Pit bike project (identification help)

[Chickenfried32]

I got this bike at a steal as it does not run. I’ve got fuel, spark and air but not sure on compression as I don’t have a attachment to fit the plug hole. Everything I’m reading says a bike won’t start with low compression and I’ve shoot fuel in the throat of the carb and in the plug hole and won’t even pop. I’ve pulled the numbers on google and have come up empty as far as what I have here.  The head is stamped with a E22 and the cylinder is stamped with 48cm with a “B” on the other side. I wanna rebuild the top end and want to ensure I buy the right parts. Any hints in pointing me in the right direction would be awesome.  Also, the adjustments on the rear shock, can anyone explain what that’s for? 

[jrhonda]

It’s a Honda crf50 all the year are pretty much the same parts
And the shock I have same one on my bike to make it soft go left to make it hard go right

[jrhonda]

Did you turn the ignition key on
It there on the right side of the frame by the front of the tank

[dirtbkr188]

Post up the frame VIN number located on the steering stem neck, it should be 17 digits long.

I can tell you that it is not an OEM Honda engine, that can be verified by posting up the engine VIN number, located just above the left side footpeg, stamped into the engine case.

[Chickenfried32]

Ignition key? There isn’t one. I have spark so I would assume if there was a key or a safety switch it’s on correct because I have spark. 

[Chickenfried32]

35 minutes ago, dirtbkr188 said:

Post up the frame VIN number located on the steering stem neck, it should be 17 digits long.

I can tell you that it is not an OEM Honda engine, that can be verified by posting up the engine VIN number, located just above the left side footpeg, stamped into the engine case.

 

[Chickenfried32]

I’m not seeing a frame VIN anywhere on this bike. 

[jrhonda]

It’s a Chinese beauty

[dirtbkr188]

The engine is a Loncin with a 39mm bore, or 48-49cc.

The frame isn't OEM Honda, there is no mounting tab for the CDI like the one shown above on the subframe.

[oldfart48]

have you check valves. Had similar honda or chonda engine set exhaust and inlet a .002 inch as a starting point, fired straight up

[Devin Thomas]

18 hours ago, Chickenfried32 said:

Ignition key? There isn’t one. I have spark so I would assume if there was a key or a safety switch it’s on correct because I have spark. 

You can have spark all you want, but something is refusing to let the engine run. On those small bikes they often come with a key or just an on/off kill switch. If there is no switch to be seen that means it’s missing one and the bike could be in constant kill. Check the wiring harness for any open plugs/wires.

[dan197man]

hold on folks he said he -HAS spark-  so that on/off arguement is a waste of time  ---IT IS TURNED ON----

said he has fuel and questionable compression  ,, any kind of compression would at least get the motor to cough or sputter

I agree with oldfart48  -check valve clearances and also cam timing ,, that motor is a honda 50 copy and really easy to work on 

if valve clearances are too open -meaning the cam never really opens the intake and exhaust valves ,

OR cam timing is off , such that the cam opens valves at the wrong time , that motor will never fire-up 

do a you tube search for checking valve clearances and cam timing on the honda E22 motor  it is easy 

they are ALL THE SAME 48cc-154cc as far as procedure , just differences in the amounts of spacing or timing degree

pay attention to the 48-54cc one they are what you have , dont be too judgemental against the chinese copies ,,

they are damn good xerox toys at 1/3prices ,,  the metalurgical quality is the biggest difference =cheeeeper $$$$$=

just gotta be smarter than your toyz

DDD

 

[Chickenfried32]

Pulled apart the head today and the cylinder walls, head gasket and everything is clean but the exhaust valve. Here are some pictures, maybe y’all see something I don’t. 

 

[turbo_bird]

Have you pulled the carb apart? Could be gummed up. The pilot jet especially is pretty tiny in these things. The one I had the float bowl was held on with special screws that the heads break off during assembly, I had to use my Dremel to cut slots in them to use a screwdriver. Low compression isn't too big a deal, mine had the engine seized because water had gotten in the cylinder and caused lots of rust and pitting. I cleaned everything up as much as I could, but the pitting was pretty deep. Still ran fine though. Check that the cam timing is right though, should be a mark on the cam sprocket that lines up with another mark on the head when the piston is at top dead center.

Kristian

[Old Fart Syndrome]

 

Check your flywheel key.  If it sheared then that is the problem. . . . .probably.

[bweighmaster]

Just looking at the valve adjustment caps ,  somebody has already been into it .   Valves need  .002 - 003 in .  Clearance .   I set the valve adjustment when the oppisite valve is fully open at it's highest point .  

[Chickenfried32]

6 hours ago, Old Fart Syndrome said:

 

Check your flywheel key.  If it sheared then that is the problem. . . . .probably.

If they key is sheared the fly wheel wouldn’t be turning, right? 

[dirtbkr188]

32 minutes ago, Chickenfried32 said:

If they key is sheared the fly wheel wouldn’t be turning, right? 

Not necessarily, the taper of the crankshaft would still hold the flywheel in place after the nut is tightened, but the flywheel would still be able to slip while in place.

Valve adjustment of .002" for intake and .003" for exhaust is the correct setting, but it is done with both valves closed and the engine cold.

Edited September 23, 2019 by dirtbkr188

[Chickenfried32]

3 hours ago, dirtbkr188 said:

Not necessarily, the taper of the crankshaft would still hold the flywheel in place after the nut is tightened, but the flywheel would still be able to slip while in place.

Valve adjustment of .002" for intake and .003" for exhaust is the correct setting, but it is done with both valves closed and the engine cold.

Have no problem there with the engine being cold as it’s never fired yet. I’ll check the to see if the key is still there tonight when I get home. 

 When I had the head off yesterday everything looked great inside, no wear on the walls, piston looked great and a perfect head gasket. As I was putting the timing chain back on I started thinking if I turn the cam sprocket to where the screw hole align I would have 3 different settings.. is that making sense at all? At what position should the can be when I align the 3 screw holes? 

[sbest]

I've worked on these engines. Not exact copies of a Honda. Things like piston rings and valves can be slightly different dimensions from Honda so Honda parts may or MAY NOT work. I bought a pit bike for the kids cheap for the exact same reason as OP. New piston rings were $9 from a Chinese bike dealer and solved the problem. Ran for years after that. 

Too bad you didn't test the compression before disassembly. Below 110psi is "well worn" territory. If you are under 100psi it is very hard to get started and under 70psi it won't even start on a push start. Put some compressed air into the cylinder with a sparkplug adapter and listen for where it leaks.