Kz440 1981 just won't rev!! Please help

Iv recently brought a kz 440 75%finished chop project. Now I can imagine this bike hasn't been run for a very long time. I have 2 sets of carbs one set are the original kz 440 with good diaphragms clear jets and air ways clear, and a set for a kz 400 in good con. I also have a single carb for a honda cb 500. I have a really good 2 into 1 intake manifold witch leaks nothing and original boots for the original carbs. With the 2 into1 manifold I can choose to use just one carb from each set. Iv had the bike ticking over and spluttering on all carbs. The bike runs best with one of the original carbs on it ( I had it ticking over sweet for 15mins or more today) playing with the mixture screw doesn't have much affect at all and it doesn't want to rev!! If I open the throttle it does nothing ?! Apart from when you hold it open for 20 seconds or so it stalls I'm gessing because it's flooded? Soo why won't it rev!! I'm quite sure that haveing bp7es plugs is fine.


Any help would be so great fully appreciated. Thanks for reading

Try unhooking your throttle cables from the carbs and revving the engine by hand. This will rule out any throttle cable problems

Thanks for reply I have been revving by hand

Are you running pod filters or has the carb jetting been adjusted at all?

Yes a pod I don't have an air filter box. I know this can cause problems but iv put various things around the filter to try and restrict air more. Nothing makes a difference it just won't rev!?

And jets are standard kz 440

It sounds like you could still be getting to much air in the pods. Theres not really much you can do to restrict the airflow without adjusing the jetting. It's a lot easier to get a stock bike running than one with pods so it may be worth finding an air box on eBay. If you don't want to do that you'll probably still need a jet kit and adjust the jetting as needed to get everything tuned right

Ok thanks but iv tryed 3 different carbs and none of them make a difference. Surly it should pick up a little

Sounds like you need go over it all. Battery voltage , any mechanical ignition advance, onto valve clearance and then carb sync.

If it runs on two carbs and you are trying to feed it with just one of the two, well that shouldn't work for you.

I was thinking the problem could be deeper. Iv cleaned and greased the timing advancer and I'm confident it's right as it can only been in 2 positions. And if that was out it wouldn't tick over for a length of time. But I'm wondering if the valves are dirty and aren't sealing properly? Would this stop it from revving? There is reasonable compression

And it ran better than iv ever heard it with a single kz440 carb on it. With both it won't tick over for long at all

After striping the top end of the motor down I found that both top piston rings had worn berry thin and had broken up!! Luckily the bores are still unmarked. Once I fork out for a replacement set and fit them I'm hoping that my problem will be solved.