00 BMW 1983 R100RS To RT Break-In And Shake Down Log

My experience with my builds is that as I break-in the motor I also will find various issues I have to fix and adjustments I need to make. This is the log of what I did for the first 600 miles riding the bike during the break-in and shake down period.

1983 R100RS Public Unveiling At Out First Coffee Shop Ride

1983 R100RS Public Unveiling At Our First Coffee Shop Ride

First Engine Start And First 10 Miles

Start Odometer: 84,218 miles.
Ending Miles Since Rebuild: 10

As part of the first engine start, I rode the bike 10 miles with the RPM between 3,500 and 4,000 RPM with brief bursts to 4,500 RPM and then throttle off, coasting until 3,500 RPM. This helps pump oil everywhere and forces the rings into the cylinder walls to promote sealing the rings.

Fixes and Adjustments

  • After the engine got hot, I had to drop the idle by adjusting the throttle stop screws since the idle had gone up to about 2,500 RPM when the motor got hot. I expected this since the carbs were set statically and I erred on the side of a higher idle so the engine would start easily.

30 Miles Since Rebuild: Fixes and Adjustments

After I completed assembling the bike, I took a 20 mile ride to get the engine hot enough that I could adjust and balance the carburetors dynamically.

  • Mirrors won’t hold position.
    • Tighten the mirror tension nuts.
  • Handlebars see too high for comfort.
    • Lower the handlebars.
  • Slightly high idle.
    • Adjust and balance carburetors.
  • Turn signal switch is intermittent on right turns.
    • Sprayed electrical contact cleaner into housing and operated switch a few times. This seems to have fixed it.

Charging System Problem(s)

Starting at about 30 miles after the rebuild, I had a problem with the charging system. The GEN light would come and the volt meter would drop below 13 volts. Sometimes the volt meter pegged at 16 volts. After working my way through diagnosis I found multiple cause. I also managed to create new causes for the problem as I went along. Sometimes I screw up, and occasionally, frequently and often. πŸ™‚ I decided to put all the diagnosis and testing in one section so you can see how various causes affect the charging system.

  • Mile 28: GEN light comes on intermittently and Volt Meter jumping around.
    For the first 28 miles, the GEN light was off. Then it began to come on for awhile and then go off. Volt meter jumped at the same time.

    • Tightened up the battery ground wire and (+) wire, but they seemed pretty tight.
  • Mile 85: GEN light comes on intermittently and Volt Meter jumping around.
    • Pull front engine cover. Found “Y” terminal bolt and nuts loose. Removed stator cover and tightened the bolt and nut. Reinstall stator cover.
      NOTE: Could have been a cause, but see other issues found.
  • Mile 120: GEN light comes on intermittently and Volt Meter jumping around.
    • Check the fairing sub-harness wires to the volt meter. I was able to pull the two BROWN volt meter ground wires off the female spade terminal. They had not been crimped tightly. I soldered them to the female spade terminal and attached it to the volt meter.
      NOTE: This may have been a cause of the erratic volt meter.
Failed Fairing Sub-Harness Volt Meter Ground Wire Crimp

Failed Fairing Sub-Harness Volt Meter Ground Wire Crimp

    • Checked voltage regulator plug. Removed the wires from the plug and all crimps were tight. I soldered the wires in the female terminals as a precaution. Then I crimped the female terminals so they would be tighter on the voltage regulator terminals. The plug was hard to install so I figured the spades were tight.
      NOTE: In fact, what happened is the BROWN ground female spade terminal was pushed out of the socket so it touched the voltage regulator terminal intermittently, as I found out later. I crimped that spade terminal too tight.
    • Check BLUE wires on white plug behind the starter relay. They are tight.
    • Check alternator wires and diode board front phase wires are tight on terminals.
      • The “Y” terminal bolt was loose again. I removed the stator and the cover. I replaced the 18 mm long M5 bolt with a 22 mm long bolt. I added a split washer under the first nut along with the split washer under the second nut. Everything seemed tight now. I reinstalled the stator and cover.
        NOTE: And, I failed to get the stator flush against the three shoulders on the inner timing cover. This caused the rotor to contact the stator and tear up the laminations of the stator and score the rotor fingers as noted later. Much of the later flakiness is likely due my creating this problem.
      • The rear brush wire looked like it was not extending all the way. I loosened the nut that secures the ring terminal on the brush holder and rotated the ring terminal to provide more slack in the brush wire. Now both brushes extend the same distance.
      • I verified that the insulators on the “DF” brush were not cracked or broken. They were okay.
  • Mile 133: Volt meter pegged at 16 Volts.
    • I removed the voltage regulator. I found I had bent the ground terminal flat against the bottom of the voltage regulator. After I straightened the terminal, the voltage still went to 16 volts. I replaced the voltage regulator under the assumption I broke the internal connection to the ground terminal.
      NOTE: This was caused when I crimped the voltage regulator plug terminals and got the ground terminal too tight. Therefore the voltage regulator lost the ground path to the (D-) brush on the stator cover. Consequently the voltage regulator behaved as if I put a jumper between the BLUE and BLACK wires on the regulator plug, i.e., the voltage regulator was out of the circuit.
  • Mile 137: Volt meter pegged at 16 Volts.
    • I removed the voltage regulator and pulled on the wires in the regulator plug. the ground wire pulled right out of the plug. The tab that secures it in the plug was bent over backwards by the force of installing the plug on the voltage regulator.
      NOTE: So not only did I bend the voltage regulator terminal, it pushed the ground wire out of the socket so it wasn’t touching the voltage regulator ground terminal. I opened up the male spade and unbent the retaining finger and installed the terminal in the voltage regulator socket.
  • Mile 187: Surging in Volt Meter from 13 volts to 16 volts.
  • Mile 200: GEN light stays on all the time.
    • I parked the bike and used my VOM meter at the battery terminals. I started the engine and reved it to 3,000 RPM. The dash volt meter showed 15 volts but the VOM meter showed 14.3 volts. However, at idle, the GEN light came on but voltage at the battery was 13.1 volts.
    • Pulled the rotor and stator. I found the rotor was contacting the stator. I replaced them both.
      NOTE: The last time I had pulled the stator to fix the loose “Y” terminal, I managed to not get it seated evenly in the three shoulders of the inner timing cover.
  • Mile 300: GEN Light Off at idle. Full charging at 2000 RPM.
    • It looks like I have corrected the various causes of the problems in the charging system included several problems I created for myself. Oh well, live and learn. πŸ™‚

85 Miles Since Rebuild: Fixes and Adjustments

  • Slightly high idle
    • I rebalanced the carburetors.
  • Rear shock feels harsh.
    • Found rebound damping on left was 16 clicks and 23 clicks on right. Should be more like 10 clicks. I reset to 10 and then backed down to 6 clicks after a test ride. Much smoother and no feeling of the rear getting loose on bumps in the corners.
  • Oil cooler obstructs front engine cover bolts.
    • I slide the cooler over so I can get an Allen socket on the front cover bolts without removing the oil cooler.

140 Miles Since Rebuild: Fixes and Adjustments

  • Turn handlebar to full stop on right and engine RPM increases.
    • Adjust throttle cable Bowden screw to add more slack to handlebar cable.
  • Right horn not working.
    • Horn wire got caught in front engine cover when I was diagnosing charging system problems. I repaired the wire and added zip ties to secure the horn wires to the middle fairing bracket, which I had forgotten to do.

200 Mile Checkup

At this point, it’s time for a 200 mile check up.

  • Check valve clearances.
    • Left: Intake 0.004 in; Exhaust 0.006 in.
    • Right: Intake 0.004 in; Exhaust 0.006 in
      I had set these to 0.006 and 0.008 inches. So they closed up 0.002 in. I reset the valves: Intake-0.006 in; Exhaust-0.008 in.
  • Ride for 15 mins to get the engine hot.
  • Check timing. “Z” is at the bottom of the timing window at 3,000 RPM.
  • Balance carburetors.
  • Change engine oil and transmission lube.
    • Some light grey paste on magnetic engine drain plug
    • Some light grey paste and some metal bits on transmission drain plug. This is expected due to new 5th gear and bearings.
  • Check fasteners are tight
    • Rear turns signals and tail light are loose.
      • Tighten the turn signal stalk clamping screws inside the housing.
      • Tighten the tail light nuts inside the housing.
    • Right side rear sub-frame bolt a bit loose.
    • Left top rear shock bolt a bit loose.

Fixes and Adjustments

  • Install tank bag straps and tank bag.

230 Miles Since Rebuild: Fixes and Adjustments

The engine is running smoothly. The clutch action is light and the transmissions shifts very smoothly. No clunk when going from neutral to first.

  • When turning handlebar, the kill switch is pushed to off position by the tank bag.
    • Adjust handlebars so they are a bit higher.

300 Miles Since Rebuild: Fixes and Adjustments

The charging system is working now with no GEN light coming on after the bike starts. There are some fluctuations of the volt meter, but this is not uncommon with these meters.

  • Upper right bolt that secures upper center to upper side panel came loose. Installed with blue loctite.
  • Lower side panels are too far from lower center panel. I loosen the lower side panels and align them with lower center panel and attach the lower center panel to the lower side panels and then tighten up the bolts mounting the lower side panel to the lower fairing bracket and then the bolts that secure the upper and lower side panels to the middle fairing bracket.

600 Mile Service

At 600 miles, I did a complete service including replacing the engine, transmission, drive shaft and rear drive fluids and the oil filter. I checked the head bolt torque (25 FT-Lbs) and the valve clearance. I went around to check bolt and nut tightness.

The engine oil was clean and the oil filter showed no sign of metallic debris. The transmission magnetic drain plug had a few shards of steel, but much less than at the 200 mile service, so I think the new bearings and fifth gear are getting broken in.

The left side valves were as I had set them at 200 miles; Intake 0.006 inches and exhaust 0.008 inches. However, the right side valves had again closed up 0.002 inches: Intake 0.004 inches and exhaust 0.006 inches, so I reset them to 0.006 and 0.008 inches, respectively. Since the valve clearance on the right is not stable yet, I’ll check the valves again at 1000 miles.




14 thoughts on “00 BMW 1983 R100RS To RT Break-In And Shake Down Log

  1. Sounds like a few growing pains, but to be expected. It’s a whole new motorcycle again. Thanks for the detailed account of your breaking in period. It helps others on there projects also.

    • Mike,

      Indeed. When everything is disassembled and rebuilt, it takes some fiddling to fix your mistakes and improve the ergonomics. πŸ™‚


  2. Thanks for this post – makes me feel so much better about my own issues as I continue to work on my R90/6. Even after years of working on bikes, it’s the little things that can pop up and you just have to put your head down and sort it out.

    • Stephen,

      Indeed, it’s why I posted this one. Folks often think, mistakenly, that I’m a guru at airhead mechanics since I publish detailed documentation about the four bikes I rebuilt. But I am an amateur and there are always mistakes, tweaks and improvements to make after I “finish” a build. I expect that to happen and am reluctant to call a bike reliable until after I’ve put 2,000 miles on it after a rebuild. So I still have a way to go on this one. πŸ™‚


  3. Well, we all are human and I appreciate the information and determined troubleshooting that leads to a better understanding of ourselves and our machines. Hope that all the gremlins are purged from your bike and safe reliable transportation is the result.
    From all of my troubleshooting of my own created problems, I am glad that I didn’t pursue my aviation career. Pobody is Nerfect!
    Thanks for being a great example of true honesty and devotion.

  4. Brook, seeing as this project is almost wrapped up I’d just like to take a moment to thank you for the resource you have created here. I went through most of my 83 RS right along with you during the lockdown, and I don’t think I could have done it without you. I have a habit of tearing things apart and forgetting how they go back together, but I always knew I could find the procedure carefully documented on your site! Your presentation has just the right level of detail, without diverging into esoterica. Again, I express much gratitude for the many hours you have no doubt.spent documenting this restoration.

    One thing I haven’t done yet are my front forks and head bearings. What are your initial impressions of the cartridge emulators?

    • Hi Chris,

      Thank you for your kind words. It’s helpful to hear that the level of detail is useful and not too overbearing.

      The Race Tech emulators made a big improvement in low velocity fork compliance (aka, going over ripples and small bumps). The bike feels very planted and corners beautifully.


  5. Hello Brook, to occupy myself during covid-lockdown over here (UK) I’ve been refurbishing the carbs on my R75/6 rebuild. Now, it looks to me as though there at least 500 ways of setting the carbs up ranging from ‘get on your hands and knees and listen’ to ‘go out on a night with a full moon and pray to the god Bingus’.
    Given that you have probably done it more times than most I wondered what was your preferred method?
    Hope you’re staying safe in these awful times, best wishes, Martin King.

    • Hi Martin,

      For many years I used the “short out one cylinder” method of balancing the carburetors (see below). These days, I use the “Grok” Harmonizer which is back in production courtesy of Kat Dash:
      –> http://katdash.com/harmonizer/

      It beats the “twin max” balancer by a country mile for accuracy and ease of use.

      One key trick to getting them balanced easily is making sure the idle screw that opens the butterfly is at the same setting on each carburetor before you start balancing them. I put a piece of paper between the end of the screw and the tab on the end of the butterfly shaft it butts up against. I loosen the adjusting screw enough to slide the paper in between them and then tighten the screw until it just grabs the paper. Doing this on both carburetors gets the butterflies closely synchronized.

      Plug Shorting Method
      It’s important to ground the spark plug cap when balancing the carbs using the shorting method. I use an old spoke and the screw terminal off a spark plug. I screw the spark plug terminal about 1/2 way onto the end of the spoke and screw the other end of the terminal onto the threads on the top of a spark plug. So I need two spokes and threaded spark plug terminals so one is installed between each spark plug and the spark plug cap. I plug the spark plug cap on the end the spoke which fits snuggly in the hole of the spark plug cap.

      Then I use a plastic handle screwdriver to touch the spoke and the cylinder to short out one cylinder. The trick is to get the same drop in RPM for each cylinder at idle to balance the carburetors at idle. Then I lock the throttle so the RPM is at about 1500-2000 RPM and use the screwdriver to short each plug adjusting the throttle cable ferrule on the carburetor to get the same RPM drop on each cylinder.

      I hope that helps.


      • Hello Brook, thanks for your reply. Sadly the Grok device was available briefly but is now sold out! However I’ll try your shorting method. I’d been put off that before because I thought I’d read somewhere that it shouldn’t be used when electronic ignition had been fitted, I use a Boyer Bransden kit. Have you heard that yourself?

        best regards, Martin King

        • Martin,

          The caution is if you haven’t grounded the plug cap you can damage the electronic ignition. But if the caps are grounded, then there is no issue.

          BTW, Katdash is going to make more of them, but using a new design to eliminate a part that is no longer available. They likely have sold out of the last of the original design, but will offer V2.0 of the Grok at some point.


      • Hello Brook

        I’m still having minor carb trouble on my R75/6 but I did spot something which may be significant. The atomisers in my carbs are different sizes, one is 11mm the other is 12.3mm in length. I’m supposing both should be the same but which length? The Bing manual shows different part numbers for these atomisers but doesn’t indicate which is 11mm and which is 12.3mm! Do you happen to know what the difference means and which I might use?

        Best Regards
        Martin King

        ps I did enjoy seeing your son’s Siebenrock engine upgrade video. Is he pleased with the result?

        • Martin,

          I don’t know what length is correct for your atomizer, sorry. I suppose you should order one for the 75/6 so you can get the correct ones.

          Yes, Branden is quite pleased with the upgrade to my first BMW which I gave him several years ago. πŸ™‚


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