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Z1 tickover problem when bike is hot
Posted: Tue Jul 20, 2021 2:56 pm
Author: TopZed
Have a recently recommissioned fairly standard Z1 from 1973 that starts and runs well, but when it gets hot after a good run it wont hold tick over and stutters on pickup if the revs fall below 2k. Running in traffic makes things worse with the engine stalling abruptly when you come to a halt and needing a few goes of the starter to get it running again.
Carbs were stripped and cleaned during recommissioning and seals replaced along with a new fuel tap. Since then I've had the choke seals redone, but the problem persists. Any thoughts?
Re: Z1 tickover problem when bike is hot
Posted: Tue Jul 20, 2021 5:41 pm
Author: Al
How recent are the points capacitors / condensors?
Quick, cheap and easy to replace and the failure mode is frequently heat related.
There are good and bad new ones.
AL
Re: Z1 tickover problem when bike is hot
Posted: Wed Jul 21, 2021 7:51 am
Author: TopZed
Thks Al. I've not checked the condensers (or the coils for that matter). Wouldn't they affect the running at speed more than the tick over? Do you have a recommended source for condensers?
Re: Z1 tickover problem when bike is hot
Posted: Wed Jul 21, 2021 2:31 pm
Author: MrDavo
Float levels? It sounds more like fuel than electrics to me, but of course it could be one of several things.
As I found out, a tiny adjustment can make a big difference here. As you should have the early type carbs, check you have the correct 2.6mm float valves fitted. Most rebuild kits seem to have 2.0mm ones, and that's what was used in my rebuilt carbs. I couldn't get the float height right with these and buggered up two of my float 'tangs' trying to set the level. Using the right valves I soon got it right again.
Z Power do the correct measurement tool for the early carbs with the big 17mm drain plugs, as well as the correct float valves and matching needles, although being genuine KHI they were horribly expensive.
Re: Z1 tickover problem when bike is hot
Posted: Wed Jul 21, 2021 3:21 pm
Author: zapo
Could be running weak mixture, what do the plugs look like?
Re: Z1 tickover problem when bike is hot
Posted: Wed Jul 21, 2021 5:10 pm
Author: Al
Do you have a recommended source for condensers?
I'm sorry I don't, I've had electronic ignition for the last some odd years.
As others have said it could be any one of a number of issues and elimination is the only thing if there isn't a clear culprit.
This makes interesting reading though if you do get new condensers.
Should be easy ish to check if you get it hot and have a look at the points whilst its running in a dark garage.
https://nonlintec.com/sprite/cap_failure/AL