[AMW]

I bought a 2001 Vulcan 750, and it was torn apart. I got it back together and it runs good, but it runs out of gas in about a block. I think the hose that goes to the petcock vacuum fitting which points straight down, is coming from the wrong place. Where is the other end supposed to go? :BLAM:

I sure could use a new petcock, because the screen on the reserve side is broken. If anyone has an extra petcock, I'll buy it from you.

 

[Spockster]

First post? Welcome to the forum!

The vac hose comes from the vac port on the left carb (front cylinder) to the port that faces downward on the petcock.

 

[Goofyfoot2001]

Heres a crappy picture that might help confuse you.

 

[AMW]

Yup... That's how it was plumbed, dammitall!!! I guess that means I have a bad diaphragm or I need to clean the carbs better.

Thanks so much to the both of you, for the help. I appreciate it.

 

[Goofyfoot2001]

Will it idle for longer than a blocks worth of gas? If so, not the petcock.

 

[AMW]

Yes. It idles and revs, but when I try to ride it, I only get a block or so and end up pushing it back. Starts again with the choke on, but won't stay running.

 

[Goofyfoot2001]

Yes. It idles and revs, but when I try to ride it, I only get a block or so and end up pushing it back. Starts again with the choke on, but won't stay running.

Have you taken apart the ignition switch under the key and cleaned and stretched the springs? I say this because my bike would idle all day but while riding would shut off. Not bumps in the road either. That switch does strange things to the bike.

 

[VN750Rider/Jerry]

The petcock on the Vulcan 750 (unlike on Hondas) is rebuildable. I've had to rebuild mine a couple of times due to leaks. I believe the problem was caused by ethanol gas. The rubber parts I replaced appeared to be melted.

 

[Rebel13]

Open the fuel cap and leave it open. Ride a bit and see if it still happens. Sounds like a dirty cap aka poogs.

 

[Goofyfoot2001]

Open the fuel cap and leave it open. Ride a bit and see if it still happens. Sounds like a dirty cap aka poogs.

I never could get that last little diaphram am off my cap but so far cleaning the cap and blowing compressed air through the vent hole seems to have cleared my occasional flub blub. So alls im going to say. Is CLEAN DAMN EVERY FLIPPIN THING ON THE BIKE.

:itchy-scr

 

[nopickles98]

Could also be a leak in the vacuum hose itself - could be letting enough gas thru for idles & even revs but empties the float bowl(s) under load.
Was also thinking misadjusted float level or float valve not opening completely but both carbs would have to be affected, otherwise you would still be able to run on one cylinder.
First & easiest thing to do is replace the vacuum hose. If you remove the old hose and there is gas in it, you have a failed diaphragm in the petcock. I recommend replacing the petcock anyway because of the bad screen, that's what I had to do - my bikes PO removed all the screens and I was unable to find those parts separate from the entire unit, you may have better luck than me though.
Good luck

 

[AMW]

This morning the petcock leaked when I turned it to 'on', so that is probably the issue. Has anyone used one of the aftermarket petcock rebuild kits from eBay?

Thanks for all of the advice. You guys are way more helpful than any forum I have been on. Never would have thought to ride it with the gas cap open.

 

[Jakzen]

This morning the petcock leaked when I turned it to 'on', so that is probably the issue. Has anyone used one of the aftermarket petcock rebuild kits from eBay?

Thanks for all of the advice. You guys are way more helpful than any forum I have been on. Never would have thought to ride it with the gas cap open.

I have used the one made by k&l and it fit perfect.

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[Spockster]

You might also be interested in the TW200 petcock mod, I've read that works well and does away with the vacuum.

 

[AMW]

I tried to start it, and now it won't start at all. I replaced the vacuum line, with a clear line, and that line has gas that appears to be going to the tank, from the carb. Pretty sure it's not supposed to have gas in the vacuum line.

I guess I'm going to have to clean the carbs again, and replace some diaphragms, in addition to rebuilding the petcock. Shoot dang! Pretty sweet bike, so it deserves some love.

 

[Spockster]

The petcock is shot. It's not supposed to pull gas through the vacuum line.

I wouldn't go into the carbs until the petcock is fixed and a test ride done. You may not need to work on the carbs again.

edit: The gas is flowing from the petcock, through the vacuum line, to the carb.

 

[AMW]

Very good advice. Bought a K+L petcock rebuild kit on eBay.

Forgot to mention that the tank had lots of rust, so I put about 80 small screws in a shook like a wet dog, then naval jellied for a couple hours. Came out pretty clean. (Didn't have the petcock installed when I cleaned it.) I am sure some rust sediment got into the carbs, since the reserve strainer on the petcock is broken. Might just have to clean the carbs better, but I'll rebuild the petcock first and see what happens.

Thanks again!

 

[Spockster]

You're welcome, I'm sure one of these is in my future, there seems to be no escaping the common problems.

 

[wmsonta]

that line has gas that appears to be going to the tank, from the carb.

If that statement is true, you have a needle/seat issue. It absolutely can happen.

 

[Jakzen]

You might also be interested in the TW200 petcock mod, I've read that works well and does away with the vacuum.

It works very well and you can buy an oem one (don't get the aftermarket crap) for less than the rebuild kit. I just make sure to shut the fuel off when I'm not riding.

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