Hesitation More Jetting then TPS


5 replies to this topic
  • dl19

Posted April 06, 2006 - 08:27 PM

#1

New 05 re-jetted for most of my anticipated riding during the year. The bike had a noticeable hesitation and cut out at constant speed. Checked all the threads and some said jetting and some said TPS. I unplugged the TPS, and did see a little difference but not a lot. Adjusted the air screw and also had less hesitation then TPS. ****FINDINGS!!!!!! I left the house today 60degrees/1000' and sunny and headed for the hills to do some road riding. It was 10 degrees warmer then it was/has been while trying to get rid of the hesitation/cutting out for quite a while. The first five miles the hesitation was there but very noticeably less. After getting into the hills and gaining 2000' the temp dropped to less then 50 with 2' of snow everywhere but the plowed roads. At one point I was riding down basically a single lane with plowed snow 4' high on each side of the road. The temp was easily close to 40, and the hesitation came back stronger and very noticeable like before. DUH????!!! even I could figure this out so I flipped a B*#@ and screamed back for the sun and warmer air to see if I was right. Hesitation again noticeably reduced as soon as I hit the warm no snow and sunny area. So to me the hard cutting out/hesitation is more related to jetting then the TPS. I also agree it is because of being too rich on the jetting. I am stoked because I am sure as it warms up to our summer temp of 80-90 my jetting will be right on. To each his own, but I am advocating getting your jetting right before messing with the TPS.

  • rich1167

Posted April 06, 2006 - 08:34 PM

#2

Sounds like your lean. If it runs better in warmer weather your lean. Check Indy's jetting chart, in the jetting thread at the top of this forum for baseline jetting. Also post your set up so we know what your running, and can give better recommendations.

  • dl19

Posted April 06, 2006 - 08:43 PM

#3

I am not lean the temperature is finally getting high enough to match the jetting I set for most of my yearly riding. I am not one to change my jetting every time the weather changes. We can ride from 1000-7000' with a 20 degree temp change easily in a days riding. So most of us in our area just try to find the best middle ground. I was only addressing the hesitation/cutting out people have including myself while running at a constant throttle position. I was trying to say that the hesitation/cutting out at constant cruising was less with proper jetting. There is a ongoing debate if it is the TPS or improper jetting. I feel it is improper jetting on the rich side that causes the hesitation/cutting out. I gues I did not explain that well enough. Hard to do with typed words at times.

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  • rich1167

Posted April 06, 2006 - 08:49 PM

#4

It's not your fault, I missed some stuff in your post :thumbsup: Not wearing my glasses. For the record I run with my TPS unplugged. I feel my bike runs better without it. No problems throughout the range. It has more power then any won could need.

  • JCORMI

Posted April 07, 2006 - 04:27 AM

#5

I have to agree 100%. At least in my case that is what it was, I was just having the same problem and was ready to blame the TPS, but once I finally got the jetting right all problems were solved.

  • OneToGo

Posted April 09, 2006 - 05:39 AM

#6

I have to second this:

New 05 re-jetted for most of my anticipated riding during the year. The bike had a noticeable hesitation and cut out at constant speed. Checked all the threads and some said jetting and some said TPS. I unplugged the TPS, and did see a little difference but not a lot....... am stoked ....... To each his own, but I am advocating getting your jetting right before messing with the TPS.


Had the same problem...YES, and I think/know the ACV masks and hinders jetting fine tuning...for the unconvinced:

I tried disconnecting TPS and "blocking" the activation of the ACV by spacer to keep the diaphragm valve seated against vacuum - see; www.thumperfaq.com for methods. There have been threads on this before - so I just wanted to see what happened...

WHY - like many I have tried to cure a curious surge at steady speed and throttle setting (on the road)- throttle constant at steady speed with very little engine load (about 60 to 70km 5th gear, slower in 4th).

Disconnecting the TPS made a slight improvement BUT, my bike had way less throttle response and power at less than half throttle - I assume the disconnected TPS adversely affected the ignition map. So, I plugged it back in and rode. Apart from the slight surge I feel (very un-scientific I know) that the jetting was cleaner now in the lower 1/4 throttle setting than before the ACV mod. There was a bit of popping on decel that I could dial out with a 1/4 turn of the fuel screw but that made the bike a tad rich (slight stumble).

For info, I'm using 168MJ/JD red#5/48PJ/40LJ/70SJ - all mods and Q2 PowerBomb.

I feel now I probably need to raise my needle clip, just about make it 95%.
Anyone got PERFECT JETTING??? Apart from INDY of course..

My .02 worth for anyone trying to fool with TPS. :thumbsup:




 
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