carburetor kerfuffle '76 kz900

I have a 1976 KZ900 with stock carbs, 4 into 1 exhaust and velocity stacks. It came with the stacks on it and I might change them out for something else later. For the time being I'd like to just get the bike running as is and then sort out the pods/air cleaner situation later.

When I got the bike it had electrical problems and now all of those are fixed plus it has a Dyna Electronic ignition and an after market reg/rec. The timing is spot on and the valves seem to be adjusted within tolerance.

Here's what the bike is doing........

It starts right up with the choke on and idles. Once warm when I try to turn the choke off it won't idle and dies.

The idle adjustment is turned all the way in and I've tried it at all possible settings with no avail.

With the choke half on it will rev up to red line with no hesitation. I suspected it was clogged pilot jets so I cleaned the carbs.

After cleaning the carbs thoroughly there was no change at all.

I forgot what jets are on there but I cold look at them again and post that info later.

Does anybody know what I should check first in this situation?

It sounds to me like someone removed the stock airbox but did not rejet (or properly rejet) the carbs, so they are running too lean. I suggest you either replace the airbox or rejet the carbs and see if that solves the problem. Ed

650ed wrote: It sounds to me like someone removed the stock airbox but did not rejet (or properly rejet) the carbs, so they are running too lean. I suggest you either replace the airbox or rejet the carbs and see if that solves the problem. Ed

I'd second this. Sounds exactly right.

Anybody know what size jets would work with stacks? The PO told me he road it with the stacks on but you know he could have been less than truthful.

SeattleKZ wrote: Anybody know what size jets would work with stacks? The PO told me he road it with the stacks on but you know he could have been less than truthful.

He also could have ridden it with the choke half on. I've actually been told by a potential seller that you "need to do that" on a bike I looked at (I walked away).

QNman wrote:

SeattleKZ wrote: Anybody know what size jets would work with stacks? The PO told me he road it with the stacks on but you know he could have been less than truthful.

He also could have ridden it with the choke half on. I've actually been told by a potential seller that you "need to do that" on a bike I looked at (I walked away).

Haha, yeah, I've herd some pretty funny stuff from people relating to carbs.

I'll try putting some pods on it and see if that makes it better. If it does then maybe I'll try to find a stock air box or just find a jet size/setting that works with pods.

Have you checked the carb holders for vacuum leaks? I had the same problem with my 650 and found the holders leaking at the mounting surface of the head.

elfmagic17 wrote: Have you checked the carb holders for vacuum leaks? I had the same problem with my 650 and found the holders leaking at the mounting surface of the head.

not yet, i usually check those at idle but haven't been able to get to do that. i'll try to check them

Why would you want velocity stacks on a street bike, arent the rings wearing out fast enough for you ? There is no shortage of posts on this, give it a try. The secret is to put "any date" in under the search length or you only get the last week or so

mtkawboy wrote: Why would you want velocity stacks on a street bike, arent the rings wearing out fast enough for you ? There is no shortage of posts on this, give it a try. The secret is to put "any date" in under the search length or you only get the last week or so

I didn't put the stacks on it....like I mentioned in my first post. I do want to put on a stock air box or pods...like I mentioned in my first post. I did not know the search secret though and will try it.