electrical issues on MY GS?

[Bud]

OK, so, Battery is all charged up, take short rides around town, everything is fine.

If I take a long trip, the left carb (only 2 on my bike) tends to flood (I need to clean it, but I am terrible at syncing) and the bike has very little power to spare. If it doesn't crank on the 1st or second try, It won't go. If it sits for a while between it will start.

I replaced my reg/rec this year, but not the stator. I am getting a good ~14 volts from the charging system when the bike is running (~3500 RPM).

Any Ideas? Should I just go though and clean any connection I can get my grubby hands on???

 

[chiphead]

I'm more confused than usual here.
You are getting a good charge rate. You state the carb is flooding. Is this why it "won't go"? Or do you mean it won't turn over with the electric start? If that is the case, what is the battery voltage when it won't turn over? Use a hydrometer to check each battery cell to make sure you don't have a bad cell. If the cells are good and the voltage is good then I would guess you may have a starter that is getting ready to cough up a hairball. You may be able to take it apart and clean and dress the armature.

 

[Bud]

If the carb floods, it won't start the first or second try, then the battery dies.

The startor sounds great, but when I have tried starting it over 2 or 3 times (about 5-10 sec each) it just slightly dims the lights, no turning over. if I let it sit for a bit, then it will crank right over (may not run, but it will turn)


I do not have a hydrometer to test, I will look into one. With a bad cell, with the bat still show 12 volts, but not hold it as long (kinda like using a AA instead of a D)? All levels are full as well

 

[nabrams]

If your voltage is OK and it starts after letting it sit for a while then it has to be a starter problem. The inside of your starter may be dirty - clean it (been there, done that). When the electrical components heat up they perform poorly if the contacts are dirty (brushes to armarture) - that explains why it turns the engine after cooling down. If it still has this problem after cleaning it out then you may need a new (or decent used) starter.

 

[Matt Vann]

I may be waaay off base here, but I had a similar problem that was due to bad connections at the coils. One coil would stop working thus causing a loss in power and gas mileage. I cleaned all of the contacts thoroughly and fixed the problem.

 

[Bud]

running great today, quick clean of the carbs last night, I really don't know what it is, gunna get the bat checked today.

 

[bwringer]

You also seem to have the classic textbook symptoms of a bad petcock.

Carb #2 floods because of the inevitable leak in the fragile and very thin 20-25 year old vacuum diaphragm. The rubber sealing disc inside is also most certainly worn out. It happens to every old motorcycle.

Replace the petcock and forget about this particular issue for another 20 years.

Results have been mixed at best with the petcock rebuild kits, so personally, I wouldn't bother. A new one is only $45 - $60.

DO NOT run the bike using the prime setting -- that's a great way to end up with a crankcase full of gas and engine damage.

 

[Bud]

Darn it, I was thinking bad petcock too.. Lat night I took off the carbs.

I would just like to say, HUH??????

here is a drawing of them (I'm no artist)

very odd to me.

so anyway, I'm looking at it and it seams pretty clean, also, I can't get them off the bike. Just can't find where to slide them out.

So back on they go. Now they're not leaking and it's time for the little guy to go to bed.


This morning I start it up and look at the intake boots (I had a bit of trouble with them last night) HOLY CRAP! That's what's been leaking.

So my leak is comeing from the intake boots. Right where it connects to the carbs, the airbox it about 1/4 - 1/2 inch off and doesn't have the screws to hold it in place, but I tried to push it back and couldn't get it to move that direction. Any suggestions?

 

[Bud]

Better image of the carbs
http://alpha-sports.com/spst/1986%20GS550L/07.gif

and air cleaner
http://alpha-sports.com/spst/1986%20GS550L/01.gif

 

[Bud]

The world may never know

 

[steve-lloyd]

Don't agree with bwringer when he says that running on the prime position will fill the crancase with gas. Many older bikes, such as Hondas, do very well without a vacuum operated petcock. They simply have an off, on, reserve tap operating on gravity.
Thier "on" position works the same as the Suzuki "prime" position. The only way the crancase could fill with gas is if the float valve in the carb is leaking AND the petcock is left on prime while the bike is not running.
This is the only advantage of a vacuum operated petcock - you don't have to remember to turn the petcock off after a ride.:-|

 

[Bud]

I have an old honda with that kind of petcock, you forgot that the bowl drain also has to be plugged. Tru you may have forgotten because most of them are, but they do have a drain on them so the crankcase doesn't fill with gas.

 

[bwringer]

Don't agree with bwringer when he says that running on the prime position will fill the crancase with gas. Many older bikes, such as Hondas, do very well without a vacuum operated petcock. They simply have an off, on, reserve tap operating on gravity.
Thier "on" position works the same as the Suzuki "prime" position. The only way the crancase could fill with gas is if the float valve in the carb is leaking AND the petcock is left on prime while the bike is not running.
This is the only advantage of a vacuum operated petcock - you don't have to remember to turn the petcock off after a ride.:-|

Thanks for the clarification -- a GS will run fine using prime, but you do have to remember to shut it off when you park.

I don't know about y'all, but I don't have the steel trap memory required to shut off the gas reliably. But using prime will certainly work when you're just trying to get the %$#! thing running before you spend too much money.

 

[dpep]

If I have read your problem right, it is electrical. A carb problem may keep your bike from firing; it won't keep it from turning over. It sounds like the starting problem is after the bike has been run long enough that the engine and electrical components are heated up. Heat increases resistance. After the bike has sit long enough to cool down, the resistance drops and you are back in business.

Tracking down the point of the resistance may not be easy. It could be in the wiring, the connections, a ground, or a component...or at multiple points. The cheapest thing to do initially is to check and clean all connections and grounds. You would likely want to begin with the starter circuit. You may also want to run your stator check with a hot engine to see if you get different results.

You may have a carb or petcock problem as well, but fixing it isn't going to remedy the problem of not starting when hot.

 

[Bud]

SO, I got it down to 2 issues.

1) Not starting when hot. I think this will have to wait untill #2 gets fixed

2) Float needles not sealing.

I can't ride it now because it dripps gas all over when I stop. not for terrably long, just long enough to get everything covered. It needs a petcock rebuild or replace, and a carb rebuild.

Unfotunatly, that are some messed up carbs, and I can't change them. ooh well, looks like I know what I'll be doing this weekend.

 

[cdub]

? for you guys- if i run my 81 gs850g in prime will it wreck it? no gas comes out of it when in the on position. i have only checked this when the tank is off the bike???

 

[frosty5011]

? for you guys- if i run my 81 gs850g in prime will it wreck it? no gas comes out of it when in the on position. i have only checked this when the tank is off the bike???

That's because when you checked it, you probably did not apply a vacuum to the vacuum line on your petcock.

 

[cdub]

o okay i have evidently only had gravity fed ones before, ive never had a petcock with 2 lines comin from it, the last 5 bikes ive had. so if i pull off the line when its back on and connected it should pour gas out then? is there anything wrong w leaving it on prime and blocking off that vaccuum line? why are all petcocks not gravity fed???

 

[frosty5011]

o okay i have evidently only had gravity fed ones before, ive never had a petcock with 2 lines comin from it, the last 5 bikes ive had. so if i pull off the line when its back on and connected it should pour gas out then? is there anything wrong w leaving it on prime and blocking off that vaccuum line? why are all petcocks not gravity fed???

It's an extra safety for you, in case your float needles/valves are leaking, or you have a sticky float. With the engine not running, gas won't flow through the line.

Just put a length of hose on the (smaller) vacuum nipple on the petcock.....and direct your fuel line from the petcock into a suitable cannister. Put the petcock on "ON"....and suck on the vacuum hose....fuel will flow, if the petcock is operating correctly.

 

[vtcycle]

Don't know, But I kinda like the drawing better:-D

peace,
michel