Need urgent help on this one. It's hard to start and when it does, it doesn't idle. - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 16 (permalink) Old 08-15-2011, 09:44 PM Thread Starter
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Need urgent help on this one. It's hard to start and when it does, it doesn't idle.

Hi. I took out the carbs, cleaned them, put them back together and put them in the bike. It wasn't working right, it would idle fine but when you opened the throttle it would have no power, revs would go up slowly, I was half expecting it to die.

So after the carb clean, it starts after quite a while of trying and then it doesn't idle, I can keep it alive with the throttle but doesn't idle at all. If I let go of the throttle it dies. Suggestions please
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post #2 of 16 (permalink) Old 08-15-2011, 09:54 PM
If only it had 6th gear..
 
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Can you smell gas when it is running?
I when you throttle it does it rev smoothly until it dies or is it sputtering and coughing below a certain rpm?
Pop a plug out of each cylinder and see what they tell you.
where did you set your idle mixture screws at, how many turns?
What happens when you turn the black idle screw?

Do you have the original surge tank and ears?

Last edited by DavesVulster; 08-15-2011 at 09:57 PM.
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post #3 of 16 (permalink) Old 08-15-2011, 10:21 PM
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There is a black knob on the left side of the engine. Turn it in that should help with idle. Maybe, give it a try.

02 honda sabre 1100
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post #4 of 16 (permalink) Old 08-15-2011, 10:43 PM Thread Starter
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Quote:
Originally Posted by DavesVulster View Post
Can you smell gas when it is running?
I when you throttle it does it rev smoothly until it dies or is it sputtering and coughing below a certain rpm?
Pop a plug out of each cylinder and see what they tell you.
where did you set your idle mixture screws at, how many turns?
What happens when you turn the black idle screw?

Do you have the original surge tank and ears?
I can't tell about the gas, cuz I've been messing with the carbs all day and all I smell is gas... plus, one of the petcock's outlets popped out halfway at some point and some gas poured out, so the smell is there.

It does seem to rev smoothly, it dies when I let go of it.

I set my mixture screws to 2.5 turns, then tried it up to 3.5 and nothing changed.

I don't have the black knob on the idle screw I just have the long spring-like thingy that the knob attaches to. That's the way the carbs came with the bike.

I do have the original surge tank and ears... still need to buy the filters to get rid of the ears. I got everything for the carb, just missing the filters.

Last time I worked on the carbs I used red silicone to seal everything that had a gasket on it... this time I didn't. I already kicked the carbs out of the bike (new, faster method of taking out the carbs) and I'll try sealing them with silicone and setting the idle a bit higher with the screw (I can still turn it with some pliers but only when the carbs are out I think).

I think these two things are gonna be the last attempts for today. Sunlight is going away

Thanks guys... I'll let you know what happens.
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post #5 of 16 (permalink) Old 08-15-2011, 10:48 PM
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you said it would idle fine but when throttled it would cut out, mine did that after reassembly after stator change and after looking carefully I lefy one vacuum line off the carb, hooked it up and all was good. hopefully you overlooked one!

1986 vn 750 aka "Huck Farley"
42,000 miles
Rick's stator and rr
Tuxedo stator cover mod
pickup coil mod
dampers replaced
agm m/f battery
Harley sportster exhaust, degoated
Hid conversion
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custom "vn750.com" grill cover
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acct to mcct mod https://www.vn750.com/forum/showthread.php?t=17917

rekeying locks, https://www.vn750.com/forum/showthread.php?t=7309

stator replacement walkthrough, https://www.vn750.com/forum/showthread.php?t=11369
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post #6 of 16 (permalink) Old 08-15-2011, 10:52 PM
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Ceal, don't use silicone on carbs. That stuff will go into ever little air hole that it can find and stop up the carbs. MHO
You will now need compressed air to clean them out.

02 honda sabre 1100
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post #7 of 16 (permalink) Old 08-15-2011, 11:13 PM
If only it had 6th gear..
 
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"I already kicked the carbs out of the bike (new, faster method of taking out the carbs)".... wish I had thought of that method when doing mine... oh the time I'd have saved" . Oh man niterider's correct, no silicone in those baby's. Also wibs point about the vacuum line is correct. Even one line cracked or unplugged could cause it to die if the idle is low enough. Mine runs at 1000 but if I pop a vac line it'll drop to half that and chug like an HD. If yours was lower than that to begin with it could certainly die out. On the missing idle screw, could you get a small pair of vise grips on it before you mount the carbs back in then release them when you've got it idling where you want it. Hopefully it's just a matter of vacuum or that idle screw spring to low. Good luck. Will be waiting to hear the results.
Dt
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post #8 of 16 (permalink) Old 08-15-2011, 11:29 PM Thread Starter
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Dang... guess I'll need new gaskets for the carbs then... anyone know of a kit, or do I have to get them separately?
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post #9 of 16 (permalink) Old 08-16-2011, 12:30 PM
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post #10 of 16 (permalink) Old 08-16-2011, 03:46 PM Thread Starter
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Yea, I guess I meant the o-rings... English is not my first language, so I get some technical names wrong sometimes.

When I don't use silicone on the very edge of the diaphragms I can hear a slight vacuum leak. The diaphragms are in good shape and they look like they seat well, so I dunno why that happens. Maybe the lid is the one that might be bent or something.
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