• Content count

  • Joined

  • Last visited

Community Reputation

10 Good

About frankenduro

  • Rank
    TT Newbie

Profile Information

  • Location
  1. That's approximately how mine looked when I got mine (although mine had a lot of flat black spray paint overspray on it). It's actually a very convenient place for the wiring, as the bullet connectors are all very accessible there. I had to rebuild my entire electrical system, so the accessibility was important. I think I tidyed up the wiring a bit with a few cable ties when I finished but made sure none of the wires would be stressed with handlebar movement. I'll take another look at mine, but yours looks pretty normal to me.
  2. If the speedometer gives you trouble, the easiest solution is to install a Sigma Sport bicycle cyclocomputer. It is cheap (~$20) and provides a multi-function digital display, and the ones made by Sigma Sport can easily handle motorcycle speeds. Instead of the magnet provided by Sigma Sport, get the tiny rare-earth magnets sold by Radio Shack and epoxy one on using JB Weld. The only drawback is the lack of a backlight, but, for another $9, you can get a Sigma Sport green LED light that shines down on the display. Granted, it's not going to help you win any "concours d'elegance," but what do you expect from someone named frankenduro?
  3. The Clymer Honda XL/XR 500-650 Singles 1979-1993 manual specs the valve clearances for all models as follows: intake 0.05 mm (0.002 in.) exhaust 0.10 mm (0.004 in.) Valve adjuster locknuts for 1979-1982 are spec'd at 15-18 N-m (11-13 ft.-lb.). It describes the cam chain tensioner adjustment for all engines except the later RFVC engines as: 1. Start engine and let it reach normal operating temperatures. 2. Let engine idle. Loosen the tensioner upper bolt and the lower locknut 1 1/2 - 2 turns. 3. When the tensioner bolt and locknut are loosened as described in Step 2, the tensioner will automatically adjust to the correct tension. 4. Tighten the tensioner bolt and the locknut securely.
  4. cleonard is right about the leaking gas. I've had both a stuck float and a tiny crumb of rubber fuel line stuck on the seat of the float valve. Either way, gas would fill the carb. Take the bottom off the carburetor and see what's wrong with the float valve. Be careful not to break the intricate parts of the plastic float, and be careful with the accelerator pump shaft (which has a corrugated rubber boot over it, or at least did 27 years ago). Make sure you don't loosen the cam chain tensioner bolts too far and have the assembly fall apart inside the engine. I think I loosened them two turns each, but I wouldn't rely on my memory for that. I read and repeat back word-for-word the precise details of the procedure in the Clymer manual whenever I do it. The 1979 XR500 engine should be basically the same as my 1982 XL500 engine, except for things like your lighter flywheel, AC-only stator, and your reed valves in series with your regular intake valves. The valve specs for the XL500 are .002" intake valve clearance and .004" exhaust valve clearance. The following website seems to think the numbers are the same for the XR500, which doesn't surprise me:
  5. Sounds just like mine, top end smoke and all. You can download the shop manual in English from There is a schematic diagram of the wiring and electrical components, including wire colors, in the back of the shop manual. The ignition circuit is pretty simply. There's an alternator winding (looks like black/red wire) going to the ignition module. The ignition module has what looks like a black/white wire going to the kill switch and ignition switch (grounded to kill). The ignition module has a green wire to ground, green/white & blue/yellow wires to the pickup coil located inside the right crankcase cover, and a black/yellow wire to the ignition coil primary winding. The ignition coil also has a ground wire and, obviously, a spark plug wire.
  6. The first question to ask about synthetic oil is "what is synthetic oil?" As a result of the Mobil/Castrol lawsuit, synthetic oil is either Group III (hydroprocessed petroleum base stock) or Group IV (polyalphaolefin (PAO) base stock). Except for premium synthetic oils, like Amsoil or Redline, almost all synthetic oils are Group III oils. Since Group III oils are just highly-refined petroleum oils, trying to distinguish synthetic oils from petroleum oils is not as clear cut as most people seem to think. Considerations such as wet clutch compatibility depend more on the types and amounts of additives, especially friction modifiers, such as molybdenum compounds, not the type of base stock. Motorcycle oils, whether "synthetic" or not, are usually MA rated and do not include friction modifiers. Motor oils for heavy duty applications (e.g., diesel trucks) usually also do not include friction modifiers. I've read that the Rotella T synthetic 5W-40 that I use would meet MA specs if not for its higher ash content. I would definitely avoid adding most additives, especially ones like PTFE, which don't belong in an engine, much less in a wet clutch. In an air-cooled engine, I'd be particularly concerned about the possibility of decomposition of fluorinated additives, like PTFE, yielding hydrofluoric acid, which is the last thing I would want in my crankcase. The bottom line is to avoid oils containing friction modifiers (which usually have "energy conserving" on the label) in wet clutch applications and to change the oil often. I use the Rotella T synthetic 5W-40 because it's the cheapest Group III that almost meets the MA rating, which encourages me to change the oil frequently. I'd consider using Rotella T non-synthetic 15W-40, as it's even cheaper and 15W-40 uses a more viscous base stock similar to 20W-50, while 5W-40 and 10W-40 use a less viscous base stock similar to 10W-30. As you can see, after the Mobil/Castrol lawsuit, I don't put much emphasis on synthetic vs. non-synthetic.
  7. I'm thinking of making a homemade case saver from sheet steel (auto body panel scraps). Should I have any hope that mere sheet metal will be enough to prevent damage from a broken chain? My 1982 XL500R already has a bite out of the upper rear left crankcase cover above the countershaft sprocket from what I presume was a broken drive chain of a previous owner. That missing material leaves enough of a gap that I suspect another broken chain would bind up there pretty tightly and really break up the crankcase cover. I'm thinking of bending up some ears on the sheet metal to attach to the motor mount and let it take most of the force at the leading edge of the case saver. I'd also leave a couple of tabs to attach the sheet metal to the small bolts that hold the countershaft sprocket cover in place. I might weld some reinforcements along the unsupported span of sheet metal that would bridge the previously broken gap. The way I look at it, as long as the sheet metal is curved to smoothly funnel the chain onto the countershaft sprocket, it shouldn't have to bear a lot of force. Is that a realistic enough expectation for me to go ahead and give it a try with sheet metal?
  8. It all depends on which light bulb wire is connected to the tail light filament (dimmer) and which one is connected to the brake light filament (brighter). I suspect the white wire is connected to the tail light filament and the green wire is connected to the brake light filament. If so, the way I describe should work. If it's the opposite, then the way you were going to wire it should work. You can check by connecting 12 volts (or whatever the correct voltage is (e.g., 6 volts for older bikes)) between the light's brown wire and the light's green wire and seeing how bright the bulb is, then disconnecting it and connecting the 12 volts between the light's brown wire and the light's white wire and seeing how bright the bulb is. If the bulb is brighter with power on the green wire, then wire it the way I describe. If the bulb is brighter with power on the white wire, then wire it the way you were going to wire it.
  9. Make sure there is a fuse inline with the red power wire (probably near the battery positive terminal). Connect red power wire to brown brake switch wire and white tail light wire. Connect purple brake light switch wire to green brake light wire. Connect brown tail/brake light ground wire to ground (e.g., bike frame or battery negative terminal). If you see a lot of sparks, smoke, fire, etc., disconnect the wires and reconnect them differently.
  10. I double-checked mine, and the deer feeder batteries are 5 amp-hours, which is 67% extra capacity compared to the OEM battery, the Yuasa YB3L-A. Regardless of capacity, I am happy with a $16 motorcycle battery. Here's a photo:
  11. mauricedorris, I wouldn't say the previous owner bolted "the wrong head" on to the cylinder, as the bike has ridden since I've owned it. I suspect the previous owner may have switched to the XR head either of necessity (e.g., trashed cam journals on the original head) or some preference of which I'm unaware. The exploded diagrams on the site are probably the best way to see the differences between the XL and XR engines. The XR engine supposedly had no generator/alternator, a lighter flywheel, a different spark plug, and, at least some model years of XR500 supposedly had reed valve induction -- see: I hadn't considered that the XL and XR oil ports might not line up precisely, but that's an interesting thought. I do know that oil leaks out around the heads of the stripped bolts, as they cannot be torqued enough to prevent it. I'm not sure whether the bolts attach the head to the engine (where I would agree with your concerns about loss of compression) or merely attach the rocker cover to the head. While I haven't measured compression, I can certainly feel a fair amount of compression, and the engine runs reasonably well.
  12. Not wanting to spend a lot on a battery, I just bought two 6-volt sealed-lead-acid gel cell batteries (each the size of a square 6-volt lantern battery) marketed for deer feeders at Walmart for $8 each. I think they are 3 or 4 amp-hours, so they meet or exceed the original battery capacity. I soldered their spring terminals in series to provide 12 volts and insulated those unfused connections very well. They don't fit perfectly in the original battery compartment, but it's nothing a few nylon cable ties couldn't accommodate.
  13. mauricedorris, "Of course, my more ambitious plans are to convert it to 12v..." As a 1982 XL500R, it should already have a 12-volt electrical system. I know mine does.
  14. mauricedorris, The 1982 XL500R and XR500 top ends are not exactly the same. I was looking at the XL500R top end diagram on to see if I could reduce the amount of oil that drips out of mine, and its shape didn't match the top end on my XL500R engine. I looked at the diagrams of 1979-81 XL500S top ends, and they didn't match either. However, the diagram of the 1982 XR500 top end looked exactly like what I have. I don't know if there are any internal dimensional or functional differences, but, externally, the XL500R and XR500 top ends are easily distinguishable. Not only did the previous owner apparently change the top end, but he also managed to strip a few of the bolts in the process, leaving plenty of room for oil to leak around the loose bolts. Whenever it comes time to take the engine apart, I'll probably end up machining some threaded rods to replace the bolts, as described here: (English translation) and here: (original German with photos).
  15. mudbug97, I've got an XR top end on my 1982 XL500R, and it works fine for me. I don't know if there were any complications installing it, as it was on the bike when I bought it.