81 kz550 high rpms

Hey everyone.
I just put my airbox back on my 81 kz550 after the last owner changed to pods without rejetting. The bike will start up and the rpms start fine but if i add throttle they shoot way up and stay there even after the throttle is pulled back in. I thought the airbox was the problem but i guess not. My intake boots and air box boots are brand new and installed tightly. Im at a loss. Anyone know what might be causing this?

To totally eliminate the possibility of it being a throttle control or cable problem you may want to try this as a test - disconnect the throttle cables at the carbs; start the bike; use your hand at the carbs to momentarily bump up the throttle; let go and see if the idle comes back to normal. If it does, there's an issue with the cables, cable routing, or throttle control; if the idle stays high, you now know for sure it is unrelated to the throttle control or cables, so those variables have been eliminated from the troubleshooting process. Ed

Thanks ed. I'll give it a shot tomorrow

Would also double-check fitment and tightness of the clamps that hold the carbs inside the carb holders.

A loose or ill-fitted clamp could cause an air leak.

Good Fortune!

Thanks for the reply Patton. I was spraying the carb cleaner around the boots to look for vacuum leaks and both the intake boots and the air box boots are leaking because the engine revved up to 5000 rpms while spraying. Both the intake and airbox boots are brand new and the intake side is screwed onto the carbs at the head and at the carbs as tight as they can go. Is there anything I can do to stop these leaks? Also would you recommend keeping the spring type clamps that come connected to the factory kz550 air box or would you recommend buying new clamps similar to the screw on ones that hold the carbs to the intake?

nickleo373 wrote: Also would you recommend keeping the spring type clamps that come connected to the factory kz550 air box or would you recommend buying new clamps similar to the screw on ones that hold the carbs to the intake?

To double-check for confirmation of air leak in carb holder area --- at lowest sustainable idle rpm (perhaps about 1000 rpm), could spray each carb holder with WD40 while watching for exhaust smoke (indicating that WD40 is being ingested into the cylinder).

Possibly a vacuum cap/plug is cracked or torn or loose-fitting.

Would continue using the stock spring type clamps for holding the air box hoses onto the carbs.
Might be mistaken, but thinking the stock hose is molded for placement of the spring.

An air leak at the carb holder -- engine side of the carbs -- usually has a more dramatic effect than an air leak at the air hose connection or through an ill-fitted or torn air hose.

Good Fortune!