Wheel Bolt Issues - (Trail Tech Speed Sensor)

[ross_g]

Hi Guys,

Managed to get out today and attempt to fit my Trail Tech speedo. Things we're going well until I started on the speed sensor.

So a general question, I was trying to remove one of the wheel bolts to replace it with the supplied magnetic bolt, however when "unscrewing" any of the bolts the things simply rotated but didn't come out. One side of the wheel was using an allen key type bolt and the other side a nut. I've attached some pictures if anyone can shed some light on whats going on. I hope it isn't threaded.

Second question, has anyone fitted a Trail Tech Speed Sensor to an R65? With the front wheel having two disc breaks there doesn't seem to be an easy mounting point for the sensor. Any ideas?

I've attached a couple pics of the mounting of the speedo also, it actually fits quite nicely on my renthal bars.

[Bob_Roller]

I'm just taking this at face value on what you posted .

You need to have an allen wrench in the bolt head and a socket on the nut side to loosen the the fastener .

[georgesgiralt]

Hello !
Is the yellow light on display a charge light , If yes, where is the oil light ? If no, you'll experience charging problems soon....

[ross_g]

The yellow / orange light is the ignition light that shows when the electrics are on. I haven't got under the tank yet to sort out all the wiring / lights.

Can you expand on your rather cryptic statement?

[Bob_Roller]

The airhead BMW bikes, have a unique 'feature' in the charging system .

The red 'GEN' light is part of the excitation circuit for the alternator .

If there isn't a light bulb, or a 330 ohm resistor in the circuit, the alternator will not work, you'll just be using the battery as a power source, the battery will discharge in about an hours use, possibly less .

[ross_g]

Ah good to know, I'll have a look when I go under the tank and see whats what. I have actually got the batter on charge now as it ran down pretty quick so that might actually be the issue. I'll let you all know, thanks for the heads up.

[montmil]

I have the TrailTech Vapor digital instrument on my '81 R65. I didn't even consider using the wimpy looking, magnetic-head bolt supplied to trigger the speedometer sensor.

Instead, I scuffed and cleaned a small, circular pattern on the brake rotor mid way between two of the bolts. I then used old 'ol J-B Weld to secure the rare earth magnet to the disc. Been there for years now.

I also trimmed away a small portion of the raised ridge on the front of the fork lower to match the length of the sensor. Relieving the standing ridge provided more contact area to attach the sensor.

A new Vapor is on the bench; soon to be fitted to my R100S. Will use the same install technique.

[ross_g]

Cheers Montmil, think I'll do something similar, it occurred to me that the bolts in the front wheel might be full bolts with a nut on one side, I need to go out this evening and have a look but I've not be able to find an exploded view of the front wheel. I have to say so far the Haynes R65 manual - well the twin manual - is pretty crap.

[montmil]

Ross_g,  For some decent exploded views of major assemblies, check out the parts fiche on most all BMW dealer websites. Here's a few I occasionally refer to:

http://www.ascycles.com/
http://www.bobsbmw.com/
http://maxbmwmotorcycles.com/

[Ed Miller]

Mine is set up like Monte's, and works well.  

[montmil]

BTW, the untrimmed black zip tie shown in the photo was originally installed as I really didn't trust the double-face foam sticky tape used as the sensor attach. The zip is still on the bike, but trimmed properly.

On this deal, I'm kind of belt and suspenders sorta guy.

[Ed Miller]

That double sided tape didn't hold with mine.  Maybe something to do with constant high speed road spray, mixed with dirt.  I use a couple of those cable tires.  Trimmed.

[montmil]

That double sided tape didn't hold with mine.  Maybe something to do with constant high speed road spray, mixed with dirt.  I use a couple of those cable tires.  Trimmed.

I knew it might happen! And even trimmed, too. [smiley=beer.gif]

Any bets the off-road enduro racers have theirs secured with something besides sticky tape. Yep. Bet so.

[ross_g]

Just a quick on monte, what did you do to mill out that section on the fork? Just a file and elbow grease?  

[montmil]

Just a quick on monte, what did you do to mill out that section on the fork? Just a file and elbow grease?  

First two cuts were made with a round chainsaw blade file. These woody-woodchuck files are great for detail metal work in aluminum or steel. I did not want to leave a 90-degree square corner on the fork leg for fear of introducing a stress riser.

A small mill file dressed down the remaining section of the standing ridge.

Done.