rejet for summer..??


9 replies to this topic
  • PATHPOUNDER

Posted April 22, 2007 - 05:40 PM

#1

I noticed on todays ride..my hot start was not performing as it has in the past..The bike wouldnt start with it pulled..and then started with it closed..
It ran well,but I was thinking I may need to rejet for summer,its starting to heat up down here..Maybe this is why..too lean..???

  • Yamahafan

Posted April 22, 2007 - 05:58 PM

#2

How hot is it? What is your current jetting? I generally jet for 75 degrees and then go down or up one main jet size for each 15 degrees.

When it warms up your existing main will become too RICH, not too lean.

Regarding hotstart - Were you starting the bike when it was already hot?

More info please.

  • grayracer513

Posted April 22, 2007 - 08:20 PM

#3

When it warms up your existing main will become too RICH, not too lean.

That's right.

  • Racer24

Posted April 22, 2007 - 08:46 PM

#4

less O2 concentration in warmer temps..so basically you are getting less air into the bike, therfore the bike becomes richer, because there is less air, that means that there is more fuel then there is air...

  • PATHPOUNDER

Posted April 23, 2007 - 04:40 AM

#5

Thanks guys..so my bike is getting richer...Yes, the bike was not overheating but hot after lots of 2nd gear singletrack..normally when it doesnt start, Ill pull the hot start and it will fire right up..yesterday that didnt happen..and it fired..after I closed the hot start and kicked again..It was about 80 yesterday here, and 90 and 100 are just around the corner..

Last summer when it got hot and humid..the bike started running like crap so I dropped the needle a position and it cleaned it right up..

do you guys ghange your mains in the summer..?

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  • Yamahafan

Posted April 23, 2007 - 05:08 AM

#6

What jetting are you running now?

Yes, I drop my main jet one size (#168 --> #165) in the summer for 85 degrees or warmer.

  • Racer24

Posted April 23, 2007 - 01:39 PM

#7

Thanks guys..so my bike is getting richer...Yes, the bike was not overheating but hot after lots of 2nd gear singletrack..normally when it doesnt start, Ill pull the hot start and it will fire right up..yesterday that didnt happen..and it fired..after I closed the hot start and kicked again..It was about 80 yesterday here, and 90 and 100 are just around the corner..

Last summer when it got hot and humid..the bike started running like crap so I dropped the needle a position and it cleaned it right up..

do you guys ghange your mains in the summer..?


Yes Warmer temps mean the bike is getting richer...i change my main for the summer and winter (170,175 or 180 )

  • PATHPOUNDER

Posted April 23, 2007 - 03:28 PM

#8

What jetting are you running now?

Yes, I drop my main jet one size (#168 --> #165) in the summer for 85 degrees or warmer.



I have a 165 main in now.....I dropped my needle one groove position...bike ran great all winter and was fine the other day..cept for the hot start not acting as it normally does...

  • Yamahafan

Posted April 23, 2007 - 04:45 PM

#9

What year bike do you have? If your bike ran fine I wouldn't fiddle with it. You might try a #162 when it hits 90 just to see what affect it has, but if it ain't broke, don't fix it.

P.S. It is funny that you are asking about summer jetting already when I just had my first ride on Saturday.

  • PATHPOUNDER

Posted April 23, 2007 - 05:35 PM

#10

What year bike do you have? If your bike ran fine I wouldn't fiddle with it. You might try a #162 when it hits 90 just to see what affect it has, but if it ain't broke, don't fix it.

P.S. It is funny that you are asking about summer jetting already when I just had my first ride on Saturday.


Yeah,this is Arizona, we had our first one hundred degree day in March...And I betting in the next couple weeks it will be in the mid to high nineties..

Yes, I may try a 162 when it warms up more..Im also going to check the valves...Its been a while..Its an 01 426..great machine..Its been running awesome..just the hot start thing on Sunday was definatly different..

I rode some awesome singletrack on Sunday..and there wasnt any hill that bike woudnt pull..And let me tell you..there were some long steep ones..!!!:applause:





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