Recent content by jpmobius

  1. jpmobius

    Ton up SR250: 100mph, 100kg, 30hp

    Having plowed a fair bit of this ground myself, I have a couple of observations. There is a lot to be said for a linkage system, but there is a requirement that is often so difficult to meet that a cable starts looking very appealing. The issue is a result of the suspension motion. In order...
  2. jpmobius

    purpose of this part

    All assemblies of this sort are the same. The idea is to create a solid structural element out of the axle. Imagine taking the bearings apart so you only have the inner races. When you assemble all the components together and tighten the center bolt (axle) down, you create a ridged beam that...
  3. jpmobius

    Ton up SR250: 100mph, 100kg, 30hp

    That is a good solution. The factory places the pull rod connection point at pretty much the only good spot, so incorporating the original portion can't go too far wrong. It would be a good idea to consider the leverage of the oem setup as you will likely want to have similar effort required...
  4. jpmobius

    CB350F - Carbs keeps overflowing

    You should be able to simply replace the overflow tubes. They are simply pressed into the bowl, but may also have some sort of sealant. Aluminum expands slightly more than brass when heated, so after figuring out how you want to grab onto the bowl and tube, put them in the oven on max temp...
  5. jpmobius

    Ton up SR250: 100mph, 100kg, 30hp

    Not too sure where you are on the foot control levers, but going to pass a couple of things along early just in case. First, and this may be obvious, the lever arm that pulls the brake rod needs to be at 90o or greater to the rod. This looks to not be possible with the lever in your pics as...
  6. jpmobius

    The z50 Zombie, Back from the Dead - a Honda Mini Trail resurrection

    FWIW, this is pretty nearly exactly the process I use for non-catalyzed spray can paint - Duplicolor engine paint nearly exclusively these days as it is available everywhere near me. Really great durable results. I bake about 30 minutes after the last coat a little cooler and for about an...
  7. jpmobius

    CB350F - Carbs keeps overflowing

    JB weld, Marinetex, and others are fine for intermittent exposure to gas, and even work in fiercely hostile applications, (like exhaust ports!) but don't seem to be permanent submerged in gas. Soldering is really quite easy and is a permanent repair. Check out some you tube vids. Regular...
  8. jpmobius

    Dirtbag Oil-Boiler

    Indeed. The idea is to remove the impact of suspension motion from the brake action. If you imagine the wheel locked by the brake, the bike not moving, and the suspension moving up and down, you will see that the contact patch of the tire actually moves back and forth very slightly. This is...
  9. jpmobius

    Should I Get Larger Carburetors? - Honda CL200

    Sure. The amount of power you get from any engine is a function of how much oxygen you can get into the combustion chamber. It is the limiting factor because you are restricted by the available oxygen in the atmosphere (unless you artificially add oxygen). Generally, it is a straightforward...
  10. jpmobius

    Should I Get Larger Carburetors? - Honda CL200

    As a generality, most engines will benefit slightly at max output with a slightly larger carb. The penalty is also general, sacrificing partial throttle performance. 99% of the time a larger carb is a bad idea on a stock engine, which is what you have. If you significantly increase the...
  11. jpmobius

    2x stroke street tracker - project coming together slowly.

    Definitely clean everything when it is apart. It seems to be a very common perspective that cleaning blast media from complex parts like engine cases is troublesome. I have never found this to be true. The fact is that you need to go to a very high level of cleaning if you plan to do engine...
  12. jpmobius

    1983 XV500 Cafe Racer

    It is important when examining these things to stay focused on the individual elements. The kinematics, or mechanism of how the shock is actuated is completely unrelated to the swing arm itself. The actual swing arm, that is the link that goes between the rear axle center and the axle center...
  13. jpmobius

    1983 XV500 Cafe Racer

    For what it's worth, I have a comment and a couple of observations. If helpful, great, if not, please keep sailing, you're doing some great work. Personally, I tend to work through the numbers a fair bit, but I get tired of it pretty quickly, and once I think I am in the ballpark, I'm ready to...
  14. jpmobius

    1983 XV500 Cafe Racer

    Ok, since you obviously have been putting some thought into all of this, I'll take a shot at explanation without a diagram. First, there is nothing pertinent in comparing the action of a telescopic fork and the linkage of your rear suspension, even with the simple rear system system here. The...
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