The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Patrick_Krivacka on April 06, 2010, 02:42:43 PM

Title: tach not working/hookedup
Post by: Patrick_Krivacka on April 06, 2010, 02:42:43 PM
Took my new to me '80 r65 out for a short spin yesterday and remembered the tach isn't working/ hooked up. The PO had mentioned this in one of his original emails, but I had forgotten it. How hard is this to hookup and how would one go about it? thanks
Title: Re: tach not working/hookedup
Post by: Bob_Roller on April 06, 2010, 03:02:32 PM
The signal for the tachometer, comes from one of the ignition coils, I assume you have the dual coil set-up .

One connection of the coils should have a couple of  black wires, one for the coil, and one goes to the tachometer .
Title: Re: tach not working/hookedup
Post by: Patrick_Krivacka on April 06, 2010, 03:13:45 PM
Thanks Bob. one more thing to add to my list.
Title: Re: tach not working/hookedup
Post by: Patrick_Krivacka on April 07, 2010, 10:12:36 AM
anyone have experience with acewell speedo/tach replacements? Since my bike is a frankenbeemer (read 'new nc r65' in the chit chat section) I might as well make any changes that I like.
Title: Re: tach not working/hookedup
Post by: NC Steve on April 07, 2010, 11:03:03 AM
Quote
anyone have experience with acewell speedo/tach replacements?

Nope, but you might want to take a good look in here too, http://www.trailtech.net/computers.html , at the various electronic gauges available. There are kits out there that'll do just about everything but steer the bike for you.

 Several members here have used the Vapor combo system, and a search should turn up some older threads about the installation, price, etc. As I recollect, they were surprisingly inexpensive, especially when compared to rebuilding stock BMW gauges.
Title: Re: tach not working/hookedup
Post by: Patrick_Krivacka on April 07, 2010, 02:25:39 PM
thanks steve. I did the search and found a lot of good info. I must say I prefer the acewell as far as looks are concerned, but the vapor seems like a good product too.
Title: Re: tach not working/hookedup
Post by: Rob Valdez 79 R65 on April 07, 2010, 04:22:26 PM
i-man, I would not be surprised if the tachometer in your instrument cluster is cable-driven.  I don't know what year the type-247's (non-r65/45) switched to an electronic tach.  Our bikes (type 248) have had electronic tach since inception.

You could find an electronic (BMW) tach if you like the look of stock, and install it.

Or there are several aftermarket alternatives.
Title: Re: tach not working/hookedup
Post by: montmil on April 07, 2010, 09:14:10 PM
Looking back to the earlier posted photo of the new i-man "R65" it appears that the gauges are very different from OEM R65s in that there's no instrument cluster housing, cow's tongue, central ignition switch nor turn signal idiot lights.

A veritable rolling Buffet of BMW Bits, this one is.

Monte
Title: Re: tach not working/hookedup
Post by: Rob Valdez 79 R65 on April 07, 2010, 09:58:25 PM
Quote
Looking back to the earlier posted photo of the new i-man "R65" it appears that the gauges are very different from OEM R65s in that there's no instrument cluster housing, cow's tongue, central ignition switch nor turn signal idiot lights.

A veritable rolling Buffet of BMW Bits, this one is.

Monte


It is a BMW cluster, just not one from a '78-'84 R45/65.

It also appears to have a type 247 head light bucket, so the ignition switch is most likely on the left side mount of that.

This cluster is from a 'S' model, but it will give you the idea:
http://www.mklsportster.com/r100s/r100s%20-%20cluster.jpg
Title: Re: tach not working/hookedup
Post by: Patrick_Krivacka on April 08, 2010, 07:10:20 AM
yes, the ignition switch is on the left side. My motorcycles a freak ; (
Title: Re: tach not working/hookedup
Post by: Rob Valdez 79 R65 on April 08, 2010, 04:09:41 PM
Your motorcycle is not a freak, i-man.  This sort of thing is quite common with airheads.
Title: Re: tach not working/hookedup
Post by: Patrick_Krivacka on April 08, 2010, 07:25:27 PM
thanks rob. i'm just goofin' around. I love the little freak!
Title: Re: tach not working/hookedup
Post by: Patrick_Krivacka on April 18, 2010, 07:55:01 AM
i finally got around to taking my bike apart to do the spline lube this weekend. I discovered a wire (as well as a very funky coil installation. see my thread 'weak battery') that didn't have a home. could this be my tach?
Title: Re: tach not working/hookedup
Post by: Barry on April 18, 2010, 08:08:14 AM
The wire to the Tachometer is black so that could be the one. It connects to term 1 on the front coil of a twin coil set up or the earthy side of a dual output coil.
Title: Re: tach not working/hookedup
Post by: montmil on April 18, 2010, 10:22:35 AM
i-man, suggest you trace any/all loose wires prior to plugging them into a potentially incorrect circuit or spade connector. Did you mention if you have a manual w/wiring diagram? Could save... something.

Monte
Title: Re: tach not working/hookedup
Post by: Patrick_Krivacka on April 18, 2010, 12:01:40 PM
Barry, problem is my coil is very non-original. i have a photo of the coil that the PO rigged up in the thread titied 'weak battery? '.
Monte, good suggestion on checking with the manual.
Title: Re: tach not working/hookedup
Post by: Barry on April 18, 2010, 12:35:50 PM
Quote
my coil is very non-original.
It doesn't matter what the coil is it will still have two connections :-

One will connect to the the ignition switch via the engine stop. Original wire color green/blue.

The other will connect to the points or ignition module. Original wire color Black.  The tacho wire doubles up on this connection.
Title: Re: tach not working/hookedup
Post by: Patrick_Krivacka on April 18, 2010, 01:27:11 PM
thanks for that barry. Assuming (yes, i know all too well what happens when you ass u me) that that is the tach wire, what would I need to contrive to get the connector in the photo to connect to the coil? Would I have to hook some kind of male connector to the coil? other?
Title: Re: tach not working/hookedup
Post by: montmil on April 18, 2010, 03:50:18 PM
Quote
...what would I need to contrive to get the connector in the photo to connect to the coil? Would I have to hook some kind of male connector to the coil? other?

Check out a solid hardware store like Ace or a Radio Shack or similar and prowl through the electrical connector bits. From the photo, it's hard to tell what you've got with your "fence post" coil rig, but you should be able to fab a workman-like attach point.

Monte
Title: Re: tach not working/hookedup
Post by: Patrick_Krivacka on April 18, 2010, 05:21:53 PM
'workmen like' is something I'm comfortable with. I'll see what i can work up after figure out that it is, in fact, the wire for the tach. thanks all.
Title: Re: tach not working/hookedup
Post by: Rob Valdez 79 R65 on April 19, 2010, 01:02:08 PM
i-man,

There are brass or copper spade connectors that are 'U' shaped, with the arms of the U spread out a little.

On the flat, or bottom of the U, is a hole for the nut & threaded stud connector on most coils.
Finding these on a shelf might be a little hard.  You might try an auto parts store, too.
If worse comes to worse, I have a couple of old ones on my old coils I replaced a few years ago.

Please check these two wiring diagrams (depending on the year of the wiring harness):

1978-1980 (http://www.pbase.com/tomfarr/image/121670650/original)

1981-1984 (http://www.pbase.com/tomfarr/image/121670651/original)
Title: Re: tach not working/hookedup
Post by: Patrick_Krivacka on April 19, 2010, 09:18:19 PM
thanks for the links rob. one (of many) things I don't understand about wiring diagrams, is how do I determine that this one wire is the one for my tach? I mean, it just pops out of the harness, so how do I trace it back to the tach? also, a few people have commented on my instrument cluster being originally for a bike other then the r65. how does this fact fit into the equation?
Title: Re: tach not working/hookedup
Post by: Rob Valdez 79 R65 on April 19, 2010, 09:34:55 PM
Quote
thanks for the links rob. one (of many) things I don't understand about wiring diagrams, is how do I determine that this one wire is the one for my tach? I mean, it just pops out of the harness, so how do I trace it back to the tach? also, a few people have commented on my instrument cluster being originally for a bike other then the r65. how does this fact fit into the equation?

What color is the insulation?

Brown is ground.

I think there is a green (or green/blue, as Barry said) or a combination of these two that connects to the coil.

I'm not sure what the black wires are for.  (I am at work, and I can't see the wiring diagrams.)
But they are not ground.

Title: Re: tach not working/hookedup
Post by: Patrick_Krivacka on April 19, 2010, 09:40:07 PM
thanks for the fast response! i'll have to check, but it's black with a ? stripe. i'll look tomorrow. any thoughts on how the non r65 cluster fits into this puzzle?
Title: Re: tach not working/hookedup
Post by: Rob Valdez 79 R65 on April 19, 2010, 10:08:44 PM
Quote
any thoughts on how the non r65 cluster fits into this puzzle?  


Speedometer - no problem.

Tachometer - look at the leading edge of the instruments, down below, and see if it has a place to put a tach cable with threads for a retaining ring (just like the speedometer).  If that is what you have, you will never get it to work with your R65 engine.  The older engines had a cable take-off at the bottom-left side of the timing cover.  It probably drove off the camshaft.

The various lights were hooked up to the R65's wiring harness as best as they could manage, I expect.  It wouldn't be real hard, but it would make a mess of something.

If you want a working tachometer, you will need to replace what you have.
BMW has one that is identical to yours, but electronic.  I suppose you could just replace the tach side.  It's been a long time since I've seen the inside of one of those clusters.

Or, if you don't mind going hi-tech, you could get one of these digital clusters like a couple of the guys here have done.  That will give you a tachometer, I believe.  (and a bunch of other goodies).
Title: Re: tach not working/hookedup
Post by: Ed Miller on April 21, 2010, 12:29:52 PM
The diagram posted by Rob above only shows a brown wire going to the tach.  I'm not sure how that's even possible.  I just had the same wiring diagram printed up here at work full size color (19" x 28") and laminated.  These people sure are friendly.  

Title: Re: tach not working/hookedup
Post by: Patrick_Krivacka on April 22, 2010, 07:29:27 AM
thanks ed. I hope to be able to look into it this weekend and I'll report back. Is there a problem with riding without the tach? I sure hope not!
Title: Re: tach not working/hookedup
Post by: nhmaf on April 22, 2010, 08:36:31 AM
I-man, just don't over-rev the engine without the tach on there and you should be fine..

Ed, I checked the diagrams from Rob's links and they appear to be basically the same diagrams as that are found in the Haynes manual, though it appears perhaps someone tried to correct/augment the Haynes manual's diagrams because the Haynes manual doesn't even show the tachometer at all (at least my copy doesn't)

I checked my Clymer manual, which has the wiring diagram drawn different (and is harder to read and not colorized) but at least it does show the tachometer in the circuit.   The tachometer wiring shows that it should have (3) wire connections:  
a Brown wire (to ground)
a Green/Blue wire (to +12V power with keyswitch on)
a Black wire going to the primary (low voltage) side of one of the coils - it actually shows it connecting to the same terminal on the coil that the ICU wire does (81-84) or the Black wire from the condensor (78-80)

Hope this helps,
Mike