I’ve been an exceptionally busy beaver with the bikes. As I mentioned in my previous musing, I got the Honda Shadow up, and now she’s fully tuned and ready to go. I had a couple of issues with old hoses and o rings that were leaking, specifically coolant hoses. I replaced every o ring inside of the engine, but decided to risk using the old o rings and hoses on the coolant, intake, and fuel systems. That was a terrible idea, and I’ve replaced virtually every single hose and o ring on the outside of the bike. I don’t have any pictures of this, but needless to say that rubber hardens and becomes quite brittle as it ages, especially when exposed to UV light, and doesn’t do a good job at being rubber after 20 years. Also, be careful installing o rings, because I might have pinched a water pipe o ring, causing it to leak. I had to wait again for new o rings to replace it. We’ll see if it was just me wrenching an o ring in incorrectly, or something else.
I worked on my buddy Zhuul’s 1987 TW200. We basically rebuilt the bike from the ground up. He had the frame and swingarm repainted, and it looks awesome. The swingarm especially looks cool, because the paint looks like it’s cast iron, which makes the bike look super rugged and steampunk. I then spent a whole week messing with an after market carburetor that he purchased to replace the OEM carb. Tuning that bike, I have learned something: I hate slide carbs. As a quick reference: most carbs on just about every bike I’ve ever ridden is a constant velocity (CV)/diaphragm carb. Basically, the throttle opens a butterfly valve, which increases pressure inside the carb, cause a diaphragm to pull up on a needle that sits inside of a fuel jet, allowing more fuel into the cylinder and making a bigger boom. A slide carb, which is a simpler carb, basically has a throttle cable connected directly to a slide. When the throttle is pulled, it pulls the slide up, which raises the needle manually, allowing more fuel in. You’d think that the slide would be better, because the throttle is connected directly to the needle, rather than waiting on a pressure differential to build in a diaphragm to raise the carb. However, tuning a slide carb is super finicky. Engines in general like different fuel mixtures at different RPM’s, and CV carbs are really good at metering how much fuel is going into the engine at those RPM’s. Slide carbs aren’t as effective at doing that, so you’re really stuck with tuning the carb for a select RPM range, and getting poor performance outside of that range.
Finally, I got my 1978 Honda XL125 running. It also has a slide carb, but I’m so done with tuning them, that I’m looking for a silimar sized CV carb to throw on and call it a day. That little bike is fun to ride around though. It’s a kickstart only, and so far I’ve had 3 people try to kick it over, and only 1 has managed to do it.