High Idle, Backfiring at Low RPMs after Rejet

[MNgs500]

I recently rejetted to 20/65/142.5 with a K&N Lunchbox and Stock Exhaust(Drilled). Prior to this I did a horrible rejet of 17.5/75/132.5 with bogging at 6k.

My current problem is when I first start it idles wherever I set the idle screw(1400rpm), once I rev the engine it will hang at 5000-6500rpm and this will be the new idle. The bike has great power at 7000k-redline. I readjusted the the mixture screw to 2.5 and 3 turns out but doesn't do anything different. I did make sure the throttle snaps back.

Any help would be great.


I can get pictures once I get home.

[JAS6377]

Check the vacuum hose routing and for leaks around the carb boots. High, or hanging, idle is generally caused by a lean condition.

[MNgs500]

What can i do do fix the lean issue. As i said i put richer jets in the accomondate for the air lunchbox and standard rejet

Sent from GS3

[MNgs500]

Sent from GS3

[MNgs500]

Sent from GS3

[MNgs500]

found this crack in the t tube that is on the carb breather tube could this by my problem

Sent from GS3

[MNgs500]

So last night I installed a single #3 washer on each needle. This helped with the mid-range. I do notice small backfiring at idle when i snap the throttle. my current setup is:
Pilot-20
Mid-65
Main-142.5
1 Washer
3 turns out
K&N lunchbox intake
Stock Exhaust

Any help would be great. 

[Gorilla]

have looked at this thread?

http://gstwins.com/gsboard/index.php?topic=41199.0

[rexpepper651]

have looked at this thread?

http://gstwins.com/gsboard/index.php?topic=41199.0

thank you, this info was helpful.

[MNgs500]

I have looked at it and most i tried yo eliminate the first time. The throttle snaps back everywhere the chock does go back to regular position. I do check all the seals and tightened them good not sure how to do the wd 40 check. But for the idle i start the bike intially and the idle sets at wherever i adjust it to. Then if i rev ot holds at 4-5k and if i try to lower the idle screw ot slowly drops but lower then my inital set idle.

Sent from GS3

[rexpepper651]

wd40 check is easy start the bike and spray small mists of wd40 on the carb boots if no engine rev move on to airbox carb boots and so on till you find where the air leak is. you from minnesota?

[BockinBboy]

Idle should only be set once the bike is fully warmed up.  I'd say at least 10min running, some might say more...

Also on the choke - Do you mean 'goes back to regular position' as in at the handlebar?... or did you actually check that the choke mechanism at the carbs is returning properly and spring is connected correctly, etc?

- Bboy

[MNgs500]

wd40 check is easy start the bike and spray small mists of wd40 on the carb boots if no engine rev move on to airbox carb boots and so on till you find where the air leak is. you from minnesota?

sweet I did that i noticed the carb boot between the engine and boot the wd40 was going through there so I will replace those hopefully that is the problem. And a lot of going through there.

And yes im in Ramsey, Minnesota

[MNgs500]

Idle should only be set once the bike is fully warmed up.  I'd say at least 10min running, some might say more...

Also on the choke - Do you mean 'goes back to regular position' as in at the handlebar?... or did you actually check that the choke mechanism at the carbs is returning properly and spring is connect right, etc?

- Bboy

Both the handlebar lever and the slide on the carb goes back it is very stiff though when pull the choke on.

[MNgs500]

On the carb boot#21 it looks like the gasket is replaceable#22.

[attachment deleted by admin]

[rexpepper651]

awesome dude! havent see any other gs's on the road here in mn im in washington county.

[MNgs500]

awesome dude! havent see any other gs's on the road here in mn im in washington county.

I have seen about 3 others in the past 2 years of riding but I just ordered the carb boot locally going to pick it up I really hope this is the problem. I love my bike its my first and I just have to much fun on it

[attachment deleted by admin]

[rexpepper651]

yeah i try an get most my parts either at bobs cycle or the hitching post right down here on concord. my first bike too such a joy to ride! safe riding! hope you get everything squared away!

[MNgs500]

This part is becoming a real challenge to get.

[rexpepper651]

partzilla might have the gasket and the boot. i got my boots from hitching post but i dont think mine had a gasket too.