hey,purchased 1982 r100 early this summer ...over 130 000km on the engine tranny has been replaced around 75 000km.strong runner with no obvious issues except a light head gasket leak and a lingering charging problem.plannig on doing a full tune up this winter and try to track down the genarator issue. anything i should look for?? i am going to be doing all the work with an experienced motorcycle mechanic but i was told that the charging problem was quite common on these old bikes....anyone have any wisdom on where to start???the genarator light will only turn off after 6/7 km of highway riding so i find myself draining the battery a lot having to keep it on a tender most nights would like to resolve this before buying a new battery.any advice ,tips would be greatly appreciated.thanks!!!! -jason
Fill in some info on your profile. Like where you are and bikes you have owned or do own. What you say is a slight head gasket leak could be the valve cover? Unusual Alternator problem. I have a feeling this one might actually be dirty or loose connections. It is almost always suggested to clean and tighten the electrical connections and other than making owners a little more familiar with the lay out of their bikes it seldom does much good. I think this time you may find a loose wire or dirty plug in. Other than this small suggestion I don't consider myself too much of an electrical expert so I'll just watch for awhile. Welcome to the Asylum.
thanks for the reply guys,will have access to full garage so a multimeter wont be a problem,from what the previous owner told me the generator issue has been going on for the last 10 years or so but he had a garage to store the bike everyday so keeping it on charge was not really an issue.i dont have this luxury .... and my everyday commute isnt always highway or very long for that matter so i killed the battery a few times this summer.was never an issue for longer rides because it will get a full charge after 15 min /5-6 km of riding.pretty much on the dot the genarator light will turn off after that time....strange problem.i have the manual for the bike so i can do all the steps for testing the charging system .....but wanted to see if anyone else here has dealt with something similar.sorry for the huge pic.
Buy the charging system manual from Mottorad Electric. Also buy a set of solid diode board mounts, you are very likely to need them because you will be removing the diode board. The old rubber mounts often break when you try to take the nuts of the studs. if they break when you are riding, it can be pretty expensive, not to mention getting towed home. Always disconnect the battery ground at the battery before removing the front cover. leave it disconnected. Clean every connection on the diode board. You have to take it off to get to the ones on the back. (Thats where the mounts cause trouble). I like a stiff wire brush or running baking soda through an air eraser (away from the bike for that one. Clean every connection on the Alternator (It does not have a generator). Be very careful when taking wires off studs with nuts. There are special, and very small, washers involved. The right ones must be in the right places. Do one at a time and keep track of things. Then pull the plug off the votage regulator. More scrubbing there. The voltage reg. side itself is easy, the plug isn't. if it's really cruddy you can make a special tool for it. Ask. You are looking for two bright clean lines where the female engages the male. Nothing else will do, it's only 12VDC, won't punch through any oxide layers. Look for a white plug in the area with a blue and a black wire. Clean that one. Blue wires are critical to charging, as your new manual will explain. if you have the starter out (a good idea if you put in the solid mounts but you don't have to, lesser of evils situation) clean up all it's connections for the fun of it. You like doing this stuff. Also spin the starter with your fingers. If it is stiff it's bearings need lube. minimum. it will draw too much current when starting, which will also run you down. Then clean the battery terminals and connections. Bright shiny everything. Sandpaper will work here. Remove the ground strap at the transmission. Clean the end of the strap. Clean the hell out of the bolt and especially the hole through it, it is the transmission breather. put it back with your fingers and tighten it with your eyelashes. It is easy to cross thread or overtighten and strip. All sorts of careful with it. Check the speedo cable boot while you are right there. Any crack or hardness, patch w/ goop and order a new one. Keep the RPM's over 3000 when you ride or it won't charge.
The battery. Its always the battery. Symptoms could mean a poor bat that will take a charge but very slowly.
wow plaka,thanks lots of useful info...so are you saying that at low rpms the bike doesnt charge???i do lots of city driving so kepping it at 3000 rpm its always ideal.will buy the charging system manual for sure
No. I said: "Keep the RPM's over 3000 when you ride or it won't charge." but I actually meant something else. Wanted to see if you were paying attention. Put a meter on the battery and rev it up to 3600 or so. At what RPM does the voltage suddenly increase, indicating charging?
There are other reasons to keep the engine above 3000 rpm when riding. These engines like higher rpms. It is kinda hard to describe but the engine should never be lugged. These motors are not to be ridden like a Harley D. The Harley has low end torque and is made to pull differently. The European style engine runs better at higher rpm.
Drop me a pm or email I'm close to your location, you could ride by. Also, remember to turn the Petcocks off when you are not using the bike. It's a good habit to learn. Paul
