Z650B 1976

irhobotolo · #1 PostAuthor: **irhobotolo** » Tue Mar 24, 2009 11:34 am

not a massive problem but its annoying me now !!!!
i have rebuilt the bike and stripped and cleaned the carbs.
all of the jets are clean. float valves are sealing. floats not punctured.
the slides are all free and seem to be at the same heights. the bike has
standard pipes and airbox. the carbs are low milage....however.........

the bike starts on the choke and ticks over fast.
turn the choke off and it ticks over at 800 rpm as it should.
so far so good !
when the bike gets warm the tickover goes up to 1600+ rpm.
the screw adjuster can be fully out and the tickover wont come down.
the throttle cables are ok and the engine is very smooth so i dont
think the carbs are too far out of sync.
any ideas or advice appreciated.

PAULJAC47 · #2 PostAuthor: **PAULJAC47** » Tue Mar 24, 2009 12:31 pm

Hi had you set carbs with vacumn gauge? if so what did you set them at sound like you may have an imbalance Cheers Paul J...

Steve S · #3 PostAuthor: **Steve S** » Tue Mar 24, 2009 12:58 pm

Couple of things,could be an air leak does the throttle rise and lower smoothly or does it take time to drop? or are the carbs set up properly? when you turn the screw adjuster out is the carb linkage hitting against the stops? if not are the cables preventing the slides from lowering enough or they are adjusted incorrectly :?:

irhobotolo · #4 PostAuthor: **irhobotolo** » Tue Mar 24, 2009 6:46 pm

Steve S wrote:Couple of things,could be an air leak does the throttle rise and lower smoothly or does it take time to drop? or are the carbs set up properly? when you turn the screw adjuster out is the carb linkage hitting against the stops? if not are the cables preventing the slides from lowering enough or they are adjusted incorrectly

The throttle slides lower smoothly and quickly.
The rubbers front and back are new with no leaks.
The carb linkage is hard against the stop.
The slides are fully down with throttle shut off.
I dont have any vacuum gauges but are thinking about getting some.
If i push the throttle stop hard the tickover comes down a bit but its
only a problem with the engine hot. When its cold it ticks over at 800. :oops:

Pigford · #5 PostAuthor: **Pigford** » Tue Mar 24, 2009 7:58 pm

I got a similar ongoing with my Lawson.... :roll:

Could be a hair line crack in the head :??

It's most likely drawing air in somewhere. Are valve clearances OK :?:

Is there any slack in the slide linkage system - where slide is fixed directly to link arm :?:

I am at a point where I have re-torqued the head... Now gotta degree cams in & re-check ignition timing (again!) :cry:

Steve S · #6 PostAuthor: **Steve S** » Tue Mar 24, 2009 9:22 pm

Have you tried playing with the air mixture screws /combined with the tickover screw when its warm? to see if it has an effect on the tickover. In theory you should be able to increase the speed slightly on the air screws and then reduce the speed with the tickover screw if that is the linkage allows. :roll:

Davy Doherty · #7 PostAuthor: **Davy Doherty** » Tue Mar 24, 2009 9:32 pm

Jezz another 650 what the f**k is going on???? am i in the wrong club ??

Pigford · #8 PostAuthor: **Pigford** » Tue Mar 24, 2009 9:37 pm

No matter what.... a Z650 is still a baby ZED :wink:

Family lineage :!:

Davy Doherty · #9 PostAuthor: **Davy Doherty** » Tue Mar 24, 2009 9:40 pm

Bollox next youll be saying z250 are welcome

Pigford · #10 PostAuthor: **Pigford** » Tue Mar 24, 2009 9:44 pm

Davy Doherty wrote:Bollox next youll be saying z250 are welcome

Errrrrrm, sorry Davy, but I do believe they only have 2 cylinders.... :roll:

irhobotolo · #11 PostAuthor: **irhobotolo** » Wed Mar 25, 2009 9:53 am

Thanks for your ideas guys. I appreciate it.
I am going to have another "play" with it today and maybe get some
vacuum gauges to see if carbs are out of sync with each other.

my appologies for owning "only" a z650 and i can see your point since
its the Z1 owners club. I have owned several big fours and built a 78
Z1000A2 with a 1105 race spec engine built and ported by NCK racing which i raced
at long marston and then rode home on ! Those were the days
EFD119T where are you now ? come back home to daddy !!!!!!!!!
The slabs on my parents back yard still have a patch where i did a
burnout nearly twenty years ago :twisted:

phil churchett · #12 PostAuthor: **phil churchett** » Wed Mar 25, 2009 9:58 am

EFD 119T was last taxed in 1990, is listed as being blue and 1015cc.
Do you have any pics?

irhobotolo · #13 PostAuthor: **irhobotolo** » Wed Mar 25, 2009 11:24 am

phil churchett wrote:EFD 119T was last taxed in 1990, is listed as being blue and 1015cc.
Do you have any pics?

WOW.....

it was blue before i had it sprayed and rebuilt it.I never changed the log book after the build.
i have photos of it before and during the build but not digital ones to post
here. i sold it about 1990 when i was mortgaged to the hilt but would
love to know where it is now and would buy it back. the man who had it offered me loads of money for it so i sold it. BAD MOVE.
he was as mad as a hatter and phoned me a week later to tell me how
none of his mates could believe how fast it was !!!!!!

phil churchett · #14 PostAuthor: **phil churchett** » Wed Mar 25, 2009 12:59 pm

The tax expired in August 1990, it isn't sorned.

#15 PostAuthor: **Taffus** » Wed Mar 25, 2009 1:06 pm

Keep them 650's coming if it annoys "Waldorf (paully) & Statler (Davy)" the more the merrier

Z650B 1976

Z650B 1976

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