Engine runs but dies when i release the clutch

I have a 1995 KZ 1000 police bike that I'm bringing back to life after being in storage for 3 years.

So far what i've done is cleaned the tank, cleaned the carbs (i'm not a pro w/carbs so something may not be right), charged the battery. I was able to get the bike running so i decided to test drive the bike around the yard and when i released the clutch the bike died. tried it and again and it died again. the third time i got the rpm's up and it wanted to die but i kept giving it gas until i got it moving.

I know this isn't normal. Where do i go from here? could there still be something blocking the carbs? Oh during my test drive i did not have the air box boots connected to the carbs. They are a beast to get back on. Could that be the problem?

I had a GPz750 that would do exactly the same thing if the air filters were not on it, start instantly and rev great in neutral, but as soon as I put it in gear and tried to take off it would fall flat on it's face, put the filters back on and it eas fine. So yes, I think it probably is the lack of filters.

Stupid question, but is your kick stand up?

yes the kickstand is up and i checked the wires going to it also. I'm going to try re-installing the airbox boots this weekend and see what happens. If anyone have any ideas please let me know. I'm almost certain it's something very simple i'm overlooking cause it runs so good when it's not moving. I'm going install some new plugs too.

First, let the bike warm till it is ready to run without choke. Then adjust your idle mixture. This is done by fiddling the idle screws on the top/front of the carburetors right next to the vacuum ports. You do have the vacuum ports plugged or connected to what they are supposed to, don't you? Turn the mixture screws in till they VERY VERY LIGHTLY seat then turn them out 1.5 turns. If that doesn't do the trick, swap the pilot jets for new ones as the BS34 style pilots are hard to clean if they are used and blow carb cleaner through the small holes on the intake manifold side edge of the venturi.

Tw.., I have a similar problem on an earlier bike than yours (1975 Z1B).
Starts easily with normal choke, idles OK, revs well. I allow 10 min to warm-up, then rev and gentle release clutch, up my steep drive...... It dies!
I initially checked the timing, plugs and air-cleaner, they were OK. I still haven't fixed it. However, its performs OK on a (say,40 mile) ride!

Perhaps it could be my pilot-jets as per WG comment! I thought at cruising speed it was the pilot jet that was the main operating circuit of the carb.

Once we sought Tw out, I would appreciate some help!

RegardZ

This is a long shot, but I don't think I'd mentioned it, so if it doesn't help you guys at least it'll be in the archives.

My bike used to be a PAIN to get started below 75 degrees outside. It took tons of choke, and the slightest throttle would cause it to stall out immediately. Ditto clutch -- any load on the engine would cause it to die immediately.

After 5-10 minutes of warming up, a little throttle no longer caused the engine to die immediately. Once I could gently get it to move, I'd run a few blocks and eventually the bike was fine (until I shut it down again, that is).

It turned out that the vacuum fuel petcock diaphragm was bad, and was letting fuel get sucked into the vacuum line from the carb. Not just a little bit -- you look at the line, there was nothing but gas in it, with just a few air bubbles moving through the line.

I replaced the diaphragm, and made sure that there's no gas leaking into the vacuum tube. Immediately the problem went away.

If you have a vacuum-actuated petcock, make sure there's no gas getting into that vacuum line.

Good luck!

Chet is very correct. I never think about vacuum petcocks as I ain't got any but the symptoms on a VM carb with air screws? Hmmm Garn, pull the carbs and pull the pilot jets and air screws. Cover both openings with your fingers and spray carb cleaner into the hole on the venturi edge on the side where the pilot jet is. You should be able to look into the venturi and see a spray out the little hole behind the needle jet. If you can't see a spray, you really need to disassemble and dip and then blow them out with compressed air. I have developed a few tools to help me clear the internal passageways but generally dipping and compressed air will clear any clogs. The second cause is the pilot jets themselves. If you have new Mikuni pilot jets, you are OK but if you use aftermarket pilot jets, they sometimes don't counter sink the holes in the heads. If you flow carb cleaner by spraying in the nozzle end to watch it come out the intake end, it will not diffuse evenly... it comes out more in a splatter. I think this effects gas intake flow when gas comes in (opposite direction) as I have noticed that the aftermarket jet needles sometimes don't work as well as evidenced in tuning problems. If you have older jet needles, they really can sometimes not be cleaned very well and should just be replaced. In addition, the needle jets on your bike may be ovaled (worn) and cause poor gas flow which is evidenced especially in the off idle transition. Unfortunately, there is no replacment source I know of. The P series needle jets must be swapped out from donor carbs if they are worn.

I found the problem. my pilot jets were clogged. I cleaned them and reinstalled and the bike runs as good as new.

Thank everyone for the feedback.