Throttle not dropping

[07_25_stl]

Bike idles great on startup. When I give it a blip of throttle it stays at 4k. If I bang it into gear, let the clutch out slow it will move forward and then idle normal when putting back into neutral. Give it throttle and the same thing.

Spent today tearing the carbs apart, cleaning (fluid, air & wire). Dont think anyone had ever touched the carbs, idle plugs were still there. Pulled the plugs and set the idle screws at 2 1/2.

Checked for vacuum leak all over the carb & airbox, nothing.

Here is a video:

[Linkin]

Do you have the choke on when doing this? My newgen does this with full choke, idles fine, and once warmed up (choke still on) the revs shoot up to 4k or more

[Ghostt]

Originally Posted by 07_25_stl

Bike idles great on startup. When I give it a blip of throttle it stays at 4k. If I bang it into gear, let the clutch out slow it will move forward and then idle normal when putting back into neutral. Give it throttle and the same thing.

Spent today tearing the carbs apart, cleaning (fluid, air & wire). Dont think anyone had ever touched the carbs, idle plugs were still there. Pulled the plugs and set the idle screws at 2 1/2.

Checked for vacuum leak all over the carb & airbox, nothing.

Here is a video:

Set idle @ 3 turns out, pre 08's are way lean from Kawasaki, check for vacuum leaks, and don't overlook the petcock, check for proper operation, and inspect ALL vacuum lines.

[07_25_stl]

This is post warmup, no choke.

[Motofool]

Originally Posted by 07_25_stl

This is post warmup, no choke.

Have you verified that the choke plunge in the crabs closes all the way, leaving the cable loose?

Are the valves adjusted?
Those can make idle erratic.

Are the O-rings of the idle mix screws soft and good to seal properly and stop air from leaking in?
Putting some grease over the heads of those screws is a simple way to test that.

If everything fails, I would try testing another CDI, due to the tach problem and this one.
CDI is supposed to retard the spark timing for low rpm's.

[Ghostt]

If ANY parts are in ANY doubt, replace them.

[07_25_stl]

Choke closes all the way, verified.

Valves are next on the list to do.

Put new o-rings in yesterday as part of the carb rebuild.

The idle isn't erratic, just doesnt return to idle after giving it throttle. It is like the throttle doesn't return but I have made sure that it does.

I am well versed with carbs, used to working on jetskis. Rebuilt several Polaris with blown piston rings.

[07_25_stl]

Adjusted it to 3 turns out. When cold everything is great. Once warmed up though the symptom returns.

Will tackle the valves next.

[Ghostt]

Once you get it back to running properly, I'd do the main needle shim modification, also IMHO the mains are lean from the factory, pick up one size larger main jets, and some 4mm washers to shim with, cheaper than a rip off jet kit IMHO

[cadd]

I have the same exact issue with my 09. While riding, when I close the throttle, rpms don't drop immediately. Takes a few seconds for it to drop from 4k down to the 1300 idle speed.

I can be cruising along at 7k rpm and when I close the throttle and pull the clutch in, same thing. Takes a bit of time before the motor drops back down to idle speed.

Like you, I tore the carbs apart 2x to clean. A/F screw to 2.5 turns out.

Used carb cleaner (and starter fluid) to spray around boot areas to check for leaks. All negative.

I just got used to it. No harm, no foul.

Have you noticed your mpg suffering? I'm only getting in the low to mid 40s riding normally. And when I get aggressive, I'm in the high 30mpg range.

I'll keep an eye on this thread to see if you find a solution to the issue. Good luck!

[07_25_stl]

Picked up the bike 2 weeks ago for a steal, haven't really taken it out to even know about my mpg.

[edward2014]

My bike used to idle around 4~5K. It could not tune the knob down. My shop suggest to rebuild the carb and find it have pins bend a little bit. Don't know whether we have same problem. Just my 2 cents

[fast1075]

You still have plugged air bleeds, pilot jets, or transition ports.

[Ghostt]

Originally Posted by fast1075

You still have plugged air bleeds, pilot jets, or transition ports.

Finally somebody else whom understands the workings of a CV carburetor, thank you kind sir, I was starting to feel all alone here.

On a less serious note, try some this stuff I hear it fixes everything that could go wrong with the bike, 1000 times better than SEAFOAM.

[jkv45]

When you had the carbs off did you completely remove the idle mixture screws and clean the passages? Did the screws have an o-ring and a washer on them?

Did you remove the Pilot Jet and run a small soft wire through the holes, then spray with carb cleaner and blow out? Did you remove the Main Jet and jet holder, and do the same?

Gas is fresh?

Have you synced the carbs?

What does it do when you add 1/4 choke when it's hot? Run better or worse? Does the hanging-idle problem go away or get worse?

[07_25_stl]

Originally Posted by jkv45

When you had the carbs off did you completely remove the idle mixture screws and clean the passages? Did the screws have an o-ring and a washer on them?

Did you remove the Pilot Jet and run a small soft wire through the holes, then spray with carb cleaner and blow out? Did you remove the Main Jet and jet holder, and do the same?

Gas is fresh?

Have you synced the carbs?

What does it do when you add 1/4 choke when it's hot? Run better or worse? Does the hanging-idle problem go away or get worse?

removed all screws, jets, etc. Used copper wire through each and every hole. Separated each carb and let each sit in Chem-Dip. Rinsed, cleaned & blew out with air.

When cold I can crank the throttle all the way up and it will drop down correctly.

When warm 1/4 or 1/2 throttle rpm will stay between 3500-4000. Put it in gear and let out a little and the rpms will drop as expected.

My only concern is that it bangs into 1st when the rpms are that high (separate issue, clutch cable is stretched and getting replaced).

[jkv45]

Originally Posted by 07_25_stl

removed all screws, jets, etc. Used copper wire through each and every hole. Separated each carb and let each sit in Chem-Dip. Rinsed, cleaned & blew out with air.

When cold I can crank the throttle all the way up and it will drop down correctly.

When warm 1/4 or 1/2 throttle rpm will stay between 3500-4000. Put it in gear and let out a little and the rpms will drop as expected.

My only concern is that it bangs into 1st when the rpms are that high (separate issue, clutch cable is stretched and getting replaced).

That's making me think it's getting additional fuel from the enrichment (choke) circuit. I would look into that like Motofool suggested.

I'd also look at the color of the plugs - which would be dark if that was the case.

I know you checked, but that is also typical of a vacuum leak.

Dropping into gear at higher RPMs from neutral has got to be hard on the trans. I don't think it's a clutch issue, I think it's because there's a significant difference between the part of the trans that is spinning and the part that isn't.