Possible Carb Problem

[bollypne]

Hi all, I've had my carbs off that many times i think i can do it with eyes shut, almost.
Seems the bike is running ok ish, ticks over nicely, best since i got it. Goes like stink when opened up, quite a suprise really, I had a 1200 bandit before the Z, so i was well made up. Enough, i degress. So at speed she seems to run well.
Starting is one area of concern, fires up easy enough but it is misfiring, choke on briefly. Misfire is gone when revved a bit, wont idle on choke but soons settles when warm.
Also, after she is warmed and run a few miles, tickover is fine but opening the throttle slightly/slowly results in roughness, a harder throtlle blip goes through with little/no roughness?

Checking the plugs after a good run shows no1 plug to be very clean, possibly weak, the other 3 show sootyness.
Carbs have all new jets, needle and gaskets. Full kit.

Also yesterday, towards the end of quite a hard run, probably 80ish for about 30mils(A50 from Derby to Stoke). Engine cut out at about 70 for 3seconds and then ran again! I did not catch the cut off switch.

Any thoughts/advice would be good.

Colm

[bollypne]

In addition to replacing the carb jets etc i also checked valve clearances. Some needed adjusting. I was a bit worried about chacking adjusting the valves as i had never tocuhed shims before. Easy.

[bigmac103]

Hi Colm,
My A4 won't Idle 'till it's warm. I had problems similar to you, turned out just to be a dodgy plug. I also changed the wiring to give more voltage at the coils. Chrisu gave me this link and it worked a treat.
http://www.wgcarbs.com/index.php?option ... &Itemid=26

Plus I think you should sort out the valves first and start a process of elimination.

B

[bollypne]

Hi, valve clearances are now all good and still same issue. Also changed plugs to Denso. Will check the link, Thanks.
Colm

[Rich]

Engine cut out at about 70 for 3seconds and then ran again!
Check for loose connections, springs in the kill switch, ignition switch broken wires - 80 ish for thirty miles is normal use.

Checking the plugs after a good run shows no1 plug to be very clean, possibly weak, the other 3 show sootyness.
Carbs have all new jets, needle and gaskets. Full kit.
Check and adjust the fuel heights then synchronise.

[bollypne]

Engine cut out at about 70 for 3seconds and then ran again!
Check for loose connections, springs in the kill switch, ignition switch broken wires - 80 ish for thirty miles is normal use.

Checking the plugs after a good run shows no1 plug to be very clean, possibly weak, the other 3 show sootyness.
Carbs have all new jets, needle and gaskets. Full kit.
Check and adjust the fuel heights then synchronise.

Cheers Rich, new switches fitted a little while back. So off with the carbs again. Smashin, though it is easy.

[DogsbolloxofZ1B]

Did you change the needle jets along with the needles? These need to be a matched pair! Occassionally you'll get away with replacing just the needle but often you'll have mixture problems i.e. can't dial the mixture in with the airscrew.

My 2cents.

[chrisu]

carbs balanced ??? - mine were WAY out after fitting new carb kits !

Crap in the fuel filter - you do have one don't you ......... ????

[bollypne]

New needles fitted with needle jets. Not sure how to 'dial the mixture in' with the airscrew.

Will be checking carb balance again this weekend.

thanks

[Steve S]

This may help.........Turn in the air screw of each carb fully but not tightly and then back it out 1 1/4 turns,start engine and warm up, adjust idle to about 800-1000 rpm.
Adjust each air screw 1 at a time,first turning in one direction and then the other until the highest idle is determined,if the idle rises too much adjust accordinly using the main idle adjusting screw.Note: if any any carb air screw can be turned in to less than 1/2 turn from full in,without idle change there is probably trouble with that carb(ie pilot jet/blockage etc).
Once highest idle is set turn all air screws in equally a small amount,readjust idle and check with vacuum gauges if needed.
Hope this helps good luck.

[bollypne]

This may help.........Turn in the air screw of each carb fully but not tightly and then back it out 1 1/4 turns,start engine and warm up, adjust idle to about 800-1000 rpm.
Adjust each air screw 1 at a time,first turning in one direction and then the other until the highest idle is determined,if the idle rises too much adjust accordinly using the main idle adjusting screw.Note: if any any carb air screw can be turned in to less than 1/2 turn from full in,without idle change there is probably trouble with that carb(ie pilot jet/blockage etc).
Once highest idle is set turn all air screws in equally a small amount,readjust idle and check with vacuum gauges if needed.
Hope this helps good luck.

Cheers, will give it a go, love messing.

[KeithZ1R]

Also yesterday, towards the end of quite a hard run, probably 80ish for about 30mils(A50 from Derby to Stoke). Engine cut out at about 70 for 3seconds and then ran again! I did not catch the cut off switch.

Any thoughts/advice would be good.

Colm

three seconds is a long time I would go with Rich cut out swith has bounced

[bollypne]

Also yesterday, towards the end of quite a hard run, probably 80ish for about 30mils(A50 from Derby to Stoke). Engine cut out at about 70 for 3seconds and then ran again! I did not catch the cut off switch.

Any thoughts/advice would be good.

Colm

three seconds is a long time I would go with Rich cut out swith has bounced

cheers Keith, new switches fitted recently. Will be checking all connections over the weekend.