Monday, January 11, 2010

MKII in the Time-out corner

After seizing up my Magnum and taking a 2 mile walk of shame home in November, I sat my MKII in timeout, which is an excellent opportunity for a moped to think about what it has done, as it gets to watch the other mopeds go out for rides, while it has to wait to be fixed. The time has come for me to reclaim my title, so I brought the engine inside. After the seize, it came unstuck easily, and this was at least the 3rd seize on this cylinder. You may recall when I put it together last year, the piston was having clearance issues in the rear of the skirt. I sanded the skirt enough to let the piston drop clear of the exhaust port, but it still wouldn't fall out of the skirt. I decided to run it anyway, and at least one of these seizes are the result of too tight of a clearance in the skirt. and you can see some of the awesome drag marks of melted ring smeared across the piston. It took me about an hour of gently prying, cleaning and sanding to coax the piston back into run-able condition. A bit of heavy sand paper and some lighter polishing paper let that piston drop right through, and the rings have been liberated from the grooves, and are once again, springy. A fresh hone of the cylinder, a nice coat of Amsoil and I'll be back on the road in no time. I am going to powder coat my exhaust and intake since I've got them off the frame. No after pictures today though, sorry. Just look for me at the front of all the other Metra80 magnums.


-T said...

Piston should fit better without the rings on it. Give that a try. Best of luck!

gaber said...

markryan and i are about to start up our own battle of metra 80s, i'll have to give that ringless piston trick a try. thanks for the tip travis!

Anonymous said...

I have to put my bike in time-out all the time. little jerk just wants to act up.