running rough all of a sudden???

[Surfpilot]

Yesterday I rode to work as usual...then I exited the freeway and immediately she began to run rough. I drove for a mile and when I came to stop, the engine quit. Although, it starts right back up no problem and will run all day. I drove it again today...same thing. Runs rough, sounds choppy, definitely lacks power.

I am suspecting a lack of fuel. Possibly a blocked petcock filter??? I'm pretty sure the petcock has never been replaced/rebuilt. Ideas please!

[Barncat]

MY GS was running like crap, thought it was fuel issues(which was partly to blame).

What I found was the bigger problem was, my #2 carb had a cracked O-ring on the head side.

[Surfpilot]

I hope that's not the issue. I just overhauled the carbs 9 months ago. New rings all around....

[chef1366]

Usually problems that just "spring up" are bad gas or electrical.

[tom203]

Sudden problem? I vote for bad gas. But if you're unsure of petcock/ filter, now might be the time to satisfy your curiosity - doesn't take long.

[SteveM]

I'd suggest you fill up with premium and add an ounce or two of Sea Foam to help clean things a bit.

[BassCliff]

Hi,

Premium (high octane) gas is not necessary, or recommended. Just a good regular gas like Chevron or similar. I also use a little Sea Foam once in a while for maintenance.

You might want to visually inspect your bike. One day mine started acting intermittently weak. Then it totally went south and seemed like it was running on two cylinders. I took off the tank, seat, side covers, and started going over hoses, wiring, etc. And I found this.



Keep us informed.


Thank you for your indulgence,

BassCliff

[Surfpilot]

I was a little suspect of bad gas. Just to be sure I'll pull the tank tomorrow and inspect the petcock filter as well as the rest of the bike. Although I'm certain she's firing on all four...but thanks for the photo Basscliff. I'll let you know what I find.

[steve murdoch]

A lot of the time the petcock filter is missing...you might want to look in the bottom of the float bowl of the #1 carb for rust paste/debris.

[Steve]

I'd suggest you fill up with premium and add an ounce or two of Sea Foam to help clean things a bit.

I suggest you NOT fill up with "premium", but go ahead and add an ounce or two OR MORE of Seafoam to help clean things up.


There is a very popular MIS-conception that "premium" gas is better gas. Don't want to burst any bubbles, but the the only way it's better is that it's better at resisting self-detonation of the mixture, which is caused by excessive temperatures that are usually due to high compression ratios or some foreign material that is stuck in the combustion chamber.

Unless your engine physically demands it, stick with "regular" gas. That's what it was designed to use, so please use it.

.

[Redman]

.....
.... and immediately she began to run rough.
...
...

You said "rough", you didnt say stumble, you didnt say dies out like running out of gas. Makes me think more about ignition.

Do you know if sparkplug caps have been replaced in any recent decade? or might still be original? They are replaceable (twist-pull off of the wire), they do go bad, and cost about $5 each. Can test them with ohm meter, should be about 5K ohm each (if I remember right, consult a manaul).

But, opps, this is the "fuel/carbs" forum, so maybe I cant say anything about ignition, can only give fuel/carb related answerr. (joking)
And, Cliff, you cant post that picture of ignition coil here either. And what is the big albino monster that is holding the coil?



PS: And, yes, as others have said; premium gas has no more power, no more BTU's per ounce, than regular gasoline. Higher octain just means it can withstand higher compression (learned that it physics classes).
Although, I have read in magazines that sometimes the higer octain gas also has a little bit more additives for cleaning out deposits.

.

[oldgsfan]

I had a Suzuki 650 that did something like this once. It would be running fine, then run really, really rough and finally die. It once left me stranded on the Oakland Bay Bridge.

The next day, it would run fine, but the problem kept getting worse and worse. Cleaned out the carbs.. it would run fine, then it would start acting up again.

Finally, replaced the petcock. No more problems.

[Surfpilot]

Ok, today I pulled the petcock and drained all the fuel from tank. Petcock filter was clean. However, before I did this I splashed a little water on the exhaust pipes after driving for ten minutes (this is my way of checking whether I'm running on all four). The number 2 pipe was "less hot" than the rest...there was spark though. hmmm. so I also pulled apart #2 carb. Everything was normal and clean. Put it all back together, new tank of gas and she runs great...I dare say better than ever. We'll see if it holds.

Not sure why #2 wasn't firing, but It seems as if the problem was bad gas. Weird.

[tom203]

Weird ? let's hope not. Does this bike still have a vacuum operated petcock ? #2 pipe not hot ?, maybe #2 plug fouled from petcock vacuum hose. Removing petcock and checking its filter was good thought, but did you check for correct petcock operation? It could be leaking fuel down vacuum hose, fouling #2 and worst slowly drizzling into crankcase. Check oil for signs/smells of gas.

[Big T]

What Tom means is you should check your oil level to see if the crankcase is filling up with fuel.

Then, remove the oil filler cap and see if the oil in the crankcase smells like gas

It is likely you need a new petcock. It is 30 years old, after all.