TOPIC:

Hello can anyone help my 82 is not running on no 4 have checked comp (good)have checked Spark (Good) have cleaned the carby to death still wont run properly on no 4 cyl exhaust pipe only just gets warm rest are to hot to touch .
Steve

Hi Toy,

No symptoms on 3 huh? Have you checked the floats, wet method?

Can you find a second set of carbs to swap, just to be sure about their state.

Carbs being equal, Got to be valves.

Bill

Hello Steve:

You did not mention where your idle circuit screw is set at. If it's too far in, you will get a cool or warm cylinder condition.

If you find you have turned this screw out beyond 4.5 to 5 turns out, you probably have an internal carb issue, 1st idle circuit partially clogged, 2nd, float level, 3rd, vacuum leak?

How's the base idle sound? Can you get the engine to quit with turning the base idle screw out? This would suggest an overall tight induction system with little to no air leaks.

Like Bill states, A wet float level is a must to know where your fuel level is. Service fuel limit (float level) is 6.5 to 8.5 MM. As measured from the bottom of the carb body.

what condition is the spark plug in? Is it lean, rich, or chocolate brown?

Hope this helps, keep us posted.

Todd.

Thanks for all your suggestions Number 3 runs ok swaped leads incase one side of coil had died no different still nothing on 4 checked float 6.5 below havent had it running long enough to get a plug colour . changed manifold incase of vacume leak has 160 compression all cylinders .i think its carby blocked tryed as sugested on forun to soak in diesel for a week and hi pressure blowing it out and Carby cleaner still no Joy .Is it worth ultasonic cleaning .

Depending on what you use for solution, and depending on how strong your ultrasonic cleaner is, it can be the best method to clean your carbs. I use a 50/50 mix of white vinegar and soft water. With a few drops of dish detergent. Make sure you thoroughly rinse the vinegar off of the parts when done.

When you blow out your carbs with compressed air, do you use a rubber tipped nozzle, to force the air through the passages? This is the best way to pressurize the small passages.

For Mixture adjustments, I recently ordered the ColorTune Plug Tester to visually detect what the flame is doing at idle. This can be useful in quickly determining what your cylinders are doing at idle.

do you have your factory coils? If they are old, they may indicate a good spark off of the cylinder, but could be weak with fuel in the cylinder.

Without taking your manifolds off, you can detect air leaks with electrical contact cleaner, or starting fluid on the boots. Listening for a rise in RPM.

This bike is sensitive to spark and idle mixture. If one or both of these are off, it will run like crap.

Regards.

Todd.

Steve,

I had this issue with a mates Z1300 a few years ago.

We tried everything but one cylinder would not run on idle (was ok over 1500 revs) so it was a pices of crap or some kind of blockage in the primary circuit tunnels.

We ended up replacing the carb body...........job done !

Sonic cleaning will remove light coatings of crap from the insides of the tunnels but will struggle to disolve a lump.

Have you managed to remove your pilot jets or are they stuck ?
You can get thin wire down the hole to the jet if stuck.
Also make sure the air intake tunnels from the REAR of the carbs into the pilot cirduit are clear as these often block.

Try a tin of wd40 with the red straw attached & poke in EVERY hole on the carb body & see where the wd40 exits to make sure EVERY tunnel is clear

Pete f