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Offline Trav-i

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Carb slide question
« on: November 30, 2009, 06:46:51 AM »
Hey guys,

I was wondering if there is a way to distinguish between the slides for 1 and 2 carbs from the ones for 3 and 4?  The reason I ask is back when i built these carbs I was still pretty new and had to scavenge two slides from another set because of rust and I really didn't pay attention to which carbs I got them from.  This set has never really run right it always popped and spit and would would never get close on syncing, there always all over the place plus while idling i would just rev on its own and then go back down.

Plus this past weekend I put a different set of carbs on and it had a big difference they synced right and run down right well.  So I know there is a problem in the set i built and I think it is an incorrect slide somewhere.

As always any information is greatly appreciated.

Travis

P.S.  the bike is a 73 750
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Offline Seamus

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Re: Carb slide question
« Reply #1 on: November 30, 2009, 02:27:08 PM »
First thought is were the two new slides the same as the existing ones? (number/size under the slide). Did you swap the needles from the originals? Are the needles on the same position for all 4 carbs?
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Offline TwoTired

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Re: Carb slide question
« Reply #2 on: November 30, 2009, 02:34:44 PM »
You do know that the bottom of the slides have cutaways on the inlet side only, right?
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Lloyd... (SOHC4 #11 Original Mail List)
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Offline ekpent

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Re: Carb slide question
« Reply #3 on: November 30, 2009, 02:44:43 PM »
2-tired you are friendly tonight. The slides are basically the same for all 4.When you say rust-nothing in these has to much steel but they can be messed up with a rust film from the gas tank that can cause an idle hang-up.It really sounds like you had a real dirty bank of carbs and the new ones are not as bad.Do a full tune up on the bike(not expensive) and maybe check the sync.  Also give the gas tank a real good look for rust-  A little bit is TOO much--Eric
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Offline TwoTired

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Re: Carb slide question
« Reply #4 on: November 30, 2009, 04:09:31 PM »
Quote from: ekpent on November 30, 2009, 02:44:43 PM
2-tired you are friendly tonight.

Please explain this comment.
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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline ekpent

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Re: Carb slide question
« Reply #5 on: November 30, 2009, 04:22:15 PM »
Two-Tired- It sounds like he had a bad set of carbs to work off from.Your suggestion was good but there was not much to go on from there to work with. I always like to hear what you have to say that may take the problem a little deeper and to the root of the problems.I respect your knowledge on all :D
« Last Edit: November 30, 2009, 04:31:42 PM by ekpent »
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Offline TwoTired

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Re: Carb slide question
« Reply #6 on: November 30, 2009, 05:47:47 PM »
On many Keihin Carbs, there is a slot on the side of the slides.  The left two carbs have a slot on the opposite sides relative to the right two slides.  If you put a slide from a right carb into a left carb, the slide cutaway faces the wrong direction.
I don't know for certain the early 750 carbs have this slot arrangement, but suspect so.  Having one slide that faces the wrong way will simply not allow the engine to run properly.

My earlier comment was to find out if the OP was aware of the cutaway direction.
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Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Bob Wessner

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Re: Carb slide question
« Reply #7 on: November 30, 2009, 07:04:24 PM »
Quote
I don't know for certain the early 750 carbs have this slot arrangement

Yes, same set-up and arrangement. Insert the slides in the wrong bodies and you end up with just what TT describes.
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