Author Topic: Any CT90 experts on this forum?  (Read 1130 times)

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Offline motorhead55

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Any CT90 experts on this forum?
« on: March 14, 2009, 08:06:12 PM »
I got a good one. First, I have worked on Hondas for 43 years with my first being a Sport 50 C110.
I have a real problem issue right now with a 1970 trail 90. Background: The bike was rebuilt 1000 miles ago with bore and new piston, New valves and valve job, carb rebuilt, and clutch replaced. It has run great until reciently. I was riding it home the other day and on throttle, it slowed and felt like it was siezing. I thought maybe something might be in the carb abd leaning it out. Carb was spotless inside, fuel flow is excellent from the tank to the float bowl. I tried another test. I ran it up into 4th and when it started to slow, I shut off the gas and immediately stopped. I opened up the float bowl drain and waited until the fuel all drained out. It took 30 seconds or so, so I know that the carb is NOT starving for fuel. What is wierd is that the engine will bear down to almost a stall in fourth gear. I can push the shifter forward to disengage the clutch without letting off of the throttle. The engine won't pick up speed until I let off of the throttle and open it up again.
Well today I pulled the top end off expecting to find a gauled piston...No such luck! Piston looks good, valves look good, crank and rod feel
fine. Could this be an ignition issue? I was wondering if a condensor was bad or the charging system was somehow feeding the coil AC instead of DC. The engine doesn't miss, it just drags down. Any help MUCH appreciated!
1976 Honda 550F bought new in 1978
2006 Yamaha TW200 TrailWay
1967 Triumph 200cc Tiger Cub
2007 Dodge 5.9 Cummins Diesel, 6spd. Stick, 4X4
1955 European Spec VW Bug, 1700cc engine, Porsche 356 "A" brakes
1939 Willys Pickup
2003 Kubota B7400