If you like our site, please consider joining our club!
By joining you will help ensure that we can continue to provide this service
JOIN HERE!

Timing Issue R 75/5; R 60/7

User avatar
cbclemmens
Posts: 216
Joined: Sun Apr 25, 2021 2:21 pm
Location: Apollo, PA
Been thanked: 4 times

Timing Issue R 75/5; R 60/7

Post by cbclemmens »

I have 2 old airheads with an identical timing problem, R 75/5 and R60/7. Both failed while running, as if the ignition switch turned off. Setting the timing by pulling the spark plugs, ignition on and turning the engine over with a hex key in the alternator bolt, the plugs fire with the F mark in the timing window. That is with the timing plate rotated full clockwise (maximum retarded). Getting one running, the timing light shows “F” at idle with the timing plate at full retard. I pulled the engine front cover off one to see if the timing chain had jumped a tooth. With the engine at TDC the timing marks line up perfectly.
Has anyone seen this before? With it happening to 2 of my bikes, it must have happened to someone else. Does anyone know how to fix this?

User avatar
Randolph
Posts: 74
Joined: Tue Jan 13, 2015 11:31 pm

Re: Timing Issue R 75/5; R 60/7

Post by Randolph »

I have the same problem with my R90/6. I have even filed the slot in the points plate to extend the rotation, but I can't get the gap AND the timing together. I finally set the plate to maximum rotation and adjust the gap to set the timing. Set the timing at full advance ~4K RPM, The idle timing doesn't matter so much. I use a dwell meter to check the dwell, but timing is more important.

I have tried three different back plates and different points with same results. I found the points marked Noris were the best. Snowbum says there were defective points years ago but they should be out of the supply chain by now.

My final solution was to install a crank driven EME hall effect timing unit. Set it once and forget it. I removed the advance cam from the points and keep it in the tool box for backup.

I'm not sure about the engine dying. I'd usually check the tightness of the grounds at the ignition coil.

-Randy

User avatar
schrader7032
Posts: 9016
Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX
Has thanked: 2 times
Been thanked: 29 times

Re: Timing Issue R 75/5; R 60/7

Post by schrader7032 »

I don't think it should ever come to filing the slotted holes in the plate in order to get the bike timed right. If BMW had meant for that, they would have made the slots longer. I'm guessing that something is wrong with the points gap. By that I mean, just setting it to the require 0.016" and then forcing the points plate to do the rest is not really the right thing to do. Sure that's the original design but things have worn. What you need to do is work with the points gap...it can vary some around the 0.016", I'd say 0.012" to 0.022", and things will run fine. Points gap is not that critical on a two-cylinder engine. The points are closed plenty long for the coil to charge up. A small points change makes a big difference in the timing.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

User avatar
srankin
Posts: 1054
Joined: Fri Jul 14, 2017 8:45 pm
Location: Spencerport, NY USA
Been thanked: 14 times

Re: Timing Issue R 75/5; R 60/7

Post by srankin »

Kurt makes a very good point, about points. The gap HAS to be correct in order to adjust timing. Please don't feel I am insulting you saying this. At one time I struggled with point induced problems and poor running.

One of my friend's bike had the condenser in the point system go bad and it caused major problems. Perhaps the points are fine but the condensers are not? I admit in my old chevy days, I would save a few bucks on not buying a new condenser when buying new points. This stopped the day I had a "good" condenser go bad and spent a lot of time scratching my head. Yep, it looked good, no moving parts what can go wrong, LOL.

While there was a batch of bad points on the market a long time back, you are most likely correct, they have made their way out of the supply chain, so I don't think this is your problem. Not unless some other source has opened up.

I am sorry to say, it has been a long time since I messed with points so I cannot give you a step by step guide to setting them.

Not to be a jerk but someone mentioned getting rid of them altogether. I didn't on my 77 R75/7 and swore some while making adjustments in parking lots while on trips away from home when the gap changed and the timing went out and pinging started. After the few and frustrating times points failed and I purchased my 78 RS, I went to a point free system and since then have never had to set or adjust timing in the miles I have put on it. The 77 was traded in for a 83 R80RT with electronic ignition, best thing BMW ever did was to upgrade. The 78 I purchased used and converted the system first thing.

I will ask at my friend's airhead shop if he has any ideas as to a solution to your problem.
Owner of a 84, R80RT and 78, R100RS

User avatar
srankin
Posts: 1054
Joined: Fri Jul 14, 2017 8:45 pm
Location: Spencerport, NY USA
Been thanked: 14 times

Re: Timing Issue R 75/5; R 60/7

Post by srankin »

By the way, I should clarify, I am NOT implying you are cheap and not replacing condensers, I meant that in my friend's bike, one went bad and we chased the points and all kinds of things before finding a supposed good, new condenser was bad.

I don't know but another thought came to mind, is there anyway, the wires to the points are shorting out?

Does the bikes have the nail style key into the top of the headlight? I have heard that those wear or get out of adjustment causing ignition cut out.

Good hunting, St.
Owner of a 84, R80RT and 78, R100RS

User avatar
cbclemmens
Posts: 216
Joined: Sun Apr 25, 2021 2:21 pm
Location: Apollo, PA
Been thanked: 4 times

Re: Timing Issue R 75/5; R 60/7

Post by cbclemmens »

Thanks you all very much for your suggestions. I already tried new points and condenser, set the gap to 0.014", which has not significantly retarded the spark. I will try changing the gap, wider and tighter. I am pretty sure the engine died because the timing shifted while driving.

Someone indicated that might be a pointless ignition system that would fit these engines. I could go for that. Is that off a later model bike? Is there an after market "bolt-on" available? Please if anyone knows where I could look I would be very grateful.

Craig

User avatar
schrader7032
Posts: 9016
Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX
Has thanked: 2 times
Been thanked: 29 times

Re: Timing Issue R 75/5; R 60/7

Post by schrader7032 »

Anton has a number of aftermarket ignitions at the bottom of this page:

http://largiader.com/articles/ignition/

There's another type called the Alpha...Motorrad Elektrik offers it. Snowbum also has a bit on other ignitions:

https://bmwmotorcycletech.info/Ignition.htm
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.

User avatar
srankin
Posts: 1054
Joined: Fri Jul 14, 2017 8:45 pm
Location: Spencerport, NY USA
Been thanked: 14 times

Re: Timing Issue R 75/5; R 60/7

Post by srankin »

Hello, I am sorry you are still having problems.

Please refresh my memory and perhaps give a bit more information.

Does the bike run now? If so, is the current issue setting the timing?

You mention the bike died, I agree a jumped tooth on the timing chain can kill the engine. I kind of think the BMW timing chain system and gears are pretty robust so unless you have a lot of miles on, or something drastic happened, I wouldn't think you jumped a tooth. I could be very wrong just adding my two cents worth.

So, agin not to be a jerk, if you are using a strobe timing light and cannot get the timing mark to retard to the timing mark in the correct position in the window, yet, it lines up and is good on static check. The problem may be as simple as your idle RPM setting. To set timing the bike has to be at idle, now I have run into various camps who have various ideas as to what the proper idle RPM should be, I won't go there except anything over 1000RPM is NOT idle for airheads. At that RPM or higher, you will be chasing your tail trying to get the timing correct.

Now one way to check timing with a light is to advance the RPM to 3000RPM and see where the full advance mark lines up.

To be honest, if the bike is running fine, and is not pinging under acceleration and load, the timing may be right where it is supposed to be.

Sorry for the long winding ramble. Cheers, and I hope you can get on the road soon. St.
Owner of a 84, R80RT and 78, R100RS

User avatar
cbclemmens
Posts: 216
Joined: Sun Apr 25, 2021 2:21 pm
Location: Apollo, PA
Been thanked: 4 times

Re: Timing Issue R 75/5; R 60/7

Post by cbclemmens »

Thanks Kurt I will check those out. If I can get rid of the points I will do that. (Keeping all the hardware so I can make it "stock" when I need to). The R 60 is not running. I can get the R 75 running but way too far advanced so I am not riding it for fear of damaging it. I have an R 90/6 with a side car that I am riding while I get the others fixed. I will let you all know how I solve this.

User avatar
cbclemmens
Posts: 216
Joined: Sun Apr 25, 2021 2:21 pm
Location: Apollo, PA
Been thanked: 4 times

Re: Timing Issue R 75/5; R 60/7

Post by cbclemmens »

Thanks srankin as well. To refresh your memory; Setting the timing by pulling the spark plugs, ignition on and turning the engine over with a hex key in the alternator bolt, the plugs fire with the F mark in the timing window. That is with the timing plate rotated full clockwise (maximum retarded). Setting the timing by this "static" method, the plugs should fire with the "S" in the timing window. The timing is probably 10 degrees too far advanced.

Craig

Post Reply