Carb setup
- Kawboy74
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Carb setup
03 Jul 2026 07:51
Well, I got the cap venting corrected but still having run issues. I methodically went through the Sudco carb setup instructions for 29’s, base line carb with 1/2mm wire using the idle screw, moved on to the others adjusting through tops of carbs. Float height at 23mm and installed carbs. New intake boots, no filters and bike will not run without 1/3 choke, reducing the idle while backing off choke makes engine race upwards to 5-6 thousand. At a loss as to cause. Initially had trouble getting carbs to accept fuel so going to try avoiding gas tank and having fuel flow into supply tube directly. Was never able to see fuel fill the filter I utilized which is puzzling even with engine off and fuel on.
Getting very discouraged as I wanna drive this thing. Any advice will be extremely appreciated.
Thanks
David
Getting very discouraged as I wanna drive this thing. Any advice will be extremely appreciated.
Thanks
David
1974 Z1A As original as I could get it
'88 ZX750R braided lines, mostly original
KZ1000 project on the bench
Burlington,Ontario,Canada
'88 ZX750R braided lines, mostly original
KZ1000 project on the bench
Burlington,Ontario,Canada
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- asphalt900
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Re: Carb setup
03 Jul 2026 08:52
Aggravating for sure. I've never used that "wire" initial slide
setting thingy so irrelevant to my process. Because the 29's used a Jet Block, have you had it pulled out? A critical thing about when using these is having a "sealed" Jet Block/Gasket/Casting assembly. The vacuum from venturi won't pull up the access of fuel from pilot if not sealed. These gaskets are paper thin mind you so castings and orientation when assembly is critical. Don't tighten that little Phillips headed screw down unless you have the slide in place. And make sure the gasket is correctly placed so "hole" in gasket is properly positioned for fuel flow from pilot. I've always used a small drill bit to position them as i lower the jet block into position. Overall, sounds like a pilot fuel issue. I take an unorthodox approach when cleaning carbs, i water blast the galleys. You can witness the flow when doing this. I know i'm bizarre and do goofy stuff..but it's better then just shooting solvent down a hole. Also because the Air Screw is unique to these make sure the hole in the end is free and clear. Some additional photos for Your 101 class of study ha.
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- Kawboy74
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Re: Carb setup
03 Jul 2026 12:25
Thanks for that info. I used an ultrasonic cleaner on the bodies for 2 hours, with heat then blew out all orifices with compressed air. I’m paranoid about pulling out those jet blocks until I’ve determined it isn’t anything else. I’m going to try a remote small fuel tank and go straight into the carbs avoiding the fuel filter. It’s strange how the filter won’t fill, even with motor off and petcock on, almost like a vapour lock. I was just loaned another set of 29’s so that will help locate the culprit.
Thanks
David
Thanks
David
1974 Z1A As original as I could get it
'88 ZX750R braided lines, mostly original
KZ1000 project on the bench
Burlington,Ontario,Canada
'88 ZX750R braided lines, mostly original
KZ1000 project on the bench
Burlington,Ontario,Canada
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- asphalt900
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Re: Carb setup
Yesterday 02:40
Perhaps moot but have you removed the individual float needle seats? There's a little filter on each float seat that snaps on, debris can build-up behind these preventing petrol flow. Also, floats assembled correctly? Look for bowl gasket to float interference too. Don't know what gaskets you are using but aftermarket replacements "could" be too wide? Just things to ponder..
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- Kawboy74
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Re: Carb setup
Yesterday 07:19
All critical points to consider. I’ve had the float valves apart and cleaned, pilot jet passages cleaned and new pilot jets installed, air/fuel mixture screws out, cleaned and reused as I don’t tend to trust much aftermarket stuff.
Float heights were set to 23mm and as the problem seems lean lower down the rpm, seemingly a lean condition, didn’t check to see if they float in gas.
My friend tried an AI app to see what could be learned and it stressed the pilot circuit, providing lots of gas flows out of the bowl nuts indicating sufficient fuel supply. I think trying the other set of carbs may also indicate the correct path as well.
Thanks for your valued input.
David
Float heights were set to 23mm and as the problem seems lean lower down the rpm, seemingly a lean condition, didn’t check to see if they float in gas.
My friend tried an AI app to see what could be learned and it stressed the pilot circuit, providing lots of gas flows out of the bowl nuts indicating sufficient fuel supply. I think trying the other set of carbs may also indicate the correct path as well.
Thanks for your valued input.
David
1974 Z1A As original as I could get it
'88 ZX750R braided lines, mostly original
KZ1000 project on the bench
Burlington,Ontario,Canada
'88 ZX750R braided lines, mostly original
KZ1000 project on the bench
Burlington,Ontario,Canada
Please Log in or Create an account to join the conversation.
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