Z1 little project........

Johno23

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Waiting for a few bits to finish the Norton, so decided to use the time to try and sort an issue with the Z1.
Anyone out there with experience of these, feel free to comment.........
The problem I’ve had with it is it runs really rich. So much so that after only a short time the plugs foul, especially cylinder 2 which basically stops running, so bike goes onto 3 cylinders:(.
I’ve taken the carbs off, all jets are std as is the exhaust and air filter. I have sent the choke plungers off to a guy who adds Viton seats to them so they should seal ok when refitted. I don’t know if they were seating ok or not but after 45 years I can’t imagine the original rubber on them was very good so hope this may help the problem. The only other thing I have noticed is that the needles are on notch 3 but I have read that they should be on 2 so will drop them the one notch which should lean it off a little. If this doesn’t work, I’ll have to go back to the drawing board. So as I said anyone on here with experience of these, please pipe up:D Bike is 1975 Z1B.
 

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Jaysus Johno,you've got some nice bikes!!!

Sorry,can't help with the problem but will follow this thread because I always loved the Zeds

Good luck mate

Kimbo
 
My 1984 CB700SC was running rich, smoky exhaust and blackened plugs on a couple of cylinders.
I found the choke pivot mechanism ever so slightly seized, and not fully opening....ie, partly staying on.
Copious amounts of GT-85 and several rapid operating motions freed it all off. :thumb
 
My money is also on sticking/not seating choke mechs, I've had same on an XS850 and XS750 back in the day.

Andres
 
Alan Milliyard had the same problem on the 6 cylinder Z1 he has just made and showed the sticking choke fix in one of his videos on YouTube


Sent from my iPad using Tapatalk
 
That XS looks great value.......... I mustn’t........No......I like those.......No!

Had the choke plungers back and I’ve put them in and lowered the needles. Carbs go back on tomorrow so hopefully she’ll be running a lot better :thumb.
 
Take a good look at the slide needles and jets,( they may well be a combined emulsion tube/jet.
The needles can move a bit and wear the top of the tube allowing fuel to bleed into the Venturi.
End result is a really rich mixture just off idle,if badly worn it will affect idle mixture as well
 
Take a good look at the slide needles and jets,( they may well be a combined emulsion tube/jet.
The needles can move a bit and wear the top of the tube allowing fuel to bleed into the Venturi.
End result is a really rich mixture just off idle,if badly worn it will affect idle mixture as well

Thanks for that will check that out. The bike has only 27k on it which I believe is genuine, I would hope that there wouldn’t be that much wear in the needle and jet with that mileage, but cert worth checking ..cheers.:thumb
 


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