Jetting question

5 replies to this topic
  • MGR8

Posted September 24, 2001 - 05:55 AM


I just had the BK mod done to my 01 is AWESOME! Don't think about doing it! The responce is excellent (on the bike stand and on the track). Instant responce! On to my question......

At the races yesterday a buddy came up to me and noticed that my header was turning blue (I am running a Ti DSP system) from the heat..his responce was that I was running the carb to lean??? Would a lean condition cause the bike to run hotter..causing the header to turn blue? I am not getting any popping on decel. I know what a bike running rich feels like, but not sure about a lean setting. Could use some help. Also, if the performance feels great to me, am I doing harm to the bike if I am running lean?

This is my setup: 168 main, 45 pilot, lifted the needle 1 clip pos. and limited the accel pump spray length to .3 seconds, VP C12


  • jaybird67k

Posted September 24, 2001 - 06:40 AM


That is normal on the DSP Ti pipe.
The blue color you see is because the carbon content of the metal is decreasing, this is very normal.
On the stock stainless header because of the small carbon content the metal turns browness colored.
I run 165 main 45 pilot stock needle, with .5 sec spray duration. VP C-12

Later, Jason

[This message has been edited by jaybird67k (edited September 24, 2001).]

  • forloop

Posted September 24, 2001 - 07:59 AM



Do you have any hick-ups in your throttle? I am trying to get rid of the WFO from idle problem. It looks like I am having to richen up the idle curcuit. I am running stock jetting now. How was the 165 compared to the 162?

01 YZ426F #85 Vet C

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  • MGR8

Posted September 24, 2001 - 08:19 AM


The jetting that I listed above is the only
combo I have tried. I don't have any hick-ups! I am VERY happy with the performance...I was getting pretty close to selling the bike and going back to a 2 stroke because of the lack of instant "hit".

It hits instantly and very hard! Just like a 2 stroke.

Sorry I couldn't help more.


  • jaybird67k

Posted September 24, 2001 - 12:23 PM


I have no hiccups to speak of while on the track, unless I let it go all the way down to idle pull the clutch in and pop it wide from idle, but this is a throttle movement that is not consistant with any riding style I know of.
One thing to remember is this bike cannot be tuned on the stand in nuetral because the timing is different in nuetral along with the rev limiter.
So back to the question "Do you have a hiccup in your throttle?" Not unless I make one by moving the throttle faster than it is meant to be moved.
I could tell a difference with the 165 main, but I put this jet in anticipating the fall weather coming on.

I'll bet you can make just about any 426 hiccup if you walk up to it on the stand and take two hands in a rolling motion and pop it.

Later, Jason

  • forloop

Posted September 24, 2001 - 03:05 PM


That's a good point. I forgot about the timing thing for neutral.

I have not noticed any hiccup on the track while riding either. There is just a very slight one on the stand.

I just like things to be perfect.

01 YZ426F #85 Vet C

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