Another One for engine miss sort of.

[saddlebum]

So the bike runs great for the first 1/2 hour. Then after that it starts to run rough and loose power like a partial engine miss But not as bad as if you were to pull a plug wire, leave it off and run it (Don't Ask). I used an adjustable spark tester and spark is good and strong. Carbs were just all rebuilt about a month ago and synced, which has been rechecked twice. Up until now the bike ran great with excellent fuel millage. Then all of a sudden it starts this. Shut the bike off and let it sit for a bit and once again it runs great for the 1st 1/2 hour and then back to missing or whatever it is.

[Squeeze]

My first Look would go at the Ignition Pick up Coil, if this checks out while testing after the miss startes, i'd look at the TCI.

[Marcarl]

My first Look would go at the Ignition Pick up Coil, if this checks out while testing after the miss startes, i'd look at the TCI.

I would then first take a look at the 5 wire plug on the left side of the bike, under the side cover to make sure all connections there are good. Squeeze is probably right but that connection has been known to create other problems, so maybe just an easy look.

[Squeeze]

Sorry Carl, but when you ohm out these five Wires, you probably look at the Connector and the Pins to stick the Wire leads in ?

 

:p

[saddlebum]

So I bit the bullet and tried 4 new plugs (marcarls idea) even though the one's in it where new and same plugs. So far its been running good and i am almost at the rally.

[greg_in_london]

Hope you got there. When I had similar problems 10-12 years ago it was what Squeeze said. The wires in the pick up coil were wired too tight as standard, so when it heated up the unit expanded and broke contact (eventually, it was nearly 20 years old by then). Mind you - if yours is an '89 - I'd have thought it was fixed by then. Mine was earlier, 1983.