Dynatek ignition for TPS stutter?


104 replies to this topic
  • ranger85

Posted July 08, 2009 - 06:01 PM

#1

Has anyone heard if this ignition cures the TPS stutter? I know the Vortex ignition has a map that seems to cure it, but I can get the Dynatek for half the price of the Vortex. The Dynatek is programmable to, so it seems like if someone knew what they were doing they could easily create a map that would fix the problem. I run one on my Raptor 700, and had it programmed with custom maps, and it really does well.

Also, I was just thinking about throwing an in line switch on the TPS wires to turn it off when I'm doing a lot of steady cruising(Which is just about the only type of riding you do in Utah). I did a search on here, and after reading some thread's on installing a TPS switch I am still confused and unsure how to install one. What switch would I need, and what wire/wires would I splice into to install it?

Thanks a lot!

  • ww44wrf450f

Posted July 09, 2009 - 03:17 AM

#2

From what I have read about the tps stutter is that something isn't right!!
IE. timing set, valves adjusted to spec., carb is clean and jetted properly to your riding conditions and maybe the tps sensor was not set right from the factory? A dynatek or vortex is to get more out of the bike and not mask it?
How much of a stumble are you getting and how much tinkering have you done with the carb jets and needles etc.

  • Mtn-Track

Posted July 09, 2009 - 05:07 AM

#3

ww44 is right. If your TPS is set right and your carb is jetted right, the stutter will go away. I spent lots of time and $$$ working that out with lots of help on here, but in the end, the dyno showed that the jetting was way too fat, even with all the recommended jetting advice I got here.:worthy:

Year: 2008
Model (400 - 426 - 450): 450
Cam Timing (WR/YZ): WR
Main jet: 152
Pilot Jet: STOCK
PAJ: STOCK
Leak Jet: STOCK
Starter Jet: STOCK
Fuel screw (turns out): 2
Needle Model/Clip position: GYTR-AIS REM. KIT "MYSTERY NEEDLE", 2ND FROM THE TOP.
Grey Wire Mod (Y/N): Y
TPS Connected (Y/N): Y
Airbox Snorkel/Lid (on or off): OFF
AIS Removed (Y/N): Y
Airfilter Brand: STOCK
Exhaust Brand: FMF POWERCORE 4
Average Altitude: 5000-14,000ft
Average Temperature: 50-80F
Average Humidity: Pretty darn DRY!
Degree of Satisfaction (0-10): 9.5
Additional Mods/Comments: This bike runs STRONG! NO STUTTER or any overheating from 5000-11,000ft, and starts instantly. Above 11,000ft some of the stutter starts to come back, but it's minimal, and it still starts right up. No bog or hesitation anywhere in my altitude range!

  • William1

Posted July 09, 2009 - 06:28 AM

#4

The WR stutter is well documented. No amout of jetting, TPS adjustment or cam tweaking can get rid of it. James Dean was on a threrad a while back slonfg with a fellow TTer. The stutter is caused by the CDI. They did many experimnets, finally testing a Vortex box. Apparently, only one of the tewn supplied maps in that box did not stutter. No one has done the tests with any other CDI I am aware of.

The stutter only occurs mid throttle when held at a constant speed. Disconnecting the TPS does reduce it somewhat (but not entirely). Eventually, I will have info on adding a bar switch for the TPS, a poor mans fix, but all I want is to be able to do road sections between trails realitvely smoothly and this fix should be the ticket.

  • Mtn-Track

Posted July 09, 2009 - 06:38 AM

#5

Sorry William, but I respectfully disagree on the stutter fix. In the end, mine was solved by leaner jetting on a basically stock set-up (with the exception of the GYTR-AIS removal kit and associated needle). I don't have a JD kit, Vortex, Dynatec, or any other timing or cam mods and my TPS is still connected.:worthy:

  • William1

Posted July 09, 2009 - 07:28 AM

#6

Not a problem, you are a lucky fellow to not have the stutter.

Every WR I have seen has it. All jetted perfectly using an in header wideband A/F sensor.

  • Krannie McKranface

Posted July 09, 2009 - 10:44 AM

#7

On James Deans web site the stutter is clearly seen as an issue with the stock CDI unit. The spikes in the RPM curve are less than 100rpms wide, which impossible to create with carb mis-tuning. When they switched to the Vortex, it went away.

My neighbor has a 450 with no stutter what so ever with the stock CDI.

Luck of the draw.

  • kurtisjones

Posted July 09, 2009 - 11:02 AM

#8

hi guys what would you recommend for a 03 yzf 450 for jetting, im sure my tps is fine and cdi, im at a 168 main 50 pilot and the little jet next to the main and pilot is a 72(leak jet?) when i pull through the gears like a mad man it seems permisable but thats tapped on the road, if im comming up through third or forth gear sitting at 1/3 throttle and roll it back slower to wide open i get such a bad stutter it feels like my chain is skippin, please tell me i got my jetting way off and the tranny is ok, any jetting suggestions im in minnesota

  • Krannie McKranface

Posted July 09, 2009 - 02:35 PM

#9

hi guys what would you recommend for a 03 yzf 450 for jetting, im sure my tps is fine and cdi, im at a 168 main 50 pilot and the little jet next to the main and pilot is a 72(leak jet?) when i pull through the gears like a mad man it seems permisable but thats tapped on the road, if im comming up through third or forth gear sitting at 1/3 throttle and roll it back slower to wide open i get such a bad stutter it feels like my chain is skippin, please tell me i got my jetting way off and the tranny is ok, any jetting suggestions im in minnesota


That stutter IS your TPS. Un plug it.

  • ranger85

Posted July 09, 2009 - 07:22 PM

#10

Yeah, after reading that thread with James Dean doing the testing with the vortex and looking at the dyno graphs you could clearly see the "spikes" where there was some weird jumps in the electrical currents dealing with the TPS. I believe everyone agreed on the bike being in a particular state of RPM and load that was making it bounce between 2 different maps, no load, and full load, causing the stutter. However, as stated, just one map on the Vortex got rid of the spikes, killing the stutter.

It is weird how some people do not notice it, or do not have it, but it is present on many WRs. And I have played with the jetting, swapping out needles, adjusting the clip all the way through the range with no change. While I can unplug the TPS, and it almost completely goes away.

That's why I think the programmable Dynatek ignition would be the way to go. If you had the software, and knew how to map the ignition, it seems like you could possibly get rid of the stutter.

Do any of the YZF's have this stutter? I know my fiancee's YFZ doesn't have any kind of stutter. Can you put a YZF CDI on these bikes, or would that mean completely re-doing all of the electrical system?

Oh yeah, and my TPS is in spec, checked with a multi-meter.

Thanks.

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  • thedktor

Posted July 09, 2009 - 09:49 PM

#11

I really don't believe the TPS is the problem, its jetting no question.

On mine running a richer needle made it stutter. A leaner needle with a fatter main jet gives excellent power and no stutter.

Disconnecting the TPS had a clear, negative, affect on low-end power – its is there for a reason!!

Steve

  • William1

Posted July 10, 2009 - 02:42 AM

#12

Yeah, after reading that thread with James Dean doing the testing with the vortex and looking at the dyno graphs you could clearly see the "spikes" where there was some weird jumps in the electrical currents dealing with the TPS. I believe everyone agreed on the bike being in a particular state of RPM and load that was making it bounce between 2 different maps, no load, and full load, causing the stutter. However, as stated, just one map on the Vortex got rid of the spikes, killing the stutter.

It is weird how some people do not notice it, or do not have it, but it is present on many WRs. And I have played with the jetting, swapping out needles, adjusting the clip all the way through the range with no change. While I can unplug the TPS, and it almost completely goes away.

That's why I think the programmable Dynatek ignition would be the way to go. If you had the software, and knew how to map the ignition, it seems like you could possibly get rid of the stutter.

Do any of the YZF's have this stutter? I know my fiancee's YFZ doesn't have any kind of stutter. Can you put a YZF CDI on these bikes, or would that mean completely re-doing all of the electrical system?

Oh yeah, and my TPS is in spec, checked with a multi-meter.

Thanks.


Not sure (absolutely, positively) that the YZ does not have the stutter. Unfortunately, swappin gCDI's is not plug and play. The YZ box is run off of AC from the stator whereas the WR is riun on DC from the battery. Some additional wiring changes would be needed. But if you are handy with a VOM, have a good YZ CDI sitting on the bench....

  • William1

Posted July 10, 2009 - 02:52 AM

#13

I really don't believe the TPS is the problem, its jetting no question.

On mine running a richer needle made it stutter. A leaner needle with a fatter main jet gives excellent power and no stutter.

Disconnecting the TPS had a clear, negative, affect on low-end power – its is there for a reason!!

Steve


The you are the second WR owner to not have the stutter. Count yourself lucky. Yes, disconnecting the TPS kills the power somewhat. The CDI falls into a limp mode. Being the TPS is merely a variable resistor, my plan will be to measure it at a certain throttle position (perhaps 1/2 throttle) get the resistance, have a bar mounted switch that when activated, disconnects the TPS and inserts my selected resistor. :worthy:

  • ww44wrf450f

Posted July 10, 2009 - 03:53 AM

#14

Ummmm, William1 , sounds like Yamaha should buy every wr owner a vortex?
What is the possability of this becoming a Sticky --- If we get enough voices and opinion's etc. ---- action talks ----:worthy:

  • William1

Posted July 10, 2009 - 07:12 AM

#15

Thing is, I bet a lot more people would complain IF they ever noticed it. Most WR riders are off road, constantly twitching the throttle and will never notice it. For those few that have their WR plated for DS or SM use, it is apparent on the first ride. I had my WR if 9 months before I noticed the stutter. I was always off road doing single track. It was not till the Shenandoah 500 and I did a few long pavement sections that the stutter became miserably apparent. Other riders could hear it and were wondering ***.
Now, in other parts of the world, like Australia, the bikes are road worthy from the factory and I here no complaints from down under. I'd like to locate a part number for their bike and see if it is different. Any Aussie riders want to get me a part number for an 08 WR250F and a 08 WR450F?

I have my doubts about Yamaha doing anything. I need categoric verification they have a part, on the shelf, that will cure it. I know a few folk there and you never know. If I can present a case and my reasoning is stronger than theirs, you never know.

  • The-Extractor

Posted July 10, 2009 - 01:27 PM

#16

How about a rheostat and voltmeter attached to the bars to test , adjust the rheostat while riding and see if you can fool the cdi with the tps wireing ? Then if you find and good spot wire in that value of resistor to the tps harness?
Mine is so bad I almost wanna sell the bike.

  • curveball323

Posted July 10, 2009 - 03:28 PM

#17

William1 I disagree strongly with your post. I adjusted my TPS after having a strong stutter where i couldn't go past 40 MPH. After adjusting it within spec and jetting my carb 2 steps down. Stutter was Completely gone!! completely. My machine is a beast now

  • SJMC_DON

Posted July 10, 2009 - 03:34 PM

#18

I am on my 5th WR... the stutter has been there on everyone of them. The TPS stutter IS well documented and proven to be a result of the CDI doing what it is supposed to do (or so I am told).

If you have a stutter, (noticeable), while riding single track then you have a problem that may or may not be the TPS or jetting

BUT

If you notice this stutter at mid throttle - cruising speed... IT IS THE TPS! Mine is unplugged and Wa-la... the stutter is gone while DS'ing.

I for one am very anxious to see this switch (c'mon William:worthy:) because I have a noticeable lag in low end response while off road riding and the TPS is un-plugged. With the IMS tank, it is not a quick and easy thing to plug and un-plug.

  • ranger85

Posted July 10, 2009 - 04:29 PM

#19

There are countless threads on this subject with pretty strong evidence showing that it is unrelated to jetting.

This is probably the best thread:

http://www.thumperta...ad.php?t=650084

Yes the TPS is there for a reason, and yes performance drops when its unplugged, but unplugging is just for those times when you are cruising.

I do notice a drop in low-end after unplugging the TPS, its almost like it takes the torque away. When you plug it back up the bike easily tanks through everything in the low-range, where unplugged, it seems like you really have to stay on the gas, almost like the brake is dragging.

I myself had this stutter the day the bike came off the showroom floor with the extremely lean stock needle. I to thought it was related to jetting till I dug around on here and found thread after thread on the issue, and jetting has been debunked on all of them.

I think there are some bikes that just don't have this stutter, or people don't realize it, or just because they can jet it out, they misassociate this very real TPS problem with a jetting issue. Chances are they have one of these lucky bikes without the stutter.

  • William1

Posted July 10, 2009 - 05:13 PM

#20

There are countless threads on this subject with pretty strong evidence showing that it is unrelated to jetting.

This is probably the best thread:

http://www.thumperta...ad.php?t=650084

Yes the TPS is there for a reason, and yes performance drops when its unplugged, but unplugging is just for those times when you are cruising.

I do notice a drop in low-end after unplugging the TPS, its almost like it takes the torque away. When you plug it back up the bike easily tanks through everything in the low-range, where unplugged, it seems like you really have to stay on the gas, almost like the brake is dragging.

I myself had this stutter the day the bike came off the showroom floor with the extremely lean stock needle. I to thought it was related to jetting till I dug around on here and found thread after thread on the issue, and jetting has been debunked on all of them.

I think there are some bikes that just don't have this stutter, or people don't realize it, or just because they can jet it out, they misassociate this very real TPS problem with a jetting issue. Chances are they have one of these lucky bikes without the stutter.


On top of that, I think there are those who also have a really poorly adjusted TPS or jetting and have other issues. These all should be cheked and resolved before any consideration about the "CDI stutter".

My WR250F will easily crack 80 (indicated) mph with a one tooth smaller than stock CS. It will do it smoothly. It will not run at a steady throtle position however, esp. mid throttle without stuttering. It is the CDI on my bike.




 
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