Build down on power-ideas? : V-Twin Forum: Harley Davidson Forums

aharp · 09-12-2009, 06:33 AM

Ok fellow tuners and dyno operators, here it goes....
I have a 95" with heads, cams, blah blah blah, i was tuning it on the dyno and got it up to 111/110, respectable for a 95 daily rider I think. So due to time constraints I was not able to finish tuning that day. I came back a few days later on my day off to finish squeezing the last few horse out and now it won't break 106/106. The motor developed a noise and turned out to have a rod out of it. New crank and pistons later (with a tiny bump in compression) and this thing still won't get north of 106/106. Ccp and leakdown don't seem to reveal anything and run conditions are very close to when it was making 111/110. I've heard they run the best just before they blow but I'm outta ideas

ryanl · 09-12-2009, 09:29 AM

FWIW, I think 106/106 is still very respectable for a 95" daily rider.

oh1deuce · 09-12-2009, 10:54 AM

If it starts, runs, doesn't ping or overheat......

Ride it!

**baggersport** · 09-12-2009, 12:26 PM

Roll another motorcycle on the dyno....something you tuned a few months ago....what'ya get? Does it match the numbers from the original tune?

.

BVBOB · 09-13-2009, 09:43 AM

Your looking at basically what amounts to around 5% difference, many variables could cause this, tire pressure, location of rear wheel to drum center, how the bike was tied down both times and possibly (and most likely) the difference in air was enough to change the final outcome. Very seldom see bikes stay consistent when dyno'd on different days, even if the weather stays close, 5% is really not that much. Consider that the barometric pressure is just a tad different from one day to the next, this will actually change the way the map sensor reads data and will change the timing curve a tad bit and change the final numbers of what is basically nothing more than a wot run to redline anyway. It sucks when you see the great numbers once but cant get them again.

aharp · 09-13-2009, 12:36 PM

It sure does bob. Thanks for the input all. I was just curious as to what others that use dynos have seen. Since nothing has changed and the bike runs great I see no reason to tear into it especially since this will only be together for a few seasons before the next build. I've certainly seen a few horse difference from best max numbers but 5-6 just caught me as being a little goofy.

claydbal · 09-13-2009, 02:19 PM

not to worry. man , my dyno is lazy, my 95 showed around 96 hp, and a 250I showed 109!

forgive the hi-jack, but looks like bvbob has a new puppy!!!!!!!!!!!!

aharp · 09-13-2009, 04:23 PM

Damn puppies, they're SO easy to get attached to. Don't know what I'd do without mine. Is it the shepherd under your name Bob?