250 big red engine help????

[sinopz]

Hello everyone, I have a few questions regarding my 250 big red engine, anyways I bought this engine a while back and polished it up to throw into my trike, it started and ran fine but it smoked like something sick and ticked pretty bad! So I took the top end off to swap piston rings and timing chain only to notice a bottom half of my piston has cracked off, I found a decent size peice of it in the screen down in the bottom. I wiggle the crank arm to check for play and there isn't any what so ever, but if I grab the right hand side of the crank I can feel a little budge,but hardly any to notice, so my question is do you think this engines junked although it ran fine? Should I work with it or toss it? Thank you in advance!!!

[aramid]

can you post photos?

if it ran fine before, it will run fine again.

the noise could be from piston slap especially since the piston skirt is broken or from too much clearance on the rocker arm.

it is also possible that the cam is going flat . . if the cam looks perfectly smooth on the top of the lobes it is likely ok.

i would guess the cylinder is worn enough to need a rebore . . you can measure it to see.

put carb cleaner in one port at a time on the cylinder head then look at the valves . . it it is wet around the valves, they are leaking slightly.
.

[sinopz]

These are a few pictures I took, I assumed it was the timing chain making the sounds because even with the adjuster pushed all the way in, I could probably of knocked the chain off with my fingers lol,and I'll try that with the valves! thanks for the reply! Any more info would be greatly appreciated!

[thcowboy]

Yeah if your a good enough mechanic do the crank bearings and just put in a new piston

[Ragar]

That Cylinder Isn't looking healthly at all from those pictures.
Can you feel the scored areas? at the very least It needs a hone, if not bored and honed.
The hard coat on that cam is gone. you can see where the bare metal is corroding due to the lack of the hard surface.
If the oil had a metallic flake to it, your bearings will need to be replaced due to contamination.

[prometheus]

I agree with Ragar. Personally I would bore the cyl and that cam def needs to be replaced. If it's not already going flat it will be soon. Sounds to me like it's hot rod time. Step up the wilder cam and a dome piston, presto you'll have a nice souped up engine. If I have to tear an engine apart I never like to put it back together stock. May as well upgrade while your in there.

[Jmoozy27]

Another member Mickey Dunlap offers 349cc big bore resleve for the 250es/sx.

http://www.3wheelerworld.com/showthread.php/172208-Big-Red-250es-250sx-349cc-big-bore-kit