Dynatek ignition for TPS stutter?


104 replies to this topic
  • William1

Posted July 10, 2009 - 05:20 PM

#21

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.


Unplug the TPS, go for a ride, ignore the performance loss, just look for the stutter. If the steady state is better, then this switch concept will work.

I'll make a concerted effort next week to come up with a game plan and parts list. A straight on/off switch is simple. A little more complex (but not much) will be to fool the CDI into thinking you are at a certain throttle position that does not make the the stutter appear. I guess I'll have to go for a road ride with a pot on the CDI, ride at mid throttle and try a few different pot settings. Which ever one gives me reasonable power and no stutter, I'll figure out what the resistance is and make a toggle setup and test that.

I promise, I'll get off my fat ass.

  • William1

Posted July 10, 2009 - 05:21 PM

#22

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.


Before you do anything, check your jetting and TPS adjustment. These must be right first.

  • The-Extractor

Posted July 10, 2009 - 05:41 PM

#23

I am so tired of messing with it it will have to wait. Ive got it running the best i can so far.

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  • James_Dean

Posted July 11, 2009 - 06:33 AM

#24

The spikes in the graphs are from RPM measurements taken at the IGNITION lead , and the jetting was not changed in the second set of graphs. These are low throttle runs at about 1/8 throttle, where you would ride on flat roads at about 30-45mph. We see the symptom on WR250's and WR450's more than any other bike, and it's been common with this model since the WR400 was produced.

Posted Image

Repeatable results with nothing other than an ignition change using the exact same jetting, which shows a good air/fuel mixture, not that it matters because this is RPM measurements taken at the IGNITION lead .

Posted Image

  • William1

Posted July 11, 2009 - 08:06 AM

#25

Thanks for chiming in James!

  • thedktor

Posted July 11, 2009 - 09:02 AM

#26

Wow that is quite something. I'm still wondering why the bikes I've owned or ridden (2004 450, 2006 450, 2007 450) have been fine - and I know exactly the speed and throttle conditions mentioned as all bikes were/are ridden on the road.

Could it be (and I'm not claiming to be an expert) that the WR engine likes jetting lean at this throttle position (ie straight portion of needle) and igniton spikes are not a problem as the engine is burning very cleanly (due to lean mixture).

An interesting puzzle!

Steve (UK)

  • SJMC_DON

Posted July 11, 2009 - 09:26 AM

#27

Wow that is quite something. I'm still wondering why the bikes I've owned or ridden (2004 450, 2006 450, 2007 450) have been fine - and I know exactly the speed and throttle conditions mentioned as all bikes were/are ridden on the road.


Steve (UK)


I have experienced it on a 99', 02', 04', and now two 07's.... up until my current bike I never really cared because it only happened on the rare ocassion I found myself at cruising speed for a constant...

With my current bike set up for DS'ing and doing a little more road than before I have it unplugged.... but I just did 50 mi. of single track the other day and I there is a noticeable lack in low end grunt.

Maybe the UK bikes are different in this matter?

  • ranger85

Posted July 11, 2009 - 04:13 PM

#28

Yeah thanks James!

Thedktor: I don't know, but I guess it could be possible if you ran the needle lean enough that it would keep the bike underpowered, therefore causing there to always be more of a load on the engine at constant cruising speed, thus the CDI/TPS staying on one map and not bouncing between 2, which causes the stutter. Of course running the bike too lean could damage the engine before to long.

Weird stuff indeed.

It would be very interesting to see if the Dynatek ignition could clean up the stutter, but I would sure hate to spend the money on the thing and it do nothing, and then spend even more money on the Vortex.

  • thedktor

Posted July 11, 2009 - 11:20 PM

#29

I don't know, but I guess it could be possible if you ran the needle lean enough that it would keep the bike underpowered, therefore causing there to always be more of a load on the engine at constant cruising speed, thus the CDI/TPS staying on one map and not bouncing between 2, which causes the stutter. Of course running the bike too lean could damage the engine before to long.


OK, here’s my take.

My bike is not running lean – I start it with the choke and can ride off almost immediately, choke off. A tiny lean-surge for the first minute then all is perfect.

At 1/8th throttle the load on the engine is minute, so the engine is running cool, even if it was running lean. As soon as any load (and hence heat) is put on the engine the fat main jet comes into play to keep things cool.

In conclusion my jetting is exactly correct (for my bike).

I have experimented with the jetting too lean and too rich and the symptoms are not that dissimilar. Too lean gives the bike a harsh snatchy, surgy and stutttery feel. Too rich and it’s a softer stutter and surge.

For this reason I’m wondering if some folks are going from the very lean stock jetting (with stutter) and then fitting too rich jetting and experiencing near-identical symptoms!!

My bike will happily run way richer than the recommended set-up. You get a tiny power increase but it WILL stutter and surge at light throttle openings.

For reference, my bike fully uncorked: #170 main, #48 pilot, GDDUS needle (UK stock). The needle is the critical bit, the S on the end is the straight part, measured at 2.77mm.

Using a thinner (richer) “Q” needle gave problems, and the “N” needle from my perfectly running DRZ gave more problems! Go figure.

N-P-R-S is 4 sizes fatter(leaner) = 4/100ths mm measured.

It would be fantastic if someone with the dreaded stutter could try my set-up. I would be very surprised, gob-smacked even, if the UK vs US CDI boxes are different??

- Steve

  • William1

Posted July 12, 2009 - 03:08 AM

#30

I have heard some CDI's do not have the Grey wire in the UK and other parts of the world.
In the US, the part number for your 2006 WR450F is 5TJ-85540-B0-00, is it the same part number in the UK?
Again, as James Dean (of James Dean Jetting, if you did not make the connection) and others have repetitively stated, it is not a jetting issue. This has been confirmed time and time again using sophisticated electronic testing gear.

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  • ranger85

Posted July 12, 2009 - 10:15 AM

#31

+1, This is not a jetting issue.

  • Thumper_Bloke

Posted July 12, 2009 - 10:20 AM

#32

I have the Dynatek CDI on my 2004 WR450. Since i sometimes ride on the street, the TPS studder was always there until i tried this ignition. Let me say, having the ignition timing set to the correct amount absolutely does eliminate the studder.

The Dynatek CDi is easy to program, and it has a 4-map switch. You can program all 4 maps to whatever you want to try, then switch them on the fly. I finally settled on an ignition curve that is real conservative under part throttle, but more aggressive wen the throttle is fully opened. :worthy:

  • The-Extractor

Posted July 12, 2009 - 10:21 AM

#33

Does the gray wire mod help with the stutter at all ? I am ready to push this thing off a cliff after riding it 20 + miles yesterday...

  • Krannie McKranface

Posted July 12, 2009 - 11:39 AM

#34

Does the gray wire mod help with the stutter at all ? I am ready to push this thing off a cliff after riding it 20 + miles yesterday...


Really? What cliff. I'll be there to catch it.
Grey wire has no effect on stutter.

UN plug the TPS!

  • ranger85

Posted July 12, 2009 - 12:25 PM

#35

I have the Dynatek CDI on my 2004 WR450. Since i sometimes ride on the street, the TPS studder was always there until i tried this ignition. Let me say, having the ignition timing set to the correct amount absolutely does eliminate the studder.

The Dynatek CDi is easy to program, and it has a 4-map switch. You can program all 4 maps to whatever you want to try, then switch them on the fly. I finally settled on an ignition curve that is real conservative under part throttle, but more aggressive wen the throttle is fully opened. :worthy:



Verrrry interesting to hear. I can get this unit at $280 or less compared to over $500 for the Vortex.

So are you saying you actually have the programming software and you made your own custom maps, or are you just using the factory preset 4 curves?

Thanks.

  • The-Extractor

Posted July 12, 2009 - 12:55 PM

#36

its been unplugged. Im just mad cause the suspenion is setup for a heavy rider , which I am not, and the trans and fork started leaking after my first ride (20mi)on it yesterday. It looked cherry when I got it. I almost miss my crf 230...

  • The-Extractor

Posted July 12, 2009 - 01:02 PM

#37

Ranger, where can you get it at that price ? Ill buy one right now !

  • ranger85

Posted July 12, 2009 - 02:24 PM

#38

Ranger, where can you get it at that price ? Ill buy one right now !



Well ebay of course, lol. I've found it cheaper before too, but I have been hesitant to buy it not knowing if it would solve the studder.


http://cgi.ebay.com/...sQ5fAccessories

  • ranger85

Posted July 12, 2009 - 02:28 PM

#39

LOL, so go buy one and tell us if it works. I'm not sure what year bike you have, but they should have them for all years.

  • The-Extractor

Posted July 12, 2009 - 02:30 PM

#40

Does it come with a factory map that eliminates the stutter or did you program your own ?

03 wr450




 
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