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Discussion Starter #1
Hello All,

I just recently purchased a 2007 Suzuki Boulevard s50 with 10k miles in it. The owner had regular tune ups at the dealer, and everything seemed okay when I bought it.

I haven't had this issue before until today, in fact, I just got dropped off from the tow truck.

Here is the issue I had:

I was in 3rd gear, and I was holding the throttle a bit, maintaining 45 mph. All of the sudden, I could feel the bike slowly losing power (or RPM's?). I shifted it up a gear, and the issue continued. I continued to lose power. After about a quarter of a mile, I was almost full back on the throttle. But the bike was not revving up. Full back on the throttle was essentially equivalent to maybe 5% throttle with normal power. After maybe 10 seconds, the bike completely stalled.

I pulled it into a residential, and tried to restart it. The electrical starter was working, but the bike wouldn't turn over. It would spurt once or twice, then nothing. I let it sit for about 5-10 minutes, and it started to turn a little bit more. I pulled the choke out, and it started.

I started driving down the street again, and maybe 2-3 minutes later, the same thing happened again. Eventually I was full throttle again, then I completely lost the rpms and it stalled. I was able to start it again, but only after waiting another 5-10 minutes.

I just gave up and towed it home.

Anyone know what it could be? The bike backfires a little bit when it idles with the choke pushed in (doesnt backfire with the choke pulled out). But I am not sure if this is the issue, since I have been riding the bike for a few weeks, and no issues.

Any thoughts? Thanks!
 

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Retired twice: Navy and as a govt contractor
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Vent in the gas tank plugged?
 

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Discussion Starter #3
Vent in the gas tank plugged?
Someone I know mentioned that.

I am brand new to bikes, so I have no idea what to do, or how to determine if that is indeed the issue.

Weird part of it is that I have gone riding like 15 times prior to this incident, with no issue what so ever. It even occurred about halfway through my ride from work to home.

How would I unclogged the vent?
 

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Retired twice: Navy and as a govt contractor
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Next time it happens open the gas cap. if you get a rush of air it is clogged. Sometimes you can hear the air but after you open it the bike starts and you can go again for xx amount of time and then it happens.

Some caps come apart and you can clean them others you have to replace
 

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Discussion Starter #5
Next time it happens open the gas cap. if you get a rush of air it is clogged. Sometimes you can hear the air but after you open it the bike starts and you can go again for xx amount of time and then it happens.

Some caps come apart and you can clean them others you have to replace
Problem is that I don't have the money to tow it again. So if it does happen, and it's something other than the vacuum, I will be out of luck.

I'll take a look at the gas cap and see whats going on with it. Maybe its clogged.
 

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Since this is fuel-injected, there could also be fuel pump issues, FI controller issues, low-battery. Can we assume you checked to see that the oil was properly filled?
 

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Discussion Starter #8
Here is a quick update guys:

So I went down today and turned the bike on. Started up just fine, and ran okay cold. Sure enough, as soon as it warmed up, the problem occurred. I didn't even need to ride it, I just revved it up for maybe 5-10 minutes.

Before I did this, I cleaned the hell out of the gas cap. It still happened, but I wanted to make sure I did it right. So it stalled, and I pull out the gas cap...No "whoosh" sound, or anything to indicate there was an improper vacuum in the tank. I did, however, notice a strange noise.

After I would start it up, it would stall after a few seconds...but right after it stalled, I could hear a weird sucking sound...Like gas funneling through the fuel line slowly. I could only hear it after it stalled.

Come to think of it, I DID use seafoam in the tank to help clear out the carbs. I wonder if it blocked the line going from the tank to the petcock, and the sound I am hearing is gas slowly funneling through the line (past whatever is clogging it). But then again, why would it only happen after being warmed up?

I thought it was possible that the line is somehow being pinched when the bike heats up, but that doesn't make much sense to me, so I am not sure.

Additional thoughts?
 

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sad thing about coils, when they are pushed(like a maniac motorcycle rider does often) they heat up, say about .5% per red line. Assume a really saavy rider that commutes to and from work everyday to beat traffic redlines about 3 times, that would make the coils age about 15% every day. 10 days of hard cranking? man that is like a file on piece of mild steel. I would get some coils.(accel are fairly good) I had an old truck once....traded the coil out of a truck some guy left at the shop, yep ran fine afterwards!
 

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Discussion Starter #10
sad thing about coils, when they are pushed(like a maniac motorcycle rider does often) they heat up, say about .5% per red line. Assume a really saavy rider that commutes to and from work everyday to beat traffic redlines about 3 times, that would make the coils age about 15% every day. 10 days of hard cranking? man that is like a file on piece of mild steel. I would get some coils.(accel are fairly good) I had an old truck once....traded the coil out of a truck some guy left at the shop, yep ran fine afterwards!
How would I determine if it is indeed the coil?

I have two spark plugs on either side of the engine, so I would assume there are two coils?
 

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Check your fuel filter
 

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Discussion Starter #12
I literally just pulled out the petcock. Fuel flowed fine into my jerry can. Ill look into pulling out the fuel filter. Im just limited in tools, thats all.
 

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Does this bike have carbs or FI? From the specs I seen on it has Mikuni carbs, and I think those are CV so might be silly but have you checked the air filter(as critter suggest)? Have you looked into the tank for debris? Is the bike normally stored outside or inside?
 

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Discussion Starter #14
Does this bike have carbs or FI? From the specs I seen on it has Mikuni carbs, and I think those are CV so might be silly but have you checked the air filter(as critter suggest)? Have you looked into the tank for debris? Is the bike normally stored outside or inside?
Hey Aphrodite,

Yeah it has carbs. I took the petcock off and looked at the filter...which looked clear to me. There was what looking to be one or two pieces of chipped pain that was on the petcock filter, but I doubt it would effect anything. The bike is stored in a car port outside, with a cover over it.

Strange thing...I just filled my tank over 1/2 using a gas can, and now I am no longer experiencing the same problem.

I figure there is some sort of blockage, and the weight of the gas above 1/2 tank is forcing fuel through. Is that what this would indicate?

Where is the air filter located? And would that apply to the issue I am having? (stalling after heating up with bellow 1/2 tank)
 

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V-twin Suzukis are very battery dependent, so make sure the battery voltage is staying up, above 13V at idle; you can test it at the accessory terminals on the fuse box.

If that is good, then you still have a restriction in the fuel path, from the strainer on the petcock to the carbs. A collapsing fuel line is common, especially if the routing makes for a tight bend. The fuel pump can be a weak point. It fills the rear carb first, then the front, and when the pressure starts to rise, a switch in the pump opens, shutting it off. When the pressure drops again, that switch closes and, if the engine is still firing, the pump starts again. The contacts of this switch can become dirty, and the pump may stop running. I don't know if the newer pumps can be repaired, but the older ones could, by taking a cover off and cleaning the switch contacts. Because the front carb is so close to the tank, it won't fill well without the pump as the tank level drops. I suspect your fuel pump is weak or inoperative. Try taking the fuel line off the rear carb, and divert it into a catch can. You can run the fuel pump with the starter button, which is easier if you remove the cable from the starter relay that leads to the starter motor. The pump should pump more than 10 ounces in 1 minute.

For some reason, I read C50 when looking at your first post; got to clean my glasses more often.

BTW, where are you? If you put your general location in your data, perhaps someone close to you can have a look.
 
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