Carburetor problem Need help please

[Jon]

1975 R90S with Dellorto Carbs, rode and ran well. I parked it for maybe 3 weeks, motorcycle started right up but poor idle, I figured it was cold. Rolled out on the street spit and popped. So now plugs show me running rich, wont idle, I removed the airbox elbows runs the same. Last balance of carbs about 2 years ago and it ran great. Anyone recommed an easy check/fix. I really think its gotta be something simple. Dont want to go right to the dealer. Thanks

 

[toooldtocare]

Check the choke cable(s) first to make sure it/they are not sticking. Since both plugs show rich it probably has to do with that instead of something to do with both carbs.

Wayne

 

[Jon]

OK thanks, good point

 

[Jon]

Check the choke cable(s) first to make sure it/they are not sticking. Since both plugs show rich it probably has to do with that instead of something to do with both carbs.

Wayne

Well I feel the choke cable moving inside the cable sheath on both sides. The engine runs better when I apply choke at Idle but I still have to hold high RMP's on the throttle to keep engine running.

 

[47512]

1 make shure the pilot jets are clean, take them out and blow through them.

2 Make shure the floats are good, ethanol in the fuel will attack some plastics, hollow floats will leak and and take on fuel whitch makes them heavy and raises the level in the bowel= rich running.

 

[toooldtocare]

Dells are easy to damage, so carefully remove the large nut securing the float bowls and look for junk in them. From there you can remove the floats and jets too if needed. Hopefully you will just find some junk. When installing the nuts again be careful not to over tighten them. As you will see, there is not much metal there.

Wayne

 

[Dave Backmarker]

Rough idle on R90S

Jon,
What was the indication on the plugs that the engine was running rich? Was one plug wet? I miss gas with lead that provided a great range of colors but with unleaded, there is very little indication.

Do you use a gas stabilizer? Three weeks with 10% to 15% ethanol is enough time to start the gas to attract water and start to gum up. Does the gas have a funny green color and an unusual smell?

I also have a R90S and I've rebuilt the Dellorto's on mine. I've had the garbage gas in the Hudson Valley swell my new, plastic floats.

Was the bike outside or in a garage during the three weeks?

And... what makes you sure this the problem is with the carbs? How old are the points and condenser?

DaveM

1975 R90S, 2000 R1100RT

 

[Jon]

Jon,
What was the indication on the plugs that the engine was running rich? Was one plug wet? I miss gas with lead that provided a great range of colors but with unleaded, there is very little indication.

Do you use a gas stabilizer? Three weeks with 10% to 15% ethanol is enough time to start the gas to attract water and start to gum up. Does the gas have a funny green color and an unusual smell?

I also have a R90S and I've rebuilt the Dellorto's on mine. I've had the garbage gas in the Hudson Valley swell my new, plastic floats.

Was the bike outside or in a garage during the three weeks?

And... what makes you sure this the problem is with the carbs? How old are the points and condenser?

DaveM

1975 R90S, 2000 R1100RT

Dave, Gas Stabilizer only in the wnter. The gas was fresh and no strange color or smell. Stored inside always, the plugs were a black soot, dry color. I have only removed the bowls to this point, floats move free no dirt or crap in bowls. No points and condenser. Electronic ignition. I keep thinking it has to be something easy. Thanks for your interest

 

[toooldtocare]

Was there gas in the bowls? Do you get good gas flowing from them (bowls) off when you turn on the petcock? If not, look for fuel filter problems.

Wayne

 

[69ZEFF65]

My moneys on clogged idle jets

When any of my carbourated bikes sit for more than two weeks the idle jets get clogged. I once chased an ignition problem (black sooty plug) for a week until I pulled the carb off and found the idle jet passageway clogged solid. It sounds to me like you should pull your idle jets out and clean the orifice for starters. Sometimes a shot of carb cleaner will do it but more often than not you have to stick a wire in there to knock the hard stuff out. I took apart a new stainless steel bicycle brake cable and use the individual strands to get the stuck crud out of the jets but you have to be careful not force it or bend it up to much or you will snap it off and have to buy a new jet. I just got an R 90s cranked up and running that had last been running in the early '80s so all is not lost.

 

[ISAMEMON]

for both carbs to "go bad" at the same time, makes me believe it is not carb related

 

[toooldtocare]

for both carbs to "go bad" at the same time, makes me believe it is not carb related

My feeling too, either bad gas clogging up both carbs, bad fuel filter (not true if running two filters; i.e. both petcocks on), choke cable to carbs; each of these things would affect both of them, or ignition as the next step.

How is the spark?

Wayne

 

[Jon]

Was there gas in the bowls? Do you get good gas flowing from them (bowls) off when you turn on the petcock? If not, look for fuel filter problems.

Wayne

Plenty of fuel in both bowls when I removed them for inspection. Fuel filters are the clear inline type and I can watch them fill. On has a paint chip from inside the tank but fuel flows free.

 

[Jon]

My feeling too, either bad gas clogging up both carbs, bad fuel filter (not true if running two filters; i.e. both petcocks on), choke cable to carbs; each of these things would affect both of them, or ignition as the next step.

How is the spark?

Wayne

Spark is good, I think the choke cables is working and the ignition system is electronic so I figure it either works or does not. Very discouraging to not be able to ride.

 

[69ZEFF65]

clean your idle jets!

Can't hurt to try this.

 

[toooldtocare]

Can't hurt to try this.

Sounds like good advice. My old R90S would often require me to drop the float bowls and clean junk out from time to time, and rebuild the carbs once in awhile.

Wayne

 

[helmut_head]

Quick fix.

Sell that pretty thing to me and I'll fix it?

HH

 

[ISAMEMON]

Spark is good, I think the choke cables is working and the ignition system is electronic so I figure it either works or does not. Very discouraging to not be able to ride.

so it was modified to electronic ignition ? brand, how old ? and yes some will work or not work, some however "limp" home

 

[toooldtocare]

Back to square one. I just got home from a ride on my 07 Triumph. The bike has carbs and the last ride was fine just a few weeks ago. This ride was not, I had the same problems you are having, sputtering, backfiring through carb, slow idle, so slow I had to hold the throttle open just to keep the engine running. However, it ran fine once underway.

I looked under the tank and found a hose off one the carb's manifold. This hose apparently allowed too much air in that carb and leaned out the mixture at idle. What about a vacuum leak on your garb? Are the clamps tight? I know on Dells there is no rubber coupling like on bikes with Bings on the front, but maybe the fitting is loose?

Wayne

 

[Jon]

Sell that pretty thing to me and I'll fix it?

HH

This one.....still dont run right