kz1000J, Popping at Idle and While Riding

Vintage3
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kz1000J, Popping at Idle and While Riding

11 Apr 2015 12:27 - 12 Apr 2015 07:14

Guys,
Wondering if anyone has any thoughts on this. Started bike again today after one week of sitting and she is now popping while idling and popping alot and running rough while riding. Choke is in. All four cylinders appear to be running (header pipes are hot). Initially I believe one cylinder was not running while idling. Over winter I started her every 3 weeks or so (per Ed's advice as opposed to draining the float bowls) in warm storage and she fired up and ran great on idle. Carbs fyi were rebuilt two years ago (oem kit), cleaned last summer (again) and the float bowls reset so bike would not run as rich. Also last summer timing was checked and OK, the ignition system on bike is new oem and checked OK and the compression was good. Gas also has stabil in it. I checked the spark plugs and they have black soot on them. Do you think a jet(s) is gummed up? Motul I believe carries a product you can put in your gas to help clean the carbs? Seafoam? Would this help? I seem to be in a position where the carbs are having to be taken apart every year to be cleaned. I think my biggest problem is I don't ride it enough. Thanks.

Last edit: 12 Apr 2015 07:14 by Vintage3.

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78kzturbo
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Re: kz1000J Carbs

11 Apr 2015 12:31

#667514

just clean the carbs.

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kz1100warrior
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Re: kz1000J, Popping at Idle and While Riding

13 Apr 2015 03:52

#667761

Check your vacums, make sure your airholes are plugged and your vacum from tank is on correctly.

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SWest
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Re: kz1000J, Popping at Idle and While Riding

13 Apr 2015 06:58

#667771

Check you valve adjustments.
Steve

Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229

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Re: kz1000J, Popping at Idle and While Riding

13 Apr 2015 07:38

#667775

Vintage3 wrote: Guys,
Wondering if anyone has any thoughts on this. Started bike again today after one week of sitting and she is now popping while idling and popping alot and running rough while riding. Choke is in. All four cylinders appear to be running (header pipes are hot). Initially I believe one cylinder was not running while idling. Over winter I started her every 3 weeks or so (per Ed's advice as opposed to draining the float bowls) in warm storage and she fired up and ran great on idle. Carbs fyi were rebuilt two years ago (oem kit), cleaned last summer (again) and the float bowls reset so bike would not run as rich. Also last summer timing was checked and OK, the ignition system on bike is new oem and checked OK and the compression was good. Gas also has stabil in it. I checked the spark plugs and they have black soot on them. Do you think a jet(s) is gummed up? Motul I believe carries a product you can put in your gas to help clean the carbs? Seafoam? Would this help? I seem to be in a position where the carbs are having to be taken apart every year to be cleaned. I think my biggest problem is I don't ride it enough. Thanks.

I had am similar issue, also had leaky carbs from the overflow tubes... I drained out all the old gas, put 1 gallon of 100% gas (no ethanol) mixed with about 3/4 can of seafoam. Turned petcock to prime and let the bowls fill up until overflowin again, turned the bike over a few revolutions to get the !is inside, then let it sit 24 hours....

Came back to it, and the overflow problem was fixed, drained the mixture out via carbs, then filled tak with 100% gas and the remaining 1/4 can seafoam, started her up and she ran amazingly....

Maybe worth trying before tearing off the carbs...

1980 KZ750H LTD-- pods-- vance & hines 4-1 --speedo/tach/blinker/switch deletes -- brat style

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AlexDeyo
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Re: Re:kz1000J, Popping at Idle and While Riding

13 Apr 2015 08:43

#667779

This sounds pretty identical to my issue I'm having right now. I am adjusting the valve clearance and I have also bought a carb rebuild kit and will be doing a lot of tunning. You can check out my post.

First and current bike: 1979 Kawasaki KZ650B3

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bountyhunter
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Re: kz1000J, Popping at Idle and While Riding

13 Apr 2015 12:36

#667801

Do you have inline filters?

Has the tank and petcock been thoroughly cleaned?

Second on the idea of filling the carbs with cleaner like Seafoam or Gumout and letting them sit a few days then drain and refill with gas.

1979 KZ-750 Twin

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Vintage3
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Re: kz1000J, Popping at Idle and While Riding

14 Apr 2015 19:01

#667964

Guys thanks for the comments. Called the shop that did the last work on the carbs and they indicated based on what I described the gas has likely turned and noted too that 9 times out of 10 with the problems described this is the case. In retrospect I would not be surprised as I did not ride the bike much last summer and never actually fully depleted a tank before adding more fuel along with fuel stabilizer at points. I'll syphon the tank and put in some new gas and let you know how it goes over the next few days.

Cheers,

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bountyhunter
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Re: kz1000J, Popping at Idle and While Riding

14 Apr 2015 19:45

#667972

Vintage3 wrote: I'll syphon the tank and put in some new gas and let you know how it goes over the next few days.

Cheers,

Turn the tank upside down and shake it then rinse with mineral spirits or clean gas.

I still vote for a "cleaner soak" in the carbs then flush with clean gas. Whatever curdled in the tank probably gunked up the carbs.

1979 KZ-750 Twin

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SWest
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Re: kz1000J, Popping at Idle and While Riding

14 Apr 2015 20:59

#667988

Yup,yup,yup.

Steve

Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229

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Vintage3
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Re: kz1000J, Popping at Idle and While Riding

15 Apr 2015 13:04

#668083

Thanks. Put in new gas. Bike is definitely running better after a few kilometers with less back firing - but it is still popping out of the exhaust. There is also a little hesitation off the start. I was told by my shop to run a tank or two on the new gas and it should resolve itself. Is this the case primarily because there could still be gunk in the jets - assuming there was with the old gas? If there was no gunk, I gather the new gas would deliver good performance right away.

Also is it bad for the bike to ride it in this popping condition?

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SWest
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Re: kz1000J, Popping at Idle and While Riding

15 Apr 2015 13:20

#668084

Have you checked your valves?
Steve

Z1b1000 1975 Z1b
kzrider.com/forum/11-projects/598262-kz-...-will-it-live#672882
kzrider.com/forum/2-engine/597654-poser?start=240#704229

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