on/off throttle surge gsxr750

OK the TRE makes it smoother in the lower roms when you ease off the throttle...and raising the idle helped as well.

HOWEVER, I still have the same problem. There has not been any problems as far as the ECU throwing any codes. Just when you go to ZERO throttle it feels like somthing cuts off....as if you had capped something off tone of motor changes to a more muffled sound....lower tone...and then when you get back on the throttle it hestitates then kicks in...the rpms don't jump up anything maybe liek it is a delayed reaction...I DON"T KNOW...

Going to ride it this way tomorrow all day and see what happens...

maybe its the secondary butterflies closing too soon or maybe there is a vacuum leak .
Again I will keep you posted.

saga continues....really surprised that noody has experienced this withour a solid solution...dont worry i will get to one eventually.

Scotty J.

 

+1 Piper. Hey Scotty, I had the same problem with my 06 gsxr 750. Every time i twist the throttle from 0% the bike would jerk which made it particularly interesting while in the middle of a turn. It always did this - as stock, with PCIII, and recently with my Bazzaz. I believe the stock map tends to run a little lean at lower RPMs. Lean = snappy response. Do what Piper suggested and that should fix your problem. I added fuel at 0-10% throttle between 4000-8000 (I think) and problem solved! I can roll on in 2nd with out any jerking and no worries. Anyone try a Z-Bomb? Vs Ivans?

 

I'll get the TRE, every little thing that might help.
Did you guys loose your gear indicators? It does that on Kawis, not sure about gsxr.

 

Well Rode a couple hundred miles today I did turn the idle up to 1500 but again it is still there. At this point i do not want to confuse this with the herky jerky stuff because the TPS and TRE did nothing to change my issue. If I let off the gas the engine sounds like it just turns off then when getting back on the gas It alomost hesittates then kicks in...so yes it jerks a bit.

ran into a buddy of mine he said on his girls 600 he disconnected the secondary butterlies and left them wide open. The butterflies seem more likely the culprit but the hesitation in response could also be the map throttle sensor.

Another guy said that he has experienced this before with a bad cush drive. I am going to check my cush drive and front sprocket but I do not believe that to be the issue.

Anybody have a map they care to share with me to see if it makes a difference?

Anyways here is plan of action:

1. check cush drive and front sprocket (highly doubt it)
2. check servo exhaust valve i have a slip on and no cables so i need to make sure the plate is no longer in there or kept open
3. change the map and see if that makes a difference
4. make sure when bike is running and hooked to lap top there is no hesitation between revving it and registering on the map..
5. Check or disconnect butterflies make them stay open.
6. unplug the PC3

I will get an answer and by the number of views this thread has I am assuming many have this issue.

Scotty J.

 

Its a snappy response but its more of a hesitation than just a quick response....when i let off the gas the bikes engine tone changes it becomes deeper...its like there is no engine breaking, just wants to go to idle...at higher rpms like if i wick it up to 12k and then let off the you have the engine breaking and rpms drop slower without the "tone" of the motor change.

I will try raising the idle to 2200 and see if that changes things then I will work on the map. I sounds more liek the butterflies to me..only thing that makes sense...because the engine sounds like you just put a cap on it...it does not feel like lean condition...its something other than the map I believe

 

I replaced the cush. drive with brand new rubbers and adjusted the chain to the tightest allowed per the manaul, no change. As for as disabling the butterflies goes, they are there to smooth response. Maybe check to see if they are testing correctly (ohm) when closed at the connector, see manual.

 

Did you read the herky-jerky thread on gixxer.com as was recommended?

I now have 86,000 miles on my 06 750 and I had tried everyting imagineable to fix this problem.

The cause is two-fold.

First, the ECU cuts fuel when you close the throttle (Deceleration Fuel Cutoff - aka DFCO). The solution is to adjust the TPS (the main TPS, not the secondary TPS) so the minimum throttle opening is 3% (connect laptop to PC3, adjust properly adjusted TPS to read 3% - you can also do this by measuring the voltage at the TPS but I forget what the magical voltage is... it's in the herky-jerky thread).

Second, 0-3% throttle openings run lean. If you only adjust the TPS as mentioned above, the problem will be totally eliminated since the fuel map is now going to be richer across the board. For racing performance, this is not ideal, so after adjusting the TPS to 3%, you need to have the bike mapped correctly and dump in a bunch of fuel from 0-3% or even up to 10% if necessary until the problem goes away.

 

Indeed it seems like the secondaries are not opening at all when it happens and the motor sounds choked, along with loss of power etc. Then there is vibration and that choked sound when you add more throttle. I went through all that same crap man. Mine's got 19k on it now after I fixed it. Smooth as butter. Hope you find a solution.

 

Should I even bother with the TRE?

 

I would not...imho

 

OK so you are saying the TPS on the bike does not matter?its the TPS on the PC3? So where should the TPS on the bike be ? I have it per manual in the middle. I thought I read the correct thread but apparentl I did not.

Thanks I will dive into this....

Scotty J.

 

Adjust the TPS on the bike so the PC3 software shows the throttle position is 3% open, which should set the line on your gauges to the top position. What you are trying to do is trick the ECU into thinking the throttle is never closed.

 

Got it! so the second step is to make sure I add fuel to the 0-3% throttle settings on the map so it has enough fuel and you say I may have to go all the way up to 10% throttle position adding fuel correct?

Thanks again...

Glad you stopped by...

 

Good info. too bad I don't have a PC.

 

Check the butterflies...unplug or disconnect so they are wide open all the time and see if that helps.

 

After you adjust the TPS as I described, you will already be running rich. You do not need to add more fuel...
UNLESS
After adjusting the TPS you then get your PC3 properly mapped. Then you will need to dump more fuel at low throttle openings.

That's ok. You can do it with a volt meter. You want to take the positive voltage reading on the pink wire. Adjust it to 1.2V with the bike running and idling at 1,200 rpm. Try it out. If you still get a little herky-jerky, adjust it to 1.25V.



One way to tell if your TPS is properly adjusted to "fix" the problem, when the bike is running, in gear, you pull the clutch lever all the way to the handle bar. Normally, the bike will slow to a lower idle. When you let the clutch out a little, the idle rises. That is the normal, factory design, but we want to eliminate that. With the TPS adjusted as I mentioned, when you pull the clutch lever all the way in, nothing should change... the ECU will think you have the throttle slightly open so it won't drop the idle.

I hope I'm not making you more confused. Suzuki's design is way over-complicated.

 

Hey that Hurts....

 

OK hooked up the laptop and set the TPS while bike was idling at 1250 so that it read minimum 3%...Took a very short ride and did notice a difference when I get back on the gas its not jerky much smoother.

I did notice thhat if i revved up to say only 5k then off throttle it would almost do the same as before so i hope that maybe more fuel below 5k rpms will help smooth it out.

Thanks again...and i am going to take the TRE off to see what difference if any I feel.


Scotty J.

 

Pink wire on the TPS?