02GF74
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| posted on 15/7/10 at 01:00 PM |
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who knows their way around mikuni vm26 carbs?
these puppies:
Got these on my Z1000 and have problem with idling.
You can see the knob (to right of centre) in photo that is to adjust the idling.
I can adjust idle so it runs at about 500 rpm ( a bit too slow) by turning the knob clockwise. To get idle to run a bit faster, I give the knob maybe
1/2 a turn and it is about 1,000..... but when I blip throttle (open to about 4,000 rpm and close) the idle drops down and stays around 2,000 rpm,
much too fast.
So I wind the knob out until the above does not happen and then it idles too slow.
I can turn the knob maybe 10 degrees between the stagewhen idles is at 800 to 2,000 rpm - seem a bit weird that it is so sensitive.
Throttle is a 2 cable affair - one to open and once to close but I don't think there is problem with the close cable as the above happens if I
push on the carb throttle lever thing.
Any body come across something like this? Of have any idea what I should look for?
some ideas:
- remove airbox and see what the throttle slides are doing
- remove both throttle cables and see what happens
- remove the carb top covers and see what is going on inside the carbs (top comes off to set slide ehight for sync'ing).
- spray or dab petrol with brush on inlet rubber to head to find air leak
- block off inlet to one carb in turn to see if problem is located to one carb?
- get a big sledge hammer and hit things at random
[Edited on 15/7/10 by 02GF74]
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tony-devon
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| posted on 15/7/10 at 01:25 PM |
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are they balanced properly and are the linkages and probably the little springs between the carbs all working properly?
sounds like some of the slides arent shutting properly
failing that my Z1000 had many a garage stumped, I found that the chockes werent all fully seating back in, had to pull it all apart and put a shim or
two on a couple to make sure that they were fully pushed closed when you turned the choke off
the previous owner must have spent over £1000 in bills trying to sort it out, its got dyna coils, programmable dyna ignition, and still it ran mega
rich, fouled plugs and generally played up, but on random pots
LOL
heavy is good, heavy is reliable, and if it breaks, hit them with it
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02GF74
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| posted on 15/7/10 at 01:33 PM |
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quote:
Originally posted by tony-devon
sounds like some of the slides arent shutting properly
if that were the case, if I unwound the knob, the enginewould never stall but it does.
nice and shiney A2 BTW, you still have it?
good idea about the choke plungers, will check those.
[Edited on 15/7/10 by 02GF74]
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RichardK
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| posted on 15/7/10 at 06:36 PM |
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I've worked on a few vm carbs but none that look like that.
Do the inlet boots look ok (especally in between 2&3), have you tried spraying carb cleaner around the inlets when idling. Apart from that they
are so simple devices and can only be in need of a good clean out, ultrasonic if possible and try and get a refurb kit which includes any
"O" rings that could have perished.
Available from here http://www.oldbikebarn.com/Motorcycle_Parts?search=KZ1000
I do have the vm manual but doesnt look like yours so probably wont be of much use but you're welcome to it if you want it.
Cheers
Rich
[Edited on 15/7/10 by RichardK]
Gallery updated 11/01/2011
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02GF74
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| posted on 20/7/10 at 08:36 AM |
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I removed the covers and looked inside - the throttle slide is attached by a ball joint to a small cylinder - pressing on the slide I can see play on
the ball joint (spring loaded) so I am sure the problem is there.
will take 'em apart to see what the story is and if that can be adjusted or fixed, hmmmm....
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