Hey guys I'm having an issue at 3500 RPM's where at pretty much no load the bike starts surging... we noticed it on the dyno and now I see it happening on the street. I think it may be that the voltage is off on the new throttle bodies I just installed what do you think????

Did you check for a lose ground wire?

unhook the pc and make sure it's not that first, as HUB would say......kinda

My ground on my PC is good it's right to the block. I'll unhook my PC and try that next. The bike runs great but right at 3500 with very little to no load it starts jerking. As soon as I give it throttle it goes away. But it's starting to drive me nuts. I have no idea what it could be. I just had competition cnc do a super sport head and degree the cams and install 47mm throttle bodies and got my ECU reflashed not sure if any of that has something to do with it what do you guys think?

You've made a lot of changes to the engine. Start with one change at a time, and check it.

What was the last change you made before this started?

Yeah I think there may be somthing with the ECU. We changed the fueling at that RPM and it didn't change the surging. I need to call the guy that did the flash.

Had that happen one time last summer. I am sure it was wet connectors on the SpeedoHealer.

The Bonneville has the exact same connectors that go inline at the speed sensor wire. You might just check those. I kind of doubt that is it but its a thought.

I never messed with the TPS. I did with the sub's sensor though. Since they 'kinda' have the same body the same parts inside, same sensitivity, I would imagine? You move it a smidgen of a bump, she codes. Yes, maybe a tiny bit of move before it codes, but it is so spot on via factory wise, to me it's a waste of a move. Forget the TPS. No code present.

Forget the cam setting. If it goes away the second you move it, one of two things left. Electrics or air flow. Forget the 47mm. It instantly goes away, correct? Forget the PC, it instantly goes away. Say yes, this is what it feels like. I am on a DFI bike for digital tone is the ping, not a buzz.

It could be the only thing left of the mods... Does a flash feel like a digital ping to you? Buzzy, but the buzz has narrower waves? If you saw waves on a screen, had the rheostat to make the waves closer together or farther out, that digital tone to me is a buzz, but real fast. More a tone than a buzz. Like the waves are shoulder to shoulder. More like a piano tuning fork. And that puppy does not buzz.

Is that the feel of a, sound of a tone to it? A digital tone... Ready? KINDA tone?

If it is... I think you might have narrowed it down. You tried what I would have. Good luck!

Hub I would say its more like a wave than a buzz.....if I chill with real light input on level ground it will roll like a wave. (surging) I'm hoping it's the PCV ground wire location that the builder changed... I'm going to put it back where it was tomorrow.

No, not the way to remove the PC out of the electrical loop. See, when you remove the ground side of the PC, it still has a ground at the injectors. You would have to take it completely out of the loop by removing the hot side. Then take a ride. If you removed ground and it is still there... I don't know? If the hot side is off, for sure, there is no if ands or bust your balls, the flash guy will want you to cover all bases. I doubt the other guy moving the PC ground did anything new. Ground is ground. The PC works or it does not. This to me is leaving that variable open for question.

Do this. Change to that good ground you know. Just make sure it was doing it with your original ground or it is a waste of time [as] you saw it on the dyno.

Well I swapped the wire and just have to try it....Gonna be a cold ride but going to ride her in to work. I'll let you know how it goes....I know its a long shot but lets hope....

Well checked all grounds and moved the PCV ground and nothing. I checked the volts on the main and sub tps and they were right on. This reminds me of a pick up truck I had and it was the same thing in over drive with little to no load it used to make a driveline noise and jerk forward.. This is the same thing and I'm wondering if after the super sport head and degreeing the cams it's kind of the same deal. What do you think?

Rook said something that maked sense.I took my 43 rear tooth sprocket off.I put back on the stock 41.So I figured I needed to redo my Speedohealer.Take out the GPS and I couldn't get it right for nothing.But what I did notice is it stuttered a few times around 3500.Well I checked with the Gearing commander site and un plugged it was only 2 mph off at 90mph.So I removed the S/H and it hasn't stuttered sense.Mabe that could be it.
Craig

^^^^?????easy enough to try it. Just unplug and reconnect as/stock. The speedo will be off but you should know if the motor is operating normally right away.

Well I unplugged it and still nothing.... This one is nuts for sure.

Ok so I checked the TPS voltage through the PC and the volts were low for sure. They were like 0.520 when they should have been 0.632 after i looked deeper the tps sensor was a little lose (not a lot but lose) I set it right at the correct volts and wow just on the stand way crisper for sure! cant wait to ride her!

Very good!!!!!

"cant wait to ride her!"...how do you guys do that????I mean...fix something on your precious...and then put off checking it out IMMEDIATELY?????

* Last updated by: Grn14 on 3/27/2012 @ 11:03 PM *

Grn I hear you big time! I want to try it out and see how she rides big time but it was late and today its going to rain some....I'm thinking I may have to ride anyways...

Well rode her into to work today even know it’s going to rain.....She is FIXED!!!!!! Guy's thanks for all the help I really appreciate it for sure.....Man this baby rips!

Well, here I assumed your 47 would come back all tight and within book spec? So much for handing off shit to someone. That is why I'm so anal and want everything in-house. I need to win the lotto.

And another thing. That is not buzz, but, 'tone' is watt I thing you heard? These sensors are balanced in the digital. Welcome to the sound of Tone Tuning out the buzz < How else could I say it?

She IT! I'm just saying. IF... If you found loose, and to bore is to remove plate to remove shafts? If there were main or sub plate removal... WOT are the odds something is being sucked in all loose down the road? I'd be worried... We send something out, find a pattern it comes back?

I just sent someone a message. Said, I want the same guy, not try your new guy, because he gets the work out faster? You assembled the stuff you wanted done, and do you see anything out of line? It lines up so well, we never have to modify or alter his work.

I'm only assuming.

Naa its all good I went over the bike real good and ten safety wired her. It was just snug not super loose. The guy is a good builder for sure. Motor runs great!