tweakedlogic
Been Around the Block
Before you get too excited, the engine is stock and worn out. I've got some K&N filters and pipes. Most of my performance came from removing everything that didn't make it go or stop or pass inspection. My estimate when they pulled it in was 25 horse power and 15 ft torque.
I was surprised on a couple levels. My power estimate was conservative. HP was 28.2 and TQ was 18.3. The most surprising thing is that I'm run super rich. That's surprising cause the way the bike was acting I thought I was lean. Another surprise was that my points are floating about 1500 RPM earlier than they should. Not sure about what to do about the points at this time. future plans are to go electronic.
As for the rich fuel mix, an intelligent person would say to change the main jet to a smaller size and re-run. You might have wondered why I used Tweaked logic as my handle... Well, I thought it might be better to add more air instead. Hopefully gain a few extra numbers over what I would get if I just dialed in the jetting.
So i spent half the day porting and polishing my carbs. The idea is to have the throat of the carb act more like a velocity stack, and smooth things out so the air will flow better. I also put a knife edge on the butterflies, and cut off half the butterfly shaft. Tomorrow I'll be on the hunt for flat screw heads that hopefully will sit flush with the butterfly (those kind that are tapered down on the head). If I find a suitable screw set, I'm going to have to camfer the screw holes. Before the flamers start in, that high polish is only before the fuel. I did smooth things out a little behind the jets with some 320 grit by hand, but that's all. I only used the die grinder and polish on the throat bell before the fuel jets.
I couple months ago I ported and polished a spare head I had around. Valve job and new seals and all. I was waiting to install it until I gathered some more parts, like new pistons, cam and such, but I may go ahead and put that on too.
I will probably still have to change the jets and maybe the air jets. We shall see. I'm shooting for an ever so slightly lean mix, preferably flat across the power band. It's not horse power I'm after though, it's toque. I want the biggest torque number I can squeeze out.
I know it's kind of pointless doing this to a motor I know needs a new top end. But it's nice to have a base line, and then see what every mod does. At only $40 a pop for the dyno, and my time spent on modifying parts, I'm not really hurting anything.
I was surprised on a couple levels. My power estimate was conservative. HP was 28.2 and TQ was 18.3. The most surprising thing is that I'm run super rich. That's surprising cause the way the bike was acting I thought I was lean. Another surprise was that my points are floating about 1500 RPM earlier than they should. Not sure about what to do about the points at this time. future plans are to go electronic.
As for the rich fuel mix, an intelligent person would say to change the main jet to a smaller size and re-run. You might have wondered why I used Tweaked logic as my handle... Well, I thought it might be better to add more air instead. Hopefully gain a few extra numbers over what I would get if I just dialed in the jetting.
So i spent half the day porting and polishing my carbs. The idea is to have the throat of the carb act more like a velocity stack, and smooth things out so the air will flow better. I also put a knife edge on the butterflies, and cut off half the butterfly shaft. Tomorrow I'll be on the hunt for flat screw heads that hopefully will sit flush with the butterfly (those kind that are tapered down on the head). If I find a suitable screw set, I'm going to have to camfer the screw holes. Before the flamers start in, that high polish is only before the fuel. I did smooth things out a little behind the jets with some 320 grit by hand, but that's all. I only used the die grinder and polish on the throat bell before the fuel jets.
I couple months ago I ported and polished a spare head I had around. Valve job and new seals and all. I was waiting to install it until I gathered some more parts, like new pistons, cam and such, but I may go ahead and put that on too.
I will probably still have to change the jets and maybe the air jets. We shall see. I'm shooting for an ever so slightly lean mix, preferably flat across the power band. It's not horse power I'm after though, it's toque. I want the biggest torque number I can squeeze out.
I know it's kind of pointless doing this to a motor I know needs a new top end. But it's nice to have a base line, and then see what every mod does. At only $40 a pop for the dyno, and my time spent on modifying parts, I'm not really hurting anything.
