Toasted rod. Crank salvageable?

[LightningTeg]

Engine started knocking one day. I think it was from not properly breaking in engine from the get go. The oil changes always seemed to have a metallic sparkle.

Anyways, the rod is toast. But what do you think about the crank? I’d really like to take the cart on vacation to an off-road park in Kentucky next week but I can’t find a stock crank for a 420. Rods are cheap however. Think it would hold up for a day of riding if I just got another storod ($15) and slapped it back together? I can probably get it on the lathe at work and throw some emory cloth on it to clean up the light scarring and just run some thicker oil.

 

[mckutzy]

Id say try it and see...
Check with stock and Measure to see how out yours is, compare the difference..

 

[karl]

The rod is soft aluminum, so the crank usually is just fine. I use muriatic acid to dissolve the aluminium transfer off the crank, once fizzled away, hit it with some fine scotch brite, hope for the best.

 

[vpd66]

Take some fine emery cloth and clean up the journal. Then get a micrometer and measure the journal for taper and to see if its out of round. There should be service specs for the journal size. The main thing that will cause it to fail will be too much clearance between the the rod and crank journal.

 

[LightningTeg]

Went ahead and ordered another rod. I think with some cleanup it’ll last until I can get serious about rebuild.

 

[chimmike]

Yeah, crank looks fine, I don't see any scoring in the journal. I wouldn't use anything abrasive to clean the journal personally. Paper towel and some b12 chemtool.

 

[LightningTeg]

Rebuilt everything, cleaned the motor real good and built a new exhaust pipe.

WOW. The exhaust change made a massive difference. It runs so good now.
Basically went from the 1” (21mm ID) that came with the stage 1 kit from go power sports to a 1-1/4” (29mm ID) and RLV muffler.

 

[landuse]

Nice going!!