My 2nd Gen is sick...

[Cerviperus]

Alright, I need some help. I'm guessing I have a fouled plug or two, but I want to see if that's the general consensus. Whenever I'm forced to ride for a while in first and second gear, say while checking out a campground as I did with my father earlier in the week, or caught in stop and go traffic for a while, my bike decides it doesn't want to run right anymore. When given gas, the thing coughs and sputters and pops, and just generally acts like it doesn't have any get-up-and-go. It still runs, I haven't had it die, but until you get into third or fourth gear, it just acts like it's a struggle to get up speed unless I really hammer it. I checked my air filters, and they both look like new, and I've been fighting the issue off and on all summer, so I throw out the thought of bad gas. I've also run a full can of Sea Foam through it to see if maybe I had some buildup somewhere, but it seemed to have little effect.

 

I'm guessing this all works into my mpg, which at 34 on a good day seems low to me, not to mention my 28-30 normally. Am I right in thinking this sounds like a spark plug issue? I've had a couple other guys (my dad included) throw that out there, though they're about as mechanically inclined as I am.

 

So, if the plugs are a good place to start, does anyone have (or have a link to a good walkthrough) of how to check the plugs? I'm guessing the rear two are no big deal, but unless I'm missing some serious tool it appears I have to take off my tank to get to the front ones. So far the owner's and service manuals haven't proven much help.

 

Thanks in advance for any help & advice.

[Johnh]

Is there any possibility the choke is not completely off? Sounds to me as though it's loading up at low rpm, and when you get on it, she clears out if I understand you correctly.

[Squidley]

I would start at the plugs and just put new ones in there. Yes you do have to take off the tank (not a big deal) and the forward dogbones that connect to the engine.

 

I would recommend that you just go back to the original plugs and not worry about Iridium or anything fancy. The choke mention by John is also a good one, make sure it is completely off. These are starting points to go by, if your still having troubles after the plug change let us know and we'll chisel it down and figure it out

[Cerviperus]

Is there any possibility the choke is not completely off? Sounds to me as though it's loading up at low rpm, and when you get on it, she clears out if I understand you correctly.

The choke is completely off, as far as the choke knob is concerned. Which brings me to another point... the bike (whether good or bad) never seems to need choked. Even in the winter months when it's cold starting, leaving the choke on for more than a second or two and the engine dies. I've never been able to leave the choke on without also opening the throttle a bit, or it dies. I've never really considered that an issue though since I've never had a problem starting it. Is there a setting, sort of like for the idle adjustment, that I should check? Or is the knob basically the thing to look at.

 

As far as the plugs go, I'll have to tackle that next weekend. I leave in the morning for a week in Cincinnati, OH for work, so I don't want to get started on that project only to leave in the middle of it. I'll report back.

[muffinman]

Justin

After you change the plugs if problem is still there I would suggest that you look for vac leaks at the top and bottom of the carbs there may be a slight leak causing the bike to run the way you stated (dont ask me how I know)

Jeff

[concours]

No, no, no.... 30 something MPG means he's WAAAYYYYY too rich.... and NOT a vacuum leak. Been "jetted"? for aftermarket pipes or air filters? or stock? The enrichener system (choke) can be the problem if one or more carbs has a plunger not seating properly. Also a sunken float (or misadjusted float... anyone been IN those carbs?) will do it. Fouling plugs is either too much fuel dumping in (MOST likely) or an ignition problem (coil, wire, cap, etc.)

[BradT]

No, no, no.... 30 something MPG means he's WAAAYYYYY too rich.... and NOT a vacuum leak. Been "jetted"? for aftermarket pipes or air filters? or stock? The enrichener system (choke) can be the problem if one or more carbs has a plunger not seating properly. Also a sunken float (or misadjusted float... anyone been IN those carbs?) will do it. Fouling plugs is either too much fuel dumping in (MOST likely) or an ignition problem (coil, wire, cap, etc.)

 

I agree here as this is where I would start. After replacing the plugs. Run for a bit and if it still chugs at low speeds, take plugs out fora look. If there wet and black Running rick was the problem, now how to fix depends on what is causing it.

 

A bad battery can cause a weak spark unless the RPMS are high. This is a similar problem My Wifes Virago had. Could not stop fouling the plugs, untill I ran it hard for about 20 minutes. Then it cleared up. Put along and they fouled up again. I changed the plugs and the battery (Knew it was bad), and never had the problem again, It has been two years now.

 

Brad

[hig4s]

It never need to be choked, even in cold weather. Mine often needs to be choked in hot weather, and I can leave it half on and walk away it will idle fast but fine.

Makes me think your choke (enriching lever) is not working properly. It may be all the way in, but not all the way off.

[Sailor]

I have/had a problem with the choke lever. It seems to bend very easily. Get under there with a pair of pliers and make sure it is actually moving through the full range.

[BuddyRich]

Try a can of Seafoam. If that don't do it and you have changed plugs then let Yamaha fix it under warranty

[Ozark]

I'm not tje mechanic many of these guys are, but it does sound like the choke could be the problem. Could also explain low mileage. Just my two cents worth.

[chollahan]

Mine did the same thing, but is caused by an electrical problem that is making my coils go bad on the back cylinders. I troubleshot as far as I could and had to take it to the stealer and see if they could figure out what the problem is. I have gone through 3 coils so far. As soon as I would replace it, it would burn up on the test run.

[stardbog]

Sounds Very simular as my problem @ Fort Collins. Running on 3 cilinders. When is ideling it's hard to say bike run on 3 cilinders, but luck of power, poping, and poor gas milage.... As other say Check out spark plugs or Coil. Wire is built in to coil , so you have to change whole thing to have good Spark. Check as well 2 wires attached to coil. Could be loose or coroded.

 

:080402gudl_prv:

[chollahan]

Not trying to jack the thread or anything, but I just called and checked on my bike after they have had it for 2 weeks. It's not a good thing when they tell you it may be a "gremlin thing" and they may have it for a week or two more.

[James Ardrey]

It does sound like a choke issue only because you say you don't have to choke it to start it cold. You may have fouled one or more plugs or are very carboned up as a result of running so rich.I would think that if the coils were bad it would run bad at any speed. Call me crazy!

[Al Bates]

Check your carburetor fuel vent lines. It's a small rubber hose, looks like a vacuum hose. There is one on each side. The left two carbs are on the left side and the right two carbs are on the right side. Both are behind the air filters. (hidden) I pulled them out and place them just under the air filters so I can monitor what is going on. (check pic's below) If there leaking fuel you can smell it. If you can see them you can monitor them. If there is any fuel coming out of them, mostly at idle, there's a problem. It's running rich. Pull the spark plugs. Check and see which plug is running rich, if that is the case the plug will be wet and black.

 

THE FIX:

Fine out watch plug= carburetor and change the needle and seat, check the float level.

[Cerviperus]

Wow... so I've been behind on a few threads. I guess that's what happens when you're away from town for a while. Anyways, here's an update...

 

Last night my dad and I tore into the thing to get to the plugs (man that's a lot of work just to check spark plugs). The two in the front, and the back right one looked almost new. They had very little carbon on them if any, and the ceramic was still nice and white. The rear left one on the other hand was pretty black. It was corroded or anything, but had quite a bit of carbon on it. We checked it for spark, and the spacing, and everything looked to be in fine shape. We took a wire brush to it and cleaned it all up, and check it's spark again. Still, everything looked great... constant sparking action.

 

Now, I did find a couple interesting things in the process. The first on which (not really part of this fix) made a huge difference for me. Whoever last had the seat off did not put it back on properly, you know how it's supposed to slip underneath a catch so it won't come up in the rear. Well, once we got it back on like it was meant to be, it lowered my seat hight by a good half inch or more. Holy crap... what a world of difference that made!

 

Ok, now on to the second, more notable issue. When we moved the tank back, I decided I wanted to check my petcock while we were working on it. I shut the gas off, pulled the hose, and low and behold gas still flowed. Not nearly as fast as with it on, but any gas while it's off is not a good thing. So I need to get that fixed while it's still under warranty. Also during this time, while taking the hose off, I noticed gas start coming out the side of the hose!! There was a cut in the hose. It wasn't far enough back to cause gas to spew out while running, but I'm wondering if it wasn't sucking air into the engine, causing it to run like garbage. So, I made a note of which plug looked the worst, and we put everything back together (with a repaired hose), and I took it for a spin.

 

Instantly it sounded better when I started it up (maybe it was in my head, who knows). I started to go down the road, and it popped and coughed a few times for about a mile, then it cleared right up and ran like a top. Could it be that it truly was air in the fuel line and it just took a little bit to clear and all will be fine now? I'm not sure. I plan to ride it as much as I can over the next week or so to find out if all is better, then if not I'll take it in. I have to take it in for the petcock assembly anyway.

 

So after all this, does this help to narrow down any of your thoughts on the problem, if it wasn't the hole in the hose? Or are we still leaning towards the choke assembly?

[GeorgeS]

I would have Replaced the plug that was Dark.

 

Also, might be the coil for that plug should be replaced.

 

Also, take cap off that plug and measure resistance thru the Cap.

Should be close to 5000 ohms.

 

Did, you closely check, the Choke lever cable to lft rear Carb, to make sure it going fully back to the Un Choked Position ??

 

 

Next time you pull the Tank, and take out All Four Plugs, I would also do a Compression check, Post results of this test.

 

Question: ?? As long as you had the tank Off, WHY Did you NOT Replace All the PLUGS ?????

[concours]

My bike also needs NO CHOKE when starting in the morning. Garaged, unheated... usually 60 degrees or so. I bought the bike used so don't know what normal is.. smells rich on the idle, maybe someone backed out the idle mixture screws. Can anyone else chime in on this? Need more baseline info. Have you all tried cold starting with NO CHOKE and a CLOSED throttle?

[Cerviperus]

Question: ?? As long as you had the tank Off, WHY Did you NOT Replace All the PLUGS ?????

I didn't replace any of the plugs because three of them look almost brand new. The questionable one is in the rear, so if it does need changed, it can be done without removing the tank.

[chabicheka]

sorry...cant help.

you see....us first generation owners dont get much problems with our bikes, and thus are not very good at solving bike problems.

but fret not. you have lots of company here. with so many second gen owners, there will be no shortage of guys who have experienced similar and other problems and are well versed as to how to fix them. good luck.

[GeorgeS]

How a plug " Looks " means Nothing.

 

I have bought NEW plugs, and found bad ones out of the Box.

 

If your haveing a problem with one cylinder missing, Replace the plugs before you start Ripping and Tearing Anything Else.

[KiteSquid]

I agree with GeorgeS, as a set of 4 plugs is inexpensive.