1981 GS850 problem

[max]

Hey guys thanks for helpin me out. I've got an issue with my 850 and I'm totally stumped. Im no bike mechanic, but I tore apart my old Kawasaki before and figured it mostly out, and I've been through this Suzuki as well just using general trial and error techniques I learned after years of historic car ownership. Anyways, here goes.

I bought this bike about 2 months ago, running perfectly even though I bought it out of a barn. Lots of power and a blast to ride, nice steady low (700rpm) idle. After I got it I noticed that once the tank got a little lower in fuel, about the time to switch to reservior, it seemed like the engine was ahving a hard time receiving fuel. I assumed that the valve or the reservior filter was getting scummy so I took it apart and found a lot of rust in the tank. Cleaned that up, flushed out the lines, emptied each dirty carb reservior and changed the fuel filter. problem solved, right? Wrong.

The problem got worse. Soon, no matter how much fuel was in the tank the engine would stumble, show marked lack of power, stall out at red lights, and sometimes even refuse to start. So I replaced all the rubber fuel hoses, got a bigger fuel filter, and finally took apart the carb and sprayed every moving part with carb cleaner and cleaned it with pipe cleaners. Now, the bike will start after sitting for a while but die out after a minute or two once (I suppose) the carb reserviors empty out. Obviously the engine isn't receiving gas quickly enough but I've run out of things to clean. I don't think it has a fuel pump, just gravity, so thats not the problem, I don't know what to do.

As a side note I also tested the strength of my sparks by pulling out a spark plug wire, sticking a screwdriver in the wire and turing over the engine. I found the spark to be almost non-existant, about half as strong as the spark my lawn mower makes! I don't think this condition is causing the problem but it's something I'll want to address anyways. All the electrical connections are good, what should I look for in this instance?

One other thing, I think i might be interested in replacing my 4-1 exhaust with a louder 2+2 (loud pipes save lives after all.) I live in Baltimore, any ideas besides eBay where I could locate a set of pipes?

Any help you guys could give me would be really appreciated, this bike is basically cherry and I'm really eager to get it back on the road before the season drags on too long. Thanks a lot

Max

[chef1366]

Your fuel filter is starving your motor. Try running without and see if if it helps. You need 5/16 open hose flow from tank to carbs.

[rustybronco]

First thoughts... your idle is to low should be about 1000-1100 rpms how is the fuel flow out of the petcock in the prime position into a container? also the fuel line must run down hill all the way to the carbs.

[Jethro]

If you didn't actually remove the floats and clean the needle jets and filters in each carb, it's probably plugged up with rust. I suggest starting at the top: take the tank off and see if it flows fuel nice and fast. Then make sure you have the right size fuel line, as chef said, 5/16" is the fuel line size, a fuel filter in the stock line size will be restricting fuel. Then take the carbs off and clean them- but don't just spray them down, take them apart (you'll have dozens of parts on the bench- clean them all). Then hook up your tank to the carbs and with the float bowls off see if fuel is pouring in ok to each carb. Then make sure your floats are set prefectly with clear tubing attached to the float bowl drains.

[max]

Thanks guys, now I have a couple of things to try. First, the line I was using was 1/4 inch, with what appears to be a fuel filter for a very small automobile. Second the filter was forcing the line up a bit, not directly down. Finally as I recall I failed to check the rust on the jets when I cleaned the carbs. All of these things I will address tomorrow.

The petcock functions perfectly, just gushing out in the prime condition and flowing equally well when suction is applied to the vacuum hose in the other two positions. If this rectifies the problem then I won't hesitate to coat that rusty tank with some tank liner.

Thanks again, I'll keep y'all posted with what happens.

[suzukizone]

1981 GS 850 problem

Hey Max, where are you in Balt? I got an 81 GS 850 G & Live in Carroll Cty. Are you me with a different name?

Anyway, a thought on some of that problem. If the vent on the gas cap is plugged, this will slow down & eventually cut off fuel supply. My guess is this will be more of a problem with a full tank than a partially full one as the vacuum lock will take effect sooner. If I am wrong on this ya'll can shoot it down, I got thick skin from eating too many pizzas.

I had a bike or two with clogged vent on the cap & it is easy to overlook. Don't think that's all. If tank is rusted it really should get a good interior scrub out and a coating as it will continue to plague you elseways.

My two centavos.

DH

[ccs]

One other thing, I think i might be interested in replacing my 4-1 exhaust with a louder 2+2 (loud pipes save lives after all.) I live in Baltimore, any ideas besides eBay where I could locate a set of pipes?

Take a look at: www.mashonline.com


Charles...

[semerm]

?

make sure your fuel line is not kinked too.