Please help before i torch the fken thing

[Mr Hammers]

So. Three days i've wasted trying to sort the carbs out on the bandit. Three days of nice weather that i should be spending buzzing about hither and thither...but instead spent dicking around with the bastard carbs on the sodding thing. Man, i'm so pissed off with it right now.

Ok, deep breath.

Right. So it was running mostly ok, then started playing up by idling really fast, or slow to respond to throttle, and generally running a bit crap. So i pull the carbs off, give everything a damn good clean, blow out the jets etc.

Put it all back together and now it's only running on 2 and half cylinders (two pipes were 100 degrees, one about 70, and the other practically room temp).

Buy a carb repair kit. Fit new diaphrams, new jets, springs etc. Put it back on, and it runs. Sort of. It revs fine and is responsive, but shutting off the throttle causes it to drop the revs to a point where it stops completely.

It will idle, but only if you gently back off the throttle. As soon as you rev and shut off quickly, it dies.

One thing, in the new carb kit it looked like there were two main jets for each carb. As it's an aftermarket can on it thought it best to fit the bigger of the two. Now i'm not sure i should've used the smaller jets (maybe the big ones are for the 1200...?).

Could that be the cause?

I could just take it all apart yet fucking again, in fact sod it, i'll go and do that now.

But....am i missing something obvious here?

What else could cause it to die so quickly after revving?

Any help very much appreciated as the Striple is also on the naughty step as the bloody thing has yet more electrical issues (not charging this time) so i can't use that atm either. The Bandit was supposed to be the backup bike......

Cheers.
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A Guide To Powerbands

[Pete.]

Holding up idle revs is an indication of lean mixture. Diaphragms should have no part in it because the slides should be fully down at idle. It's either an intake air leak or not enough fuel.

Have you done all of the things in this thread?

https://www.banditforum.co.uk/forum/index.php?topic=69488.0
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Mr Hammers]

[struan80]

The idle trimmer sticking?

[Pete.]

[stinkwheel]

Does it have a fuel pump and is it working?
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Mr Hammers]

[Pete.]

Make sure the idle circuit metering screws are all assembled correctly. Spring, washer, o-ring. If they are wrong the idle mixture will be all to hell.

BTW you are right that is a drain screw not mixture control. The idle mixture screws are the ones with the springs.

EDIT: Bandit mk1 slow running circuit diagram:
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Mr Hammers]

[WD Forte]

Wouldn't you need to use some vac gauges to balance these carbs?

Never had me mitts on a Bandit but on most multi cylinder engines
we'd set it up to spec, (float height, mixture screws set the same
(often around 1/34 turns or so )
then finally use the gauges to fine adjust the butterflys
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bikers smell of wee

[Pete.]

Yes, butterflies badly out of whack can make them run very poorly. You can get them very passably balanced by holding them up to the light and matching the crescent of light around the throttle blades.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Mr Hammers]