07 Sputtering at high speed- is this normal?
Posted February 09, 2007 - 12:41 AM
Posted February 09, 2007 - 05:42 AM
Oh yeah, another contreversial subject while at the DYNO with my UK 2004 model I explained about the Grey Wire Modification, we ran the bike on the Dyno with and without the grey wire and there was no performance gain!
Just got my 2007 model WR450F and I am still prepping it and will run it in this weekend, when I get a few hundred miles on it to bed everything in I am straight back to the DYNO shop to get this bike running correct from the start. I think it cost me £120 last time, but in my opinion money well spent!
On my 07 model I have done the throttle stop mod, removed the restrictor from the exhaust and made a blanking plate to remove the AIS system as described by one of the TT members, plugged the hole in the Air Filter Cage (I never would have noticed that hole without Thumpertalk!) Thanks to all the TT members who have posted advise on how to access the carb on the 07 model, without their posts I would never have managed to access the carb!
I am waiting to go to the DYNO to see if the Grey Wire Modification on the 2007 model does actually make a difference and the same time see if removing the Airbox Snorkel shows any difference on the DYNO.
Unfortunately the lovely new 07 model Tail-Light is no use here in the UK because there is no way to modify it to be able to hang a Registration Plate on - so I have mounted the Acerbis LED Tail light with number plate holder which fits and looks good! Wired in front and back brake light switches (Genuine Yamaha ones are best with braiding and a 90 degree rubber cover) and a fitted a horn.
Sorry I got a little distracted from the original STUTTER question - my answer is to get your jetting set up correctly at a DYNO tuning centre. The DYNO doesn't lie. Or the alternative is lots of Trial and Error trying different jets on a Carb that is such a mongrel to access- If you decide on the Home Trial and Error basis I think from the positive comments from TT Members you should invest in the JD Jetting Kit? or better still take the JD Kit to a DYNO tuner.
I will let TT members know if the DYNO shows any performance gains on my 07 model for the Airbox Snorkel removal and the Grey Wire Mod.
Cheers, Alex Robinson - UK
Posted February 09, 2007 - 09:46 AM
My plan is to ride it stock for awhile, then do the mods... And only the ones that really make a difference.
Please update us when you get the Dyno results!
Posted February 09, 2007 - 11:13 AM
Posted February 09, 2007 - 11:50 PM
TPS Sensor. I am sure I will not be popular questioning other peoples advise, but I can tell you my experience with Stuttttter and the TPS on my WR450 2004 UK model. I had the Stuttters and did ....
Oh yeah, another contreversial subject while at the DYNO with my UK 2004 model I explained about the Grey Wire Modification, we ran the bike on the Dyno with and without the grey wire and there was no performance gain!....
Cheers, Alex Robinson - UK
Most dyno tuners use only full throttle to evaluate the power. If you take more time to evaluate different throttle positions, the results are significantly different with the Grey wire connected and disconnected.
The following graphs are results from holding a steady throttle at 1/8, 1/4, 3/8, 1/2, etc. Notice how only full throttle looks identical, while the lower throttle ranges have major losses with the grey wire connected.
---Grey wire connected on the WR250F---
---Grey wire disconnected on the same bike---
Posted February 10, 2007 - 01:50 AM
Excellent, thanks again!
Cheers, Alex Robinson -UK
Posted March 06, 2007 - 06:34 AM
Posted March 06, 2007 - 11:10 PM