No Power after warm-up. '82 Urban Express
Posted: Fri Aug 16, 2013 8:57 pm
Just acquired this bike.
It starts very good.
It has good power when cold.
After one trip around the block, take-off is sluggish.
It will reach 30 mph on level ground.
Spark plug is tan and apparently pretty recent.
When traveling at 30 mph, and starting up a slight grade,
the bike will slow to 20 mph very quickly.
If the grade is steeper, the bike will slow even more, to 10 mph.
When traveling at 30 mph on the flat, the throttle is at 1/2 open.
Any farther open on the throttle, and the motor starts to loose rpm and sound
like it is increasing the air-flow, but not the fuel-flow.
I tested compression hot, with throttle WOT and showed 140+ p.s.i. with a reliable gauge.
I am suspecting some carbon build-up in the cylinder.
IS THAT condition likely to rob the motor of power to the extent described ?
I don't think the carburetor is the reason for this poor performance, but will be starting with a complete
dis-assembly and soaking just because i want to see for myself the status of the carburetor.
Your assistance will be helpful in finding the problem.
What are the items I should inspect while having the carb off ?
Please post any opinions and experiences regarding this scenario to help me return this sweet Urban back to it's full potential.
It starts very good.
It has good power when cold.
After one trip around the block, take-off is sluggish.
It will reach 30 mph on level ground.
Spark plug is tan and apparently pretty recent.
When traveling at 30 mph, and starting up a slight grade,
the bike will slow to 20 mph very quickly.
If the grade is steeper, the bike will slow even more, to 10 mph.
When traveling at 30 mph on the flat, the throttle is at 1/2 open.
Any farther open on the throttle, and the motor starts to loose rpm and sound
like it is increasing the air-flow, but not the fuel-flow.
I tested compression hot, with throttle WOT and showed 140+ p.s.i. with a reliable gauge.
I am suspecting some carbon build-up in the cylinder.
IS THAT condition likely to rob the motor of power to the extent described ?
I don't think the carburetor is the reason for this poor performance, but will be starting with a complete
dis-assembly and soaking just because i want to see for myself the status of the carburetor.
Your assistance will be helpful in finding the problem.
What are the items I should inspect while having the carb off ?
Please post any opinions and experiences regarding this scenario to help me return this sweet Urban back to it's full potential.