Z1OwnersClub GB

This could be the same problem as Toycollector, however, I didn't want to to steal his thread.

I've done this often. Got the ignition timing spot on (within reason, seeing it doesn't idle too well). Then I get this situation where it will rev up but it takes its time coming back to idle, Meaning I can't "blip" it.... I can't remember what I usually do to get that throttle spontaneous.

Dyna S fitted, usual NGK (BE8 S) plugs, carb springs good (early model), throttle cables are free. Tried three different adv/retard mechanisms, all springs feel a little on the weak side. New rings recently fitted. Balance of carbs seems OK by gauges. Air screw set at 1-1/4 turns. Can't remember pilot and Main jet sizes ) hoping not to go there yet! Air-box fitted with filter.
Moved timing to both extremes.... Still has a time lag, where engine runs on with throttle backed off? ...... HELP!

RegardZ.

could be:-
too lean
airleak between carbs and engine
cable too tight........

Check your rubber manifolds for cracks leaks. My Gpz11 with FI used to do a similar type thing when the valve shim cleareances were a bit too tight.

Check synchronisation of carbs as well as movement of cables.

Thanks, Taffus, Pasc & Rich. I'll start with checking the shims, if that don't fix it, I'll pull the carbs (balance & mixture) and seal the rubber inlet manifolds.

Cables seem OK. Oh, I'll probably give the rubber inlet manifold a spray with WD40 to see if I notice a change in revs to see if I can pin point the problem. I'll give some feed-back when I solve this problem.
RegardZ.

Oh yea is it on side stand have you checked the cable routing.

Further to this problem of not being able to "Blip" the throttle of a Z1 recently overhauled.

I sealed the inlet maniflod with "Three- bond" and it seem better. I also reduced the size of the pilot jet from 20 to 17.5. Air screws set at 1.5 turns. Problem solved! A good blip.

I put the air filter in and noticed it was not as good, but acceptable!
I'm now thinking of reducing the pilot jet to 15.
At this time I noticed a slight chuffing at the exhaust manifold an obvious leak. I fix that next!

I do, however, think my main problem, as suggested, was a leaking inlet manifold.

Regardz.
PS. I'll open the air screws out to 1 3/4 turns first, before reducing the pilot jet size.

Garn, if you go too lean on the pilots, it may start cutting out when pulling away, coz they were prone to that - due to lean (emissions) set up

Have you checked the fuel heights - that will have the biggest effect on the pilot jets, although I would expect it to stall not keep on revving when shutting off if the pilots are too rich. Is it better when the engine is cold or warm are all the slides closing.

There was a marked difference when I inserted the air filter. It was great til that point indicating, when air flow is restricted it doesn't like it and wants to have a time lag before getting back to idle.

I have checked the float bowl levels (upside-down 23 mm from gasket surface) I will check them later with the plstic tube and bottom screw 17mm adapter.

I'm still to turn air-screws out from 1-1/2 to 1-3/4 turns. Also still to fix leaking exhaust manifold.
RegardZ