nasty lag at quick decel..?


5 replies to this topic
  • thumpin hard

Posted July 01, 2007 - 12:41 PM

#1

it breathes,hotcam stage2,white bros e 2 pipe,ran well untill i had a cam installed and had it dyno tuned at a shop..at sea level it is spot on with a 150 main and i put in a 55 idle jet..but this vacuum slide keihin carb has a nasty drop off when you decel quickly..if you are on the highway and go downhill it dies out and then come back for a good 1-2 seconds..anybody know if it could be a slide or needle problem? i wonder if the slide spring is weak or maybe too stiff or long with the addition of the cam. any help here would be really appreciated!..heck i am beginning to wonder if it is something electrical..but unlikely..and i have tried going down to a 145 on the main..just seemed too lean then. thanks!

  • Dual_Dog

Posted July 01, 2007 - 03:12 PM

#2

it breathes,hotcam stage2,white bros e 2 pipe,ran well untill i had a cam installed and had it dyno tuned at a shop..at sea level it is spot on with a 150 main and i put in a 55 idle jet..but this vacuum slide keihin carb has a nasty drop off when you decel quickly..if you are on the highway and go downhill it dies out and then come back for a good 1-2 seconds..anybody know if it could be a slide or needle problem?

Definitely a CV (XRL) carb problem that can be remedied. Have you done the standard CV carb mods yet, meaning drilling the (2) vacuum piston holes & shimming the jet needle? Those changes are critical for solving the well-known XRL performance issues, along with rejetting & adjusting the pilot screw. :thumbsup:

I ride at sea level all the way up to 5K & higher in elevation (stock cam) with richer jets, a shimmed needle a drilled slide with no issues. Other mods include a slip-on pipe, Uni air filter & no air box snorkel.

i wonder if the slide spring is weak or maybe too stiff or long with the addition of the cam. any help here would be really appreciated!..heck i am beginning to wonder if it is something electrical..but unlikely..and i have tried going down to a 145 on the main..just seemed too lean then. thanks!

These bikes are set way too lean from the factory to begin with. After any intake, motor or exhaust mods it only gets worse, much worse...

Before your cam mod & with all the other mods, you should probably be running at least a 158 main & a 58 pilot, nothing smaller at sea level. With a cam mod you're now looking at having to go with larger jets, say 160 or 162 main & a 60 pj. It does take some experimentation to get it dialed in, but jets really aren't that expensive & the return on the investment is well worth it. :thumbsup:

Keep Ridin'
D_D

  • thumpin hard

Posted July 02, 2007 - 07:42 PM

#3

Definitely a CV (XRL) carb problem that can be remedied. Have you done the standard CV carb mods yet, meaning drilling the (2) vacuum piston holes & shimming the jet needle? Those changes are critical for solving the well-known XRL performance issues, along with rejetting & adjusting the pilot screw. :busted:

I ride at sea level all the way up to 5K & higher in elevation (stock cam) with richer jets, a shimmed needle a drilled slide with no issues. Other mods include a slip-on pipe, Uni air filter & no air box snorkel.


These bikes are set way too lean from the factory to begin with. After any intake, motor or exhaust mods it only gets worse, much worse...

Before your cam mod & with all the other mods, you should probably be running at least a 158 main & a 58 pilot, nothing smaller at sea level. With a cam mod you're now looking at having to go with larger jets, say 160 or 162 main & a 60 pj. It does take some experimentation to get it dialed in, but jets really aren't that expensive & the return on the investment is well worth it. :thumbsup:

Keep Ridin'
D_D



thanks for the input,i checked the sixe of the holes and the shim..it is a 30 shim and the two holes are opened up to 5/32.. i am going to try opening up the main to 160..but i doubt it will help with the lag at decel.
once again thanks,but i am back at the same problem..but maybe a litle less lag with the 155 main over the 150 main..hmm?:thumbsup:

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  • Denn10

Posted July 03, 2007 - 06:25 AM

#4

Id swear i already posted on this with others??? deja vu or what?? Oh well i would go 58/160 or even 162 thats what im using on mine here and others also it works well. The pilot will help your decel it helped mine

  • Dual_Dog

Posted July 03, 2007 - 03:46 PM

#5

What is the pilot screw set at & how's the condition of the spark plug?

  • thumpin hard

Posted July 04, 2007 - 08:42 PM

#6

plug is new..i tried the 160 main..but with the 60 or even 58 idle jet i had to turn the screw all the way in...and i put it back the way it was for comparison..now it is cutting out in the mid range..and opens up with full throttle..maybe i have to bypass the sidestand now..seems i have an electrical problem too!!...

update : the cutting out was that the slide spring was too short..i tried to lengthe it and it helped..no more cutting out and the delay is shorter...but it seems way too rich with the 160 main as i had to turn the pilot all the way in with a 58..maybe a 55 would work...but i woner if i have some other problem..i disconnected the sidestand switch and the bike still runs....i had tried to ake the green plug under the seat and cut the wires as shown here...but it didnt disable anything..it still acts as though the shift switch is still active??





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