Graphs look nice and smooth and a good shape. What lift were your heads done to? You have a good torque number because you have a 45 inlet close with 10.5 comp. Most folk these days seem keen to break the compression gauge...... That bike as shown above in that graph needs more fuel at WOT. If you are happy with the way it runs, thats the main thing.

lushy, i will find out about the heads and get back to you, what size tb would you recommend

Lushy , i know with EFI can get away with large air intake as electric fuel pump.

But the motor can only use so much air, so giving it more than it can use, you might get few more horses but would expect TQ a bit lower at cost of HP.

If you think otherwise you would have lot of experience tuning, just i would love to see a Timed dyno Graph to show how quick it made power & torque over a smaller TB. I like to check how long they take as well as at what rev.

:-) The engine will only take what it can use. If the throttle body is a bit too big it will just make the same power at say 90% throttle as it does at 100. A throttle body is an air valve, it has absolutely nothing to do with fuel delivery, not like a carbg which needs air speed to pull the fuel out the jets.. A Yam 250 MX bike ( yes 250cc ) has a 44mm throttle body, they run fine. An R6 Yam 600 has FOUR 40mm Throttle bodies, they run well to. Etc etc. You can't really give it more than it wants, the motor will take what it needs. I have yet to tune a Harley with a throttle body too big. When I first saw the 103 stg 4's with a 58 I jumped for joy, at last a decent fucking throttle body. Just done a stg 4 sporty and they run awesome with the 58, smooooth all the way thru.

I am hearing you there Krash, I guess my point is that all the throttle bodies available for Harleys are not too big. The 62 and 58 Harley ones have a good shaped plenum on the back of them, I don't have a bench but Hoody does obviously. To my mind the actual area where the air come in has to be something not an orifice at some point, the air comes out of the sky, we can flow the sky. Hilly, you are right there,one has to be careful tuning the larger ones to get nice response down low, similar to tuning say a Ducati 848 or newer with the giant oval throttle bodies on basically a 450cc cylinder. Even the early 250 Hondas with 50mm TB. One can get them to not be "touchy"

OK guys so do i need a bigger tb or not

 

I find the FBW Harleys trickier to get right off the bottom, but have worked out a system which is very good at getting data to adjust via MAP. I have recently been tricked again by Harley who have put (it seems ) a convertor into there SEPST to make it tuneable via TP. I find THAT harder than when it was by MAP. Might be just me :-). What is done to your bike? I recently did a 110 with a 62 TB from a hurricane kit and it did 135hp, can't remember torque, but BIG. It was great to ride and only 10.6 comp, easy all year runner. Having said all this the rest of the package needs to be up to the task, obviously ( maybe not??) slapping a 58 on a stock motor is probably a waste of time. Equally trying to get 125 hp from a bike with a 110hp exhaust is a waste of time. Have a nice day gentlemen.

my 106 that Lushy tuned runs a 60mm TB and it has plenty of torque.
its still very smooth down low but wind her on a bit and it all happens pretty quick.
Still loving it

 

I was only going to go a 55mm or so TB but got the 60 very cheap and dont regret fitting it at all

Daggs, those TBs are a nice bit of kit. I am not sure why they are not more commonly used.

no I haven't mate, there is a 1/8th mile track just over the border so maybe one day.
To be honest I've never dropped the clutch on it, too worried about snapping a belt.
the thing pulls wheelies with no effort at all just roll off the throttle then snap it back on and up she comes.
doing a few passes would be a buzz but not at the cost of possibly having to pull all the primary off for a premature belt change

depends on how much more money you want to spend. I had Lushy tune mine with a 52mm TB. Was going to go for a 58mm TB but it was going to cost well over $800 probably closer to $1000 with all the other bits and pieces needed. e.g new air cleaner, new manifold, plus throttle body

I fitted a set of magnaflow F bomb pipes yesterday and went for a spin, bike seems to be a bit more responsive from 3000 rpm and the power seems to stay on a bit longer so maybe the vance and hines propipes were holding it back a bit. It will be interesting to get it back on the dyno

thats why I took my Pro pipe off and went for S&S turbos mufflers, and standard header pipes

Steve , I found out testing on DJ 250i & at the track 2 into 1 have there TQ at lower rev but the TQ fall's off sooner, the duel's take longer to get there TQ but hold the TQ till higher rev's, that won't change EFI or carb the pipe's you use can make big gains or loss's depending on your set up the duel's for me made a big difference I used to ride the bike anywhere & also take to the track to double check the dyno was not liking , for me a change from supertrap 2 into 1 with 12 disc open end cap to stock head pipe & cycle shack slip on ( tapered end ) baffle removed. Got me a gain of half a second quicker & 12mph faster in 1/4 mile that in anyone's books is a big gain. On Dyno the HP went up 10hp but big difference was the TQ curve it came in strong at 3,000 rpm & left the 2into 1 @ 3,500 help the TQ to higher rev. But most important it made HP &TQ quicker I like to time how Quick they make there power & TQ. If your near Willowbank and they have street meetings you should test see what it will do check trap speeds as they just tell you how much HP then when someone talks Dyno read outs you can also compare quarter mile time & speeds, after all you are not just trailer ing a bike to the dyno are you? Cheers

 

Krash i am thinking of going to benaraby drags later this year, I will give it a run then, its only done a few hundred ks since rebuild so a bit more running in before playing real hard

Great Stevo!

Yes give it a good run before going to track, tell your friend who thinks you should have more HP from set up to go too so he can show you what his trap speeds look like. They long black dyno the best way to see what works!