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Mr Hammers |
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Mr Hammers World Chat Champion
Joined: 10 Jul 2008 Karma :
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Posted: 18:31 - 25 May 2024 Post subject: Please help before i torch the fken thing |
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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. ____________________ A Guide To Powerbands |
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Pete. |
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Pete. Super Spammer
Joined: 22 Aug 2006 Karma :
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Posted: 18:47 - 25 May 2024 Post subject: |
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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 ____________________ a.k.a 'Geri'
132.9mph off and walked away. Gear is good, gear is good, gear is very very good |
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Mr Hammers |
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Mr Hammers World Chat Champion
Joined: 10 Jul 2008 Karma :
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struan80 |
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struan80 World Chat Champion
Joined: 04 Nov 2014 Karma :
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Pete. |
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Pete. Super Spammer
Joined: 22 Aug 2006 Karma :
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Posted: 21:14 - 25 May 2024 Post subject: |
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Mr Hammers wrote: | Pete. wrote: | 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 |
Cheers, Pete. Apart from taking out the brass plug (which i'm a bit reluctant to do tbh, as it just introduces another variable) i've done everything else on there.
Just before taking them apart again i took it for a quick spin up the road, see how it behaves. It was sounding ok but i think slower, and then it just stopped, wouldn't start again, and i had to push the bloody thing home (and uphill too).
Before i pull them off yet again, i'm going to double check the petcock as i repaired that a little while ago...and after you said it could be fuel starvation, i'm wondering if something's up with that. |
Don't remove the brass plug. That's just something I did to show what was in there. ____________________ a.k.a 'Geri'
132.9mph off and walked away. Gear is good, gear is good, gear is very very good |
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stinkwheel |
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stinkwheel Bovine Proctologist
Joined: 12 Jul 2004 Karma :
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Mr Hammers |
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Mr Hammers World Chat Champion
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Pete. |
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Pete. Super Spammer
Joined: 22 Aug 2006 Karma :
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Posted: 11:05 - 26 May 2024 Post subject: |
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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 |
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Mr Hammers |
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Mr Hammers World Chat Champion
Joined: 10 Jul 2008 Karma :
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Posted: 21:05 - 26 May 2024 Post subject: |
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Pete. wrote: | 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. |
Yes, i saw that and was very conscious of making sure i put them in correctly (looked at a parts diagram) but, i could only see one on the four idle screws i took out. I couldn't see anything left in the bottom of the other channels and tried using a pick to extract anything that might still be in there. Either there wasn't, or i couldn't see/get to them.
That said, if anything could cause the issues, that'd be a good bet i think. The pilot jets are now brand new btw, the old ones looked a bit ropey, so i don't think it's them.
Quote: | BTW you are right that is a drain screw not mixture control. The idle mixture screws are the ones with the springs. |
Good to know! Incidentally, i can see the tops of the idle screws poking through into the main bore....is that normal?
It's all back together now, and i've opened the idle screws another 1 turn. Although it still idles unevenly and tries to cut off when shutting off the throttle, it seems to be better than it was. I'll go for a little ride tomorrow and see if it cuts out completely again. Hopefully not! ____________________ A Guide To Powerbands |
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WD Forte |
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WD Forte World Chat Champion
Joined: 17 Jun 2010 Karma :
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Pete. |
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Pete. Super Spammer
Joined: 22 Aug 2006 Karma :
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Posted: 08:16 - 27 May 2024 Post subject: |
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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 |
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Mr Hammers |
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Mr Hammers World Chat Champion
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