NEED advise on how to troubleshoot a over-reved HS 49cc 4stroke bike motor, please

[billybleu97]

I was cruising along near top speed cleared the hill started downhill when engine made a wierd noise and died. I'm a noobie and was unaware i shouldnt "full throttle" 75% of the ride. the motor will still start and idle fine - but if giving any throttle there is a complete loss of power and it mkes a bit of a rattling noise. where/what should i start looking or to determine what i broke.

 

[darwin]

There's been a few posts exactly like yours lately, clutch was the culprit. I would pull it apart and you'll probably find a spring or 2 have come apart in the clutch. When you use the pull start does it feel like grinding at all or unusual?

 

[billybleu97]

I HADNT NOTICED ANY GRINDING OR ODD NOISES . WOULD OVER REVING BE LIKELY TO CAUSE A SPRING MALFUNCTION? i know nothing about small motors. a friend of mine was leaning toward a stuck or broken valve/rod maybe?

 

[darwin]

It's easier to check the clutch 1st which is a known issue than to pull the motor apart. We're not there so your going to have to use common sense on where the noise is coming from. Clutch would be my 1st area of interest. if it's over reving it could be that the clutch isn't engaging. I don't know exactly what over reving means unless you mean 10k rpms or a crazy number. Those engines are recommended to not go over 8500rpms.

 

[billybleu97]

sorry i forgot to say thankyou for your help. while i have it opened up is there any greasing or other things i should take a look at. i believe i have a single chain trans - should i look into upgrading the trans or will it suffice.. I plan on riding on paved roads 30mi max trips to walmart for groceries and such. so it has to carry me (240lbs and prob 20lbs cargo as well) when it was runnning fine i was 290 lbs and it would get up to 32mph (stock kit no upgrades or tweeks) the only prolem i ever had was the chain poping off (willl be getting spring tensioner) and s**theads in cars who dont know how to use mirrors or turn thier head and open thier eyes(almost got flattened by a suburban) little road rash and some scratched paint, but no bigggie

 

[billybleu97]

my bad the engine isnt over reving i'm a dolt and ride with trottle full on.. i thnk i overreved the engine - full trottle down hill full speed then kaplut - she quit on me

 

[Chainlube]

Post a picture of your motor and we'll let you know what part to take off and inspect or post pictures of what's inside.

 

[billybleu97]

its a stock hau seng 142f 49cc. at the moment the engine is ina box at a buddys house. heading there later today to retrieve it.

 

[billybleu97]

i think i red somewhere overreving can cause valve to float/get stuck/get outta sink - is there a simpltons way to check for that....once again i only parroting what little bit ive read up - i may be totally way off of course