650 triumph idle problem

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Aug 6, 2005
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As I do every Spring I set out to get my dwindling fleet of motorcycles running for the season. As a general rule my 70 tr6r has always been the most reliable bike I have owned. I got it running last week, rode it around town a bit and parked it. Took it out a couple days ago and about a mile from home it started running erratically sputtering, wanting to die. I had to keep throttling it up to keep it going. I got it home and yesterday went out to see if I could figure out what was wrong. Had spark and gas, but it seems to want to abruptly die at 1000-1100rpm's. This is a guess by sound since the tach and speedo haven't worked for a decade. So to keep the thing running I have to keep it idling at 1200+ which is way too high. I have had the carb on and off the bike four times totally dismantled and meticulously cleaned. I have access to the pilot jet from both sides and have used a guitar string to make sure the pilot is clear. I have blown air, carb cleaner and gas through every opening in the carb I can, but it still runs the same. If I mess with the air mixture it does react by 1/4 turns, but it has always been set at 1-1/4 turns out and run fantastic. The slide has a sleeve and is one season old. New needle one season ago. Nothing has changed on the bike since I rode it last fall. I know it has to be something silly simple, but it eludes me. As many ideas as I can hear the better and thanks in advance.

Tim
 
Try some different plugs , good to try easiest first .

Gas cap venting ok ?
 
You dumped the fuel tank completey and washed it out ? Im sure you did but
do everything you can so you know that is one more thing it isnt.
One step at a time covering ALL bases.
 
Why is it always one of the first things I should check that I checked last? After going through about every option available I decided to change the plugs that were put in new last fall. So I put a couple new Champion N3C's in it and it fired up and idled down to about 600 rpm's w/o faltering. So I set the idle a bit higher and turned it off so I could enjoy the rest of my evening. I will test ride it in the morning. Thanks to those of you who threw out your ideas. It's always good to get some reinforcement so I don't feel like a total nut job. :oops:
 
It turned out not to be the plugs after all. IT ended up being the ground wire where it comes off the battery and connects to the frame. The nu and bolt were extremely loose casing the cut out at low idle. It also explains the spitting and sputtering I experienced on the short ride through town. Thanks to TimS for the old saying 90% of carb problems are electrical and vice versa. I rode it for a half hour at different rpm's and speed without an issue. :mrgreen:
 
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