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Post by coolbean on Dec 19, 2005 20:31:07 GMT -5
I have a stock 1978 SR500E that I purchased about 6 months ago. It has about 12,500 mi. I completely rebuilt the stock carburetor using a S.C.I. Keyster rebuild kit.
Using full choke (closed), the engine starts fine - often on the first kick - even in below freezing weather. I let it warm up for 5 minutes or so before backing off the choke. After about 10 minutes of riding, the engine stalls out while idling at a stop light. And then it won't start back up, no matter how many times I kick it. If I let the bike sit for 10 minutes, it will start back up like nothing ever happened.
Does this sound familiar to anyone? Does anyone know how to fix this problem? Other than this, the bike runs great!
Thanks for your help.
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Post by G Man on Dec 20, 2005 0:28:09 GMT -5
First of all, welcome to the forum!
The thread is titled Carb Flooding. Are you certain that the carb is flooding? When did you rebuild the carb and at what point has this situation occurred? You may have to re-check your work and/or see if something has since failed in the carb. Did the kit come with a new inlet needle assembly? Perform a pressure test on the inlet needle to see if it is holding. Maybe see if the float is floating. Have you done a plug check? You need to determine if you have a fuel issue or a spark issue. Once you have double checked your work, get the specs for the stator(magneto) and check it to see if all is well. If you can re-create this situation at or near home, it would be the best time to try to determine what it is that is failing. Keep us posted.
G Man
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Post by miker on Dec 20, 2005 10:33:50 GMT -5
A couple ideas...
1. Gas tank or float bowl vent? If the vent is plugged it can get too hard to draw fuel from until it sits for a while to let pressure stabilize. I've only had this happen on boats, but it's just like you describe.
2. Fuel line partly blocked, either in tank, filter, gas line, carb, wherever... you use up all your fuel and then the engine stops until some time passes to let more drip thru.
3. Almost sounds like vapor lock in a way, too...
Be sure and let us know what you find out. I'd start by pulling the gas line off the carb and making sure there's good flow. When it stalls, try opening the gas cap for a second and see if it starts then (would indicate vent problem).
miker
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Post by coolbean on Dec 22, 2005 1:36:02 GMT -5
thanks miker and g man for your advice.
g man - i never tried to start the engine before rebuilding the carb (back in june), so i don't know what it ran like before. i did check the plug, and it comes out dry and clean. i don't think it's a spark issue.
i will look into the rest of your suggestions and let you know what i find out -- yours too miker.
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Post by canucksr on Dec 22, 2005 11:52:55 GMT -5
Could be the float level or the needle not seating correctly. My 79 SR had a similar problem at one time and it was the needle and seat. The carb was filling with gas faster than it could be burned. The rubber part of the needle was worn and not closing off the fuel delivery.
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Post by Bronson7 on Dec 22, 2005 19:13:52 GMT -5
Canucksr, I doubt it's a bad needle/seat if the plug is clean and dry. If it's flooded, you can usually smell it and your plug tends to be wet. Some fuel running out of the bowl vent would be another sign of a bad needle/seat. This could be checked by putting a Mighty Vac on the vacuum line going to the fuel shut-off, pulling a vacuum, and checking for fuel running out of the bowl vent. When you say you can't get it started after it stops, did you try to choke it? Also, once it's running, does it run better going down the road with partial choke? If yes, it would indicate an overly lean condition. Do you get spark knock at even a moderat engine load? Sounds like a fuel starvation or spark problem. I don't know about the SR's coil, but a bad coil also causes what you're experiencing. The coil gets hot, breaks down, and when it cools off it's good to go till it gets hot again. Not saying that's what you have, but food for thought.
Bronson7
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Post by Bronson7 on Dec 22, 2005 19:17:49 GMT -5
Ooops, forget the part about the Mighty Vac> I'm confusing my PC800 with my SR. We have a prime position on the SR.
Bronson7
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