Woow i need help somebody post a reply!

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#1
K i got a 50cc fourstroke horizontal engine in this lil bike i got its like a panterra or somthing small like that. so we took it completely apart and put new rings in it and now when i start it. It runs but it makes a loud ticking noise sounds like somthing hitting somthing i thought it might be the valves hiting the pistion but i dont no if thats possable. Im completley stumped can somone please help me :bang:
 
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Papakeith

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#2
Wesley, I'm going to move this to the repair forum. You're likely to get a better response from people over there.
My WAG would be that your cam timing is a tooth off and in causing some interference between the pistons and the valves.
 
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#3
thanks

okay all give that a shot thanks for movin it for me lol i dont really know how to use this forum i just joined today. so you think i should just spin the cam sprocket back a lil bit and put the chain back on? would that make sence to you? cause it almost sounds like the valves are hitting the piston.
 

Papakeith

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#4
I would suggest you get a manual and learn how to time your engine properly. To just
spin the cam sprocket back a bit and put the chain back on
is a recipe for disaster. If the valves have hit the piston they are now bent and will need to be replaced.
 
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#5
It runs

thanks for your help. i spun the timing chain back one so it was at top dead center. It runs perfect now theres no knocking noise comming from the engine anymore. but now theres a nother problem lol it doesnt want to acelerate. when its at idle it revs up normally like it should but soon as i put it in gear it doesn't speed up it bogs down. i think it might be a dirty carb or somthing what ever you think im lookin for info so that would be great. thanks for helpin me get rid of that annoying noise tho lol :nod:
 

Papakeith

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#6
:bang: :bang:

The lack of power might be due to the valves failing to seal when they close.
 
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#7
I'm with Papakeith on this if that is an interference engine (wich im pretty sure it is) then if the valves hit the piston there bent I/ve seen valves hit pistons on many engines and still run but the valves were bent and had a tremendous loss of power. when that valve hit the piston :bang: and put a slight bend in the valve stem when it closes it is not going to seat/seal properly causing compression loss (the enemy of a strong motor) and since there is not much of a load w/o it in gear it will run fine but when you put it in gear you have created a load and the engine is not powerfull enough to get ya going. that being said i wouldnt run it anymore as further damage may result in a extremely damaged head.

remove the valves and roll them on a flat surface or take the head to a machine shop for inspection also inspect the piston w/ a bright light to check for marks/crack

good luck let us know how it goes
~Brian
 
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#8
Papakeith said:
I would suggest you get a manual and learn how to time your engine properly.
Good luck with that. Chinese knockoff bike. Better to spend a $1.74 on a cup of coffee and apply the rest towards saving for a name-brand bike sometime in the future.
 
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#9
it works :D

thanks all you guys for your advice. the bike now runs perfectly it was just the airfilter i put on it it was aftermarket and caused it to suck to much air and not enough fuel so i just put the stock one on and it runs fine now. it leaks oil tho lol thats the only problem now. gotta remember its a china bike lol. now my plans are to take that engine out and store it just incase i blow my new one up. im getting a 90cc engine to replace the fitty its got manual clutch and everything. also im gonna put exaust and intake and paint it and stuff its gonna be a sweet lil bike all put some pictures up when im done :)
 
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#10
Sounds fun. My son-in-law has a 125 big pit bike that is a lot of fun until it wears out my rear end in about 20 minutes. I need to get skinnier or he needs to get a softer seat on it.
 
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#12
No i didnt it was a peice of crap filter that came off a pocket bike lol and i thought i might try it but it didnt work. would that have made a diffrence if i oiled it?
 
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#13
oil is going to restrict flow to some point and if the filter is designed to be oiled then I would say yes it would help, but if its off of a pocket bike it may not be designed for oil treatment since it is not a offroad bike.

you could try where you got the bike or try to match it up w/ another bike brands filter at your parts store that can be oiled. the oil really helps to keep the engine clean I use PJ1 but i have been hearing more and more about the ease of use w/ NO-TOIL

~Brian
 
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#14
Most of the ones I've seen use a pod type air filter. Usually pretty easy to find at a Cycle Gear store or online.