Categories: all aviation bicycle gadgets misc motorcycle theater

Tue, 02 Mar 2010

A milestone is reached

As I mentioned in the previous post, I made myself an adjustable CL175 camshaft last fall. That must have been around October. In order to do that, I pulled the camshaft from a spare engine I had, and did the modifications, cutting down the sprocket and pressing on an adapter flange.

Around the same time, I realized that my street CL175 (as opposed to the race CL175) was making these odd, and somewhat disturbing clanking noises at idle. It sounded like a loose cam chain, or loose valves, or something. I adjusted the valves, and adjusted the cam chain, but all to no avail. I knew I wanted to test the adjustable camshaft I'd just made on the street bike, so this seemed like a perfect confluence of events: tear down the street engine to look for the rattle, and reassemble it with the new camshaft installed.

That way, I could make mistakes on the street engine without imperilling the race engine. I have another street bike, so it was no hardship to do without the street CL175. I don't have another race bike, and if I messed up that engine, I would be unhappy. It turned out to be a good choice, as I ended up bending one of the valves as I was working on the street engine; the street engine has old valves, while the race engine has new valves. I would have been annoyed indeed to make that mistake on the race bike.

The problem, of course, is that life (in the form of holidays and theater) got in the way. I found that between Thanksgiving and the end of this last run of shows a few weeks ago, I just didn't have time to work on the project. What little free time I did have was dedicated to things like sitting still for a few minutes, or going to bed before midnight, or occasionally collecting the terrifying dustbunnies around the house and introducing them to their new home in the circular file.

Finally, though, all the shows ended, and I've been able to pick up the project where I left off. The last few days have been full of engine work. This morning, I was mysteriously awake two and a half hours earlier than normal, so I decided to seize the opportunity and work on the bike. I was close to done, and it was just possible I could finish it this morning.

As I continued work on the project, I realized that I just had two major tasks left: reconnecting the exhaust, and reinstalling the gas tank. Both of these things are fairly simple to do, and by around 8:45, I had the bike completely reassembled, adjusted, oiled, gassed up, and ready to go. I kicked the motor over a few times to get the oil system primed and pumping. Then, it was the work of mere moments to flip on the choke and press the go button.

Lo and behold, after a few cranks, it fired up, and ran as if nothing had happened! It's just as finicky about starting as it was before the teardown, but I can't say I'm entirely surprised by that. I ran it through the initial 10 minute "Do nothing but idle" phase of Duke's break in method from the Ninja250 board. I'll have to modify it for the CL175, in terms of target RPM, but that's the basic method I'll be following to break in the new rings.

It was a glorious feeling to finally have this long-stalled project going, and working again. I can't wait to go home tonight and start riding it again. I'm sure there's more work to be done to get everything set just right, but the correctly aligned camshaft promises noticeable improvements in power and economy.

(Man, you can really tell the difference between the real camera and cellphone camera pics, can't you.)

Update: It's been pointed out to me that I left my handful of readers hanging! Did I find the rattle? Well, maybe.

As I tore the engine down, I was discouraged to find that there really wasn't anything that should be causing the rattle. It sounded like it was coming from the head, which is why I was thinking valves or cam chain. It all looked about right as I took it apart.

When I reassembled the bottom end, I did discover that one of the oil baffles under the crankshaft (which are held in place with spring tension) was loose. I bent it a little bit so it'd exert some pressure against its retaining pin, but that was the only thing I found that was a likely source of rattling inside the engine.

As I was reassembling the whole thing today, I ended up inverting the muffler a couple of times, and noticed a very loud clanking coming from it -- apparently one of the internal baffles has come loose. That's even less likely to be the source of the rattle, but it was pretty loud as I handled the muffler, and I suppose anything is possible. I'd love to ditch the stock muffler (which is heavy and makes taking off the exhaust pipes a serious pain), but that's more fabrication than I'm ready for right at the moment.

So, the answer is a solid maybe. When I started the engine this morning, it didn't rattle, though. I'll take it.

Posted at 11:00 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.