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Discussion Starter #1
This is a slight continuation on a previous post that I had. I started a new thread to try to get it some more exposure...

If you want some background...

http://www.vn750.com/forum/showthread.php?t=20174&highlight=madeinsin

My Vulcan still does not like to move after its been sitting for a while. I start her up with choke on and let her run. Ease of the choke after about a minute and let her run for another 4 to 5 minutes.

I jump on her and put her in first. I let of on the clutch and the RPM Gauge skyrockets to 4 to 5 k without me giving any gas at all. Then it just as sporadically shoots to zero and turns off. If I let off on the clutch in time the bike will continue to run. I play this game for a while before she actually starts to move forward when I let the clutch out like shes supposed to. It took at least 5 minutes to get this to happen tonight. Temp outside was 40 degrees.

After I started moving It drives fine. If I stop at a stop sign and take off I have no issues. Works great.

I stopped a friends house on the way home and KEPT HER RUNNING while I went inside. Came back out and right back to the same issue. Took me 4 minutes to get her moving finally then.

I hit 5 lights with NO ISSUE.

So it seems to me that this happens after the bike sits in one spot for an extended period of time.

Thoughts? Questions? Ill try whatever you guys throw at me.

Kevin- To answer some earlier questions you had . . . There may be some immediate hesitation but I dont feel like its anymore than me just having a good gas to clutch ratio when I start out. Im still getting a feel for it... Carbs condition is unknown other than the fact that I followed directions on this forum and put seafoam in them to clean them up. Never been in the carbs before and I've only had the bike for a month. He said he didnt drive it much this year.. Very little.. and I have new iridium plugs and wires..

RakerBill- The problem you have sounds very similar to whats going on here. Any advice on how I can investigate this issue?

Thanks ahead of time all and much apprecaited!

Jay
 

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Ok gonna give this a shot while i munch on some more Cheetos. Ok, an engine that normally runs out of fuel, meaning if the carb runs dry, will increase in rpms as the final drops of fuel burn up because of a lean mixture. Its normally about 100 to 150 rpm increase but not a 1000 or 2000 rpm increase. Its possible, and im saying possible that the idle mixture fuel flow is being stopped by trash or something in the carb thus an increase in rpms, but that should happen for only a moment then the engine dies. How long does your HIGH RPM increase last? Ive never had this happen on my VN but its something ya might think about. If your bike runs fine between red light to the next red light its using the other jets in the carb for higher rpms. I know this sounds kinda far out there, but if its not in the carbs then it might be a fuel blockage problem going to the carbs. Could be you've adjusted the idle up for a fuel supply problem and once the fuel begans to flow at its normal rate again you get the high rpms. Do you have two fuel fliters on the carbs or just one fuel filter for both carbs?
 

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Discussion Starter #3
Cheetos are good. But I am killing the Crunch N Munch myself!

The RPM increase is only a second if I continue with giving it gas and try to accellerate. What I can do is let back of on the clutch and the rpm's will return to normal.

I will say that when I cleaned the cabs out with seafoam my petcock leaked when I moved it to the off position and then leaked again when I moved it to the on position. Obviously it's beginning to take a crap. Maybe that's holding up the fuel supply in some way?

I just recently adjusted my Idle screw to keep my RPM's at 1100 before that the previous owner had the idle rpms around 2k.

And lastly.. Im not sure if I have any fuel filters.. I don't know what they look like yet. I will look them up in my clymer manual and track it down and let you know with that answer.

Thanks for your advise and taking the time.. Enjoy the Mighty Cheeto!
 

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Discussion Starter #4
ok.. So IF my bike has the filters it seems as though they would be in the gastank attached to the PETCOCK from what I can tell... I followed the fuel lines to the carbs and didnt see any other filters present. Is the only way to get to this filter removing the gas tank, and petcock to inspect?

Thanks Again

jay
 

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Ive never had my petcock off of the tank. I think there is a filter screen there. Im sure others will chime in with there thoughts to!. Most folks here run either a single or dual fuel filter between the petcock and the carbs. There are some photos in the gallery of them. I have two very small inline filters on my VN700. Its kinda weird the owner of your bike had it set to idle at 2000 rpm, ponders if he was having the same problem your now having but overcame it by just setting the bike to idle at an higher rpm. Do a search on carb filters, should pull up a link to some pics of filters.
 

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I lean to electrical, so here is another point of attack.
I think I would make sure all my safety switches were clean and in good condition, particularly, the kickstand and transmission neutral switches.
If you want to test whether a dirty safety switch is giving you grief, temporarily ground pin 12 (blue wire on my '91) of the 10 pin connector on the jb. Grounding this point on the jb bypasses the safety switches for the ignition. I would rule this possibility out before disassembly of the tank and petcock.
I am a firm believer in the safety switches that are for the riders benefit on the VN750. If you find that the problem goes away when pin 12 is jumped to ground, do not be satisfied running it that way. I recommend servicing the defective switch asap, and removing the grounding jumper.

Good hunting ...
 

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The only stock "filter" is the internal screen on the petcock feed tubes. Inline fuel filters are a good idea IMO, and I had two (one on each fuel line) on my bike, but there is very little room for them. After I removed the failing Kreem liner and rust from the tank, and rebuilt the petcock, I removed them and haven't had any problems.

Here's a pic of a typical fuel filter:http://www.amazon.com/Visu-Filter-I...4?s=automotive&ie=UTF8&qid=1296068296&sr=1-14 Many auto parts stores carry them.
 

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Crap, I WAS in 5th gear.
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I'm gonna go with a faulty petcock, but then, I don't have to rebuild it! Here's my theory: At idle there is less vacuum to actuate the leaky petcock and the carb bowls aren't filling causing a lean condition. Once you give it some throttle, the bowls start filling again.
 

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Discussion Starter #10
Hey All-

I ordered those filters today... Seems to be a no brainer for 2.99 a piece...

So far I do believe I managed to fix my problem with your help. My kickstand switch was sticking... I sprayed wd 40 on it and work it in and out and so far I've not had the problem again.. I will say I couldnt repeat the issue by pushing on the switch... But so far no reoccuring issues...

Thank You guys. Much appreciated!!

I'll let you know if it comes back and if it was the final fix.

Next on the agenda.. lube the splines..

Thanks Again!

Jay
 

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Discussion Starter #12
Funny you say that cause just ordered a petcock rebuild kit... I figured no matter what I dont want a petcock that leaks when I change it from off/on/reservere so why not rebuild it. Thanks for heads up and advise.

Thanks

Jay
 

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Make sure you get the little projections on the internal plate aligned properly. If you don't, it will leak like a sieve.
 

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Discussion Starter #14
Will do and thanks!
 

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I'm gonna go with a faulty petcock, but then, I don't have to rebuild it! Here's my theory: At idle there is less vacuum to actuate the leaky petcock and the carb bowls aren't filling causing a lean condition. Once you give it some throttle, the bowls start filling again.
 
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