Need help with Yamaha Chappy

[sdchronix]

So I recently bought a Yamaha chappy lb50 and am having a few issues. It runs fine at anything under 1/4 throttle but anything more and it bogs and wants to die. it won't pull me up even the smallest slope. If im going downhill I can pin it and it runs fine.
It does this both in Low and Drive. The carb has been cleaned. I ordered a new spark plug but haven't gotten it yet.
It seemed that it was just dumping oil into the motor so I bypassed the oil pump for now and just mixed the gas. The air filter was horrible so I have an aftermarket one on there for now until I can get an OEM replacement.
Any advice?

 

[low_rb]

Ive never had one of those but ive had verry similar issues on other bikes.

PW50 i recently got wouldn't run right, had a new carb and cables put on it by previous owner trying to sort it and it was the choke cable being to short(cheap chinese thing)

LT50 the exhaust port was 3/4 blocked with carbon build up

 

[my67xr]

Welcome to Minirider's

Make sure you drop in here and introduce yourself.

What ratio fuel/oil are you running in it ?
eg; how many ml's oil to how many litre's

It sound's similar to my LB80 Chappy when i first got it running, it made sort of a booowaaah noise and was slow to go through the rev's.
My bike had been sitting unused for year's before i got it and the fuel bowl and jet's had gummed up.

I think your's may be a bit lean in the top end.
Did you strip the carby right down, with the jet's removed, air screw, and emulsion tube all removed?
Then you need to soak the carby in something like Yamaha Carburetor Cleaner dip overnight then give it a decent blow through with compressed air ?
The jet's need a good soak and then poke a thin strand of copper wire through all the hole's to make sure there isn't any gum restricting the hole's
The pilot jet has small hole's across it, and so does the emulsion tube, make sure they are open
Also check the small hole is open at the bottom of the thread's where the pilot jet screw's into in the bottom of the carby.

There is a link below in my Signature to my Chappy build

Cheer's, Craig

 

[headsmess]

"dumping oil in engine"..."now mixing"

i assume its a two smoker with oil injection?

did you block off the oil pump line to the carb? make sure it isnt leaking, cause thats a 2-3mm hole in the side of your carb.

but, it definitely sounds like carb issues.

^^^everything he says above^^^^

check emulsion tubes, it never hurts to pull the carb apart again, try taking the main jet out altogether just to see if it runs without it (should cough and splutter and wet the plug if everythings ok when given full throttle. dont expect it to rev!), make sure the needle has the e-clip securely attached, um....

make sure the bowl vent is open and breathing.