I can only relate to cars. To get an acurate dyno readout with a car, you always dyno in the gear that is direct 1 to 1 ratio. In other words, if your car has an overdrive ratio in 5th, you dyno in 4th (which is a 1 to 1 gear ratio)

Is it the same for motorcycles? ... Seems strange what my dealer said about there dyno: They say the Sportster does not have an overdrive transmission ... That's fine ... They say 5th gear is actually a 1 to 1 ratio [But] they say they always dyno the Sportys in 4th. That goes against what I understand it should be dyno'd in.

I asked the dealer if there DynoJet will indicate a different max RWHP if dyno'd in various different gears, and he said yes ...... So, what gear should the 5 speed Sporty be dyno'd in to get accurate numbers? ... Certainly dynoing in 4th will give a different max rwhp than dynoing in 5th (or 3rd for that matter).

Thanks,
Ron

Turbota

When I had my Sporty Dyno'd a couple of weeks ago I'm sure he ran up into 5th, when I glanced a the Speedo he was doing about 110-115 mph!! Don't think you can do that in 4th with a 883!!! :yikes

Mine was dyno'd in 5th

Mine was in 5th as well, where max power was produced.

thanks ...

I've heard you get the best dyno tune in 4th, but bigger hp #s in 5th. Another list I get went over this about a month a month or so ago, there was a reason, but I can't remember exactly what it is.

Interesting how some are getting 5th gear dyno runs and some are getting fourth. Many shops will dyno in whatever gear will max out at around 100 mph. First, because they don't want to turn their dyno much quicker than that and second because of the stress on the rear tire.

I think I have a copy of a dyno sheet somewhere that shows bike going through each gear to redline. I'll see if it is on my work computer and post it here tomorrow. But it'll show how much higher the hp readings are in fifth than fourth.

I'm still waiting for someone to tell me why putting your bike on a dyno is such a great idea....

Bragging rights? Fine tuning? WTF??

:confused: :confused: :confused: :confused: :confused:

Both I guess, but I used it to really fine tune it. You can tune every situation you could put the bike in and do it in a controlled climate. Much safer than doing a bunch of back road test and tune sessions. Plus if you use the dyno with eddie brake and air fuel meter correctly, you'd be surprised by how much better most can tune their rides than doing it by ear, feel, etc.

That's it?!?!?!?! REALLY!?!?!?!?

Bikes aren't ridden in a controllled climate...

Its kind of like audio engineers who use spectrum analyzers.....if your ears can't hear it, find another job.... lol

Test and tune SEEMS like a slower way to go, but a more true indicator of how your bike ACTS when YOU RIDE it.....

Call me old school.

No offense, just my opinion....Your opinions are always welcome, your are one of the more learned posters here, and I value your advice....I hope you appreciate my "civil dissention"

:)

Actually, when I used the words "controlled climate" I wasn't refering to riding around in a air conditioned room, but rather a safe place where you can subject the engine to many various load conditions and monitor air fuel ratio's without having to do it on some back road.

I've been tuning cars and bikes for more years than I care to admit and I can honestly tell you that I have found power on the dyno when I thought it didn't exist. And I did it all in a matter of minutes instead of hours or days of riding. FWIW, old school is always the best approach first (which is exactly what I always do), but you really should put it on a dyno and see how close old school got ya.

The dyno is a great tuning tool if used properly.

Great idea! But, I really do worry about having to sign a waiver....my bike runs so great, and I have little trust when I turn over control and sign away my engine....

Other than that, I can see it as a useful tuning and/or benchmarking tool. And I CERTAINLY understand the need for tuning that fine for any high-performance needs....

I guess I shouldn't give a crap about a dyno....at least for now..

Thanx!