550 ran awesome yesterday, today, won't start. any ideas?

[brand new bike zealot]

I got home from work yesterday and my bike was running awesome, sounded and felt great. Then this morning I go out to fire it up and it starts on two cylinders (not uncommon) but wouldn't get past that. I ran it for a few minutes, but realised the other two really didn't want to kick in properly. I felt the pipes, outside ones were ripping hot, and insides were hot. I gave up and drove.

When I got home I went to see if it had cheered up but now I can't get anything more than maybe 4 bups and a mighty backfire or two. I've got gas, but tried starting on prime and reserve but no go. After a lot of cranking and kicking, I found it almost wanted to start with the choke at about half, rather than the usual initial full.

All my tools are at work, so I haven't pulled any plugs or anything, but I'm pretty sure it's a spark issue, and now a draining battery from too much cranking issue. Any ideas what could cause such a sudden failure to run?

One other but of information. On Friday, (the last day rode before yesterday) I gave it a quick bath and got a little overzealous with the rinsing and got the points a little wet. I took off the cover and let it dry out and the bike started and ran fine. Don't know if that could be coincidence or not.

I know the points are worn, but do they sometimes just stop working like that?

Sorry about the novel and thanks in advance.


josh

 

[Outlander]

I don't know if this will help at all, but I would check your plugs. Ten to one, they are fouled. Give em a quick clean, and they should be okay. Next, since your bike has points, I would pull the cover off, take your wifes smallest emery board, open your points with a small screw driver and gently insert the emery board and give em a quick file. Usually a bad connection in the points will not give you decent spark.

I use to have to do that to an older bike, and it works. Points must have a clean contact surface.

 

[Guest]

Check if cold cylinders match one condenser.Could be shorted from condensation.

 

[brand new bike zealot]

So i ran some emery paper between the points and cleaned out the residue, and kicked it over for a while, still just cylinders 1 and 4 getting any heat in the pipes. I don't have my socket set here, but I'm sure the plugs are fouled right up. I gave myself a pretty good jolt off both sets of points arcing them with a screwdriver (sometimes I don't learn the first time). This suggests to me the condensers are doing their thing... Am I correct in that? If the points aren't doing their thing correctly then the energy generated would just be released at the wrong time. Does my logic seem correct?

Right now I'm tired of kickstarting so I'm going to let the bike think about how stupid it's being and hopefully cheer up and actually fire next time. Failing that, I'll have to pull the plugs and clean them I guess.

 

[Guest]

Aside from fouled plugs - other possible reasons may be either a bad plug cap connection, or a bad coil. The left coil fires cyl #1 & #4, the right coil fires #2 & #3.

Pull the plugs one at a time and ground them against the head; turn it over and check for a nice blue spark.

mike

 

[Mattsmotoz]

No doubt about it your plugs are shot. Seen this to many times. Carbs lean out and cook plugs. Must replace can't clean. Have you done anything to your bike ie airbox mod, exhaust mod, rejet carbs? Easy fix but watch high rpms til your sure you have a handle on this. The next thing that goes is pistons. Good luck.

 

[brand new bike zealot]

GRRR!

So I pulled each plug and cranked it and got a decent spark, but it was a little intermittent. I've checked the gap and static timing and both are fine.Checked the plug gap, and it was fine. Plugs are about 4000k old, and a little black, but nothing fluffy or obvious build up to my very untrained eye. I've brushed them all with a stiff plastic brush and rechecked their gap. Cracking the points with a screwdriver yeilded a weak spark, so I decided that light and patience level allowed for me to swap out the condensers.

I bought the condensers off ebay and of course they are wrong (stupid me) but now I get a killer bright blue spark at the plug and with a screwdriver at the points, but the engine still won't fire, be the petcock at prime or res or on or whatever. There is still a few liters of gas in it, as I usually fill at about 185k, and I'm only at 156. Besides I can hear gas sloshing around.

The fact it ran normally one day and basically not at all the next is what baffles me.

The only other thing that I can think of is some drunk goof or crack addict (no shortage in my neighbourhood) thought it would be hilarious to switch my plug leads around. How do I tell they are still on the right plugs?

To summerize my rant here's what I have troubleshot.

- spark was intermittent, but not really any weaker than normal. Switched out condensers, spark now f-a-t and blue, could still be considered intermittent.

- stinks of gas after a bit of cranking, plugs are wet when pulled, so that suggests to me some gas is getting fed to the cylinders.

- Most confusion comes from fact things seems to be getting progressively worse as far as amount of heat on the pipes. Morning of failure, heat on all pipes, next day of struggling, heat on outside pipes. Today, pretty much nothing.



I'm grumpy now. Any help would definitely cheer me up.

 

[Outlander]

I hate to ask, but when was the last time the carbs were broke down and cleaned? If they were cleaned and all the o-rings were replaced, take a small tube, or oil can, (prefered) and put some gas into it. Take out a plug, and pour a small amount of gas into the cylinder, replace the plug and crank her over. See if she'll fire.

If she does, it is definate carb issue. I know it seem strange, that on one day, you are riding around, the next day, you are flat on your back. It really is a puzzler.

 

[brand new bike zealot]

It's been almost 2 years (6000k) since the carbs have been torn down. It has been run year round though, no sitting through the winter in my clime. I've run bardahl through the carbs a couple times (ya, I'm too chicken to pull them and clean them myself) just to pretend I'm doing maintenance...

One thing I might add is, When I mess with the points with a screwdriver, I occasionally get a back-chuff from a cylinder. Some gas in there I guess? Maybe I'll give the gas directly in cylinder game a try, but I don't want to explode....

 

[TheCafeKid]

Eh...Hate to burst your bubble on your carb/spark quest, but when's the last time you adjusted the valves? If its been as long as its been since you tore the carbs apart, you are WAY WAY past the adjustment interval, and THIS ALONE would cause all of the symptoms you describe. As these motors get older, the valves receed INTO the head, making the clearance TIGHTER, thus, eventually the valves will NOT close all the way. Lean conditions then result, and no amount of fiddling with carbs or spark will correct it. In fact, the more you mess with the carbs, the worse off you're going to be when you get the valves adjusted, because now the air/fuel ratio will be completely different. This is NOT an optional maintanence issue if you want the bike to run. If you continue to run the bike without adjusting the valves, eventually, it wont start at all, and worse your're going to burn all of your valves and torch your pistons/rings/cylinder walls. The valves should at LEAST be checked every 3000 miles, and maybe or maybe not they would need a couple shims changed out. The tollerance for clearance is .03-.08 mm. Thats not alot of headroom. I suggest that you check into the clearances before you do anything more with your spark or carbs.

 

[brand new bike zealot]

giving up. phoned my mechanic. Electrocuted myself a few more times, and made sure gas was making it out of the tank, plugs are getting fuel, deafened myself with a few mighty backfires. yarrrrr..

 

[catbed]

i agree with cafekid. check your valves.

 

[SqDancerLynn1]

Valves ? forget them for now, it was running yesterday. Go check that you have 12v at the coils & replace the spark plugs, remove the plug boots & trim 1/4" from the end, reinstall . If that doesn't do it ? replace the coils. You can get some good used ones on Ebay for $25 early 90's Rf900,bandit,GSXR

 

[Guest]

Here today and gone tomorrow is usually electrical. Points, coils or connections.

 

[a550w]

Yeah! I can see were this guy is at

Yeah! I can see were this guy is at

I had simular trouble with my gs550t just the other day. I drove it with my girlfriend on the back while it was driving fine; sudenly then a loss of power & hesitation. Got home checked the pipes-left side had a weaker blow from the exhaust, checked the heat from both pipes-appeared one cylinder was not firing correctly. I changed all plugs with correct plugs & gap.... Still having the same trouble. I'm thinking it maybe the ignition coil, carbs, & or combination valve seating......At this point I just don't know.

 

[chuckycheese]

Yeah

Yeah

Here today and gone tomorrow is usually electrical. Points, coils or connections.

Yeah....I'm constantly amazed at how quickly things can turn to sh*t on these bikes!

 

[Nessism]

Yeah....I'm constantly amazed at how quickly things can turn to sh*t on these bikes!

Things turn to sh*t because most people don't do maintenance.

What amazes me is when people buy and old bike and then scratch their head when it doesn't run right. What are these people thinking?

These GS bikes are OLD - 30 years old in some cases. The carburetor o-rings are hard and dried out, the valves need to be adjusted (many GS bikes have never had a valve adjustment), the brake system is full of sludge (which can NOT be flushed out by just changing the fluid), wiring harness has corrosion and needs to be cleaned, etc.

Do the basic maintenance when you first get the bike and it will be reliable. Do the bare minimum and the bike will continue to break down all the time. Pretty simple.

 

[Sick Steve]

Eh...Hate to burst your bubble on your carb/spark quest, but when's the last time you adjusted the valves? If its been as long as its been since you tore the carbs apart, you are WAY WAY past the adjustment interval, and THIS ALONE would cause all of the symptoms you describe. As these motors get older, the valves receed INTO the head, making the clearance TIGHTER, thus, eventually the valves will NOT close all the way. Lean conditions then result, and no amount of fiddling with carbs or spark will correct it. In fact, the more you mess with the carbs, the worse off you're going to be when you get the valves adjusted, because now the air/fuel ratio will be completely different. This is NOT an optional maintanence issue if you want the bike to run. If you continue to run the bike without adjusting the valves, eventually, it wont start at all, and worse your're going to burn all of your valves and torch your pistons/rings/cylinder walls. The valves should at LEAST be checked every 3000 miles, and maybe or maybe not they would need a couple shims changed out. The tollerance for clearance is .03-.08 mm. Thats not alot of headroom. I suggest that you check into the clearances before you do anything more with your spark or carbs.

that figures.... how does one do this?

 

[chuckycheese]

That too

That too

Things turn to sh*t because most people don't do maintenance.

Well, that too, but things just plain go wrong with these old bikes. Old people can take very good care of themselves....but they still, inevitably, develop health problems. The concept is pretty simple and undeniable. You've just gotta do the best you can!

 

[brand new bike zealot]

almost 2 month follow up

almost 2 month follow up

Just thought I'd give the answer (so far) to my engine issues. Turns out that the plugs were very fouled, combined with spent points and condensors. After fresh plugs, new points and condensors, she's back to running like an absolute dream, well as absolute as can be expected for a 30 year old machine..... Had the carbs synched at the same time, but they really weren't too far out so I don't think it had much to do with the original problem.

It's been 1000k since the fix, and when I pull the plugs, they are light brownish, about right as far as I can tell. Yippee!

I also got a new to me back tire put on, so I feel a little more confident on anything other than jet black blacktop on a sunny day!!

Back in love with my GS!