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Categories: all aviation bicycle gadgets misc motorcycle theater Sun, 28 Mar 2010This has definitely been the Weekend of Motorcycles. The first race of the season is coming up next weekend, and the race bike had been essentially ignored all winter. I'd put it away with vows to do a bunch of stuff "over the winter," and of course, nothing came of that. Well, that's not entirely true, but nothing happened until this weekend, which makes a pretty poor showing of "over the winter." As I've mentioned before, I made up an adjustable camshaft last fall, and then left the project to sit for about 6 months as other bits of life intruded. Finally, a month or so ago, that camshaft made it into the street CL175, and I've been riding it around. However, piston ring problems have plagued me, and so I don't really know if it made all that much difference. Well, I'd reserved time in my schedule this weekend to work on the race bike. The main thing I wanted to do was to put new tires on, which I accomplished in a surprisingly short period of time on Friday evening. Faced with the remainder of the weekend, it occurred to me that I actually had time to swap that camshaft from the street bike to the race bike. Heck, I needed to take the street engine apart again anyway, so why not kill two birds with one stone? The point of the cool new camshaft was to put it into the race engine anyway. So, out came one engine, then the other. I'm getting really good at pulling engines from CL175s, I must say. Lots of practice. The head came off the street engine this morning, and I went through the procedure of degreeing the cam on the race engine -- it's potentially different for every engine, so you have to check. As it happened, the cam as set was working out to 104.5° or 104.75°, which is so close to perfect (in theory you want it a tiny bit advanced for race use) that it wasn't worth changing anything. Of course, it wasn't as simple as all that. In the process of pulling things apart, I discovered problems that had to be solved, notably a dent in the cylinder head that was right on the border of the right combustion chamber. There were actually scorch marks on the head where hot combustion gasses had escaped, and I'd found soot outside the engine right there earlier. That required about an hour of patiently swirling the cylinder head on top of a piece of sandpaper on the granite surface plate I picked up over the winter for exactly this purpose. Life got a lot better once I figured out how to tape the sandpaper down so I wasn't trying to hold it with one hand while grinding the head with the other. As long as I was at it, I also removed the brittle, ancient gaskets from the cam-end bearings, a process that took way longer than I had hoped. However, this will hopefully cure that head of its oil leaks without resorting to sealant goo like I did last time. The sealant goo was perfectly effective, but I was worried that it might be clogging vital oil passages. Earlier, on Saturday, I'd actually pulled the head off a spare engine to swap it on to the race engine, and reworked its valve seats. Then, of course, I discovered that one of its sparkplug threads might be stripped, which would have complicated things unnecessarily. The reason for all this head swappery was that my original race head, due to a communication error with a machinist a couple years ago, has the wrong size sparkplug holes. This rendered one of the special tools I made useless, so that I couldn't set up the fancy new cam. Anyway, today was spent almost entirely standing in the garage, making slow but steady progress. The new race head (which was formerly the head from the street bike) has been beautifully reworked: it's newly very flat on its sealing surface, it has newly cut valve seats and new valves, and the cam-end bearings have new gaskets. This combined with the known-good rings of the race engine should make for a respectable engine. I hope I can get it out to the dyno before the race, just to see what changes I made (I took it to the dyno last fall to get a baseline). I wrapped up my work this evening around 8:45, and decided judiciously that although technically still legal, firing up my mega noise machine late on a Sunday night was probably not the best way to keep my neighbors happy. Still, it was nice to get the race bike completely back together this weekend, and know that I don't really have anything outstanding I need to do. There are surely things that it still needs, but at least it's back together, and I don't have any more work ahead of me than I did before the weekend started, and the bike is at least theoretically in better shape. It was a good weekend, although I'm ready to not stand for a while. Posted at 22:56 permanent link category: /motorcycle Categories: all aviation gadgets misc motorcycle theater Written by Ian Johnston. Software is Blosxom. Questions? Please mail me at reaper at obairlann dot net. |