Go Back   Motorcycle Forum > Manufacturer Forums > Kawasaki

Reply
 
Thread Tools
Old 08-26-2009, 01:37 PM   #1
kwackernut
Registered Member
 
Join Date: Aug 2009
Posts: 4
Talking ZXR750R tickover problems

My ZXR750R (K) was laid up for a couple of years following a problem and is now nearing completion. I have cleaned and rebuilt the flatslides using an ultrasound bath, set the float height and re-sealed the inlet rubbers. The bike will fire up easily and run (and respond ) well on choke, but as soon as it warms up and the choke is off, the bike will either go straight to 5,000 rpm or settle at tick over where the slightest movement of the throttle kills the engine or sends the rpm upto 5,000 again. Sounds like an air leak - but how, the inlet rubbers are not split and are hylomar'd to the head. All attempts at balancing fail because i think the fault is more fundamental than that.
The pilot screws are set to 1 and 5/8th's out.
I have also checked the wiring to the fuel pump and solenoid (Does the fuel pump only operate when the starter is engaged ?).
I noted that the needle valves are set at differing clips for the outside and the inside pots, carbs 1 and 4 are 4th groove from top, carbs 2 and 3 are 6th groove from top (these have not been adjusted since it last ran well).

If anyone has any advice i would appreciate it as im pulling what hair i have left out !

Kwackernut (Dying to get that manic grin that comes from ZXR ownership back).
kwackernut is offline   Reply With Quote

Sponsored Links Remove Advertisements
Motorcycle Forum
Advertisement
Old 08-26-2009, 02:19 PM   #2
longride
Super Duper Mod Man

 
longride's Avatar
 
Join Date: Nov 2001
Location: Anywhere they let me
Posts: 10,479
Default

Sounds like your pilot jets got clogged up when it was laid up. I know you say you cleaned the carbs, but pilot jets are awfully small and need to be looked at. Since it idles and runs at 5000 rpm +, I'd say the pilot jets are the culprit.
__________________
I'm a knucklehead
longride is offline   Reply With Quote
Old 08-26-2009, 03:16 PM   #3
seruzawa
The Toad

 
seruzawa's Avatar
 
Join Date: Nov 2001
Location: 8501 ft.
Posts: 17,461
Default

Make sure that the choke is completely off. Many of those bikes had mixture enrichening curcuits and if the choke lever on the carb bank is not completely closed the bike will run very strangely. In the past I have had to rig a spring on the actuating lever to make sure it stays closed. I'm taking about the choke lever on the carbs, not the choke control on the handlebar.
__________________
"Make no mistake, Communism lost a big argument - one we know today as the 20th century."
seruzawa is offline   Reply With Quote
Old 08-27-2009, 11:59 AM   #4
kwackernut
Registered Member
 
Join Date: Aug 2009
Posts: 4
Default ZXR750R Carbs

Quote:
Originally Posted by longride View Post
Sounds like your pilot jets got clogged up when it was laid up. I know you say you cleaned the carbs, but pilot jets are awfully small and need to be looked at. Since it idles and runs at 5000 rpm +, I'd say the pilot jets are the culprit.

Thanks longride. You may well be right, although i cleaned them in the ultrasound bath, the drilling for the pilot jet is very small and could easily be blocked. Hopefully the bath can dislodge the fuel varnish, if it can't, im not sure what else to do to clear it - im loathed to stick wire in the hole. Kwackernut.
kwackernut is offline   Reply With Quote
Old 08-27-2009, 12:08 PM   #5
seruzawa
The Toad

 
seruzawa's Avatar
 
Join Date: Nov 2001
Location: 8501 ft.
Posts: 17,461
Default

Quote:
Originally Posted by kwackernut View Post
Thanks longride. You may well be right, although i cleaned them in the ultrasound bath, the drilling for the pilot jet is very small and could easily be blocked. Hopefully the bath can dislodge the fuel varnish, if it can't, im not sure what else to do to clear it - im loathed to stick wire in the hole. Kwackernut.
You can use soft copper wire carefully. Works pretty good.
__________________
"Make no mistake, Communism lost a big argument - one we know today as the 20th century."
seruzawa is offline   Reply With Quote
Old 08-27-2009, 12:16 PM   #6
kwackernut
Registered Member
 
Join Date: Aug 2009
Posts: 4
Talking ZXR750R Carbs

Quote:
Originally Posted by seruzawa View Post
Make sure that the choke is completely off. Many of those bikes had mixture enrichening curcuits and if the choke lever on the carb bank is not completely closed the bike will run very strangely. In the past I have had to rig a spring on the actuating lever to make sure it stays closed. I'm taking about the choke lever on the carbs, not the choke control on the handlebar.
Cheers Seruzawa. I have just been and checked the choke lever, the carbs have a spring return on them, the linkage is smooth and the lever returns to fully off when selected on the choke control. Thanks for the advice. Kwackernut.
kwackernut is offline   Reply With Quote
Old 08-27-2009, 12:20 PM   #7
kwackernut
Registered Member
 
Join Date: Aug 2009
Posts: 4
Default ZXR750R Carbs

Quote:
Originally Posted by seruzawa View Post
You can use soft copper wire carefully. Works pretty good.
Thanks again Seruzawa. Will give it a try if all else fails. Kwackernut.
kwackernut is offline   Reply With Quote
Reply


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off