Tuesday, April 2, 2013

Engine Setbacks

After acquiring both dirt bikes, my plan was to use the case and engine internals from #1, the cylinder from #2, and the head from #2.  I knew #1 had been starved of oil, but the engine appeared to be in really good condition; better than #2's.  Remember, #2's had a 2" deep oil/dirt/grime sludge pool in the bottom of the case after living exposed outdoors.  However, after this weekend, it seems everything will be sourced from #2.

I began removing parts from #1's engine with the goal of having it out of the frame and on the bench by the end of the weekend.  The first part to be removed was the old piston since I wanted the connecting rod hidden from danger down in the case while I wiggled the case out.  So I go to remove the wrist pin clips but there are none, they have already been removed.  I push on the wrist pin with my finger, but it doesn't budge.  I grab the piston with my other hand to rock it back and forth while pushing on the wrist pin, but it doesn't rotate, it doesn't even move.  The piston is completely fused in place with connecting rod.  And that's when it hit me; when this engine ran out of oil, it wasn't just the head, piston, and cylinder that were punished by overwhelming friction, the internals were too.  The same internals I intended to use for my running engine.  Fail.

So the new plan is to use #2's internals and case with #1's stator cover (#2's is damaged).  Unfortunately, this means I will be splitting the case, not to replace parts, but to clean everything of gritty goo.  This also means I will be making that specialty tools purchase I was hoping to avoid.

To take my mind off the case and to make some progress, I went to work on the broken exhaust studs in #2's head.  I have been soaking them in PB Blaster twice a week for two months.  Those studs should come out with a Fischer Price screwdriver by now, right?  Not the case.  Not only did my left-hand drill bit not grab the bolt and break it loose with a satisfying "pop" that I expected hoped to hear, it didn't bore 1/32" deeper into the stud. So much for using an Easy-Out at this point.

A trip to work and a talk with one of the machinists who has taken special interest in this project yielded a solid carbide drill bit. After an hour of patiently making small chips, I have two 1/4" diameter, 1/2" deep holes where broken studs used to be.  Success.

(Before the second stud was bored)

In goes the new Easy Out, and out comes... and Easy Out with chipped ribs and no stud carcasses.  Fail, again.

So the new plan is to somehow fixture the head, overbore the stud holes, and Heli-Coil new M8 threads.  That's the plan anyway.

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