Hey guys. What would cause a 49cc huasheng to lose power after warming up? Kinda a weird issue, too.. After running wide open throttle for about 10 minutes, running between 7200-7500 rpms, it just starts bogging down to the 6300 rpm range and wont let it get any higher, it starts getting really "jerky" feeling too.. when i got home i lifted the back tire off the ground and it revved right up to 9000rpms with no problems. It has the ezmotorbike q matic pacesetter transmission, and with the jerky feeling it was making, i was wondering if this could possibly be in that clutch? All input is welcome! thanks guys!
Huasheng losing power after warm
- Thread starter Jakeguy24
- Start date
Old Busted Hotness
Well-Known Member
Check the temp, it could be overheating. They like to run around 200 degrees at the cylinder head.
i took it out again this morning after letting it cool completely. I was able to get it up to 6800-7000 the first couple minutes but after that it wouldn't go above 6300-6500 for the life of me. numerous times throughout the ride i got off the bike and lifted the back tire off the ground, and it revved up to 9000rpm with no problem. numerous times. I get right back on the bike and i can barely get past 6000 now. This is all being done on flat, paved ground, no wind..
Old Busted Hotness
Well-Known Member
Question time:
1: How old is the engine. Lots of miles, or is it new?
2: What's your overall gear ratio? I have a feeling it's too high. No-load speed is 8500, ideally you'll be able to hit that wide open on level ground.
3: Most telling, what does it sound like? Wide open max speed (level) should sound like AAAAAHH (like it does when testing with the wheel off the ground). If it's going AAAWWW or OOHHH then it's fighting against the gear.
4: Related to 2 above, how's your takeoff torque? Do you need to pedal from a stop?
These engines (all engines, really) are naturally tighter when cold. Get an IR thermometer and check the temp at the cylinder head. After a full-load run you should be around 200-220 degrees measuring between the valves (that little fin-gap on the left side of the engine).
You really don't want to run full throttle all the time. They're a lot happier at half throttle. Gear down some and the engine will be able to hit its power band at 25-28 mph cruising at half throttle.
1: How old is the engine. Lots of miles, or is it new?
2: What's your overall gear ratio? I have a feeling it's too high. No-load speed is 8500, ideally you'll be able to hit that wide open on level ground.
3: Most telling, what does it sound like? Wide open max speed (level) should sound like AAAAAHH (like it does when testing with the wheel off the ground). If it's going AAAWWW or OOHHH then it's fighting against the gear.
4: Related to 2 above, how's your takeoff torque? Do you need to pedal from a stop?
These engines (all engines, really) are naturally tighter when cold. Get an IR thermometer and check the temp at the cylinder head. After a full-load run you should be around 200-220 degrees measuring between the valves (that little fin-gap on the left side of the engine).
You really don't want to run full throttle all the time. They're a lot happier at half throttle. Gear down some and the engine will be able to hit its power band at 25-28 mph cruising at half throttle.
Old Busted Hotness
Well-Known Member
And a good thought it is. If the exhaust valve doesn't fully close, you'll lose power as soon as it heats up.
hazmat
Active Member
get microdrill set and go up a size on your jet and check float needle paint likes to get stuck in there check oil and see if cylinder leaked gas in case and a valve lash thats all there is really
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