Sunday, May 1, 2011

The Art of Motorcycle Maintenance

I was planning a nice long ride for the weekend. Got a plan, got an iPhone tracker software to mark my route as I go and take pictures, set up alarm clock at 7 and was hot and ready to go by 7:30. But ... decided to remove excess oil which I slightly overflew on Thu. Went down with the wrench, turned the oil plug... and busted it. Busted the oil plug hole in a crankcase. It's so shameful I can't even tell what I did but I had to tell it to bunch of different people today so: I was just turning the bolt the other way all way long till the whole threat went off. My mind was still sleeping, or cross-wired, or something. Shame. And shit. This is a hard one.

Shortening the long story of browsing internet, all auto-parts and hardware stores in San Jose - from 9am to 4pm, hearing opinions, panicking, talking to so many people, learning tons, thinking hard, computing the crazy diameters, threads bolts and taps between metric and imperial - after all day of running like a chicken with the head cut off, I get my bike fixed by midnight. And generally enjoyed the day. Well we'll see tomorrow - I hope it gets fixed.

Tech details (feel free to skip to next paragraph) - Vulcan 800 has M12-1.50 oil plug bolt. Bolt is all fine but the thread on alluminum crankcase is totally stripped. Options: 1) oversized / self-tapped bolt (haven't found the right size), 2) helicoil repair kit ($80, they got M12-1.25 and M12-1.75 but not 1.50), 3) rethread for a larger bolt and 4) change the crankcase. I bought the repair manual to see how to take off the crankcase. Manual said "take off the whole engine". Ok, not easy. And helicoil not easy any more: to drill for it the bike needs to go up, and it takes a serious lift to get it high up. No luck finding oversized bolt M12-1.50. Then I though a) oversized bolt is no better tap the hole and install normal bigger bolt b) helicoil is only better to get original bolt, but in this case who cares. After long computation for inner diameters, taps, threat sizes, etc, I went for 1/2''-13 imperial bolt which I found in OSH along with the tap. Coarse threat is good for aluminum, inner diameter is almost identical (no drilling), 0.7mm extra metal to hold, threat step doesn't quite match, well ok. I was not sure about few thing: it's longer, not as flat as the factory one, and head is larger so it may not leave the space for the socket to screw it. Looked at the repair manual to see what is inside. Crankshaft, looks like enough space for extra 5 mm. Got aluminum and metal-rubber washers - put the two together. Enough space for the larger socket - great. Tapped the thread carefully - oil is still running so lubrication comes for free. Turn back each 1/4 turn. Put it all together, tightened the bolt, put the oil in (waw it takes so much oil more then the manual says where does it all go?) Ran the engine for few minutes, and set it in the garage to see if it leaks overnight.  Yeah I didn't know all these sizes taps threads and stuff, but store after store and shop after shop the empirical experience came together into a logical model. This smart guy has all the thinking and formuals, and go here for sizes:

As a by-product I built a motorcycle lift, as per this spec. With inflation the cost of this project came up to almost 50 bucks - ok I'm cheating I bought the drill set.

Ok now it's time to relax, wind the alarm for 7 Sunday morning and hit the road tomorrow. No screwing with the bike in the morning any more.

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