Twin plugs

[VAL. H.]

How vulnerable are the lower plugs of a twin plugged head when the bike is dropped or ridden off road?

SHMBO's twin plugged R100GS is fitted with the OE crash bars and I was wondering what to expect if the bike is dropped etc.


Val.

 

[(RIP) maverick]

I dropped my GS last year in Namibia every single day and never suffered a broken plug or even the leads for that matter. Even going off the road into the bushes over rocks, trees and crap the bike was ok

One problem I did get was the leads on the lower plugs not sealing properly and getting wet causing it to stop dead in it's tracks. If you every ride in rain or through big puddles and the bike dies suddenly. Take the bottom plug caps off and make sure they are dried out. As we were crossing rivers had to squirt alot of silicon sealant into the plug caps and it worked fine even recently did some fair river crossings without any hassles

My bike is also fitted with only the OEM crash bars

 

[MickDB1]

Same as last guy said
never had any problems with damage
I had red rubber cpas on mine
I cabletied them onto the plug porceline tight if yer follow
never drowned them out either
not woth doing to an 80 though

 

[Voyager]

One problem I did get was the leads on the lower plugs not sealing properly and getting wet causing it to stop dead in it's tracks.

How have you connected the plugs ? ? ?

Sounds as though you have one coil feeding the left pot (both upper & lower plugs) and the other feeding the right pot.

I suspect if you short out that arrangement you will get total loss of sparks.


I have one coil doing the lower pair and the other doing the upper. I haven't noticed any mis-firing in the wet.

Am I on the right track - or just talking bollix ???


By the way . . . I binned my 100GS on a wet corner in Glen Shee last year. The crash bar swivelled round, letting the l/h rocker cover hit the road. I rode it home OK and the lower plugs (and the uppers) were untouched.


Bob.

 

[brassmonkey001]

How have you connected the plugs ? ? ?

Sounds as though you have one coil feeding the left pot (both upper & lower plugs) and the other feeding the right pot.

I suspect if you short out that arrangement you will get total loss of sparks.


I have one coil doing the lower pair and the other doing the upper. I haven't noticed any mis-firing in the wet.

Am I on the right track - or just talking bollix ???


By the way . . . I binned my 100GS on a wet corner in Glen Shee last year. The crash bar swivelled round, letting the l/h rocker cover hit the road. I rode it home OK and the lower plugs (and the uppers) were untouched.


Bob.

I don't know if this is the case as I've never looked at a twin plugged beemer and how it's set up, but I don't see how shorting out the lower plugs would stop the engine running. Surely the upper plug would still fire and thus the engine would continue to run?

 

[MickDB1]

I had 1 lead from coil 1 to pot 1 the other lead to opposite pot
Also mixed a top with a bottom
HTHY

 

[Voyager]

Twin-plugging uses two twin-outlet coils (usually, someone is bound to have a different set-up ).


Mine is set up with a pair of Dynacoils thus (I have since re-wired the complete bike, before anyone comments ):

Now, I suspect that both HT outlets come from the same windings, so if one outlet (on lower plug) is shorted out (with water) there won't be a spark from the other outlet (on the upper plug - or wherever).


By keeping one coil feeding the top (dry(er) side) and one feeding the bottom (wet side) plugs, I hoped to keep at least one plug sparking.

As I said - might be complete bollix - I'll have to do more off-roading to confirm my hypothesis


Bob.

 

[(RIP) maverick]

How have you connected the plugs ? ? ?

Bob.

Hi Bob,

To be honest I have actually never looked at the setup but basically if the lower plugs got wet the whole thing stopped. It would not start until the caps and plugs were dried again. The bike is in South-Africa at the moment so a bit hard to run out to the garage and check as I am based in Essex......innit

Looking at the trick we did with the silicon sealant would basically go down that route and problem sovled. Instead of using silicon sealant a silicon grease that will still conduct good is probably better. This bike is my tourer and it puts a new perspective of bimbling around, to give you an idea in six days I took over 600 photographs riding around Namibia. Hardly speeding along putting it through it's paces. The bike was a 80GS but fitted with Mahle 1000cc piston/barrels and rings by Sheck in Germany. If you crack it open it goes like hell