#3 Cylinder Issues (Video)

[Lotsokids]

When I purchased my 1999 V-Max, it was a very cold day, so when I test rode it, I did not hit the throttle hard. When I got it home I noticed a wire cut at the #3 coil connector. I repaired it, and ran good. But when starting cold, there is a loud occasional "POP" coming from #3 cylinder (custom exhaust - has it's own pipe). Sometimes (maybe twice a week) when riding, I can feel the loss of a cylinder, I assume #3. Today, I noticed something audible like a "chirp" at idle or slow roll on the throttle.

Here's a video I just recorded today:

http://vid5.photobucket.com/albums/y177/Lotsokids/V-Max/New%20VMax/Cylinder_pop_zpsrh2lhjvi.mp4

At 0:20, in the original video, I can see one pop where it blows fuel out I assume.

So should I start with a good carb cleaning? Is there a connection with the problem with the coil wire being cut? Not sure how long the previous owner ran it without firing on #3.

Thank you in advance.

 

[Lotsokids]

Today it ran great. Not really popping this morning. All 4 cylinders were "singing." Intense power when whacking the throttle.

BUT...

I added some carb cleaner and filled with my usual super unleaded. Within 1/2 mile it was backfiring and popping very loudly at all power settings about 5 miles to work. Embarrassing pulling into the parking lot.

Just wondering how this is all connected. I suppose I could easily swap coils and see if the problem follows. :confused2:

 

[Miles Long]

Today it ran great. Not really popping this morning. All 4 cylinders were "singing." Intense power when whacking the throttle.

BUT...

I added some carb cleaner and filled with my usual super unleaded. Within 1/2 mile it was backfiring and popping very loudly at all power settings about 5 miles to work. Embarrassing pulling into the parking lot.

Just wondering how this is all connected. I suppose I could easily swap coils and see if the problem follows. :confused2:

I'm not a carb guy, but in Hungary, what octane level is "super unleaded"?
The stock vmax engine is designed to run best using regular gasoline - 87 octane.
Cheers!

 

[Lotsokids]

I'm not a carb guy, but in Hungary, what octane level is "super unleaded"?
The stock vmax engine is designed to run best using regular gasoline - 87 octane.
Cheers!

I use 100 "Racing" fuel.

 

[Hellboy]

I have had this exact same issue. Sometimes my bike was only starting on 3 cylinders other times it ran great and after stopping for fuel would spit and pop. Because I have rebuilt my carbs somewhat recently I assumed it was electronic and swapped plugs, leads and coils only to find that it was none of these. just a few days ago I did the "shotgun" (cleaned carbs) on the one cylinder that was causing the problem and so far so good, no trouble again. If it isn't electronic I guess it has to be fuel. I also discovered that testing the running condition with the airbox top off of the bike does not work. My bike runs like crap with it off which confused me for quite a while. It just would not rev past 4000rpm after I cleaned the carb. I then, for some reason placed the airbox lid back on and it ran perfectly??? To lean I guess without some airflow restriction. Good luck.

Matt

 

[Miles Long]

I use 100 "Racing" fuel.

And the reason:ummm:
The subject of gasoline octane level for the max has been hotly debated previously.

 

[maleko89]

87 baby! lol

 

[Lotsokids]

And the reason :ummm:

I like to run the best fuel through my bikes. Even in the U.S., I always bought premium high octane (92 or 93). It keeps the carbs and heads clean and easier on the bearings.
Years ago, I owned a Yamaha Radian 600. I could pull the front tire up with 92, but not with anything less.

 

[jfeagins]

I like to run the best fuel through my bikes. Even in the U.S., I always bought premium high octane (92 or 93). It keeps the carbs and heads clean and easier on the bearings.
Years ago, I owned a Yamaha Radian 600. I could pull the front tire up with 92, but not with anything less.

So with some 200 octane, you should be able to launch that thing to the moon!!

I'm going to go find myself some 50 octane - because I hate wheelies. :biglaugh:

 

[sdt354]

And, high octane in an engine designed to run 87 octane will carbon up the valves and eventually lose power, when they fail to seal properly. High octane has a misconception of being superior gas. It burns slower than lower octane. I've got a motor right now with under 15k. The heads need to come off for this reason.

 

[Traumahawk]

I also discovered that testing the running condition with the airbox top off of the bike does not work. My bike runs like crap with it off which confused me for quite a while. It just would not rev past 4000rpm after I cleaned the carb. I then, for some reason placed the airbox lid back on and it ran perfectly??? To lean I guess without some airflow restriction. Good luck.

Matt

Your right. Without the airbox in place...you allow TOO much air into the engine..thats why it runs like crap. Thats also why to run pod filters....etc....you have to install air correctors into the tops of the carbs.

 

[Hellboy]

I was pretty pissed off with the bike/myself after the shotgun and it didn't run right. I don't know how this has never come up before. I guess I usually put it back together before running it? Anyway, I've started it for 3 days in a row now with all 4 running well. I love it when a plan comes together.

Matt

 

[Lotsokids]

Today I accomplished the "shotgun" carburetor cleaning as described here:

http://vmax.lvlhead.com/tips/shotgun.htm

My #3 cylinder has been "popping" at idle. Guess which idle mixture screw broke when trying to turn it? Yep... #3!!! :bang head: I was as careful as I could be, and soaked it with WD-40. Still broke.

I accomplished the cleaning on all the other carbs, and did the best I could with #3. I was still able to drain all the bowls and shoot cleaner through the jets.

Got it all back together and started it up. It idles MUCH smoother. No popping at all. I haven't taken it on the road yet, but I'm sure it will be fine.

Thanks for the help, y'all. :clapping:

 

[Lotsokids]

Problem returned. It was sputtering some today. Last few refuels I've used 95 octane (lowest I can find here). The problem is only occasional. Remember, I just pulled 11.77 in the 1/4 mile on May 1. So I'm back to thinking possible idle circuit problem. Again, the mixture screw is stripped and stuck (see my last reply above). I could tell today it wasn't running right. Got on an open stretch of road and cranked the RPMs up to the redline. Ran like crap - popping and sputtering badly during the acceleration, and after at steady speed. It seemed to run much worse after that event. Yesterday it ran well, and pulled VERY strong.

Question: Since the coil wire was broken for some time prior to me purchasing the bike, would this have affected that cylinder (head) due to running without firing? Unsure how long it was running like that. But dirty valves should be a consistent problem, not once every week or two.

But starting when cold, #3 cylinder (only) consistently pops until warmed up. :confused2:

 

[Hellboy]

Since my last reply to this topic I now strongly believe that some of my problem was the battery and the initial volts when starting. It's winter here and I was just starting the bike in the shed for 5 minutes or so at a time. Doing this more than a few times without riding it was basically just draining the battery but not recharging it back up. Over time the battery volts got low and It wouldn't start on all 4 cylinders. I've replaced the battery and now instead of just idling it, I take it for a 15 minute ride every time, even if it's cold. It's been about 6 weeks and I have not had any further problems.
Also, I keep hearing people say that the Vmax was designed to run on only 87 octane. Fuel octane can be either MON or RON. I don't know what rating they use in Hungary but here in Australia they use RON (Research Octane Number) which is much higher than MON (motor octane number). Our 91 is the same as American 86 because in the U.S. They average the two which is called DON (road octane number). The V-max manual clearly says to use a minimum of 86 DON or minimum 91 RON and if there is any engine pinging or knocking to use higher, 95 should be fine if Hungary uses the research octane number???

Matt

Matt

 

[Lotsokids]

Now the problem is becoming more consistent. Sputtering and popping again today.

This time, I went to full choke and revved it a couple times while riding. It cleared up immediately.

Not sure how that's connected, not being a carb specialist. To this point I have "shotgunned" the carbs (minus the cylinder in question - #3). Drained all float bowls. The fuel drained appeared clean.

 

[veebooster]

Your pilot circuit is plugged if the choke clears it up. If the shotgun didn't work you may have to tear the carbs down to clean them up.

Dale

 

[Hellboy]

Now the problem is becoming more consistent. Sputtering and popping again today.

This time, I went to full choke and revved it a couple times while riding. It cleared up immediately.

Not sure how that's connected, not being a carb specialist. To this point I have "shotgunned" the carbs (minus the cylinder in question - #3). Drained all float bowls. The fuel drained appeared clean.

Full "choke" is making it run much more rich. Which is basically confirming that it is most likely too lean to start with, Not enough fuel, too much air. On a vmax and most other bikes the choke doesn't actually choke off the air but adds more fuel which is the same end result. A choke is so called because that is what they did, they choked off the air supply which increased the fuel to air ratio. By adding more fuel instead of less air you are still just increasing the fuel to air ratio. There are still of course several things that could be causing your problem???


Matt

 

[Lotsokids]

Your pilot circuit is plugged if the choke clears it up.

Actually, I wasn't clear in my description. I went to full choke, kept it running and gunned the throttle a few times, then choke back to OFF. Ran fine after that.

 

[Lotsokids]

Well, I dropped off the bike at the local mechanic today. I showed him the idle mixture screw that was broken. He was very upset, and said he will try to work on it, but I may need a new carburetor if he cannot remove it. I also told him I needed the bike by Thursday evening, because I plan to drag race on Friday and Saturday. He said he would do his best. His prices are very good. A couple years ago, he rebuilt a set of forks on an FJ1200 for about $45. That would have taken me all day.

I went on a long ride with a group on Saturday. My bike was popping and sputtering, and running mostly on 3 cylinders for the first 50 kilometers. Then it cleared up and worked fine for the rest of the day. I tried applying the choke again while riding, but no improvement. Seems very spontaneous, but happens once about every 3 days of consistent riding.