BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

celticus wrote:What is the "Clipping Resistor" for?

Mark

You might check out the thread for a detailed explaination, but the quick one is - it prevents voltage spikes from getting into your electrical system. Some relays use a resistor, some a diode. Problem with a diode is you have to maintain polarity or the smoke will come out (or in this case - nothing will happen since the ZFE will shut off it's output when it sees a short..)

EDIT - most relays have either a resistor or a diode built in - it should show on the wiring diagram for the relay. I'd suggest getting one with the resistor since it's polarity insensitive.

Don, If that is so my relay must have one built in. It works just fine without an external resistor. That schematic might be a little misleading to a novice although it did finally answer most of Frede's questions on the actual wiring of the aftermarket horns.

Mark

celticus wrote:Don, If that is so my relay must have one built in. It works just fine without an external resistor. That schematic might be a little misleading to a novice although it did finally answer most of Frede's questions on the actual wiring of the aftermarket horns.

Mark

It will work fine - the risk is damaging other electronic components on the bike. Chances are good there is one built in, if it has a diagram it usually indicates it.

I wouldn't lose too much sleep over this. The diode or resistor is there to limit the voltage surge that occurs when the current to the relay coil is interrupted. But the inductance of the relay coil is certainly less than the inductance of the horn you're replacing, and it's the inductance that causes the surge. So it's pretty safe to say that any other components on the bike already have adequate protection built in.

Well, There you go.
Thanks Neil.

mark

I had to look up that resistor also. After reading the explanation I remembered that most, if not all, the relays in the old telephone central offices (where the dial tone came from) had a similar component, although it was composed of a resistor and a capacitor. The difference was that those relays operated thousands,or tens of thousands of times a day and usually operated through contacts of other relays. I rarely operate my horn, preferring to use the brakes instead, but it's nice to have a loud one when you need it. So I wouldn't worry about the resistor, but it shows how much thought the person that made that schematic put into it.

Close, but not quite right, Harry. I don't want to turn this thread into even more of an electrical engineering course, but I think it's worth understanding the distinction.

You're absolutely right about the telephone exchanges. If the relay coils were unsuppressed, there would be a tiny spark across the constants of the relay connected to the coil each time the contacts opened. Over time, this would degrade the contacts. It might take years, but that equipment was designed for 30+ year life, so it was important.

The solid-state circuit driving our horns is different. If the electronic switch has a maximum voltage rating of, say, 60 volts, a surge voltage of 61 volts could destroy it. And that's not over time, it could happen on the first surge. So it is necessary that the circuit be equipped with protection sufficient to suppress the maximum expected surge. Again, since the relay we're adding produces smaller surges than the horn we're removing, it won't be a problem. However, if I were adding a second horn without a relay, I might want to investigate the situation further.

Got the horn, a Stebel wiring kit (thrown in), a Centech AP1, a Blue Seas 60++++amp Maxi fuse deal$32y, 8 and 14 gage wire, plus connector$ and $older and Silicon Sealer/shrink tubing.........yup count on a BMW owner to turn this in to a NASA project...I bet I'm in $110+ without the damn horn and I haven't even fried the damn CAN-BUS System yet $$$$$ $$$$$ $$$$$ $$$$$


btw............thank you Deil for all the great diagrams, and coacing on horns, canisterectomy..You too Neil..but I'm not an engineer

Schedule.
Tuesday Morning..work & buy more connectors
Tuesdat Afternoon..Canisterectomy
Tuesday Afternoon late "dummy in the Centech and Blue Seas w/ wireing.
Wendsday Morning connect electrics, and test fire.
Wednesday Afternoon..Drink heavily, and call dealer//"the F'n Bike won't start should have bought a Honda!!"

Schedule.
Tuesday Morning..work & buy more connectors
Tuesdat Afternoon..Canisterectomy
Tuesday Afternoon late "dummy in the Centech and Blue Seas w/ wireing.
Wendsday Morning connect electrics, and test fire.
Wednesday Afternoon..Drink heavily, and call dealer//"the F'n Bike won't start should have bought a Honda!!"

So three weeks later, I'm almost done All wired, horn works, and no can-bus issues. In the morning I am going to work on a couple photos, water proofing, some zip ties, maybe more tape, put my panels on and I am done .....for the moment.. my horn bracket need beefing up, and thanks to the openness of the Centech fuse block, and maxi fuse "open ness" a huge0gr sure would help with weather proofing.

Glad to hear it's coming along. Now you just have to visit Frede in LA..

Frede found a sharp BMW mechanic that is not scare of can-bus issue
and is willing to do it at home for under $300
but Frede have some "apprehensions" to give him all the addons, relays, switches and stuff
without any precise strategy prior to start the install.

Many point remains to be understood
Such as :
A) How to precisely connect the whole thing add-ons, relays, switches and stuff... SAFELY
B) How to position and secure mechanically the horn and all the other add-ons, controllers, switches, relays etc.... in proper location all over the ---> F.U.C.K.I.N.G bike .
C) How to re-locate the canister (Mechanic not "OK" to remove it)
D) Despite understanding how to wire everything Frede need some information's on what to avoid while installing everything, what are the tricks, things to do or stuff to buy and use to make the whole install SAFE !
E) To finish Frede is kind of sick to browse this forum to capture various chunks of information's rather than a more didactic and exhaustive source of information.

Frede has all the add-ons at home now:

1) Centech fuse box AP-2
2) Nautilus Horn + relay kit
3) 1 pair of Photonblaster caliper LED's
4) 2 Hella FF50 installed on Lumalink brackets
5) Scorpio Alarm SRi-900 last generation w/RfiD
6) Cellphone/GPS cable for charging while riding, must pop from the seat or in between Gas tank and handlebar.


Frede kind of canceled the MFW/Kellerman Masterflash mirrors
because its too pricey and I guess not that useful after all .

And Frede is actually so pleased to have bought a Cayenne Pro Jacket in all Black...
This jacket is very smartly designed, well manufactured, comfortable and elegant.
This is WORTH the $600 investment compare to many other brands +/- priced $100 cheaper.
I bought it a bit a tiny snug which allow me to wear it almost like a sweater...no need to open it at all while not on the bike.
It fit like a second skin.

ITS A RECOMMENDED GREAT GEAR !

I have to give a report on the HORN. I was hesitant to spend the money and time to install this horn because I rarely use the thing.

This weekend I was in Virginia, while leading six bikes along a rural highway (Rt11 Lexington) a car pulled out from the left and proceeded along in front of us. No great drama for a bunch of experienced riders but it was close. I rolled up to his rear bumper and gave him two blasts, the results were spectacular -
the driving lights attached to the horn delivered two blinding flashes to the interior of the car accompanied by two ear piercing blasts. The passenger ducked down in the seat and the driver veered across the line toward the other side of the road. It was like he was hit by two proton torpedoes.

I don't want to hear about pulling this half brain dead driver in danger. He endangered me and my riding buddies and without the precise and coordinated efforts of all the riders involved there could have been a nasty motorcycle accident and he would have been on his way down the road totally ignorant of the carnage he caused behind him. Turn about is always fair play.

I could have used some proton torpedoes or at least a death ray several times this weekend myself.

Mark

Hey, everyone... I'm about to do the horn replacement with a Fiamm and went hunting for the pigtail. After ordering the wrong part from Touratech, I can tell you that the search term to use in google is 83300402344 with no spaces or dashes. It's available all over the 'net for $20+- if you search it with the spaces in it as in a prior post nothing comes up.

Thanks for all the great info!

Bob

Don

I purchased the louder snail type horn from Aerostich and Hermy's installed it in place of the original.

John L.

Just added a Wolo “Mini but Loud” horn to my bike. Based on a post someplace around here to the effect that canbus-wise our bikes are like the two-horn RT, I didn’t bother with a relay. I used Posi-Tap connectors attached to the leads going to the factory horn and mounted the Wolo on the right-side U-shaped fuel tank bracket. Less than $20, and a marked improvement.

On my R1200S I installed the Fiamm Freeway Blaster (just the low and not both horns). Used the original connectors and that thing is loud enough for me. That gadget is available for a few dollars everywhere. Except here in Germany which is why my sister had to bring it with her on a visit from Canada.

Brgds
Oliver

I like the sound of two Fiamms at the same time, one of higher and the other of lower pitch. This sounds just like a really loud car; I think it gets more attention than a single-note horn.

And it's possible to mount two Fiamm horns up there even with the canister in place.
See: viewtopic.php?f=20&t=21512&p=189145#p189145

Hi David,

I have noticed in the post you refer to that you used extensive zip ties. How did that work over the years? I have had problems with zip ties being broken after some ice-cold winters which affects the plastic I suppose ...

Brgds
Oliver