Post by thecableguy on May 26, 2016 7:23:40 GMT -6
Here's a good one for ya. My scoot is an Icebear PMZ150-3C scooter (2 wheel) with the standard 150 GY6 clone engine.
Here's what happens. Sometimes, once it is fully warmed up, I'll be traveling at high speed (40-45 or higher) and it feels like an invisible hand starts applying the brakes, enough to slow me down 5-10 mph pretty quickly. If I slow down, it will return to normal running, but once it starts happening, any time I speed back up it'll do it again. The motor doesn't drop out, but the RPMs do decrease as I'm slowed. There is also no sound associated with this happening, no scraping, squealing, no change in the engine note.
The scoot runs great, pulls hard to 50~55, top speed about 60 on the flat @7500 RPM when this is not happening.
Things I've done to the scoot since it started happening, both to try to fix it and general upgrades:
Emissions delete
Hoca variator and 10G sliders
Gates belt
Yellow contra spring
Inspected clutch
58.5 BBK including new head and cam
New carb and intake/air filter with 38 pilot and 120 main
Manual petcock and larger fuel filter
Replaced all fuel and vac lines
Performance exhaust
Set, checked and rechecked valve gap .004 both
New tires
Inspected brakes front and rear
Several different CDIs I'm now running the Casoli from tvnacman (Thanks John!)
New coil and plug wire
NGK Iridium plug
New tires
Engine oil and gear lube checked and changed as needed
I thought I had it fixed this spring with the carb and BBK/head/cam install but it happened again last night after a long ride, as I was on a 45 mph road nearing home.
Could this be valve float? Hard to believe that problem would follow even after changing the head and cam.
I'm at my wits end here...
Jim
Here's what happens. Sometimes, once it is fully warmed up, I'll be traveling at high speed (40-45 or higher) and it feels like an invisible hand starts applying the brakes, enough to slow me down 5-10 mph pretty quickly. If I slow down, it will return to normal running, but once it starts happening, any time I speed back up it'll do it again. The motor doesn't drop out, but the RPMs do decrease as I'm slowed. There is also no sound associated with this happening, no scraping, squealing, no change in the engine note.
The scoot runs great, pulls hard to 50~55, top speed about 60 on the flat @7500 RPM when this is not happening.
Things I've done to the scoot since it started happening, both to try to fix it and general upgrades:
Emissions delete
Hoca variator and 10G sliders
Gates belt
Yellow contra spring
Inspected clutch
58.5 BBK including new head and cam
New carb and intake/air filter with 38 pilot and 120 main
Manual petcock and larger fuel filter
Replaced all fuel and vac lines
Performance exhaust
Set, checked and rechecked valve gap .004 both
New tires
Inspected brakes front and rear
Several different CDIs I'm now running the Casoli from tvnacman (Thanks John!)
New coil and plug wire
NGK Iridium plug
New tires
Engine oil and gear lube checked and changed as needed
I thought I had it fixed this spring with the carb and BBK/head/cam install but it happened again last night after a long ride, as I was on a 45 mph road nearing home.
Could this be valve float? Hard to believe that problem would follow even after changing the head and cam.
I'm at my wits end here...
Jim
