TOPIC:

I have now installed the Dyna s through a relay as advised. It has got a good spark on all four plugs. The timing is also spot on. The engine is turning over but no sign of wanting to spring into life.It has not run for a number of years so the next thing i was going to do was to remove and clean the carbs. Before i do that i was wondering if there was anything else i could check first. I have put new fuel and would have expected it to try and fire up. I was hoping to hear a sign of life but it just spins.
cheers 
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Have you checked compression ?
Have you tried spraying "easy start" into the airbox intake while cranking ? (if it tries to start then you know it's fuel related)

No, i have not done either as i was going to just do the carbs next as i think after a few years they might not be very good.I will get a compression tester and try those steps first. At least that will also give me a good idea of what the engine is like.
​​​​​​​Cheers 
    

In my signature, there is a link to a thread about "things to know" for new owners.  Please check that thread and go through the list.  It will help you get the bike running properly, and keep it what way.

Thank you for the info. As a complete novice, that will be very helpful.cheers    

starting fluid

as Wookie said above

Hi as mentioned before, try quick start aerosol spray directly into the air filter box. With a fully charged battery try the kick start if fitted. This ensures all the amps go to the spark plugs not the starter motor. Even with blocked jets in the carbs it should try. Next check for compression by taking out a spark plug. With your finger in the hole try the starter. It should easily blow your finger off the hole. If not then compression too low to ignite the fuel. The most likely culprit is old fuel turned to gum in the carb over the years. Before removing the carbs try putting some redex cleaner in the tank and spin the engine with the throttle wide open, to pull the mixture into carbs.leave it to stand a few days This sometimes dissolves the gum overnight. A carb removal is a major hassle especially if not absolutely needed. Has the valve timing been messed with? With compression, fuel and spark that's the only other thing that could stop engine running. My ltd only starts with the throttle shut, IE hands off the grip until if fires then gently open the throttle a bit. It is temperamental and sometimes awkward to start, but it's over 40 years old and to be expected. Hope you get sorted.

Thanks for all the advice. Good few things there for me to try. I will see how i get on and report back. Cheers  

These old z 650s were hard to start in the cold even when they were new speaking from experience. Be methodical and try the easy stuff before pulling the carbs off. If you have to remove them pour  hot soapy water over the air intake rubbers to soften them up  first as they usually split when being pulled off. Or a hair dryer. Good luck.

If your choke plunger seals are good they will start very easily whatever the temperature. 
In the op's case it's more likely blocked pilots from sitting and gummed up with ethanol. If it fires with easy start then it'll be blocked jets to check first. Whilst the carbs are off do a proper clean on them to rule out further issues that may be lurking. 

 

wrote:

These old z 650s were hard to start in the cold even when they were new speaking from experience. Be methodical and try the easy stuff before pulling the carbs off. If you have to remove them pour  hot soapy water over the air intake rubbers to soften them up  first as they usually split when being pulled off. Or a hair dryer. Good luck.

If the boots are hard to the point that they crack when removing the carbs, it's time to change them.  Regarding filling the carbs with some cleaner sauce, just say NO.  The only way I'd even consider that is if you rebuilt the carbs yourself, replacing all the rubber O-rings and fuel Tee's, fairly recently.  In that case, it would be worth a try.  With a bike that has sat, and likely has never had a proper carb rebuild in its life, I strongly recommend pulling the carbs and rebuilding them properly before even attempting to start the bike.  Even if it runs, the carbs are full of rock hard O-rings, which should be replaced regardless.  

Update on the starting issue. After the last post i had a good look and found the petcock was not working correctly. I replaced it with new one, charged the battery and gave it another try. It started up on the button first try and it is running very sweet considering it has not run for 15 years. I am very happy as the engine sounds very good. Lots of other small repairs like brakes to get on with now. Thanks for all the advice.