Running Rich and Stumped

[ndbaker]

Alright fellow GS'ers, I'm fed up. I've had an issue with my 1980 550e running rich since I brought it back to life in 2010. I had the carbs rebuilt at this time. The next year I did a top end rebuild and now have good compression across all 4 tiny cylinders.

I know I'm running rich because of the exhaust smell, and the smell of gas on my clothes after a ride. Unless these old bikes are meant to smell and cause global warming. I can only smell it when idling (1100 - 1200 rpm) but never had somebody follow with the throttle open.

All 4 sparks get sooty, but never done plug chop
Stock intake...this should make everyone happy
New boots
Valve clearances within spec
Redipped carbs in 2013
Verified all jets are spec
Needle valves are not worn
All float heights are exact to spec
Done highest RPM adjustment several times, with no change in exhaust smell.
I get about 160 miles to a tank
New 4 into 2 exhaust last year - no change in richness.

Any advice or suggestions? Only other thing I can think of is a bad petcock.

[mrbridgeport]

Are you running on PRI instead of ON. I don't know if your bike has the vacuum style petcock, but if you are running it on pri - you are just dumping fuel.

[tkent02]

Are you running on PRI instead of ON. I don't know if your bike has the vacuum style petcock, but if you are running it on pri - you are just dumping fuel.

That's not right, when it's on prime it's just turned on, exactly like being on with a manual petcock, or lik ebeing on with the engine running on a vacuum petcock.

It won't flow any more fuel, won't dump any. Gas mileage and richness would be identical.

[ndbaker]

Are you running on PRI instead of ON. I don't know if your bike has the vacuum style petcock, but if you are running it on pri - you are just dumping fuel.

Always "On"

[rustybronco]

160 miles per tank is meaningless without knowing how much fuel you used during those 160 miles. 160 miles on a 5.8 gallon tank would not be good.

Any GOOD pictures of the plugs sootiness?

Needle valves (fuel inlet valves) aren't the only things that can wear inside carburetors.

Are the needles properly installed? i.e. are the spacers correct for the application and in their proper order.

How is and what style of are filer are you using? For example... is the air filter a foam filter that's over oiled? That would make the bike run rich of and in it's self.

How many miles on the bike and in what sort of condition were the carbs in when you got the bike?

Did the PO/ original owner do any mods to the bike such as installing different needles and (or) needle jets? any added shims or spacers?


If your clothes smell of fuel, it's running too rich.

[tkent02]

160 miles per tank is meaningless without knowing how much fuel you used during those 160 miles. 160 miles on a 5.8 gallon tank would not be good.

I think it's more like a 4 gallon tank. Also useless without knowing how it was ridden those 160 miles, were you cruising gently or whipping it like a rented redhead?

You said the float heights were set perfectly, but did you check the actual fuel level? Sometimes it's a little off.

How is the ignition doing? Good plugs? Any chance someone altered the ignition timing? Have you confirmed the cam timing is correct?

Here's one, have you confirmed the chokes are closing completely?

[ndbaker]

160 miles per tank is meaningless without knowing how much fuel you used during those 160 miles. 160 miles on a 5.8 gallon tank would not be good.

Any GOOD pictures of the plugs sootiness?

Needle valves (fuel inlet valves) aren't the only things that can wear inside carburetors.

Are the needles properly installed? i.e. are the spacers correct for the application and in their proper order.

How is and what style of are filer are you using? For example... is the air filter a foam filter that's over oiled? That would make the bike run rich of and in it's self.

How many miles on the bike and in what sort of condition were the carbs in when you got the bike?

Did the PO/ original owner do any mods to the bike such as installing different needles and (or) needle jets? any added shims or spacers?


If your clothes smell of fuel, it's running too rich.

The gs550e tank is less around 4 gallons

Air filter is regular foam, and I don't think it was any oil left in it.

31k miles

As I said all jetting is to stock specs. Only thing not stock is the new exhaust.

[ndbaker]

I think it's more like a 4 gallon tank. Also useless without knowing how it was ridden those 160 miles, were you cruising gently or whipping it like a rented redhead?

You said the float heights were set perfectly, but did you check the actual fuel level? Sometimes it's a little off.

How is the ignition doing? Good plugs? Any chance someone altered the ignition timing? Have you confirmed the cam timing is correct?

Here's one, have you confirmed the chokes are closing completely?

Regular 50mph cruising, normal acceleration.

I did not do a fuel level check yet, thanks for the suggestion.

I replace the plugs at least once a year.

Cam timing is correct.

Chokes fully close.

Think it could be bad spark plug wires?

[rustybronco]

Jets aren't the only thing inside a carburetor...

Needle jets, air jets, needles themselves, pilot jets, etc.

Toms suggestion of incomplete closure with the enricheners is a good one. I'll add one more. Damage to the sealing surfaces of same said items?

[tkent02]

Possible but it seems iike you would notice it running funny, misfiring and such.

Which spark plugs are you using?

[rustybronco]

Chokes fully close.

How do you know for certain that they do? Did you lightly grease each plunger then lift each one making sure that each plunger retracted properly, and made sure each was not binding or being held off the seat when the rack was re-assembled? Plus, inspecting the sealing surfaces of each plunger for damage?

I would venture a guess that very few know how to make sure everything is as it should be when re-assembling the carb rack. Being clean isn't all there is.

Ever ran into a cracked carb body being the cause of one carb running richer than the other three? I have.

[ndbaker]

Jets aren't the only thing inside a carburetor...

Needle jets, air jets, needles themselves, pilot jets, etc.

Toms suggestion of incomplete closure with the enricheners is a good one. I'll add one more. Damage to the sealing surfaces of same said items?

Everything in the carb with a number (jets and needles) I matched to Bikecliffs carb spec page.

The choke closes fully and wont push further into the carb, and those seals are not cracked, how could I further test these?

[ndbaker]

Possible but it seems iike you would notice it running funny, misfiring and such.

Which spark plugs are you using?

It actually runs smooth. If it misfires I cant tell.
NGK b8es sparks

[rustybronco]

If the sealing surfaces are in good condition and are seated properly then that's one less area that needs to be looked at.

As Tom suggested, wet fuel levels are next to look at.

You have an advantage that we don't, you can see the bike...

[ndbaker]

I know the choke enriches the mixture. These bikes shouldn't smell even with the choke on?