1979 GS550L carb & timing

[Anonymous]

I finally got my bike on the road last weekend after taking a year and a half to completely dismantle and reassemble it. I started it a couple of times over the winter, but this is the first time it's all come together in a ridable form.

When I first started it this weekend, it was having a lot of trouble idling and would die when I rolled back the throttle. I figured this was due to an over-rich condition, but for good measure I cleaned the plugs (which were black) and tried again. It started fine, idled well, and had no problems with throttle use. After running it for about twenty minutes, I pulled the plugs again and they looked fine.

I took the bike for a couple of short test-rides. During the second ride, it had trouble idling and stalled a couple of times. I pulled the plugs again. #1 was black, but the rest were fine. So I figure the idle problems were partly due to #1 still running rich.

My first question is, how should I go about adjusting #1 so that it runs properly?

I also have a question about the timing. When I first started the bike this winter, I checked the timing with a strobe. At that point the bike was having trouble idling. Timing seemed to be about 10 degrees advanced of where it should be on all cylinders, so I rotated the plate as far as it would go, which was only enough to get me within a couple of degrees of the correct position. This is the same on all cylinders, and is also true for the centrifugal-advanced position.

My second question is this: It seems like it would be a good idea to put the ideal timing position in the middle of the adjustment range, so I'm a bit suspicious about the correct position here being just off the end of the range. I suspect if I could adjust it that extra couple of degrees, the bike would idle like a champion. I am tempted to drill out the adjustment so I can get it where it should be, but I know this doesn't really address the problem.

I haven't checked the timing since cleaning the plugs -- could dirty plugs be the culprit? How about the capacitors?

Thanks!

Michael

[satchmo]

This might sound stupid, and I am by no means half as knowledgeable as most on this forum, but have you checked the idle knob off the carbs.

My 77 gs550 has a knob right under the tank above the carbs and when I was having idle trouble, all it needed was a little adjustment to keep the throttle open a tad more.

Also, I find that when I'm riding around, once the bike gets warm, for some reason I have to turn the knob a bit further or the bike will occasionally stall.

Satch

[Anonymous]

have you checked the idle knob off the carbs.

I've fiddled with the idle adjustment to get it idling around 1500 rpm (about as low as it will go without dying). What happens is that after I ride it for a while, the #1 plug turns black and it won't idle at 1500 rpm any more -- needs to go higher. I can make the adjustment, but there is obviously a problem with the #1 carb which needs to be addressed more directly, since it's the only black plug.

Also, I'm taking the perfect condition of the #2,3,4 plugs as an indication that the mixture problem is not due to the air filter, which should cause problems on all the carbs. I assume the problem is simply with the mixture adjustment screw, but I'm wondering if there's a "best" way to adjust that screw, without making an adjustment; going for a ride; checking and cleaning the plugs; make another adjustment; go for a ride; etc.

Incidentally, if I do have to adjust the mixture by trial and error, does turning the screw in make the mixture richer or leaner?

There was a remarkable improvement in the idle when I backed the timing off 10 degrees, so I'm pretty sure it needs to come back the rest of the way, but not sure why that lies outside my adjustment range. I took the engine apart completely, but IIRC, the ridge that locates the ATU on the end of the crankshaft is fixed to the crankshaft, and not something that could have come out of alignment.

Thanks!

Michael

[lhanscom]

Check your float hight, and that your float is floating on #1 Carb.