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Discussion Starter #1
Hi Chaps
Can anyone shed some light on my problem. i have an o4 America that will cut out when once it has warmed up, will not start at all and some times back fires when you try. once it has cooled down it will start no problem like nothing was wrong, but once warm it will cut out again.
i have checked the fuel system and its seems ok, and have traced electric connectors and all seem fine including the battery terminals.
any one have any thoughts on this.
Thanks chaps for any info.
 

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That sounds like you might be running rich. This is not based on personal experience, but on stuff I have read. Could you provide more info about your bike? Is it stock, or have you made any modifications to the air intake system, carburettors or exhaust? At what revs does it cut out?

It could be that the mixture screw is set too rich, or possibly that the float level is too high. Possibly even the pilot jet is a little large. It will help to know what has been done on your bike.
 

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Prop is spot on with his analysis, but there may be something else going on. Does it shut down at about the same elapsed time? I'm thinking you may have a tank vent problem instead. Have you ever cracked the gas cap when this happens?

Its just a shot in the dark, but since these problems can be very frustrating, I thought I'd throw it out there. I suspect prop is correct. The carbs are too rich or out of sync or both. The real question is this: Was anything done to the bike right before this started happening?
 

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Will it idle off choke when cold, & does it occasionally BANG if you give it throttle when you try to start it when warm?
 

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How does it quit? Does it come to a sputtering halt or just quits dead. My guess is the vent issue. Check the vent line from the front of the tank to behind the left side of the transmission. It should not be kinked. Also there is a tip over valve that could plug or stick, preventing the tank from venting. It is in that same vent line. Sure fire way to check is, once the bike begins to quit or quits, crack the tank cap open to see if it continues to run or fires right up.
 

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My 07 BB (12600mi) was just doing the same thing, warms up and dies, gives you a hell of a time to start up again. Turns out it was the ignition pickup coil. My local shop had to run the bike on the test bench till it died, when it did die there was no resistance in the pickup coil, after it sit for a few minutes the voltage output was inconsistent. Since getting my bike back a week ago after the pickup coil was replaced it has been running great.
 

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Discussion Starter #7
reply from herb

Hi Chaps,

The bike will just stop dead no splutter and only when warmed up.

No ,off choke when cold it will stop, and no bang if given some throttle when warm.

Will die when warmed up, when colder or cool it will be fine, some times take a bit longer to stop than others.

Mods on bike, A1 removed, Staintunes and rejet, Side stand switch by-passed, oh yes and a sticker on my hat.

vent checked and clear, carbs seem ok,

Now that pick up coil could be a wonder, anyone any more thoughts on this.
 

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Could you let us know your jet settngs and mixture screw settings?

The pickup coil is a good theory, start with the simple stuff first though.
 

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I had an old Corvair that used to run like a champ until it got hot. Then it would shut down. There was absolutely nothing I could do to start it until it cooled down again. It was the ignition coil that was failing. As it got hotter, the resistance dropped until it was just "open". Took forever to find the problem.
 

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Based on what Herb wrote so far I don't think the carb tuning has anything to do with the issue, it's most likely electrical.
 

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Sounds like the dreaded GILL coil problem. :mad::mad:You need to try another coil. Nology in the US, actually a rebadged German coil for BMWs, would be the best bet. They are not expensive, unlike the ignition pickup coil:eek:
Phil
 

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If it only does it when it is warm....then it is one of the dreaded coil problems.

There are 3 that can go wrong....do a search for bad coil...and you will probably find your answer. It could be the ignotor, ignition, or pick-up up coil. Before you buy a Nology...take it to the dealer.
 

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Discussion Starter #13
Hi Guys, getting some great feed back ,thanks,

Jets are 125 s i think but could be 135 s not real sure dealer fitted these when staintunes were put on. go for 125
Mixture settings not sure but plugs look fine and normal.

im sure going in the direction of the coil problem at the mo, fuel does not seem to be the issue.
will let you know how it all gos. any more thoughts keep them comming.\Thanks
Hoo Roo
 
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