poor running

[GJN]

Hi,

I recently purchased a 1982 C90zz, I had one of these in the 80`s so always wanted to revisit these great bikes.
It only has 3k on the clock, its been sitting in a garage since 1992.
It appears to have a healthy spark, I gave it fresh petrol and it fires up fine but after 2 or 3 minutes of running it stops
then wont start up again unless I clean the spark plug (dry black carboned up) I've repeated this a couple of time but
the plug still carbons up. I cleaned out the Carb/jets etc, still the same, I followed the Hayes Manual and adjusted the
mixture, still the same. I have now purchased contact breakers and a condenser and will look at the timing, Have I missed
something that I should consider?
Grateful for any advise,

Graeme

[slowboy]

Hi,

I recently purchased a 1982 C90zz, I had one of these in the 80`s so always wanted to revisit these great bikes.
It only has 3k on the clock, its been sitting in a garage since 1992.
It appears to have a healthy spark, I gave it fresh petrol and it fires up fine but after 2 or 3 minutes of running it stops
then wont start up again unless I clean the spark plug (dry black carboned up) I've repeated this a couple of time but
the plug still carbons up. I cleaned out the Carb/jets etc, still the same, I followed the Hayes Manual and adjusted the
mixture, still the same. I have now purchased contact breakers and a condenser and will look at the timing, Have I missed
something that I should consider?
Grateful for any advise,

Graeme

Just a thought, air filter blocked? I've seen mouse nests in the intake plumbing on long laid up bikes.

Also rings a bit gummed up and letting a bit of oil past, hence the plug carboning up?

A couple of random thoughts, other opinions are available.

[GJN]

Thanks for the input,
Have replaced the air filter, the old one was ok,

The Haynes manual suggests
Mixture
trying a hotter running Spark plug
or if that fails it could be the ignition system?
Standard Haynes suggestions.

Which hotter running grade of Plug would anyone suggest please? would this be advised?

Thanks

[tea]

Breather hole in petrol cap ?

[JOHNBOY]

the lower the number the hotter the plug i think i am wright

[Diesel Dave]

I wouldn’t fir a hotter plug to a 6v.......

[GJN]

Thanks for the advise,
I will strip the carb again to make sure and haven't missed any blockages, replace
the points and condenser, check the timing then see what happens,

cheers

[BertrandLiv]

Hey !

I've got exactly the same problem on mine, would like to hear what you've done if it's running fine now.

Thanks