TOPIC:

Hi folks, I have an annoying problem with my 1979 A1 uk spec. It has never started easily when left for more than a couple of days, I resort to pulling the outer four plugs out and squirting petrol into the plug holes, this works a treat. However, the bike has now started to eat spark plugs virtually every time I use it. Brand new plugs last for one run only on the number 1 and 2 cylinders, they do not melt and are quite dark in colour. The bike runs well with two new plugs in it but refuses to run on all six the next time it is used. I have noticed that the engine over run is not as strong as it was and, if the throttle is blipped, the idle can sometimes take ages to settle down at the correct rpm. I am suspecting a carb issue as the offending cylinders ie 1 and 2 share different coils. Mechanically the carbs are totally free to snap shut and the throttle action is smooth and very positive over the entire range. I am perfectly willing and able to wrench these carbs out and strip them but I just thought I’d ask if anyone has had the same problem. Many thanks Marc,

1&2 having an issue is likely carburetor problems. Electrical issues would be 1 & 6 having the issue.

I've had problems where my float stuck shut and it 'appeared' to be 1 & 2 getting to much gas, when in fact they weren't getting much of any. I found this by simply pulling the drains from the bowls on 1 & 2 into a small glass and noting the difference in gas that came out vs 5 & 6. 1 & 2 had almost nothing in the bowl.

Anyway, I would start with checking out the carbs. And yes, they are notoriously poor starters. I believe member Scotch has a mod to the carbs for poor starting, but I have not actually done this on either of my KZ1300 A1's.

The revs slow to drop when you blip the throttle is caused by the engine drawing air from somewhere. Probably from the carb rubbers, check the carbs are seated properly in the rubbers and the clips are screwed up enough.

Revs slow to drop can also be caused by the sync.-adjusters being turned in too far........ usually done in the attempt to get the highest possible vacuum reading. This will fully compress the internal spring and create too much friction on the ball-links.

Plugs fouling this badly indicates excessive level in the bowls. Little room for error with a 2mm range ! Could also be the choke plunger for #1 & #2 not closing completely. There's a lot more to the Choke system then just tightening the plunger-arm and fast-idle cam screws to secure them to the choke shaft. When the choke is fully OFF you should be able to move the spools freely. The 3 plunger lifting forks can not touch the sides of the spools. .5mm - 1mm gap each side. The forks must start to raise the plungers at exactly the same time but more importantly - When the choke is OFF there should be a small gap between the top of the lifting-spool and the C-clip. NOTE: The choke lever is not intended or designed to Press down on the plungers to facilitate their closure. The internal spring does this !

......just for starters (no pun intended)