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My previous rides were all pre-owned: 81 Suzuki GS 450. 95 Yamaha Virago 750. 01 HD Superglide. 07 Suzuki SV650S. About a year ago, I bought a 2007 Vstar 1100 midnight custom with around 15,400 miles. I've only ridden around 200 miles in the past year, because I am struggling to get it running right. If it were running right, I'd be riding more than 2,000 miles per year.

I really like everything about the bike, except the most important thing: it's not running right. The bike came with Vance & Hines Classic II exhaust. The airbox is stock. The only thing I've added: LED light pods (with relay) that light up when I brake. The only thing I've changed: I bypassed the AIS, which drastically improved the exhaust popping. I learned how to remove carburetors with this bike, so that is something new to me.

When cold, the bike sometimes starts, but it's a weak start that almost doesn't happen. Typically, after warming up maybe 30 seconds on full or partial choke, the engine just quits. It won't start again after that. I discovered that the engine will continue to sputter and warm up if the spark plugs are brand-new.

I've discovered that while the rear cylinder & exhaust is getting hot after start-up, the front cylinder & exhaust is room temp. Also, the upper exhaust pipe is exhausting warm exhaust, while the lower exhaust pipe (that exhausts the front cylinder) is spitting out a mist of gasoline. After the motor dies, or I shut it off, a few drops of gas drip from joints in the lower exhaust. So, that gas in the cold exhaust pipe seems to be the best clue to what is wrong with the bike.

I'm hoping this forum can offer advice about what I need to do to get my bike back on the road!

Here is what I've tried during the past year:
I've read the Vstar 1100 wiki as well as many forum posts. I completely drained the old gas, twice. Once, I refilled with fresh 87 octane from Shell. The next time, I refilled with fresh 89 octane "rec fuel" (no ethanol). I've always used the correct amount of Stabil in every tank. Except this past week: I used 8 oz. of Sea Foam when filling up the rec fuel. I installed a new fuel filter. I removed the carburetors, removed the pilot, needle, and main jets from the carbs (I didn't remove or touch the float bowl assembly), I cleaned those 6 jets with gumout and compressed air. I reinstalled the jets into the carbs.

I've installed new spark plugs twice. Installing new spark plugs seems to be the most beneficial task: The bike seems to run better for a few rides with brand-new spark plugs, until the same problem returns. I've kept the 1-year-old battery maintained.

Thank you for reading my long introduction. What do you think I need to do to get this bike running well?
 

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what do the plugs look like when you pull them out?

unless they are totally fowled out and black, or soaked with gas, I cant imagine why changing them would help, unless maybe you have a bad plug wire, and just by fussing with it to change the plug it connects for a little bit.

Others can give advice on cleaning the carbs and jets. Sometimes just spraying them is not enough, you need to get a small steel tire like a hi E guitar string and make sure none of the little holes in the sides of the jets are plugged. It would help if you knew what size jets are in the bike. Maybe the person who put the aftermarket exhaust on the bike got carried away with oversized jets - if you dont add a high flow intake filter pod with the aftermarket exhaust you dont really need to change the jets at all... maybe just one size bigger if anything.

One thing I did catch, when you start the bike cold with the choke pulled all the way out, as soon as it starts push it in about halfway, so the bike is idling normally. Check your lights and signals and ride off, dont let the bike sit there idling with the choke on - its just to get the bike started, no need to let it warm up. About half a mile down the road push it in all the way.

The cold exhaust on one cylinder indicates it is not firing at all when it happens, the bike is running on one cylinder. The pipe will get a little bit warm because the piston is acting like a compressor, which heats up the air on the compression stroke. Until you get the bike running on both cylinders dont ride it like that, the un-burned gas will wash down into the oil pan and dilute your oil.

Also have to ask: was the bike running correctly when you disabled the AIS? That is an easy thing to make a mistake on, if you dont plug all the tubes or hoses that need plugging, it will lean out the engine - might be the problem right there.

EDIT: one other simple fix that comes up frequently, if your battery connection is corroded that can cause your electrical system to drop out - check the battery terminals to make sure they are shiny clean between the surfaces, and trace the black ground wire down to where it connects to the frame. That connection frequently corrodes and becomes weak - it will keep your bike from starting, and it will make your bike stall at idle, because at idle speed the alternator does not put out enough power for the lights and the electronic ignition by itself to keep the bike running.
 

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Welcome to the forum.
You’ve found a great place for help, lots of knowledgeable members here. Keep us updated on how you get it running right.


Sent from my iPhone using Tapatalk
 

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another standard test for a bike that is not running right is to check the compression

all you need to do is remove the spark plugs - if you have low compression, esp in one cylinder, the valves might be too tight and not closing all the way - that would really make the bike run poorly

to measure and adjust the valve clearance you have to tear it down and take the carbs off the boots enough to get them out of the way to get to the tappet covers. If you decide to take the carbs off again then definitely check the valves, all you will need is the 4 tappet cover orings: $16 for the set of four.
 

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Discussion Starter #8
Thanks to everyone for the hospitable welcome. And thanks to KCW for the abundant advice. I followed up on a few suggestions from KCW. I'll check out the links from lesbank later, thanks.

I removed the plugs (which have less than 100 miles on them): I found the rear cylinder plug very black, which is not a good sign (and I'm not sure how to trouble-shoot that black plug). The front cylinder was light brown, with a little moisture, which makes sense because its cold exhaust pipe was pushing out puffs of gas mist vapor while running. You can see the plugs in the photo. I properly gapped and installed new plugs, again. I am careful to be sure that the spark plug boot is completely inserted and making a good connection with the spark plug.

I also changed the oil, because I was concerned about the possibility of gas in the oil, and because the oil was about 1 year old, despite hardly any miles. I could not detect the smell of gas in the drained oil. I poured in 3 liters of fresh yamalube 10w40 until it was 1/2 way in the looking glass with the bike upright.

I reviewed my AIS disable job, which looked like it's holding tight (see photo). I also looked at the negative battery connection to the frame. It's difficult to get in there, but I think it appeared to be free of corrosion (see photo).

I started it (3 LONG pushes on the start button before it barely caught) and ran it (with choke) for 60 seconds. Long enough to take a video of the exhaust pulses of gasoline mist vapor from the bottom exhaust (see photo). Again, the pipe was HOT at the rear cylinder, the pipe was COLD at the front cylinder.

It's hard to say when the bike was running well, because it is inconsistent and/or intermittent. I might guess that I've tried to start it maybe 30 times in the past year. Maybe 10 of those times it ran well. Maybe 10 of those times it barely ran, but I could just barely keep it running with generous throttle until it completely warmed up. And maybe 10 of those times the engine died within 30 seconds (and would not start again). Some of those good-running rides were a year ago, and some good-running rides were a month ago. It's inconsistent.

Do you think there could be an electrical problem, like a bad wire or a bad connection? Can you recommend how I can use my multimeter to check for electrical problems? I've got no time to work on the bike until next weekend. So, I will try to learn about potential electrical problems next. I'd appreciate if you let me know what you think of the photos, and what you suggest I troubleshoot next. Thanks.
 

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ok, now we are getting somewhere

that rear plug is completely fouled out - the only way to do that is to overload the rear cylinder with gasoline - running very rich.

That could happen if the air intake all the way back to the air filter is plugged, like a mouse or bees are nesting in your intake box
or the choke for the rear cylinder (enrichment circuit) has failed and staying on all the time while you are riding
or the float level on the rear carb is way high
or the jets on the rear carb are too big (to open) or the Pilot Main Screw (PMS) is turned out too far

I know that is a long list, but any of those things could be the cause

The front plug looks like it should. It might be the rear exhaust is getting hot because its getting flooded with gas, might be gas even burning in the exhaust pipe, so the front one seem only warm by comparison. If you were to ride the bike a few miles and the front pipe never got hot, then I would think it is only running on the rear cylinder. If that is happening when you pull the front plug out after it has run for a minute, it would be soaked with gas if its an ignition problem, or it might be dry if its getting no fuel at all.

Usually when a bike was running well, and then it starts to run poorly, there is a single thing that is wrong, and the symptoms usually point to that one thing that could cause what you are seeing on the bike. Im afraid I cant draw any conclusions. Unless someone else has experienced something similar Im not sure what to point to first.

when you said the front pipe was cold after running for a minute, was it cold right where it comes out the the head exhaust port? That would indicate that cylinder it not firing at all, its just pumping the gas vapors out the tailpipe.

EDIT: after thinking this over for a minute, we know the rear cylinder is very rich, maybe the front cylinder is also very rich and it never catches and fires, so it running soot black on the rear, and the front is so rich it wont fire and just pumps the gas out the tail pipe...

that would be a single point failure, the carbs are dumping too much gas into both cylinders.

ok.... the main jets dont kick in until you have the throttle almost half way open, so focus on the PM screws. Did you adjust them or check them? Usually you carefully turn them all the way in (gently so you dont crush the points) and then back them out a specific number of turns for the starting point.

If someone turned them out too far, like they should be 2 turns and they went 4.. that would cause everything you are seeing... maybe the rear is 4 turns out and the front is 6 .. ?

Edit some more: I forgot to mention when you change the oil it takes 3 quarts with a filter change, and a little less without filter change. If you changed the filter put the whole 3 quarts in. If you look at the site-glass while filling it, the oil filter does not fill until you start the bike up for a minute - so if thats what you did check the level again, it might be about 8 oz low now.
 

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Sounds like a pilot jet issue, were the holes on side of pilot jets cleaned? As KCW said, check PMS. All directions are on WIKI. To test Spark:

 

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Discussion Starter #11
Thanks for the suggestions, KCW. I somewhat understand what you are thinking: too much fuel can prevent combustion. I'm getting the impression that this bike needs the carburetors properly cleaned and adjusted.

The following is just FYI, because maybe it can help narrow down the trouble: When I removed the carbs (10 months ago) I took apart the airbox and vacuumed the air filter. I saw nothing in the airbox at that time. It was empty and clean back then.

I also observed the choke lever properly moved through the choke cable and adjusted the choke to both carbs through its mechanical connection.

I decided not to touch the floats whatsoever, because I have no experience with carbs, and I don't know how to check the float levels, or what to do about them. I didn't want to mess them up.

If I remember correctly, the size marks on the jets indicated they were stock-sized jets (see photo).

When I had the carbs out, I took many photos. I've attached some photos. I saw plugs covering the pilot mixture screws, so I presumed they had never been drilled out or adjusted. So, I didn't drill out the plugs, and I didn't adjust the screws. Are you recommending I drill out the plugs and adjust those screws now?
 

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Welcome from Atlantic Canada. Once you get that thing running right you're going to love it.

I'm by no means a carb expert but I didn't see anything in your post about syncing the carbs after you had them off. I believe if you have them off for any reason you should resync them. That's probably not going to cause the issue you're having but it's something to think about.
 
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