Airhead Tech Pages

Timing a '79 R65


1. Disconnect battery ground (I'd recommend taking it off at the battery - since the bolt into the tranny likes to strip it's threads if it's used a lot.)

2. Remove front cover - about 4 allen bolts

3. I'm assuming we're gonna set the points, and/or replace'm.. so this is easiest done with the timing canister outta the bike.. MARK where it currently is located (white-out is good).. remove two allens and disconnect the wire. Remove point canister

4. Remove two screws in front cover, remove front cover

5. IF replacing the points - you gotta take the endshaft bridge outta the way - two screws if I remember right. Replace points and roughly pregap them (from memory I seem to remember 0.016" - just checked, manual sez 0.016"-0.020".. go for the wideish side, ie 0.020" since they will tend to wear closed. Use a little white grease on the rubbing block on the points - ie, the part that rubs on the timing lobe and makes the points open/close. It will last LOTS longer if you do.)

6. Replace the endshaft bridge - now you gotta regap the points since they will have moved a bit due to alignment of the front of the shaft. Do it..

7. Take a drop of motor oil and drip it onto the bronze bearing in the endshaft bridge.. if you don't it will squeel like hell.. let it soak in for a bit, then use paper towel to remove any excess. 

8. Put cover back on, put canister back in position as you marked it and tighten the mounting screws so it moves if you use your hands, but doesn't move by itself. Reconnect wire.

[NOTE - shaft mating between the points shaft and the end of the  crankcase can ONLY be done one way - it will be pretty obvious -  mating slot thingie is off center on purpose so you  can't screw it up..]

9. Reconnect battery

10. Turn engine over (CW) while you watch the timing window. This is easiest to do using an allen wrench in the alternator bolt - but ONLY if you've removed the plugs.. get your whiteout handy.. You're looking for:

"O" - which is "on-top", or Top-Dead-Center
"S" - which is the no-advance, Static mark
"F" - Full advance

Make a mark on the flywheel parallel to each'a these marks with the whiteout - it will make the actual timing LOTS easier. (The R65 flywheel is smaller than the larger engines - but the timing hole is in the same spot - making the marks much further away and harder to see when the engine is running - the whiteout markings will make the job MUCH MUCH easier!)

11. If you took the plugs out to make the marks - put'm back in.

[NOTE: Anti-seeze is a good thing on the threads. Don't overtighten'm. IF they are stiff at all - stop what you're doing - go to a good auto supply place and get a thread-chaser die - made for sparkplug holes. The threads can buildup carbon over time and cause binding which will eventually strip out the threads. I chase mine with the die (which won't remove any metal if the threads are OK - just carbon buildup) at the slightest sign of resistance in threading plugs in. They SHOULD go in by hand until they bed down - then about 1/8 turn with a wrench to tighten them.. If you have to use the threadchaser - use some engine oil on it to capture the carbon..]

12. Hook timing light up to either cylinder and +12v and ground

13. Start engine.

14. Shine timing light at the hole. Let engine warm til it idles well at around 800rpm. Pull trigger on light. You want the "S" mark to line up with the little slot on the left side'a the timing hole. If it does.. good. If not, turn canister by hand clockwise or counterclockwise until it does. Prolly a GOOD IDEA to wear a glove on your left hand. Exhaust burns are painful (BTDT).

15. Once above is TRUE - rev engine - fully advanced is reached somewhere > 2,500 RPM, forget exactly where, but you'll know 'cause it stops advancing! (DUH!).. When it stops advancing - the F mark should be lined up with the notch in the timing hole window.

[NOTE: If 14 and 15 can't be achieved at the same adjustment point - it means the advance mechanism in the canister is gummy.. which requires taking the whole damn fandango apart - if this is the case, write me and I'll go over that little can of worms.. but the most important adjustment is the FULL advance one - if it's too far advanced you could hole a piston or sumthin.. so you want this one RIGHT on, and the idle one isn't near as important.]

When done - tighten bolts holding the canister in place, and check timing again. It will usually drift just a bit, so it's back to make a final tweek.

[NOTE: Watch how long you run the engine doing this - you can overheat the engine - especially the first time you do it. If you have a LARGE fan - place it in front of the engine to keep air flowing around it. If you don't - limit the amount of time you run the engine, and let it cool a bit between trys..]

16. Once you've done all this and are HAPPY - disconnect battery lead again, and reinstall front cover. Reconnect battery lead.

(The reason I'm *strongly* suggesting this - it's very easy to short the diode board which lives under the front cover when taking off and installing the front cover - and it's costly if you do it.. disconnecting the negative lead on the battery avoids this unneeded expense!)

17. Take it out for a run!

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R-Tech pages maintained by: John Petty for the original author(s) and the Internet BMW Riders
Last Update: 11 September 2010