Vstar 1100 Front Cylinder Cutting Out - Star Motorcycle Forums: Star Raider, V-Max, V-Star, Road-Star Forum
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  • 1 Post By KCW
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post #1 of 7 (permalink) Old 10-04-2018, 02:02 PM Thread Starter
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Vstar 1100 Front Cylinder Cutting Out

Hi all,

I bought a 2002 Vstar 1100 back in August of this year. It only had 4600 miles on it, and so it did quite a bit of sitting over the years. He told me he did not ride it at all for the past year. There was old gas in it, and old oil... When I first rode it, it was very smooth, rode very nicely, so I bought it. I rode it for a day with that old gas in it and the old oil (which was a bit low I will say), and by the end of the first day, the carb jets were clogged up due to that old gas (my mistake for not draining the old gas out)... I could not get the engine to go high RPMS at all because the jets were so clogged. I proceeded to take apart the carbs and cleaned them. I will make note that while cleaning them, there was a small part that popped out of one of the carbs (I have no idea where from and I can't find where to put it back, picture is posted in my reply below)... The main jets were clogged pretty good, as well as the other 2 jets. Got it all cleaned up, but I set the fuel mixture screws wrong, so I had a lot of popping at idle. Now here's the odd thing... At idle, the front cylinder was not firing... Would only fire after I got the RPMs up past maybe 2k (I don't have a tach, just guessing by sound), so that made for a very jolty ride getting started from a stop. Since I am not a mechanic by any means, I took it to my friend and he proceeded to take apart the carbs again and set the fuel mixture screws correctly (which got rid of the popping), and he also said that he tuned the carbs up to where they were supposed to be as far as the gas/air mix. He unfortunately was not able to fix the front cylinder not firing problem... We tried replacing the ignition coil (and spark plug wire) and that did not fix it. We swapped the spark plugs many times to no avail... We changed the air filter, fuel filter, changed the oil, still nothing... Here's the current state of the bike:

I start the bike up and let it warm up for a minute or two at idle (remember the front cylinder does not fire at all at idle). By this point, the front cylinder spark plug is fouled and if I take it for a ride, the front cylinder won't fire at all (no matter what speed or RPM). That pipe is literally cold to the touch and I can smell gas coming from it. After the bike has warmed up, I proceed to take out that front spark plug, give it a good brushing with a wire brush/rag, and then I put it back in the cylinder. Then I really crank on the bike going down the rode and the front cylinder slowly zaps back to life, but still only fires after getting the RPMs up to 2000 or so. If I let it idle for too long, the plug fouls again and I have to take it out and clean it with a wire brush. I have confirmed that I am getting a constant spark at all RPMs by taking out the spark plug and letting it hang from the engine and seeing it spark to the frame (or any point that is grounded), so I don't believe this problem is electrical. I believe that leaves perhaps a few things... Compression of the engine (but it's only 5500 miles at this point), timing, or maybe my friend did not tune the carbs correctly and the front is just really too rich all the time? Any feedback would be well appreciated!!!

Last edited by Chris Poullas; 10-04-2018 at 04:20 PM.
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post #2 of 7 (permalink) Old 10-04-2018, 02:19 PM
KCW
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The obvious question is what was the thing that came out of the front carb?

I cant imagine there are any parts that are not necessary in the carb. If the float bowls are not set right it will starve or flood the cylinder.

If you post a photo of the part Im sure someone will know what it is. Whatever it is, it must be flooding the front cylinder with that part missing.

Since the bike was running when you got it the compression should be fine. You can borrow a compression tester from places like Pep Boys or Advance Auto and make sure.

BTW your situation is an excellent reminder: If you look in the tank of a motorcycle that has been sitting for a while and the gas is not clear, dont start the engine. Drain the tank and then fill it with fresh gas and a dose of SeaFoam. That will take about 30 minutes and cost $10 for the Seafoam. Sorry that your situation became an example to warn others.

Last edited by KCW; 10-04-2018 at 02:31 PM.
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post #3 of 7 (permalink) Old 10-04-2018, 04:17 PM Thread Starter
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Attached are pictures of the part that came out of the carb. Honestly, I'm not even sure what carb it came out of. Sorry for the lack of information. There are no threads on this part that I can see. I looked through the shop manual and I could not find a part that was similar to this... Looked through both carbs and I didn't see a part that was on one that wasn't on the other either...
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post #4 of 7 (permalink) Old 10-04-2018, 04:41 PM
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https://www.partzilla.com/catalog/ya...apc/carburetor

32 maybe - nozzle behind the main jet?!
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post #5 of 7 (permalink) Old 10-08-2018, 09:28 PM Thread Starter
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Quote:
Originally Posted by KCW View Post
The obvious question is what was the thing that came out of the front carb?

I cant imagine there are any parts that are not necessary in the carb. If the float bowls are not set right it will starve or flood the cylinder.

If you post a photo of the part Im sure someone will know what it is. Whatever it is, it must be flooding the front cylinder with that part missing.

Since the bike was running when you got it the compression should be fine. You can borrow a compression tester from places like Pep Boys or Advance Auto and make sure.

BTW your situation is an excellent reminder: If you look in the tank of a motorcycle that has been sitting for a while and the gas is not clear, dont start the engine. Drain the tank and then fill it with fresh gas and a dose of SeaFoam. That will take about 30 minutes and cost $10 for the Seafoam. Sorry that your situation became an example to warn others.
Quote:
Originally Posted by KCW View Post
https://www.partzilla.com/catalog/ya...apc/carburetor

32 maybe - nozzle behind the main jet?!


So I tore apart the carb and put that nozzle around the needle, and boom works like a charm now!!! That cylinder had so much gas that leaked out of it onto the pipe that the outer part of the pipe was smoking for the first 10 minutes of it firing lol! Thanks so much guys! I invested so much time and money into trying to fix this and I can't believe it was just that tiny nozzle that was flooding the cylinder. So here's a question, my buddy synced and tuned the carbs with that one cylinder not firing at idle... I'd imagine I have to re-sync and tune the carbs now that the cylinder is firing? I notice that when I totally give it full throttle from a stop, it does hesitate maybe once while fully accelerating, maybe due to the carbs not being tuned/synced 100%
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post #6 of 7 (permalink) Old 10-08-2018, 09:37 PM
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The rule of thumb is that if you take the carbs off for any reason they should be synced. And where you had the missing part I would say it's a must do.
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post #7 of 7 (permalink) Old 10-09-2018, 07:57 AM
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Quote:
Originally Posted by Chris Poullas View Post
So I tore apart the carb and put that nozzle around the needle, and boom works like a charm now!...
Great news. Like Northern said definitely have your friend resych the carbs, the bike needs to be running perfectly (timing, fuel supply, clean carbs, clean air filter, valves adjusted...) to be able to properly synch the carbs. You can synch them when something else is off, but then when you tune the other thing correctly the carbs will be out of synch.

It only takes a few minutes to put the vacuum gauges on and adjust the two screws with a two cylinder bike.

One other thing: take the oil filler screw cap off your engine and take a wiff of the engine oil. If it smells like gasoline at all, you should drain it out and replace it. Dont need to replace the filter (unless its due anyway). With the bike running rich to the point that the front cylinder was not firing most of the gas was being blown out the exhaust (and into the catalytic converter as you have seen). But some of it could have gotten washed down the sides of the cylinders into the crankcase. It depends on how much you rode it running on one cylinder, and maybe the float bowl was draining down when the bike was not running and flooding the cylinder too.

It doesnt take much gasoline to dilute 20W40 oil down to 1W3.

Its probably ok, but if the oil smells like gas then even the $2 / quart generic oil from walmart is preferable to oil that has been diluted with gas. I know you just changed the oil, so dont waste 4 quarts unless it smell gassy.

One other thing: before you synch the carbs ride the bike 3 miles or more to warn the engine up. Also if your bike seems balky when its cold, like cranking the throttle and it stumbles, dont worry about that. As long as it runs well after a few miles that is what matters. Carbs are always always a bit off with a cold engine.

Getting a cold engine to run well is a continuous fuss with the choke knob for the first mile or so, and then 2 or 3 miles of the idle being off with the choke all the way in, until the heads get good and hot.

Last edited by KCW; 10-09-2018 at 10:42 AM.
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