My 1989 FZR 600 refuses to start when the temperature is below double figures.

I've replaced the coils/HT leads, the original plug caps for lower resistance NGK ones, new NGK spark plugs and new battery. I've had the carbs off and given them a clean (but not replaced the jets or floats etc as carb set up strikes me as black magic!!)

After some time cranking on the starter it tries to run but never seems to catch. I don't use the choke as it seems to make it worse. Once it is going and warms up it is fine and runs well.

On a warmer day it will start 9 times out of 10 on the first try.

Any ideas appreciated.

Dave

Are you using a multigrade oil? Try a 5w-40 fully synthetic, if the oil aint been changed in a while, it may have deteriorated into a thick mess.

Does it crank fast, or is it slow?

Slow backing up what Ive said, and fast like normal means something else, maybe worn piston rings, giving too little compression.

When you used the choke did you wind the throttle open too?

If so try it without throttle. The choke is there to help in colder weather.

Yeah true, opening the throttle just undermines the choke, as letting in more air with the throttle removes the increased suction from the choke, resulting in no more fuel being let in than before.

Not been using the throttle with choke. When it does eventually start and you add the choke it dies too, so just avoid the choke altogether

Chaning the oil is on the list of things to do.

Do you know when the valve clearances were last checked. My brother had this on his FZR1000 EXUP he once had and found some of clearances had closed up and it was a pain to start from cold. Once it had warmed up it was ok.

Don't know what the valve clearances are or when they were checked! Is it hard to do? I've done valves on cars before but they strike me as being a bit easier to get access to.

Have just found some other posts after reading yours 'YPVS TONE' and it sounds like this is quite a problem on the FZR especially on the intake side. Looks like i'm not going to be riding for a while. . . . . . Really hope this fixes it