Z1A starting problems

[Tonka]

Hi, I eventually got round to finishing off my Z1A yesterday and took it for it's MOT which I am glad to say it sailed through.

However I now have a starting problem that was not there before I took it off the road. It starts fine and runs well but when it gets really hot and I switch it off and try t restart it, it just won't restart. If I leave for say 30 minutes to cool down it then starts back up.

Whilst it is in it's petulant none start mode it cranks over ok, there is a spark at the plugs and the fuel is getting through but will not even begin to fire up. It's not even trying to start on a couple of cylinders.

Can't be a coil as at least two cylinders would fire and the points have a nice spark to them. Any ideas guys?

[kev edwards]

If you are getting fuel and sparks i would check for air leaks then check camshaft timings clearances and ignition timings, a compression test would be on the cards as well

[Tonka]

If you are getting fuel and sparks i would check for air leaks then check camshaft timings clearances and ignition timings, a compression test would be on the cards as well

Hi kev, can't be camshaft timings or compressions as runs fine until I switch it off, just won't restart again until it cools down a bit. Then it will restart immediately and goes very well on the road.

It must be electrical so was wondering if it was the condensers, ignition switch, rectifier etc??? Things got me flummoxed

[PAULJAC47]

Neil,This may well be coils breaking down under load,you may well be getting a spark but as the coils get hotter they may well start to fail,if you have another set(off a running bike)swop over to see if inproves!!wouldnt hurt to test hot and cold compression either!also check vent snail is clear in the filler cap,bike would run for a time if this is blocked or partially blocked,open the cap a little when the fault occurs and note any improvement..take off yout fuel lines and make sure you have a good flow.Cheers Paul J

[sid123]

old fuel !? drain tanke and carb fill with fresh away you go

Sid

[Steve S]

What work have you carried out prior to getting it back on the road? may guide us/you to the problem.

[Tonka]

Hi, it started straight up this afternoon but must admit that it is not running as sweet as it could.

I had the carbs all refurbed last year but only just got round to fitting them the other week. new fuel in the tank as well.

It runs ok and will not cut out but if you get it really hot and then switch it off on purpose and then try to restart it, it just turns over without a glimmer of even one of the cylinders even attempting to fire up. Wait till it gets cool and it will start on the first touch of the button!!!

What should the valve clearances be by the way? I don't think these are right but confident that this is just another side issue.

Blimey - why do we bother sometimes

[kas750]

What should the valve clearances be by the way? I don't think these are right but confident that this is just another side issue.

Love that!


Tight valves will definitely give those symptoms, along with another dozen things .You need to do a compression test and check the valve clearances.....It could also be float valves leaking or choke plungers not seating...Have you done a plug chop?

[Tonka]

Hi, yep done a plug chop. Just took the cam cover top off to check the clearances but not 100% sure what they should be though.

[PAULJAC47]

Bewteen 2 and four thou,i go for 3 thou as ideal!!

[kas750]

or 0.05-0.10 in metric.

[Tonka]

Huston we have a problem then!

The clearances are nothing like that.

[PAULJAC47]

What clearances you getting Neil?

[Tonka]

What clearances you getting Neil?

My snap-on feeler gauges only go down to 0.05 and this is the only gauge I can get in some of them and that is tight when cold as well. Some of them I can't get the gauge in at all. So as this clearance is so small I doubt here is any on some of the valves.

[PAULJAC47]

Thats your problem then Mate,time for the Shim tool and club shims!!!