Huskyjunk.com :: 250 Mag Restoration

Welcome to the Huskyjunk.com Step by Step 250 MAG restoration project.

Step 3

In this step we have installed the engine. A true 1974 250 mag engine will have 2033-xxxx as the ID number. Our engine number is 2033-1245. It is easier to install the engine without the head and cylinder, it is smaller, lighter and easier to move into place without scratching the newly painted frame. We have taken this opportunity to do some performance mods while rebuilding the engine. This engine rebuild was fairly simple since the engine we used was not completely trashed but in pretty good shape.

On the inside, we split the cases and installed the following brand new parts; crank seals, crank bearings, Rod, Wiseco piston (137 P6 1.50mm), clutch plates and gaskets. After we bored the cylinder for the new piston we cleaned and matched the ports with some extensive porting on the intake and exhaust areas. We also shaved 20 thousandths off of the head for increased compression and horsepower. All of these mods done together will make a noticeable increase in performance. The original mag head was traded for a 75-76 GP radial head for better cooling and lower profile. They just look cool too.

On the outside, we cleaned it up and applied 3 coats of high temp semi gloss black engine paint. We replaced all of the old case and side cover screws with new stainless steel socket head cap screws and washers. Next we bolted it into the frame with new stainless mounting bolts and nyloc nuts. To round it out we installed the aluminum case saver, new kick lever rubber, new ML series rubber steering stop bumpers, new 10 tooth countershaft sprocket, Splitfire SF406C spark plug and new tranny case breather hose.

It is all bolted up and looking good now. MAN, THIS IS FUN !!!