Saturday, June 14, 2014

CB500

A few weeks ago I upgraded the ignition coils on the CB to Dyna ones. The stock ones were easily 40 years old and you can't replace the plug wires on them because it's all one piece. The wires were suspect so it had to be done. This install was super easy and made a big difference. However, since then, the bike has started to run poorly and seemed to be getting worse. #4 cylinder is usually dead entirely. So I started to look at the ignition system again. These are the factory points and condensers. Some guys really like these and others hate them. I really don't have an opinion yet. Issues with this setup is that they tend to need adjustment fairly routinely and can be unreliable, thus, stranding a person on the side of the road. 

There's a lobe on that cam (big nut in the middle of the picture) and as the cam turns with the motor, that lobe hits the lever on the left point (half moon shaped critter) and opens it. As the lobe passes, the lever closes and produces a spark which then goes to the plugs at 1 and 4 and fires those cylinders. This process repeats on the other side and again and again. What I've noticed is that my 1 and 4 plugs are not sparking at all so at times I'm running on two cylinders. I reset the points the other night (and even set them on the low side of the range to improve spark) but they still wouldn't produce consistent spark. I cleaned them with 1500 grit paper and acetone. The resistance was about 25-30 ohms before cleaning them and about 1.5 afterwards so it helped. Now you're not supposed to clean these that aggressively or you can ruin them but I'm trying to determine if this is the issue. This helped a lot but spark was still spotty. Then what I noticed is that (with help) if I put my fingers on top of the points and gently push down as the motor turns, then I get spark (and good spark) at the plugs. So I'm pretty sure the points are fried. Possibly because of the hotter spark being produced by the Dyna coils. So now I need to decide if I'm going to try to track down genuine Honda ignition parts (rather hard to locate) or just bite the bullet and upgrade to modern electronic ignition (probably $100 more). I've been sleeping on it for a few days and will likely do so for several more days.  


This issue has gotten really bad the last week and has resulted in zero riding of the bike. This is the right side exhaust. Cylinder 3 is on the bottom and 4 is on the top. 4 is the one that has not been firing at all. There is a small hole on the bottom of 4 (I'm sure designed to help with condensation in the pipes). That's not condensation there. That hot mess express is all fuel and oil that's mixed together and spewed out. It's nasty. It's funny when people ask me, "Are you getting fuel to the cylinder?" I say, "Yes. I'm getting fuel to #4, to my foot peg, to the muffler, and to the car behind me."


Things are slowly coming together with this thing. I passed my motorcycle safety class last week and have a helmet ordered. Once I get this situation sorted, I'll get plates and start to ride it more regularly and work out the kinks a bit more. Then I'd like to do some longer rides to the river to fish and possibly camp. I do need to come up with a way to carry gear other than a gnarly looking milk crate. I think I came up with something the other night while scratching my head with the ignition problem. I need to get some steel, bend it up and weld it together. I drew up my idea and I think it's gonna be perfect. It's going to be super simple, minimal, and clean. Once the gear is installed, you won't even see the racks and they'll be easy to take on and off. Stay tuned.

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