Loss of power, leaking and burning oil, no idle.

[zanza14x]

Hello again all,

Once again, thank you for all the past help on my '78 GS 550. A couple of weeks ago, after having ran like a top, I was taking her home on the interstate going about 70-75. It was a very windy day, and the road was quite hilly, so I did not think twice about shifting into 5th to get up some of the hills. After a while, I was leaving it in 5th, and had to shift into 4th to go up the hills. When I was about a mile outside of a small town, it just lost power. It did not stall, thank goodness, but it would not go faster than 40-50 mph in 4th, 5th, or 6th gear. Luckily, I pulled into the town and as I pulled in the clutch and it tried to idle, it died. Would not start up after that. I looked at it later that weekend and got it started on choke (~3-3.5 rpm), but died as soon as choke was turned off, even after being "warmed up". We noticed the 3rd cylinder was cool to the touch after running for a while, and the 4th was not scorching hot as it should be. I also noticed after it first stalled that it was leaking a little bit of oil. I got it out on the road, (using the throttle to keep it alive with the choke off), but it really lugged, especially after I hit the throttle, got it up to speed, but VERY slowly. I also noticed for the first time that it was burning a significant amount of oil out of the right tail pipe, (3rd and 4th cylinders). Kind of hope it is a small issue, (carbs, etc.), but fear that it could be a blown cylinder. Any advice would be greatly appreciated. Thank you.

 

[Guest]

You may have fouled plugs.
Are you sure it's oil?

 

[SqDancerLynn1]

I would start with a quick carb clean. I had something simillar happen to my 79GS850 same style vm carbs. Was running down the freeway about 85-90mph lost power & it felt like it was running out of gas- reserve no help. Nursed it home. Cleaned the carbs and I was back in business
IT may have fouled a plug too, just flooding the cyl with gas could make it smoke out the tailpipe ?

 

[BassCliff]

Hi,

Yep, do the easy maintenance stuff first. After that, with what you describe, the next thing I would do is a compression check.


Thank you for your indulgence,

BassCliff

 

[zanza14x]

Alright, that sounds like it may help. The only thing that baffles me is that my cousin and I completely cleaned and rebuild the carbs last fall with new seals and all, and it ran like a top after that. The smoke that was coming out was white, so I guess it may not be oil, but there was ALOT of it, like I said out of the 3 and 4 exhaust. I will definitely check the compression. Now I should know this, but a fouled plug? That simply means that a plug got too much fuel to it or that it just needs to be replaced? At least I have gotten the chance to take this bike apart almost completely and learn so much in only a year... Thanks

 

[DanTheMan]

Fouled plugs are usually due to oil, not gas (except in extreme flooding situations, then it evaporates). It could be a fouled plug or two. Running that hard into the wind at higher RPM could cause poor valve guide seals to allow a lot of oil past, fouling a plug or two. It could also show up weak piston rings allowing more oil past the rings under load. What was your oil level at the terminus of this run into the wind when you finally stopped? Did you check it out? Nearly running it out of oil would cause those symptoms also, and your oil light wouldn't come on under those conditions, not until you brought down in the 1k RPM range. Might want to check those things out as well.

 

[zanza14x]

At the beginning of the trip, the oil was full, and had been changed along with the filter 2 weeks before. By the time I got to the end, it was around the L, or low, mark. I did notice that when I stopped the bike after it would not start, it had and continued to leak oil. It appears to have leaked more in the trailer on the 2 hour ride home. It had done this previously, but not this severe, and it seemed to seal itself up after a while. Does white smoke usually seem to indicate too rich or? Thanks again.