Categories: all aviation Building a Biplane bicycle gadgets misc motorcycle theater
Sun, 25 Jun 2006
When Kawasaki builds a Ninja 250 (I'm a little obsessed right now, can you tell?), they make some of it in-house, and buy some of it from subcontractors. This is pretty much everybody's business model now, because in order to do, say, engines well, you have to devote a huge amount of effort to the project. If you also want to do, for instance, carburetors well, you have to devote another huge amount of effort. Needless to say, these huge efforts also cost tons of money.
So, Kawasaki buys its carburetors from another company which specializes in them: Keihin. This is good and bad. Keihin makes good carburetors, and lots of engines use them. Harley-Davidson (heavens, I know, an American company using Japanese parts? please, bear with me) uses Keihin parts on all their bikes. So does Kawasaki for the majority of bikes, and snowmobiles, and jetskis, and generators, and so on.
The practical upshot is, Kawasaki says to Keihin, "we want 1000 CVK30 carburetors," and Keihin says, "right away, that'll be $50,000," or whatever the cost is. Kawasaki takes their barrel full of carburetors, and puts them on various things, including my bike.
Unfortunately, of late Keihin has been falling down on little, unimportant things, like the precise adjustment of their carburetors. It's nothing your average home mechanic can't fix, but it's kind of a pain. In my case, they've set the idle mixture screws incorrectly (at a guess).
Now, for me to go and fix that, I have to remove the carburetors, and drill out the special EPA tamper-preventing cap. The EPA is justifiably concerned that your basic ham-fisted home mechanic will see this screw, turn it without knowing what they're doing, and suddenly their bike will be spewing lots of unburnt hydrocarbons into the air whenever they're sitting at a stoplight.
Unfortunately, those same screws also determine how the bike idles -- properly adjusted, it idles nicely all the way from cold starts in the morning, to the midst of summer traffic. Improperly adjusted (like mine are), the bike simply refuses to idle nicely. When cold, it refuses to idle without lots of choke. When warm, the idle speed hovers a thousand RPM higher than where it's supposed to be, then sinks down to lower than it's supposed to be, without any input on the throttle. It would be enough to drive a new rider to distraction.
So, I'll be pulling out the carburetors soon, and adjusting those same screws the EPA seems convinced will destroy the world. Never fear, EPA, with the bike idleing properly, there will be far fewer noxious emissions than if I left the bike in this whacked-out state.
Posted at 11:34 permanent link category: /motorcycle
The scientific method, applied (kind of)
For the new Ninja 250, which I picked up yesterday, I'm going to follow this guide as closely as possible for doing the engine break-in. It's pretty different from the Kawasaki recommended method, but following a different break-in doesn't affect the warranty (short of actual abuse, of course). That method I linked to was used by one of the competitors in the Iron Butt Rally, in which motorcycles are run over 1000 miles per day, for 11 days. It's a pretty thorough test of a motorcycle (and a rider).
Anyway, I've now done the idleing step (let the motor idle for 10 minutes, 4 hours cooldown), and the first ride (~5 miles, very gentle acceleration). I got a request from one of the Ninja 250 board members to test the compression of the engine before and after break-in, and discovered too late that my compression tester didn't have the right little adaptoid to fit the Ninja. So, I lost the chance to test it after the first step (the engine is supposed to be warm), but I did get to test it after the ride last night. About 170 PSI on each cylinder, which is low, but not shocking.
The new bike, by the way, is a gorgeous color. I was right
to stick to my guns and wait until I found a red one. The picture on
the Kawasaki website doesn't really do it justice, it's a fabulous deep
maroon. On the right is my bike loaded up into Jesse's truck -- he was
generous enough to help me get the bike home so I wouldn't have to ride
it and mess up my clever breaking-in plans.
It doesn't idle very nicely, which could either be poorly adjusted valves (possible, but unlikely), or poorly adjusted carburetors (very likely). Unfortunately, to fix the carbs, they need to be taken out, which is practically a masters course all by itself, so that step is going to wait a little bit. I think when I do the 600 mile maintenance stuff, I'm going to check the valves and pull the carbs to get them sorted out.
I'm intending to replace a lot of suspension bits, and the tires, but I want to wait on all of it until I've had a chance to ride the bike for a while, to see what the stock parts really feel like. My one reservation about constantly dissing the stock tires and suspension is that I don't really remember what they were like. Spending some time on them should be plenty of reminder.
I'm also trying a new thing on this bike, and weighing the pieces I put on or take off, to keep track of how the weight of the bike changes as a result of my modifications. I don't know how valuable it will be, but it's an interesting exercise.
Posted at 09:45 permanent link category: /motorcycle
Categories: all aviation Building a Biplane bicycle gadgets misc motorcycle theater