Any motorcycle mechanics here?

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Drache

Drache

1971 Dodge Dart Swinger
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Having a problem with dad's bike. Engine was completely rebuilt by a shop in town. Bike is a '71 Bonneville Triumph. Anyways we have a problem with one spark plug always fouling up. Always the same one. Bike runs fine with new plugs, then one starts fouling and the bike starts running crappy. Talked to another mechanic and he's stumped. Looking for new ideas.

[ame="http://www.youtube.com/watch?v=ivUj6vALND0"]Dad and his Bonneville Triumph - YouTube[/ame]
 
Fouling with what?
Carbon
Oil

What color is the fouled plug?
 
A lot of factors to look at here...
Compression and leakdown tests to assure good cylinder sealing, and similar #s on both sides.

Ignition? You basically have two seperate ignition systems on that, once one side is properly set and timed, you have to follow up with the other side.

Have you ohmed both coils, wires and plug caps? Points in good shape?

Both carbs set up the same? As in both have the same jets, and similar settings on mixture and needle height? Have they been synchronized properly? You have to first get both slides adjusted to the same vacuum, then even up both cables to pull the same.

A lot of times those old Amal concentrics end up with a lot of slide/bore wear, as well as end up with out of round bores from overtightening.

Chilton has a great book on BSA,Triumph and Norton. One book covering all the twins.

Just some food for thought.
 
Exactly as was stated above......oil or fuel? Does it blow any blue smoke?

I had the same situation with an old Kawasaki triple I bought one time. One of the jets had vibrated loose from inside the carb and was sitting at the bottom of the float bowl. It would flood out massively in a matter of seconds.
 
cudavert said:
Exactly as was stated above......oil or fuel? Does it blow any blue smoke?

I had the same situation with an old Kawasaki triple I bought one time. One of the jets had vibrated loose from inside the carb and was sitting at the bottom of the float bowl. It would flood out massively in a matter of seconds.
Click to expand...

My Daughters bike did that out in the middle of nowhere, but it only has one cyclinder.:D

Probably took me 5 min to figure it out and 15 to fix it so I felt pretty lucky about realizing that was what it was.
Idled fine, but flooded badly when the throttle was cracked open.
 
It obviously has to be a carb or ignition issue for that cylinder....doesn't it have two coils?
 
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