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Discussion Starter #1
Hey Guys!

New to the site, just found yesterday. LOVE IT! Wished I would have found when I was struggling to remove the carbs to clean.

I recently got a 94 750 from my boss. He didn't drive it much at all. It probably sat for a year or so. It ran, but not great. Took carbs out, cleaned, new airfilters, plugs, oil change and she ran great! Been riding it for a while now, probably put on a couple hundred miles.

Just 2 days ago it seems like it's gummed up again. It will fire up, rev up to 4000 RPMs on Full choke, turn choke off to idle then die. When start again, full choke will only bring it up to 1500RPMs. I can keep it running and even drive it but, I'm sure it's running lean or something. With choke on, it also smells very gassy, like it's running rich.

I read a bunch of posts on turning idle screw out (cap on it, how do you get that off), but I don't think thats the problem. I'm sure its the jets. I read a post on taking jets out with out taking carbs out, but that looks next to impossible.

I put in gas probably 3 weeks ago, and still have 1/4 tank (live real close to work). Do you think this has something to do with it (bad gas)?

Can I put in new fresh gas, and hope it cleans it out? Or is there something I can add to the gas to help clean? Or do I need to take those things out again and reclean?:BLAM:

Sorry for the long post, just wanted to get the picture across. Thanks for any advice!
 

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The idle screw does not have a cap. Its got a rubbery surface but it should turn freely. It will be located on the clutch side of the bike on the carb. Mine looks like a rubber gear. If you look at the picture, it will be to the RIGHT of the yellow arrows. Its looks like a black gear. If you turn it clockwise, it will decrease IDLE RPM, counter clockwise will increase it (i'm 85% sure but I might have it backwards). It should move freely. Initially, I had to turn mine back and forth a few times to free it up.
 

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Simple Solutions
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Hey Guys!

Just 2 days ago it seems like it's gummed up again. It will fire up, rev up to 4000 RPMs on Full choke, turn choke off to idle then die. When start again, full choke will only bring it up to 1500RPMs. I can keep it running and even drive it but, I'm sure it's running lean or something. With choke on, it also smells very gassy, like it's running rich.

I read a bunch of posts on turning idle screw out (cap on it, how do you get that off), but I don't think thats the problem. I'm sure its the jets. I read a post on taking jets out with out taking carbs out, but that looks next to impossible.

any advice!
next to the vac port on the carb there is a lead circle... to get that cap out just run a drill bit in there and that should break her free if not a pick will allow u to pull her out ... be careful not to go into the mix screw

cleaning the jets without the pull is tricky but all u need is a short or rt angle screwdriver to pull the cap off from there spray carb clen into the jets also take a strand of throttle cable (old bicycle brake cable ) and poke up into the jets

Hey Guys!

I put in gas probably 3 weeks ago, and still have 1/4 tank (live real close to work). Do you think this has something to do with it (bad gas)?

Can I put in new fresh gas, and hope it cleans it out? Or is there something I can add to the gas to help clean? Or do I need to take those things out again and reclean?:BLAM:

Sorry for the long post, just wanted to get the picture across. Thanks for any advice!
bad gas is common did u clean out the tank when u rebuilt the carbs... ?? dump in a few ounces of seafoam into the tank and top her off, install some inline fuel filters to keep more stuff out of the carbs ... may want to pull the petcock and see if its a little gummed up....

Seafoam is great u can put in full strength to eh bowls and let her soak overnight befor doing the other cleaning stuff seafoam has been known to clear up problems just in itself

when this happened to me the it was actually running on one cylinder and rather gutless ... check to see if both exhast pipes are gettin hot .... remember the front one is double insulated so it wont get as hot ...
 

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Jesus-Family-Coffee-Bike
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The Professor
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Sounds like the pilot jet is clogged.
X2 on what seebeeare said on making sure the tank&petcock are clean and adding filters.
Pull the fuel line off of the carb and let some fuel drain into an empty pop bottle to see if there's any junk commin from the tank. Hopefully you won't have to pull the carbs again.
 

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Discussion Starter #7
Thanks guys!

I said that wrong about the idle screw. I know where that is. It was the jet behind the lead cap I was talking about. I'll give the drill a try.

I did not clean the tank. Should have done that.

Seafoam - I'll give that a try first! Thanks!
 

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Discussion Starter #8
bad gas is common did u clean out the tank when u rebuilt the carbs... ?? dump in a few ounces of seafoam into the tank and top her off, install some inline fuel filters to keep more stuff out of the carbs ... may want to pull the petcock and see if its a little gummed up....

For the inline fuel filters, do I need 2, one coming out the hoses that point straight back towards the engine?

Seafoam is great u can put in full strength to eh bowls and let her soak overnight befor doing the other cleaning stuff seafoam has been known to clear up problems just in itself

Also, what do I soak? Does this mean running a bit to get into the "system" stop and let it rest over night?

Crap - tried to get the fancy quote boxes in, but didn't work. Again, new to forum. Sorry.
 

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The filters go on the two outer fuel lines coming off the petcock. The center line to the petcock is a vacuum line.

You can drain the gas from the carbs and refill them with straight Seafoam. Let sit for at least 12 hours. The longer the better. Drain the Seafoam and see if she will crank. If yes, add 1/2 can of Seafoam to a full tank of fresh gas and ride it. Repeat once if needed. If that doesn't clean the carb sufficiently, need to pull them and give them a good cleaning. Periodically adding around 3 ounces of Seafoam to a tank of gas is a good way to keep the system clean.
 

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Discussion Starter #10
The filters go on the two outer fuel lines coming off the petcock. The center line to the petcock is a vacuum line.

You can drain the gas from the carbs and refill them with straight Seafoam. Let sit for at least 12 hours. The longer the better. Drain the Seafoam and see if she will crank. If yes, add 1/2 can of Seafoam to a full tank of fresh gas and ride it. Repeat once if needed. If that doesn't clean the carb sufficiently, need to pull them and give them a good cleaning. Periodically adding around 3 ounces of Seafoam to a tank of gas is a good way to keep the system clean.
Thanks for that advice, I'm leaving work right now and going home to try the soak!! What is the best way to fill and drain the carbs? I think to drain, is that allen screw, correct? I unscrewed that once and it came leaking out.
 

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Thanks everyone!

Did the soak last night. Put a galon of fresh gas along with 2 cap fulls of Seafoam, ran around the block a few times, runs great!!

Thanks again.

I'm sure I'll be back with other questions.:p
 

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1995 750 vulcan
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yes the little allen screw is the float drain. my bike sat for 6 years and the gas was really bad. i removed the float drains and shot about half a can of gumout carb cleaner into each caburetor,to flush it out. i also shot gumout down the fuel lines into the carbs again with the float drains out. then rinsed the tank with acetone, and put new gas,with seafoam. the bike started right up! i did have to adjust the idle adjust knob (the rubber wheel one) to get it to idle off the choke, but it purrs now........kudos to this site, i'd probably still be tinkering:pepper:
 

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Terminology! :doh: There is one idle speed adjust knob on the left side of the bike under the carb. This knob adjusts your idle stop. Idle should be set at close to 1100 rpms when bike is hot. You have two pilot jets, one on each carb, and they are located next to the vacuum port on the side of each carb. Usually (if no one has removed it yet) there is a lead cap pressed in there to keep the government happy. You can pop them out to get to the pilot needles which are brass slotted screws. This jet basically only affects idle, and it regulates the amount of fuel gets into the intake at idle. If they've never been messed with, you can run them in til they GENTLY bottom out, counting the turns, then remove them and the little spring that is around them, squirt some B12 carb cleaner in there to clean the jets then replace the needles back in to the turns you counted (bottom them and turn them back out). Other than removing the carbs to clean, this is about all you need to do for the idle.
CAUTION: Someone suggested using a strand of brake cable to ream out the main jets. I would never do this as the jets are made of brass! I've used strands of copper wire to do this but never would use anything made of steel. Just something to think about!
 

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1995 750 vulcan
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worked for me...

i'm new to the site as well, and would've spent many an hour wasting my time...but this worked for me.....
drain the gas tank, and rinse it ....i used acetone as it wasnt too rusty. just to de-gum and dissolve the junk.next on the carbs,i took out the float drain-plugs, and, WITH the tank off, thoroughly sprayed gumout, or any carburetor cleaner, into the holes where the drain plugs were, as well as into the fuel line that feeds the carbs into the float bowls. (the two outside lines from the petcock, as the middle line is a vaccum line.). I alternated, and let drain between.
after six years of sittin' she fires right up and revs clean. also put seafoam in the tank to further disslodge and keep her clean!

P.s. most problems are solved , clean, clean, clean.

good luck!
 

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Search Goddess
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I'm working on the same issues with my bike now and after adjusting the black knob for the idle several times, I need to get it back to base. Thing is.. I can't remember which way is which now!
I'm talking about the black knob on the left. I figure if I get that back to 'stock' setting I can tackle the bowls and pilot jets. One thing I noticed after I got the bike back from the dealer is the right side pilot jet has a little red cap on it. Hmmmm this wasn't there before, most likely the dealer capped it? This makes the pilot jet even more suspect. (That and the fact that it set for 2 months with what I "thought" was seafoam treated gas but most likely was also swapped out by the dealer)
 

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I am having an idle issue. After it is warm, the bike intermittently idles at 1800 rpm or so....then after revving it a few times.....or driving some more...it will come back to 1100. Do you think its a vacum leak when hot?
 

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Search Goddess
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Just wanted to post an update on my bike..
Fixed a found gas leak coming from the right side petcock hose, and then noticed that the rear cylinder / header pipe was cold! Checked plug, it was wet so it was getting gas, but no spark. Upon further inspection found that one of the wires was left off of the coil.. Reconnected wire and she fires right up, climbs to 3000 rpms with choke and after warm-up, settles back to 1000 (+/- 50) rpms and doesn't stall!
So she is purring once again, and the temp is currently 30 degrees :doh:
 

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Nice! I'm guessing the mechanics are to blame for the disconnected coil? Dianna, it's like you just bought a used bike and have to figure out what the PO did to it! I hope you get a warm/dry spell so you can get out and ride!
 

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I am having an idle issue. After it is warm, the bike intermittently idles at 1800 rpm or so....then after revving it a few times.....or driving some more...it will come back to 1100. Do you think its a vacum leak when hot?
Could be. As long as your throttle cables are working smooth and hitting the throttle stop good, then I think you have a vacuum leak.
 
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