Post by mrpalmetto on Sept 21, 2015 10:28:13 GMT -5
I put a 180cc big block engine in. I installed an OKO 30mm carb. The scoot starts on a spark, idles perfectly and pulls great until I hit 45 to 50 mph. Then the pull stops, the revs go down and any more throttle makes it bog. I changed the main jets several times and the only improvement I got was yesterday when I removed the UNI filter and in would run much better and not die off both in speed or revs.
Everything about this engine runs great until I reach the one half to full throttle position and then the symptoms listed above develop. I went from a 130 to a 125 to a 118 to a 112 to a 108 main jet and have been reading the plug along the way. The best I achieved is a 118 main jet with the best performance with the UNI filter off. I hit 58 mph which is real good for a reverse trike with a windshield, but I know there is more left in that engine.
Why would it drop in revs and quit pulling at the upper range of the throttle and why does removing the air filter, which improves performance, contribute to my problems. Any help with any suggestions would be greatly appreciated.
The valves were set by the builder, so I didn't mess with the adjustments. If it starts on a spark, and pulls great thru the needle stage of the carb operation, could it be the valves. I'm really wore out and puzzled on this one.
Everything about this engine runs great until I reach the one half to full throttle position and then the symptoms listed above develop. I went from a 130 to a 125 to a 118 to a 112 to a 108 main jet and have been reading the plug along the way. The best I achieved is a 118 main jet with the best performance with the UNI filter off. I hit 58 mph which is real good for a reverse trike with a windshield, but I know there is more left in that engine.
Why would it drop in revs and quit pulling at the upper range of the throttle and why does removing the air filter, which improves performance, contribute to my problems. Any help with any suggestions would be greatly appreciated.
The valves were set by the builder, so I didn't mess with the adjustments. If it starts on a spark, and pulls great thru the needle stage of the carb operation, could it be the valves. I'm really wore out and puzzled on this one.
