TOPIC:

I just bypassed the air injection and fired up the 1981 Kawasaki KZ750 LTD, only to find white smoke coming out the exhaust and the sticky rev up problem persisting.

On accidentally tapping the throttle valve plate synchronization locknut between carburetor 3&4, the bike lost power and shut down. The locknut had around 2mm play when poked.

Suggestions?

Youtube video here:

The video is only 2 minutes long, and the main question pertains to the end where I shut the bike off by bumping the carb synch set locknut.

Q1 - Should that have the 2mm play visible?

Q2 - My buddy said that due to eliminating a potential vac leak by bypassing the air injection emissions system, that I am probably running rich. Would that make the revs stay high after releasing the throttle?

Q3 - Is it okay to tie the vac nipple on carbs 1&4 together with a vac line? I had no caps handy.

Q4 - Next steps in order: air fuel mix using Gunson Colortune, then carb sync, then timing? Or timing first?

Thx again for guidance.

Q1. No
Q2. No, the high revs at idle is usually a vacumn leak, check the intake manifolds for leaks, That is the most common cause. Another cause is the mechanical igniton advancer springs. They can get weak and go to full advance and not allow the bike to come back to a slow idle.
Q3. No, cap them off individually. Makes it VERY difficult to synch. Simply cut the tube and insert a small bolt or golf tee.
Q4. Set the idle mixture screws to best idle then synch. Once the bike is running good then use the color tuner to fine tune. You have electrinic igntion at least you should so the timing is already set and there is no adjustment on it. Leave it alone.

Yea had similar problems found it to be carb boots hold it to the engine if their not super tight get high idle... I have the tube across to I do have any problems with idle sticking... But baldy is right to advancer is under the left side cap sitting on the bike mine was jammed up little lube on it lossened it up it was a new bike..

baldy110 wrote: Q2. No, the high revs at idle is usually a vacumn leak. Another cause is the mechanical igniton advancer springs. They can get weak and go to full advance and not allow the bike to come back to a slow idle.

New airbox boots, but haven't replaced carb holders. Advance used to work great, and the bike has run great in between issues. Will lube up that advancer. Cannot find replacement springs on Z1, suggestion?

baldy110 wrote: Q4. Set the idle mixture screws to best idle then synch. Once the bike is running good then use the color tuner to fine tune. You have electrinic igntion at least you should so the timing is already set and there is no adjustment on it. Leave it alone.

Got caps for carb vac nubs on 1&4, had to reset timing due to Dyna S new elec ignition. Finally doing valve clearance check tomorrow, just got new valve cover gasket. Will do fuel screw, then sync, then Colortune and let yall know. Thx.