Thanks Scott, (and everyone else too) your mate's bike was probably a pre-1983 model, during my research I found that there was an issue with top end oiling issues with the older engine, but they totally redesigned the head from 1983.
I got bored around lunch time, so even though it was only 45 degrees F I bravely braved the cold and dragged the XR500R out of the "barn". I had to move the Yamaha FJ1200 and BMW K100RS to get to it, but luckily they both started right up, and I was able to get "Big Red" out.
With no particular priority in mind, I started by pulling the sidecovers off. The left sidecover doubles for the airbox outer cover, and I was horrified to find that the foam from the air filter had turned into oily mud in the bottom of the box. I cleaned all the gunge out, and I'll order a new filter tonight.
The XR doesn't have a battery, the best way I can describe it is that it has a magneto, which may or may not be technically correct, but regardless, with the engine off (there's no key, but unless you know the starting routine for a big high compression single, you won't be able to steal it anyway) nothing else works. (lights, blinkers, horn etc)
Neither Ken nor I have ever attempted to even kick it over, so I first checked that it had oil, then dropped the float bowl plugs and a little trickle of ancient gas ran out. I dropped the main jets (two separate carbs on Big Red, feeding into one big cylinder) and they were both clear, so once I replaced the rock hard fuel line I flushed both carbs with some fresh gas and called it good.
I located the spark plug (D8EA, same as a CB750) deep in the front of the head, so I carefully removed it with the help of several liberal coatings of WD40, I remember pulling the threads out of one cylinder on my first K1 may years ago, which necessitated removing the head to repair, so I was relieved that while a little tight, the plug came out without a layer of aluminum in the threads.
I couldn't find a D8EA so I squirted some more WD40 down the spark plug hole and kicked the engine over several times to lube the cylinder walls, and get some oil up to the head. I installed a new D7EA and threw the cap back on. Hmmnnn, I wonder if it'll start? Well much to my surprise, it started first kick! Unreal, that bike hasn't been run for at least 4 years from when it first arrived here, and how long before Ken bought it, I just don't know? I don't think I've ever been so successful with an engine that's sat for so long!
Anyway, I had to take it for a quick lap up the street, so I did, but quickly brought it back as I didn't have a helmet or gloves on. I fired it up again a little later, and once again, as long as you use the correct method (and wear boots, it's got a ton of compression) it'll start right up. I don't think I've got anything to fear from the local crack smoking dopes, as they wouldn't have the strength to fire Big Red into life, but I will either install a key switch, or a hidden kill switch.
After a couple of hours freezing in these arctic conditions I couldn't be bothered removing the wheels today, but I did junk the chain, have you ever seen a chain and sprockets in such bad condition?
Luckily enough, I have some nice new quality items ready to install:
So after an exhilarating couple of hours playing with my new toy I was quite chuffed that the engine is so good (and easy to start, as long as you're 300 pounds in your hob nailed boots) and am looking forwards to getting it on the road, probably as early as next week. It even looks a little better once I scraped the dust off!
