intermittently rich

[brand new bike zealot]

Aren't we all....

But on to my Gs, I'm trying to figure out what the cause of my problem hoping the solution will require a minimum amount of work. Here are the symptoms...

Cold start up this morning (about 5 celcius) full choke, fires right away, up to about 3000, drop it a bit and let it warm up until I can blip the gas without it bogging (~ a minute), ride for about a k and then kill choke altogether. Runs fine for another couple k, but by the time I get to work (maybe 4-5km overall) it's idling at about 500, and stalls when I blip the gas and smells a little gassy. Will still run great once the revs get up there, but idleing is bad.

Start it after work, again full choke, fires instantly and runs no choke after less than a minute. Runs great the whole way home, idling at 1200 or so.

The morning temperature doesn't seem to be a factor, as the same bad idling happened on the way home once too.

One other thing is that if I fire the bike up within 24 hours of riding it last, it literally starts in less than a second. But if I let it sit for more than that, it has to be cranked for 4-5 seconds before it catches and runs on less than four cylinders for a while. This leads me to believe the floats are leaking. Correct?

The thing is, if my floats leak, wouldn't they always leak? not sometimes work fine and other times not? This leads me to think that the choke is sometimes sticking. Can this be tested without taking out the carbs? Also, can it be fixed without taking out the carbs?

Thanks for reading my novel, all the help and support the people on this site provide is fantastic and much appreciated.

 

[mark]

The floats shouldn't be leaking unless you leave your petcock on "prime". If your petcock is on "run" as it should be, there would be no gas flowing when the bike is off, so no leak. Assuming your petcock is kept at "run", it will probably take a little longer to fire after sitting for a while due to a lack of gas in the bowls rather than a leak. If the bike has set for a longer period of time, try turning your petcock to "prime" for 15 seconds or so and then try to start the bike. It might fire right up (then turn it back to "run" of course).

Also a 4-5 km commute really isn't a very long one on a cold morning which might contribute to your low idle when you get there. It has a better idle when you get home because your engine warmed up a little more due to the warmer outside temperature.

How's it do on a longer run? Much better I bet.

You might also check your petcock for proper operation.

 

[Commodus]

Aren't we all....

But on to my Gs, I'm trying to figure out what the cause of my problem hoping the solution will require a minimum amount of work. Here are the symptoms...

Cold start up this morning (about 5 celcius) full choke, fires right away, up to about 3000, drop it a bit and let it warm up until I can blip the gas without it bogging (~ a minute), ride for about a k and then kill choke altogether. Runs fine for another couple k, but by the time I get to work (maybe 4-5km overall) it's idling at about 500, and stalls when I blip the gas and smells a little gassy. Will still run great once the revs get up there, but idleing is bad.

Start it after work, again full choke, fires instantly and runs no choke after less than a minute. Runs great the whole way home, idling at 1200 or so.

The morning temperature doesn't seem to be a factor, as the same bad idling happened on the way home once too.

One other thing is that if I fire the bike up within 24 hours of riding it last, it literally starts in less than a second. But if I let it sit for more than that, it has to be cranked for 4-5 seconds before it catches and runs on less than four cylinders for a while. This leads me to believe the floats are leaking. Correct?

The thing is, if my floats leak, wouldn't they always leak? not sometimes work fine and other times not? This leads me to think that the choke is sometimes sticking. Can this be tested without taking out the carbs? Also, can it be fixed without taking out the carbs?

Thanks for reading my novel, all the help and support the people on this site provide is fantastic and much appreciated.

You can visually verify if the choke is sticking by simply observing the action of the choke linkage on the carbs. I don't think that's the case here.

Though I agree it's a little weird, I think you are correct in thinking the issue is related to the floats - either the needle valves are not sealing and/or (probably and) the petcock is not operating correctly. As has been said already, check the petcock operation - easy enough, just remove the fuel line and turn it to 'run', and see if gas comes out. If it does come out, the petcock should probably be replaced. There are rebuild kits available, but I've never had much luck with them and I know there are others here who have come to the same conclusion.

My feeling is you will probably end up replacing both the needle valve assys and the petcock.

 

[Guest]

Charge your battery and clean all your grounds. You might be getting a weak spark.

 

[gustovh]

I don't beleive his engine is fully warmed up. I ride 6 miles 1 way to work and the old girl isn't fully warm when I arrive, I work graveyard. Though she starts on half an r with 1/4" of choke. In the summer when the nights are 75 plus she warms right up.
So before you worry too much, go for a longer ride 10 or so miles and see how she idles in the morning at the end.
Just my 2 cents.
V

 

[brand new bike zealot]

Charge your battery and clean all your grounds. You might be getting a weak spark.

One thing I've remembered is that the low idle happened once before after stopping at the store after a good half hours ride. It was rainy, so I just put it to it being a little cranky about the wetness. The weak spark is a good thought, electrics are notoriously intermittent, much more so than fuel delivery, the route I was following. I'll check that over and clean the plugs and stuff and see where I'm at then.

As to some of the other ideas, I've checked my petcock and it doesn't seem to leak on run. Had the tank off, full of gas and nothing dripped out. You never know though, as it's likely the original and was sitting gasless for over ten years before I got it.

I have a feeling that all the little things that are a little bit wrong with this bike occasionally line up and wreak some gremliny havoc.

 

[KEITH KRAUSE]

Could be lots of things. As you've said, the electrical connections and other things might all need attention and are adding up to the problem.
Poor idle as you describe (gets worse/rpm's drop as the motor warms up and gassy smell) could be from rich carburetion/poor venting/weak spark.
If venting, clean the gas cap venting. Also check for clean float bowl vent lines by blowing into the vent lines at carbs 2 and 4. Route them under the seat and be sure they're not kinked.
If carbs, inspect for gas puddling in the air box or any gas coming out of the bowl overflow lines or collecting in the lines. Generally, any float valve sealing/float level problems will cause the carbs to overflow somewhere. Replace any worn float valves or worn float valve seat gaskets. Check float levels and operation. Carbs must be clean.
If no leaking, I'd suspect the air jets at the filter side/lower part of the intake may be clogged with fuel varnish. Simple test for that is to try adjusting the side air screws using the "highest rpm method". If rpm's don't change, that suggests the air jets or air passages are clogged. As for the side air screws, they are generally set about 1 1/2 to 1 3/4 turns out from lightly seated. If yours are set significantly further in, that could be your problem right there.
It could also be poor pilot fuel screw (underneath) adjustments. They are generally 3/4 to 1 1/4 turns out from the factory. If yours are out too far, that will cause a richness problem. As for adjusting both the side air and pilot fuel screws, they will not move by themselves if their springs are operating correctly. So if the bike ran fine before and no one has played with the screws since, then the screws shouldn't be able to lose adjustment and I doubt that screw adjustments would be helpful. But if you inherited this problem from a PO then the screws adjustments should be checked/recorded and possibly set correctly.
As with most carb related problems, it takes just one carb to cause a problem as you describe.
If weak spark/electrical related, clean all connections and check for tight. Check battery connections/coil terminal connections and check for broken copper strands. Check plugs for correct heat range and gap and condition. If still running points, check for any pitting and uneven contact. Check timing/advance action. Check point dwell. The spark should be a solid bluish-white.

 

[hoyterb]

Keith forgot to mention to check the ign condensors.I had one that would be intermitant and cause a missfire when hot and seemed just like a fuel problem. Drove me nuts for two weeks and a set of floats and many adjustments etc.Just replace one at a time to find out for sure.Did you pull plugs and see which one/s are rich? If they are "paired plugs" it is probably ign related.