Jr 80 Advice

[joefish]

Hey fellas , new here so gday .

I have a 02 jr 80 , it runs good for 10-15 mins then loses all power , also it sprays oil out of the exhaust . Is it possible i can cut the oil to the fuel and just use premix as i think it may be not mixing right ?
Any other ideas that may help my son enjoy this bike for a bit longer ?
Cheers fellas

joel.

 

[sean01]

hi..
are you keeping an eye on the gearbox oil?
its been a while since i seen a jr80 but from memory they run a normal type 2 stroke engine..

anyways what im getting at is when 2 stroke crank seals are dead (gone hard or damaged) the engine will draw gearbox oil in past the seals under engine vacuum.. as a result your gearbox oil level will be less and less every ride...

is it also hard to start.. im guessing so with tht much oil in the cylinder

 

[Doc]

Joel, I have a feeling the bike has a blocked/choked exhaust or exhaust port in the cylinder. Whip off the pipe and have a look in both the pipe and the cylinder where it bolts up. Chances are you'll find it all but blocked with carbon build up causing an excessively oily exhaust residue and an engine that will overheat and lose all power after a short time. Hope it helps. Doc

 

[largey]

I agree considering it is a 2 stroke prob oiled up from some slow riding check exhaust and give it good hammering for bit to burn up any excess oil

 

[The_GDFP]

The oil pumps are pretty reliable. Using a decent brand, made for such use? Verify adjustment? Agreed, on checking the pipe and port for choked-up-ed-ness. Especially #9. Right crank seal requires case split, so hopefully it isn't sucking gear oil.