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TBS - Poor acceleration, sputtering.

6067 Views 7 Replies 4 Participants Last post by  daytonacharlie
This one has me stumped and I think I have an electrical problem. I could use some help...

I have owned this bike since new and have 22,000 maintained miles on it. The bike ran great until about 100 miles ago. I originally attributed the condition to poor fuel: Poor acceleration, bucking from about 2500 rpm to 4000 rpm. Weak power. To start, this occurred when the bike reached operating temp, but now it's all the time.

I pulled the plugs, they were about 12,000 miles old and all three were heavily sooted and appeared gas fouled. They were all identical in appearance. Assuming a rich condition, I cleaned the air filter (K&N) and checked the choke adjustment. At that time, I inspected the inside of the carbs and all appears clean. The fuel has been replaced and a shot of Lucas Fuel System cleaner was added thinking there may be deposits to clean out.

The second set of plugs were gas fouled in less than 10 miles and the bike is worsening. The bike has been on a Battery Tender, so I am sure there is 12 volts at the battery.

If it were a lean condition, I would start looking for vacuum leaks. That is how it is behaving. But the plugs tell me rich fuel or low spark. I haven't made any adjustment to the carbs and the airbox and filter are unobstructed.

The next step is to start digging into the electricals (coils, etc.) I am concerned that my issue may be in the charging system. I'll check that with a voltmeter.

I am not familiar with the ignition system on this bike. I have hotrodded small block Fords for years so I understand the principles.

If anyone has a place to start, I would appreciate it.


[ This message was edited by: Singlefin on 2007-01-04 21:20 ]
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I'm betting that it's your coils, very common problem with T3 Triumphs. Same thing happened to me, replaced the coils, cured the problem.

good luck,
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