357cc Blown Rod Revival

[karl]

Figured I would share to help save some motors from the scrapyard.

The engine is a 357cc 11-12hp "clone" MTD conglomerate engine that suffered a LOL. (lack of lubrication)

The engine has a 83 x 66 bore and stroke, so you cannot use any honda , or other clone parts. Just about everything is slightly different. Check the angle of the carburetor.

So I would need to buy a crank from MTD, that is not worth it.

Anyway I tried this old school trick and it worked great!

I wiped Muriatic acid, with a regular acid brush on the journal. I kept going for about 10min until all the aluminum transfer sizzled away. Some light scotchbrite and Its ready for service!

Wash very well, super corrosive.

Small engines dont use babbitt bearings, so the soft aluminum rod does not harm the crank much.

I wish I took a before pic, I thought It was scrap, so I did not bother.

I found a rod on ebay for $25, the total cost to revive this engine. Not too bad , this is my first big block clone.

If you try this at home please read the bottle, take all safety precautions, and use common sense.

 

[Flyinhillbilly]

We used to use muratic acid to clean the cylinders on out MX bikes when we’d stick a piston.
Never thought about trying it on a crank.

 

[bob58o]

And I thought it was only good for cooking up some meth?
Jk, nobody ever shared recipes while in jail. Lol

 

[karl]

Ill buff out, right?

It should make a full recovery.

 

[Flyinhillbilly]

Totally fixable

 

[karl]

Took a whole slice to get that dang bearing out!

The governor will removed along with the balance shaft.

 

[karl]

All better!

 

[karl]

Well I noticed a very small crack in the skirt of the piston, and the other side was chipped, so I haft to order a piston

Anyway I shall call it the 357 Magnum!

While I have it apart , should I turn the crank to 3/4 and run a 3D manual clutch, or use a sleeve and run a 40 series?

This will probably be used on a lighter go kart or minibike.

Also I want to use a different carb, any recommendations?

 

[karl]

Got the new piston in.

Just waiting on a head gasket.

Made a straight pipe, should run soon.

 

[65ShelbyClone]

Also I want to use a different carb, any recommendations?

Do you want to use an original-style or a slide carb?

I would suggest something in the 28-30mm range with a stock cam.

 

[karl]

Do you want to use an original-style or a slide carb?

I would suggest something in the 28-30mm range with a stock cam.

Slide for sure, I think Ill be going with a 28mm PWK knockoff. Yes, stock cam. Thanks.