The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Red_Hen on August 31, 2011, 08:11:26 PM

Title: Adding Grounding Posts to Diode Board
Post by: Red_Hen on August 31, 2011, 08:11:26 PM

As I'm interested in making sure my diode board is well grounded on my R65, I did some searches online and read an interesting article by Karl with Evolution Cycles in Wisconsin.

Karl noted the poor ground qualities of most BMW Airhead diode boards and added two M8 bolts; running one on the positive side to the positive starter lead and grounding the negative side to two points in the case.

Wondering if any of you have adopted this approach with your bikes?

Here's a link to the story.  

http://www.evolutioncycles.com/airhead_ideas.htm

Title: Re: Adding Grounding Posts to Diode Board
Post by: Bob_Roller on August 31, 2011, 10:56:02 PM

The R65 doesn't have the grounding problems of other airhead BMW's .

The diode board on the R65 is held in by 4 threaded studs the studs thread into the forward engine case and there is metal to metal contact between the diode board and the studs .

Most other BMW's had rubber isolators instead of metal studs, they definitely require the additional grounds .

Title: Re: Adding Grounding Posts to Diode Board
Post by: montmil on September 01, 2011, 05:21:22 AM

There are several "kits" offered to add additional grounding points to the diode board... mostly for the earlier Mk Airheads. The R65 fitament does not need the mods as the factory did the job for you.

Title: Re: Adding Grounding Posts to Diode Board
Post by: Red_Hen on September 01, 2011, 07:10:32 AM

Now you tell me  :)

I already put the post on the board and now that it's there, I'm adding two ground wires between two top mounting holes and engine casing.

I'll be "well grounded"

Title: Re: Adding Grounding Posts to Diode Board
Post by: montmil on September 01, 2011, 10:22:47 AM

Quote

... I'll be "well grounded"

Yes you will and with no worries, Mon.


Remember this little wiring tip:
Electrical circuits, just like coffee and divorces, begin with good grounds. ;D

Title: Success
Post by: Red_Hen on September 01, 2011, 06:10:32 PM

Don't know exactly what the RX was but grounded Diode board, cleaned all connections and used a high pressure air hose on connectors + dialectic grease.  Also charged battery.

Started up and red gen light went out - will have to put some miles on to know for sure but sure am learning about the electrics on Airheads.

Title: Re: Adding Grounding Posts to Diode Board
Post by: nhmaf on September 01, 2011, 07:56:31 PM

Well, that IS good news!
On my '82 LS, I noticed that :
1.  The original mounting studs were still the earlier, rubber type, and,
2.  The BMW kit of (2) brown ground wires with metal ring terminals were already installed on the upper (2) mounting bolt locations as they should be.

I'd also installed an improved diode board (from Motorrad Elektrik) last year or the year before, and that came with larger guage ground wires, which I replaced the smaller ones already on the bike.   The usual grounding point is that bolt hole in the case directly below the diode board and above the rotor.

Your problem(s) was probably a combination of factors with loose connections and/or loose ground connection at the diode board.   We'll keep our fingers crossed for you that all is well now!

Title: Re: Adding Grounding Posts to Diode Board
Post by: Red_Hen on September 02, 2011, 06:59:21 AM

I'll add that 2/4 mounting bolts for diode board were missing when I opened up the "chest" cover.  Ordered 2 and should have in a few days.

I'm thinking a bad ground and loosely mounted diode board may have been part of the problem.