about 75 hp and a 5sp transmission can achieve about 104-105mph (GPS) when the engine is fully wound out. Given the exponential factor of air resistance, an Ultra will absolutely need at least another 25 hp and probably more like 30hp to generate another 15+ mph top end speed.

But then again Don Quixote thought he cold defeat a windmill with his lance, so I guess anything is possible in the mind of those that wish hard enough