Rewiring an airhead

  • Thread starter Thread starter Fuzzy Duck
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Fuzzy Duck

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Hi folks

After months of labour and head scratching I've just about finished completely rewiring my GS. Every single wire & connector I could replace has been replaced (and I'm not talking wire looms either).

I've also done a few modifications to accomodate the extra fuses for alarm, grips, etc and added a voltmeter.

If anyone is interested I'll write a long and tedious account of what I've done, why, how, cost, tools, what I've learnt etc.

However I'm concerned that this really is dull anorak stuff and inhaling all those solder fumes has made me believe such an article would be interesting.

So is anyone at all interested?

Or is it one for the BMW journal...?

What do you reckon?
 
The last bike I completely re-wired was a single cylinder R26 of about 1964 vintage.

I would be very interested as to what you did, and how you went about it!

Mick.
 
Re-wiring

Hi Paul,

Now that the gearbox is out of the way I have nothing to winge about so post some details and I will get my sidecutters and wire out. Think Chris(aka Nobbie) has also done the rewiring and changed the diode board. Reckons it does make a difference in the whole electrical system and improves the lot.


Cheers
Dirk

:gringo
 
OK - you asked for it, so here we go...

First of all why did I do it?

Various reasons - I managed to destroy a lot of the original loom after the some of the wiring around the exhaust got loose, melted on the exhaust, short circuited and turned most of the loom into a kind of bizarre electrical heater. This caused other parts of the loom to melt its insulation, fuse into other wires and incapacitate the bike. I bodged the wiring to make the bike run, but it was messy. Adding extras resulted in lots of strange wiring and fuses littered all over the bike. After reading an article on the Airheads website (http://www.airheads.org/contrib/wireupgrade.html) I thought I'd have a go at putting everything right. The bike also had a cold starting problem that made me suspect some kind of electrical problem. As it would start OK if I managed to get it to fire up straight away - otherwise I would press that starter for ages, but the thing just wouldn't fire.

After making the decision to do it I started looking around for suitable materials. In the article mentioned above, stainless steel terminals are reccomended. I spent hours if not days trying to source these in the UK - mainly trying marine electrical suppliers as well as all the other big names, but I just couldn't get them - so I gave up.

However I did discover Vehicle Wiring Products (VHP), 9 Buxton Court, Manners Industrial Estate, Ilkeston, Derbyshire DE7 8EF, tel: 0115 930 5454, email: [email protected].

I have to say that these guys are just fantastic - and supplied EVERYTHING I needed. Wire, terminals, heatshrink, sleeving, etc... Get hold of a catalogue and enjoy! The range is excellent, the wire colour schemes are vast and they do a great range of non-insulated terminals (more about this later). They do a postal service too - but I live nearby so popped in to buy stuff.

I then started making a kind of inventory of every wire on the bike, how long it was, and where it went, as well as looking at the wiring diagram. Then I placed my first order. I decided that I wanted all the fuses in one place and all the realays in a bank. I also decided that all those crappy connectors (like the ones behind the headstock) that link one type of loom to another would have to go. All terminals would be crimped and soldered and covered in some kind of insulation. I knew I was serious when I took my hacksaw and angle grinder to the frame to remove some of those fixtures that hold the fuses and connectors (I'll post some pictures later).

I adapted my plans as I went along, as I kept changing what I wanted to do and where things would go. At the same time I had to ensure that all the wiring was going where it was supposed to go and that it would be easy to replace, upgrade etc.

The main changes to the original layout are as follows:

There are now 5 relays in a row, running lengthwise under the tank that are secured my some bits of ally (the immobiliser and FIAMMS both need a realy each). The 7 fuses are located in a waterproof fusebox that I have mounted where the original one was on the left hand side of the battery. I considered mounting this on the bars after seeing a KTM Paris-Dakar bike set-up like this - but decided that they would be better hidden away from curious fingers.

The FIAMM horns and Sola-Larm are mounted on a welded metal bracket located aobve the battery - but I plan to move these as I since bought a tool tray. I've also installed heated grips, a voltmeter (which is just a brilliant instrument) on the handlebar cross bar - thanks to some natty little 'p' clips.

The basic wiring layout is the same as the original wiring diagram - but the additional items have been added to this. Most of the wire is thinwall cable, multi-strand copper (32 strands), 1mm diameter, rated to 16.5 amps which is good enough to cope with most currents such as lights, etc. VWP have 95 different colour schemes for this kind of wire and all the types needed to copy the original colour scheme. They supply it from as little as 1metre - I bought quantities of 2metres for about half of the wiring then larger quantities of brown (for earth), black & green (for the circuits that are energised through the ignition switch) and various others... However i didn't get it right first time and had to order more bits and pieces on about 4 more occasions - I guess if I really took my time and thought it through I could have got it right first time.

I have bought some bar risers and have left some of the wiring around the headstock loose - so that I can install the risers anfdthen shorten the wires accordingly so that it is tidy.

Tools:
Good quality crimpers + cutters
Good quality wire strippers (I have some professinal ones that make it a doddle)
Heat gun (for heatshrink - much better than a soldering iron)
Soldering iron
Wire holders (crocodile clips on arms that hold the wires in place), Extension lead (so you can solder where you like)
Hacksaw & angle grinder (to remove exisitng brackets and make new ones)

Materials:
Loads of different wire - make sure it's capable of handling the amps for each circuit
Non-insulated terminals - various types to suit different locations
New fuse box and fuses (all fuses are now the blad type)
Solder
Heatshrink - various diameters to suit different applications - basically small, medium and large
PVC sleeving, spiral and slit (which is fantastic)
PVC blade insulations (that fit over terminals to protect them)
P clips (for mounting instruments and holding wiring around handlebars (nicer than cable ties)
Releasable cable ties - to secure main parts of loom to frame
PVC tape (adhesive and non-adhesive)
Interlocking relay holders (you can link as many as you like together - nice!)

I AVOIDED:
Insulated terminals (harder to solder I think)
Using adhesive PVC tape on wiring as all the wiring gets sticky and it's not nice.
Rushing things

BE CAREFUL
Make sure you follow the usual health and safety stuff around solder fumes, electricty, hot soldering irons (that melt things like extension leads - whoops)
If installing FIAMMS make sure that your loom can cope with the current they draw (10 Amps I think) - I had to add extra wiring from the battery to the ignition switch and then to horn's relay to cope with this as otherwise I think it would have blown the fuse.
Headlamp terminals - the blades on the bulb are around 9mm wide - and I couldn't find any new ones, so I had to recycle my old ones - so don't throw anything away until you've finished

Would I reccomend doing this?
Probably not - its much easier to just buy a new loom - it also took me a few months to finish as I have never done this kind of thing before - there's no manual - so I just had to take my time and do a little bit at a time, then change things around, start again - it was very time consuming. However I now understand all the circuitry and theres satisfaction that I've made every connection so that if anything goes wrong I'll hopefully know how to put it right. It's also much neater and can be improved and added to easily (eg I'm thinking of adding a GPS with its own power supply and perhaps an extra set of driving lights). Wires can be pulled out of the PVC sleeving easily and removed or added to - it's much better than all that insulation tape wrapped around everything.

Does it make the bike go faster/better?
Difficult to say as I've also added a new shock - but everything seems OK and it starts OK (at the moment)

What next?
Hawker battery - ready to install
GPS
Light for grips to show they are on
Relocation of alarm and horns
Extra driving lights + wiring
Thunderchild diode board
Replace wiring from alternator to diode board (haven't been able to source this)
Replace wiring from trigger unit
Peplace headlamp terminals for new ones (haven't been able to source these)

Top Tips
Use PVC sleeving - spiral and slit are excellent
Get to know your wiring diagram - it essential to understand what goes where, what it does & what the cuurent is
Use a heatgun and heatshrink where necessary - it makes wiring really neat.
Use non-insulated terminals and crimp and solder to ensure a good connection
Remove any extra connectors - I think these are used to speed things up in factory assembly or for ease of replacement - but I reckon they're just another thing that can go wrong and should be removed.
Take your time - it's a big job and shouldn't be rushed - do a little often and enjoy it.
Install a voltmeter - it's so useful
When joining wire together, strip about 15mm from each wire then twist together and solder and then cover with heatshrink (make sure that you slip the heatshrink on first) - it makes the connection less bulky - this method is good for multiple wire connectors (eg joining 6 wires togther - but remove more insulation as necessary)
Most terminals that are retained in a plastic holder can be removed by slotting in a small jewelers screwdiver and pushing back the latch - I even replaced the terminals in the multi wire connector in the instrument panel - but make a note of what goes where first.
Look for numbers on things like relays and plastic holders like the headlamp holder as these are included on the wiring diagram - if in doubt make a note of what goes where before removing from original loom.

Phew - that took a long time - let me know if you want to know anything else?
 
A few things I forgot to mention...

A multimeter is handy for checking circuits.
Extra terminals are useful as I damaged a few, and removed some to shorten the wire to make things neater.
I didn't use bullet terminals anywhere as I didn't think they were necessary.

I will probably buy some new relays - but at the monet the old ones work OK.
 
Thanks Fuzzy!

Think I will start looking at sections that need redo. Fitted my GPS the weekend and lovely piece of equipment. Took me a couple of hours to figure out how to plot some routes and what to do and still loads of stuff to try and remember. Friends also gave me some heated grips for my B'day and I fitted them for time being but would like to wire them into the system as it is very unneat and to many things coming from the headstock. They are lovely though and ok will admit I don't know how I ever got around without them!

Did the wiring better the cold start issue? My bike took ages to start this morning becuase if it does not take the first time then you might as well go and make a cup of tea.

Cheers
Dirk
:gringo
 
Hi Dirk

Not sure about the cold starting yet - I've now added the Hawker battery too. I think part of the problem was that I didn't really look after the original battery properly (another reason to add a Voltmeter) - but I have to say that I've not had any problems yet - however the bike is kept in a garage overnight, so it don't get that cold.

Thanks for the link Nobby - will read with interest.

Another thing I left out is the cost of doing it - so maybe I'll add it all up and post the total?


Bike goes like sh%t off a shovel - the new Ohlins shock makes a big difference

Laters
 
Kenny said:
(just to put one over Andy/jud9e) next spring?

Kenny
Think again Kenneth dear boy - I am currently in the process of talking to MH Racing in Wiltshire and a chap in London about sorting out the rear suspension, they are both suspension specialists and are White Power & Ohlins specialists so I don't think the Hagon will be on there for much longer.

I've also been trialling Dirk's Touratech single seat - its between that and a Corbin. So when the lights and handguards are on plus the seat and spring (not to mention Malky's Widetail) I think we'll just about be there.

Mind you just got Touratech's 2003 catalogue and they have a few new goodies in there - my fave has to be the WP front-end kit - Upside Down forks (big and beefy) with twin disks - nice!!! :D
 
Hi Kenny

I bought it from Motorworks - during their 10% off season a few months ago - sorry you just missed another sale last week!
 
Thought I'd revive an old thread as it seems to be the recent trend. And on message about wiring, too!

Nice to see some of the members still here!
 


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