1981 KZ440 LTD questions

Hi everyone, I picked up a 12,000 mile 440 LTD last week as a winter project... I got it running by cleaning the carbs and tank, which were in really good shape. The problem is it really hesitates and pops a lot and barely idles. I don’t have an air filter in right now but it has the stock air box and exhaust system. I did put about 75 miles on it the other night and it ran right along just not as good as I feel it should! Do you think its a possible vacuum leak on the carb boots, ignition issue or should I tear the carbs down again! I pulled the advancer cover off and cleaned / lubed the assembly.. I’m going tomorrow to pick up new rear brake shoes for it, the friction material came off the metal! I think Ill pick up new plugs and possibly wires too while I’m at the shop.. When you start it up with the choke on it runs at a high rpm but revs right up with no miss, its really only when you shut the choke off that it runs poorly. It is still on its first tank of fresh fuel so perhaps there was some nasty crap in the tank that has mixed with it.. I’m not sure! Any input would be greatly appreciated! Thanks again, Matt

Idle can be affected by leaking carb boots. I suggest, that as a matter of course, you just replace the ones you have and perform a tune as described in a shop manual or Clymers. Essentially:

1. valve adjust
2. cam chain
3. ignition timing - when you do this, check primary/secondary impedence on coils and also measure voltage to coils when you turn the key on and possibly replace plugs/plug caps and plug wires
4. sync carbs / set idle mixture

If you do the stuff I noted above, your bike will probably run fine. Go about it in the order described but, again, replace the intake manifolds if they are in doubt. Also don't neglect general lubrication; ae the swingarm, steering head bearings, chain and tightening all nuts/bolts and checking brake pads and function.

I don’t have an air filter in right now

I think that might be your problem, the bike has to be running lean without an air filter in place :ohmy:

I agree with both of the above posts. I would do a complete tuneup. Especially if the bike has been sitting a while.

I agree with every else, but I had a thought. This is going to sound stupid, but I put cotton socks over the pods I tried out for a while until I rejetted the carbs. Maybe you can stretch a rag over the box. Check for leaks in your intake boots and carb holders too.