3 dead cylinders back to life.. what?

[Seaking]

Hi guys.. buddy and I ran into a weird one today.. After a week of torrential downpour and heavy winds, the weather finally cleared enough to get the bikes out for a cold windy run.. we're die hard riders who refuse to put their bikes away..

 

When I got to my buddy's house his bike was idling very oddly...and this is where everything goes wrong to worse..

 

Full choke ON, bike barely idling.. but it's idling prolly sounds like 900 rpm.. if you touch the throttle, the bike dies.. If you take the choke off, the bike dies.. It needs full choke and don't play with the throttle.. VERY odd indeed.. We DID see this a few weeks ago in New Hampshire on a late season road trip.. but the bike cleared itself inside of 5 minutes and ran 100% since then.. so odd.

 

But this time, no go.. Nothing you could do would clear what ever was causing it.. Then we noticed that the sound was getting even more odd.. Hello, what's this.. We then noticed that the front jugs were not making heat at all.. and then ONLY the rear left jug.. (I have to stop touching hot metal exhausts.. ) try as we could, the bike would not start and stay running.. Not good..

 

Now, the bike had been sitting in his garage for a week, semi heated, but with about a 1/4 tank of fuel in it.. shouldn't have made too huge a difference.. We added another 1/2 gallon of fuel to the tank with some SeaFoam.. ya never know.. but no change.

 

It just wouldn't catch.. When you cranked the starter, you could hear the one jug catching but not igniting completely and the other jugs just going along for the ride, not firing.. I don't recall a lot of raw fuel smell either.. windy as it was.. Battery was on a tender all week before this..

 

So, we abandoned his bike for the winter.. I sadly said goodbye to my friend and hauled out of there for a quick spin before heading home and getting some fresh fuel into my gas tank for the next storage period..

 

And I get the phone call, the bike started and is running 100% fine.. HUH? Just like it did in New Hampshire.. We thought then that the bike, sitting outdoors in the overnight cold rain might have had some water in it.. But what the?

 

Breaking it down to the bare minimums, we thought what about the fuel filter? I changed his filter in July, perhaps 15,000 miles ago.. Not long in TIME but perhaps due in mileage? My fuel filter had clogged so badly that it starved the engine last year.. Then what about the pump? My pump had died prematurely and in such a weird and wild manner, maybe his is doing the same thing? But while we were cranking the engine over earlier on, the pump was getting warm, indicating to me perhaps that it is work OK.. otherwise a failed pump wouldn't make any heat if it's not working?

 

Gremlins.. what the heck.. No idea what caused this failure today, its very similar to what happened a month prior.. and now the bike works 100% no probs, lots of power and almost like it never happened..

 

How do you start trouble shooting such a problem? The bike is under warranty but the shops here are lacking in experience on these types of bikes, he might never see his bike back again..

 

Any thoughts or idea what to look for the NEXT time the bike does this again.. if ever?

 

Thanks M8

[muffinman]

Seen that happen to a midnight when I was working at cherry point I told the owner to have the shop replace the relay under the battery that everything goes through they did and no more problems

Jeff

[BuddyRich]

If it clears so suddenly I would be looking for electrical problems. Fuel problems that clear so quickly are usually only from a tank not venting. Did any body take the fuel cap off ?

[kj5ix]

Could it be that the sea foam had time to get into the carbs, and work a little magic,,,water (condensation) in gas,,,

[V7Goose]

Could be either electrical or crud in the float bowls blocking the idle jets (easy to suddenly drop away and clear the jets). Worse yet, it could be a combination - fuel on some jugs, electrical on others.

 

Very easy to tell which causes a dead cylinder. When the problem is happening, just pull off the rubber cap or hose on the vacuum nipple and spray a little carb cleaner or starting fluid in the nipple. If the plug is firing, it will be IMMEDIATELY obvious.

Goose

[Seaking]

Thanks for the replies guys, we'll have a look at those should it ever happen again.. twice this year, but yet so random a problem..

 

The gas cap was pulled, and even attempted a start with the cap removed (but hole covered)

 

I don't think the shot of SeaFoam was a fix or lead to the fix, we just tried it for lack of anything else (certainly can't hurt)..

 

Goose, thanks for the tip, we'll check that for sure.. We looked at the vacuum plugs to make sure everything looked good there (as far as we can tell).. I had been thinking clogged fuel filter or glitchy fuel pump.. afflictions that nailed my bike the other year.. But a clogged carb, yes, indeed, that's also a possibility, as that also afflicted my bike on the way home from visiting you this summer.. luckily a drain of the carb resolved that issue.. Something to consider.. Hmmm

 

Its such a weird one.. The bike won't start, it refuses like a stubborn impetuous child.. then you ignore it for a little while and try it again, all is good as if nothing was wrong..

 

The bike is still under warranty so he'll most likely take it down to the shop in the spring and see what's what.. we're on the edge of the snow fall at this time of year (yet we're still riding until then)..

 

Thanks for your comments..

[Seaking]

Well since it's near approaching winter around here, we haven't had much opportunity to test out what was wrong with my buddy's bike.. but tomorrow is a foretasted nice enough day that we're going out for a spin, only to say we rode in December heehe

 

Unfortunately, the SAME problem happened to his bike when he went to start it.,. simply would not start no matter what he tried.. it would chug weakly but no sooner you touch the throttle that it would die..

 

On a whim, buddy took his side cover off and gave the fuel pump a tap tap with a wooden mallet and all of a sudden the pump started clicking as it would when you turn the ignition key on, and the bike started fine and dandy..

 

So, this seems like the pump is intermittent and most likely on it's last leg. AND under warranty..

 

Anyone ever experience anything like this?

[skydoc_17]

Hey Pete,

I had a good friend of mine come down from the great white north a few years ago, and no sooner did he get here than his fuel pump died on him! Of course, at the time, we had NO Idea what was wrong with his bike so we took it to the local dealer. Wouldn't you know it, they didn't have any Idea what was wrong with it as well, so we hauled that RSV to the "next big town over" and after about an hour, my good friend was riding away with a brand new fuel pump, and of all things, it was covered under warranty!

You might know this VR.ORG member Pete, he lives up your way, he's a cute "Teddy Bear"

looking gent, he loved my Barka-Lounger, and could eat his weight in Ribs.

Sound like someone you know?!?!

Anyway, I'm glad you got your buddy's bike fixed!

Jean says. "Hey to the teddy bear man",

Earl and Jean

[Seaking]

LOL thanks Earl.. give the missus a hug from both of us.. We'll give you a shout when we're down your way again next summer (doing the ridge ride in May)..

 

We have a hankering for Ribs like you wouldn't believe.. =)

 

Cheers M8

[Kirby]

My bet's on either water in the fuel or a bad fuel pump, or a combination of both. Drain carbs to tell if it's water. Bypass fuel pump to tell if it's fuel pump. Good luck.

[Mike G in SC]

My guess was electrical,,, but if you supect a fuel pump you can try gravity feed.

Below is a copy/paste I've used a couple of times. It got me by till the shop replaced my fuel pump,,, warranty. And if you go gravity feed and the problem does not repeat,,, you got it.

 

 

 

Fuel pump or filter, if you get stuck on the road, here's how to set it up for

gravity feed in a pinch:

 

You can do a gravity feed to bypass the filter and pump if you want to eliminate them, to find out what's wrong. Takes about 15 minutes. Be careful about spilling fuel,,,.

 

(Remove seat. Turn off fuel petcock. Pull the tank bolt - you don't have to remove the tank, just lift the rear of it an inch or so, maybe put in a block of wood to raise it. Use a long needle nose to pull (unclamp) the feed line from the filter, then pull the line (unclamp) to the carb on the right side. Then connect the tank line direct to the carb feed. Before you try to start it,, remove the left side cover and disconnect the fuel pump connector so it won't spew it's remaining gas. Oh,,, turn back on petcock now. Try to start it. If you have a mostly full tank, it should start up and run fine,,, your problem is the filter or pump. If this works, then you have a bad filter or pump.

 

If it's the pump, you can run on gravity if you keep the tank above 1/4 full, till you get one. If you plan to do more than test,, get a $3 inline filter till you are back to normal.)

 

I ran a week and 1000 miles without a pump.

 

Yes warranty is good. The Yamaha stock part (Mitsibshi) is $300.

If you are out of warranty, someone on this forum has posted a after market $45 replacement.

 

Mike G in SC