81 kz440 need some help

Ok guys so i got this thing up and running again but am having a couple problems. When u give it any gas what so ever it seems to stay up in the idle for a few seconds and then fall back off. I am not sure why it is doing this but it is really annoying. Can anyone give me any ideas. It runs alot better since the rebuild but i still need to do some tinkering and adjusting. If any one can help me out on this i would really appreciate it. Thanks

This bike is a 81 kz440 with pod filters, cut exhaust, and dual carb setup....

I would look for air leaks on the intake side. Check the carb boots for cracks. Spray carb cleaner when the engine is at an idle and the rpm will increase.

Did you install the pods & cut the exhaust?

A number of knowledgeable folks have stated that the KZ440 needs the stock airbox to run right. Apparently, those CV carbs are difficult to tune w pods.

Bullseye! You should run the stock airbox and filter in perfect condition. These small twins are very tempermental when it comes to the intake side. I'm not saying Pods won't run on these bikes but you are way better off with the stock airbox.

If your choke is on at all what you are experiencing is completly normal, however with the choke off it should not do that. Those carburators are set up to run very lean from the factory (too lean IMO) so modifications like you have would require rejetting. With pods and an exhaust like that it will be a delicate ballance between enough fuel to get the engine to run and way too much. They are finiky and that s why it is usually best to run the stock setup. I run a mac 2 x 2 exhaust with a stock airbox and I am on the lean side myslef. I have drilled the pilot jet out a few thousandths on another bike with good results.

Well the bike is hardtailed so i dont thing the stock setup would work. I also raised my main jets this last week from 90 to 95 but that was before i did the valve job and rebuilt it. I am thinking that maybe it has something to do with my slides sticking and not completely returning to its stock position. SO i am going to tear the carbs back down and see if i can figure out anything inside.....Thanks for all the input..

RingB21 wrote:

Well the bike is hardtailed so i dont thing the stock setup would work. I also raised my main jets this last week from 90 to 95 but that was before i did the valve job and rebuilt it. I am thinking that maybe it has something to do with my slides sticking and not completely returning to its stock position. SO i am going to tear the carbs back down and see if i can figure out anything inside.....Thanks for all the input..

If not already done, would check throttle cables for clean smooth operation (not frayed internally), with routing free from kinks or sharp turns. And also assure a little slack exists for the inner cables at the throttle cable adjustment on the carb belcrank when the throttle grip returns to idle position.

And double-check for proper functioning of advance mechanism to assure it's quick complete return to idle position when reducing throttle. Best to use a strobe type timing light and watch the advancer move back and forth while blipping the throttle.

Could possibly be something as simple as adjusting the pilot screws while lowering the idle speed to achieve a better idle mixture for the pilot circuit.

Good Luck!