1980 KZ440A LTD intake issue

Hey there!

So I have a 1980 KZ440A LTD that has been professionally gone through, carbs are spotless, new carb boots, clean gas, stock jets, etc. The problem is that it won't run with the air box connected. Take off the air box and it runs fine. What I can't understand is that everyone says these bikes run like s**t without the stock air box/filter, yet mine only runs without it and everything else on the bike is stock. Help!

And thank you

If the carbs are not choked the jetting is not stock.


.

Hmmm - how is it with the air box in but the filter element out?

What exactly do you mean by "won't run"????? Does it still start? Idle? Rev up?

This is sounding like the air box wasn't installed properly or the filter is clogged or incorrect. On most Japanese bikes with CV carbs, stock / original carb set up (not only jetting, but the entire tune of the carbs) normally will start and idle (ish), but won't perform well under load or at higher engine speeds without the stock intake plumbing in place and operating properly....just my experience.

Conversely, some simpler low performance engines with slide carbs can function o.k. (ish) without the air box or any filter in place....

Runs excellent until you put the air box together then runs like crap and dies out when trying to rev it.

As soon as you put anything in front of it (the air box) I have tried with filter with out filter and it just starves for air.

Nebr_Rex wrote: If the carbs are not choked the jetting is not stock.
.

Agree 100%. If the engine runs well with no air filtration whoever when through the carbs missed something if they believe them to be clean, set correctly, and have stock jetting. Time to take another look. Ed

Okay so update.

My mechanic went through the bike again and ended up calling customer support at keihen and gave a few suggestions. After making a few small adjustments and putting the bike back together, she purrs like a kitten. Not sure what it was, but most likely a few little things compounding into a bigger issue.

Thanks for everyone's input!