bk mod now bike wont start

54 replies to this topic
  • foxz

Posted July 25, 2008 - 12:25 PM


Well i decided too do the bk mod... got everything good same jet setings as it was...go to fire it up gave it 15 good kicks till it flooded...Normaly the bike starts first kick...there is gas... looked down the air box hole and its squirtin just fine..any ideas?

  • foxz

Posted July 25, 2008 - 10:01 PM


Ok got it started...i guess when i was fiddling with the throttle cable it took the boot off the plug.. im goin to put a new plug in tomarrow... it was to late to run it but it just started for like 2 seconds and just died.. i didnt give any throttle but the choke was on... would the bk mod have nayhting to do with that?cuz all that has too do with going from no throttle to wide oopen.. iride from liike maybe 100 m too some times around 1500 ish maybe lil more... where should my jet needle be? thanks!

  • foxz

Posted July 26, 2008 - 12:48 PM


thing starts.. now i just gotta jet it... its way lean

  • YZF_MXracer71

Posted July 26, 2008 - 01:10 PM


what is the bk mod??

  • grayracer513

Posted July 26, 2008 - 01:37 PM


Try Common Threads. It's under Fuel System.

  • foxz

Posted July 26, 2008 - 01:59 PM


ok.. now i went 2 clips down on the jet needle.. it sounds and has excellent respounce but within 15 seconds of runnin the header is too hot too touch... any ideas?

  • grayracer513

Posted July 26, 2008 - 02:13 PM


Running at a standstill? The needle has nothing to do with that in the first place, and in the second place, anything short of a red glow visible in open shade after a minute is normal.

  • foxz

Posted July 26, 2008 - 02:33 PM


ok i missred it then. What does the needle hvae todo with? sorry for stupid questions lol.. should i go down size on the p.j? Its not glowing as i cant see it in the sun... but after about i dono 20 ish seconds im not able to even tap it as its very hot..

  • skthom2320

Posted July 26, 2008 - 02:36 PM


Don't worry about the header. All the modern racing 4-strokes are like that! The header will get too hot to touch right after you start the bike!!!

  • foxz

Posted July 26, 2008 - 02:40 PM


oohk... it was confusing b.c the plug is spot on not wet etc and not over killed... i just dont want too hurt the bike.. runnin stock jettin so when i take it for a rip.. i might throw in what bk said worked the best for him and start from there

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  • grayracer513

Posted July 26, 2008 - 03:42 PM


but after about i dono 20 ish seconds im not able to even tap it as its very hot..

sounds normal. Touching the header under normal circumstances could easily cause a third degree burn.

To check you pilot jet setting, read this:

The needle modifies the amount of fuel coming through the main jet to meter it correctly for throttle openings between about a 1/4 up to nearly full throttle.

  • foxz

Posted July 26, 2008 - 06:46 PM


ohk...thanks ill give it a go tomarow again.. iremember it getting hot b4... i just didnt remember how hot

  • foxz

Posted July 26, 2008 - 11:43 PM


another stupid question but if it is runnin very lean/rich what is the symtoms right away so i dont hurt the motahh.. i didnt change the jetting at all so i doubt itll be but just dont wana hurt it

  • grayracer513

Posted July 27, 2008 - 12:05 AM


It will run poorly enough that you have to fix it before it will hurt the engine.

  • foxz

Posted July 27, 2008 - 12:07 AM


so it wont idle etc... it sounds diff then it used to... could be cuz i dont have the seat on exhaust is hangin lol...since i had to take the carb in and out i didnt bother puttin it all back together just put the subframe on and tested it out

  • skthom2320

Posted July 27, 2008 - 05:47 AM


thing starts.. now i just gotta jet it... its way lean

How did you decide it was too lean?

  • foxz

Posted July 27, 2008 - 09:45 AM


b.c i thought it was geting way hot... and bk mod causes it tooo lean out maybe having to richen it up?

  • grayracer513

Posted July 27, 2008 - 02:16 PM


The BK mod modifies the accelerator pump linkage only, and does not make the carb leaner or richer in any way except while the throttle is being opened.

  • foxz

Posted July 27, 2008 - 09:52 PM


well today i opened it right up.. didnt take it any where since its still apart... but it seems to be much snappier and no bog... seems like its kinda of crappin out up top... maybe cuz i have a162 jet and bk calls for a 168

  • foxz

Posted July 29, 2008 - 10:30 PM


what jettin do you think would be the best?? 42 pj 168 main? thats what bk found was the best... any one else have any diff or do i just keep tryin to find the best...what am i looking for crisper etc

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