The BMW GS boxer twin thread

**dino3310** · 1st March 2010, 21:45

looks like a good spot to take the shooter into aswell, we could spotlight of the PD

**Padmei** · 2nd March 2010, 07:02

Very interesting reading Newguy. After seeing the head I see what you mean Eddie - the location of the sprakplug was the thing that intersted me. After reading about the additional wiring requirements I think the author summed it up when he mentioned it being a process not for the faint of heart nor short of funds.

**Squiggles** · 2nd March 2010, 09:49

I see an old school boxer twin in my future...

**NordieBoy** · 2nd March 2010, 12:37

Originally Posted by Eddieb

As Newguy mentions however thats the easy bit. You then need to get the timing set up with additional sensors, buy and find how and where to mount a 2nd coil etc.

The timing bit is interesting.

The DR just fires both plugs at the same time.

**Box'a'bits** · 2nd March 2010, 17:26

The issues re timing is not between the two plugs (though there has been chatter about that). It more abut the optimal time for the plugs to fire, which is dependent on RPM. That is why an electronic solution is probably better, in that the advance can be modified as revs increase . The older boxers use a mechanical advance system.

**Phreaky Phil** · 2nd March 2010, 19:04

My GS is dual plugged. I am using a coil pack from a Mitsi car. It has 2 twin outlet coils in one pack. I am running 2 ignition modules triggered by the stock "Bean Can"

**Padmei** · 2nd March 2010, 20:07

How do you find it Phil? did you do the conversion or was it done before you got it?

**Newguy** · 2nd March 2010, 20:36

Originally Posted by Phreaky Phil

My GS is dual plugged. I am using a coil pack from a Mitsi car. It has 2 twin outlet coils in one pack. I am running 2 ignition modules triggered by the stock "Bean Can"

wow, ok thats a new one for me. 2 x CDI's. What voltage regulator have you got going there?

**Phreaky Phil** · 2nd March 2010, 20:52

I did the conversion. I figured 2 ignition modules gave the system some "redundancy" If one fails it will keep on running. With the help of a mate who is a mechanical tutor we tested the stock coils and the mitsi coil to make sure it wouldnt draw to much current. I ordered another part of the wiring loom with the plug on it and spliced that in. Michael Dobson from Motorad in Welli organised the head drilling for the extra plug. Been running for 30000km with no problems.
I have an Enduralast 450watt charging system as I found out that the extra 2.5amps that the extra ignition draws put me on the maximum of the stock system, and heated grips etc put it over the top. The stock system doesnt get full charge till 4000rpm either

**Box'a'bits** · 2nd March 2010, 21:26

Originally Posted by Phreaky Phil

I did the conversion. I figured 2 ignition modules gave the system some "redundancy" If one fails it will keep on running. With the help of a mate who is a mechanical tutor we tested the stock coils and the mitsi coil to make sure it wouldnt draw to much current. I ordered another part of the wiring loom with the plug on it and spliced that in. Michael Dobson from Motorad in Welli organised the head drilling for the extra plug. Been running for 30000km with no problems.
I have an Enduralast 450watt charging system as I found out that the extra 2.5amps that the extra ignition draws put me on the maximum of the stock system, and heated grips etc put it over the top. The stock system doesnt get full charge till 4000rpm either

I've got the Endurolast alternator as well, & its great. I've had it on a couple of boxers now. I feel it deals to a lot of the stock systems issues, but also makes more charge at lower revs, brilliant for commuting, or slow running.

The downside of the Endurolast was that I couldn't run the Omega (?) ignition that runs off the crank, with its programable maps. Instead I run a Boyer micro-digital system, which is supposed to be optimised for dual plugs. Remembering I replaced points & a mehanical advance (though now I see some people in the US are swapping back!). I really need to book dyno time to ensure that its actually running at optimised levels....However it has run sweetly, so I haven't really felt a pressing need to do this.

Mike Dodson at Motorad organised an Engineer at Petone to drill the twin plug holes for me. The bottom side runs a shorter reach & smaller plug. However I have seen elsewhere some people weld in an alloy washer to allow normal length plugs, so top & bottom as interchangeable.

**Eddieb** · 2nd March 2010, 22:52

**igor** · 3rd March 2010, 06:42

eddie can ya mark on a map where you entered and exited please.I take it is SH1 around Rangipo thanks

**Eddieb** · 3rd March 2010, 06:58

Originally Posted by igor

eddie can ya mark on a map where you entered and exited please.I take it is SH1 around Rangipo thanks

Poutu Canal

Map your trip with EveryTrail

**Newguy** · 3rd March 2010, 15:23

Made a small mod to me rear fender
I've always thought the rear fender on the GS look a bit outdated compared to the rest of the bike. I like the classic look, but want to modernise it just a tad. So I combined the original fender with an Acerbis Nost rear fender.
I think the results aren't to bad. basically I chopped up the original and split it into 2 pieces. still used the original front bit to keep dirt off the battery.