Topic: BMW R100 Airhead

[Roach Carver]

I am not sure about the r65 but some of the snick and wheels were recalled and replaced with reinforced versions. http://bmwmotorcycletech.info/19inchrecall.html

[Scott S]

 I got the exhaust hangers installed properly and, along the way, the Brown side stand.



 The center stand went on easy with the new, longer springs.




 I need to make a stop so that it won't hit the side stand when it's up.



 The center stand is surprisingly easy to use. The bike pops right up with minimal effort and is very stable. The rear wheel isn't quite off the ground, but nothing a block of wood under the stand wouldn't fix. I'm happy!
 Now....on to the fluid changes...

[Scott S]

 I also mocked up the crash bars. I really dig this style. The plan is to eventually mount some riding/fog lights on them.

[calj737]

I hope you used a bit of Anti-sieze on those exhaust flanges! Theres a stock center stand bumper that should be installed on the left side of the frame.

[Scott S]

 I haven't done anything with the exhaust flanges yet.....did you mean the hangers?

 I saw a few bumpers in the parts fiche at MaxBMW, but they were called side stand bumpers or kick start bumpers.

  Am I supposed to have #12 in this pic?



 Or something like #11 in this pic?



 I can totally see something like #11 in the 2nd pic bolted to the center stand working.

[calj737]

#11 is for the center stand, #12 is for the side stand IIRCC.

It looked as though you had mounted the exhaust, so I was mentioning the use of A/S. If its still in place and unnerved, disregard the comment.

[Scott S]

 No....for some reason the hangers were loose. The Brown side stand uses the hanger on the LH side for the front mount. Straightened all that out while installing the center stand.

[Scott S]

 I have a manual and I'm trying to follow the directions. I've also been reading Snowbum's site, but he can get a little....verbose...and that doesn't help a person that thinks the electrical system is black magic. :permazot

 Here's what's behind my cover:



 I did the Regulator check by removing the B+ wire from the dode board (red wire on the right in the pic) and checking between it and the D- on the alternator.
 I got a very low reading.... like 0.22 volts. 

 I also did a regulator check. The regulator appears to be new-ish. I unplugged it and placed a jumper between the blue and blue/black wires. This made the light on the dash go out. That tells me the regulator is faulty.



 I'm trying to check the alternator, but I get to step 7 in my manual and get confused.
I don't see a D+ on my alternator and I can't determine what lead on the diode board that is.



 The manual says it's #6, a blue wire(s). I don't see a blue wire on mine and the spacing isn't exactly the same as this diagram.





 First of all, do I even need to go any further or have I determined that it's the regulator? What do those crazy low readings on the alternator mean? That I've done the test wrong or ??
 If I need to do steps 7 and 8, can someone guide me through that using  the pics I posted.

 Lastly, the brush holder has a crack in it, but the brushes seem plenty long and are making good contact.

 What next? I'm an absolute noob to the BMW and electrics confuse the heck out of me. Talk to me like I'm a dummy....I won't get offended.

[Scott S]

OK, my good friend and Electrical Engineer Pamco Pete came over and helped me trouble shoot. I can't begin to tell you what all we did (and by WE I mean HE...), but here's the synopsis:

The VR, rotor, diode board and alternator all test good. It appears that there's a bushing or insulator missing on the alternator, which means that the POS + brush is grounded. We used a piece of cardboard between the spring and brush to test it and the charging light goes out, voltage rises to 13.5+ when revved and everything seems to work properly.
The missing spacer/insulator might also explain why the brush holder is cracked.
Oh....and someone had the wires crossed on the brushes....probably in an attempt to troubleshoot or repair this same problem. That means that all the testing in the world "by the book" would have led me nowhere. It simply wasn't assemble properly.

Here's a pic from the web showing the spacer:

[Scott S]

It looks like all I need is a new brush holder, the proper spacers and new brushes.

Is this everything?
http://www.euromotoelectrics.com/Bosch-Alternator-Brush-Kit-BMW-R-Airhead-p/boalt-brushholder.htm
 

[Scott S]

 Here's a pic of mine for comparison. If you look closely, you can see that it's missing the washer/spacer/insulator. You can also see the crack in the brush holder and the strip of cardboard we used to get the brushes to work properly.

[Scott S]

 I also have a few more questions....

 I looked at the throttle cable while I had the tank off. There's a ton of slop in the cable. I backed out where the cable goes from 1-2 but it didn't really do much. Do I just need new cables?

 Video:

 Also, I noticed that the dual plug heads/coils have one lead from each coil going to each cylinder. Wouldn't that mean that the coil is firing on that cylinders exhaust stroke? Is that the whole point of dual plugs? Or should the coil fire both plugs at the same time?

 I also tried to check the timing and it seems way off. The "S" mark isn't even in the window, no matter which of the 4 wires I use. I didn't try to adjust it yet because I wanted to understand the dual plug stuff. The bike starts instantly and idles great. It pulls OK to 3-4K and then hits a flat spot. I can't tackle the carbs until I get the timing and throttle cable sorted.

[Scott S]

 Here are some pics of the throttle. This pic is with flash and shows the teeth/gears.



 Same pic without flash.....is that ramp supposed to be there or is that wear?



 This is the other end of the slot or groove that's closest to the rubber grip. I *think* I can see a dash or mark on the 2nd tooth.



 These are the gears underneath.



 Do I align the dot near the chain or use the dash mark ~90 degrees out? If I align the dash, there's a mile of slop. If I align the dot, it wants to skip a tooth when I turn it (admittedly, without the cover installed....only holding it down with my hand), which might indicate wear?



 Should I align the dot on the gear with the mark on the 2nd tooth on the throttle, install cover, and see how it goes?

[Scott S]

 I got the new cam, cover and throttle grip installed. Right away, about 75% of the slop was gone. I took up some more slack under the tank where the single cable splits to two. That made it even better....about what I'm used to up at the grip.
 But I'm still not getting full throttle. I noticed  that the lock nut and adjuster down at the carb(s) was screwed all the way down/in. I backed them out an equal amount (eventually, I'll get it running again and sync them with the manometer) and that helped even more. I'm still not getting quite 100% full throttle. I guess I just need to keep backing them out until I can achieve full throttle? And...now that they're backed out like that...sometimes the throttle doesn't return. Will it be better once the engine is running and I get some vacuum on the diaphragms? Could it be that the return springs are worn? Or should I have bought cables, too?

 I have a Haynes manual and it's a bit inadequate when it comes to adjusting the throttle....especially lacking in pictures. Is there a good "How-To" you can point me to? I mean, I get the basic idea....but I'd like to see it done one time.

 These screws were bottomed all the way out. Why, I don't know. Guess just keep adjusting until I can get full throttle?


 Do the springs lose tension over time? Or is something else causing the throttle to not snap back?

[Scott S]

GRRRRR!!!!
 I took the oil filter cover off so I could remove the paper gasket and now the hole that's behind the header doesn't feel right to me! It's not stripped.....yet...
 Looks like I'll be removing the exhaust AGAIN so that I can go in nice and square. I'll chase the threads and make sure everything fits smoothly. Stupid 5 minute job....

[Roach Carver]

Back that throttle screw all the way out for now. These are cv carbs if the throttle doesn't snap  back pretty easily then there is something going on with the cable. Also make sure you have the throttle tube and gear oriented for the full movement

[Scott S]

 Made a thread chaser by cutting three grooves in a bolt and it worked great! Was able to get the cover back on without removing the exhaust.

  I also got the throttle working properly. I cleaned up the bar and re-lubed everything and went through the whole adjusting process again. I think the biggest culprit was the rubber sleeve for the bar end mirror. It's damaged and, even though it didn't touch the grip when initially installed, it mushrooms out of the end of the bar when tightened up. That was making it rub on the end of the grip/throttle sleeve just enough to be a problem.
 I now have full throttle and the carbs snap back as they should. I still need to sync and adjust them....soon....soon....much closer than I was before. And, worst case scenario, I just need a new mirror.
 Anyone have a busted up Napoleon Bar End that I can rob the insert from?

[Scott S]

I had a buddy come over yesterday and we found true TDC on both pistons. My GF was helping me the other day and she said that she thought the new mark was off by 7 or 8 teeth. That didn't make sense and turns out it's off by much more, which makes sense. It appears that the flywheel is off by one bolt and they marked new TDC.
Next time I'm in there for service, I'll install it correctly.

With true TDC on both pistons, I rechecked the valves and tightened up on the intakes since they were a little loose. The bike sounded better right away. It idles nice and will rev freely in neutral, but it's still breaking up in the mid range, around 2500-3500 rpm. I synced the carbs with a manometer and that helped, but the symptoms are still there. Guess I'll be pulling the carbs. I might try taking a look at the diaphragms and dropping the bowls to pull the jets and see if I get lucky first.

RE: Timing
At idle, the mark is below the window a little bit. I have to stand to the rear of the bike and shine the timing light down to see it. At 2000-2500 rpm, it's dead centered in the window. If I keep revving, it continues to rise and leaves the window entirely.

[Roach Carver]

a lot of the time i do a down and dirty clean up on my carbs without removing them from the bike. I take off the tops and the bowls and do a little carb cleaner and air in the holes I can reach easily. That's my spring start up and it is usually adequate. as far as the timing i cant help you there. It is not that hard to get in there to fix the flywheel. Maybe a day to do the job start to finish but if you have to go in there I would go ahead and replace the rear main seal. make sure to block the crank. if you are not familliar with that procedure look it up before you dig into it. It can be a major problem if you forget to do it.

[Scott S]

 I'll do that, probably next week when I get a few consecutive days off.
 If I end up keeping this bike long term, I'll eventually get the flywheel on correctly, too.

[Scott S]

 I pulled the top and the bowl on the RH carb to take a look. Uh.....yeah....probably at least part of the problem....



 The carbs are pretty filthy. I started trying to clean it with carb cleaner and compressed air, but I think it's time for a REAL cleaning. Luckily, the diaphragms look fine. While I was messing with the carb, I noticed that the RH petcock wasn't holding. The LH has a repair on it and I knew it leaked. I got pissed and watching the petcock pissing, so I pulled the petcocks and drained the tank.
 Yup.....not gonna be able to rebuild these. Time to order two new petcocks.



 The tank wasn't too bad. Some of the factory liner has flaked off, but it's solid and rust free. I drained it, flushed with water to get all the flakes and sediment out, then flushed with demineralised water, followed by swishing some denatured alcohol around. I blew it out with air and my heat gun. I'm letting it air out now and, if it doesn't stink too bad, will bring it in tonight and set it over a heat register.

 While I'm at it, I plan on ordering new fuel line, too

 Back to the carbs: I have a bucket if Berryman's, spray carb cleaner and compressed air. I have the RH carb mostly apart. I haven't removed the choke body yet. Is it safe to dunk the carb in the Berryman's with the plastic cover on the opposite side of the choke? Other than the O-rings on the jets, are there parts that should NOT be dunked?

 Lastly, both needles have the tiniest ridge on them. I cleaned them with 0000 steel wool and carb cleaner, but there's this teeny-tiny little lip that I can barely catch a fingernail on. Is that a problem?

[Roach Carver]

I would be leary to dunk any of it that i did not take all the way apart but that's just me. I would disassemble as far as I felt comfortable with and clean with carb cleaner and fine wire. Probably would not be a bad idea to replace the needle while you have them apart and I would recommend replacing the diaphragms as well. They get stiff and don't work as well as they should. Also get genuine BMW braided hose or VW hose will work as well (or so I have been told) If you decide to take the butterflys off the shaft you need to know that the screws are peened in place so they will likely need to be replaced and possibly the throttle shaft as well? I suspect if you get all that trash out of  the system and get clean fuel in there even with worn parts it will probably run quite well. The carbs are pretty simple but are still susceptible to trash in the lines.

[calj737]

I've got a pair of professionally rebuilt, beautifully clean Bings sitting aside if you want to make a deal for them?  I'll be upgrading my carbs to Delortos for my R90 so they have become surplus.

[Roach Carver]

what size Delortos, and pump or no pump. sorry for the small thread jack.

[calj737]

what size Delortos, and pump or no pump. sorry for the small thread jack.

Still determining that variable in fact.