carb boot replacement

i noticed a puff of smoke coming from carb boot engine side during a backfire whilst warming up my 78 kz1000. its normal for her to cough sometimes with choke on during cold starts. was wondering if its time to replace the boots? figure they are original. thanx ace.

I'd order a new set from www.z1enterprises.com just to be safe. Soak the new boots in very hot water before installation. Check the carb holders and sync plugs for cracking too.

Sunlight and Ozone attack rubber bits making them crack and fail. That's another reason tires that are older than 5 years should be treated with caution, as they have lost their ability to grip the road like when they were new.

ace wrote: ...puff of smoke coming from carb boot engine side during a backfire....

If not already done, would assure valve clearances meet specs.

Too tight intake valve may allow backfire through the carb.

Good Fortune!