VM 26 Issues

[mac1029]

Okay been trying to dial in this carb to no avail, so wanted to see if the carb gurus can chime in.
Background airbox mod with K&N filter, Ebay exhaust, valve lash just reset after 100 miles to .03/.04., i am at 600-700ft elevation. Mikuni carb is jetted with 27.5 pilot with 120 main needle on center notch.
All seems to run good except when i am in the WOT position, it will pull but then hesitate and pull again like its cutting out? now after i return from a ride when i stop the idle will drop low and engine will die, but will restart no problem.
I am no carb guru hell it took me 2 months to dial in my harley, but this one has me baffled as to which way to go?

[Megadan]

Originally Posted by mac1029

Okay been trying to dial in this carb to no avail, so wanted to see if the carb gurus can chime in.
Background airbox mod with K&N filter, Ebay exhaust, valve lash just reset after 100 miles to .03/.04., i am at 600-700ft elevation. Mikuni carb is jetted with 27.5 pilot with 120 main needle on center notch.
All seems to run good except when i am in the WOT position, it will pull but then hesitate and pull again like its cutting out? now after i return from a ride when i stop the idle will drop low and engine will die, but will restart no problem.
I am no carb guru hell it took me 2 months to dial in my harley, but this one has me baffled as to which way to go?

You are likely too rich on the main jet, but that hesitation may also be the transition from needle to main being too lean, then it richens up again. Drop the needle clip down 1 notch (raise the needle) and go for a ride and see how it changes. If it still does it put in a 115 main jet and see how it behaves. If you have a 117.5 on hand you can give that a try first.

As far as dying out when you come to a stop, what is your idle mixture screw set at?n Sounds like it may be also a bit rich on that circuit as well.

EDIT: Just to emphasize this point. Make sure to wait until the bike is fully up to temp before making any notes on the change of the tune.

[mac1029]

Originally Posted by Megadan

You are likely too rich on the main jet, but that hesitation may also be the transition from needle to main being too lean, then it richens up again. Drop the needle clip down 1 notch (raise the needle) and go for a ride and see how it changes. If it still does it put in a 115 main jet and see how it behaves. If you have a 117.5 on hand you can give that a try first.

As far as dying out when you come to a stop, what is your idle mixture screw set at?n Sounds like it may be also a bit rich on that circuit as well.

EDIT: Just to emphasize this point. Make sure to wait until the bike is fully up to temp before making any notes on the change of the tune.

Thanks Dan appreciate the quick reply and will do the following

[mac1029]

Originally Posted by Megadan

You are likely too rich on the main jet, but that hesitation may also be the transition from needle to main being too lean, then it richens up again. Drop the needle clip down 1 notch (raise the needle) and go for a ride and see how it changes. If it still does it put in a 115 main jet and see how it behaves. If you have a 117.5 on hand you can give that a try first.

As far as dying out when you come to a stop, what is your idle mixture screw set at?n Sounds like it may be also a bit rich on that circuit as well.

EDIT: Just to emphasize this point. Make sure to wait until the bike is fully up to temp before making any notes on the change of the tune.

Well we have BINGO on my main jet setting, pulled great through 3/4 to WOT.
Now still got the idle issue with the 27.5 i have been at 1 1/4 ,1 1/2 and 1 3/4 turns out , now when i finish my ride i can stop and idle is normal for about 30 secs to a minute then it dies??? but it does idle down and stumble right before it does.
Edit: i did have a 25 pilot in and recommendation was to increase size due to it stalling when blipping the throttle

[Megadan]

Try the idle mixture at 1 turn out. If that doeant help, go back to the 25.

[mac1029]

Originally Posted by Megadan

Try the idle mixture at 1 turn out. If that doeant help, go back to the 25.

Thanks Dan i really appreciated your knowledge and input, especially since this topic has been wrung through the wringer, but my search didnt give me any answers.
Hope your build is going well and look forward to your videos.

[roundhouse]

dan is the man!

[Ariel Red Hunter]

Originally Posted by mac1029

Well we have BINGO on my main jet setting, pulled great through 3/4 to WOT.
Now still got the idle issue with the 27.5 i have been at 1 1/4 ,1 1/2 and 1 3/4 turns out , now when i finish my ride i can stop and idle is normal for about 30 secs to a minute then it dies??? but it does idle down and stumble right before it does.
Edit: i did have a 25 pilot in and recommendation was to increase size due to it stalling when blipping the throttle

Throttle blippers do require a larger pilot jet, or a throttle slide with less cut-away...ARH