While staring at a DR650 motor, one of the obvious differences is the second spark plug. Has anyone tried twin-plugging their Savage? I'v twin plugged more than a few Airhead BMWs, and the results are good. Of course, on an Airhead, the second plug is on the other side of the combustion chamber, and on a DR, its right next to the original. But, it must be doing some good, I figure.
One of the things that need to be done is to lessen the full advance timing (not idle). Usually into the 28-30 degree BTDC range.
Wondering if the DR ignition box would work with the Savage trigger? Or is there an aftermarket ignition box that allows one to adjust the timing curve? I think there is an aftermarket box for the DR.
I've got the second head off to be ported and fondled, so poking a second plug hole is no big deal.
Must be winter. Too cold to be in the garage...

A long time ago Porsche put twin plug ignitions into their racing cars to allow a duplication of ignition.....just like airplanes have......to allow the cars to continue racing if one ignition system failed.  They also discovered the timing could be reduced and they got additional power as a result.  With 2 big valves per cylinder....the sparkplugs had to be set off to the side of the head pretty far, and the flame front had a long way to travel to get all the way across the piston.

With the 4 valve design, the spark plug is pretty much in the center of the piston.....I don't know that a second plug would do much for the Savage.  (It does make you wonder why Suzuki did it in the DR).

On airplanes and older dirt bikes, maybe, but twin plugs on street bikes are for more complete combustion. I kinda doubt the big twin cruiser like the XL1200S and the Kawi Vulcans, and the big BMW singles are worried that the primary plug will foul.
Even with a 4 valve head and a central spark plug, it is still a pretty big combustion chamber.
Prob the only way to know for sure is to find a good used ignition box and see if it sparks with the Savage trigger.
Doubt it will make any more HP, but it might make a 97mm, high compression combustion chamber a little happier.

Armen  the 97 mm combustion camber is already happier, it's smaller due to the crowned top piston,and the temperature of the fuel mix is hotter due to increased compression.

I have read that the BMW RT1150 had surging issues at cruise speeds, and when they fixed it the bike got 2 plugs per cylinder.......I am not sure what else they may have done.

Twin plugs allow you to run less advance - and that can help provide more power.  It also allows 2 flame fronts to burn, and it can help resolve detonation issues as the temperature of the flame front is reduced (hard to believe that stuff makes any difference at 50 times a second....or whatever tiny time period the combustion cycle occurs).

I have looked at the Savage cylinder head.....and I really don't see where the second plug could fit (I have not looked at a DR head to see where the second plug is).  If the second plug is within an inch of the first one....I am not sure it would be all that helpful.

Back in the Bultaco/Ossa/Greeves late 60's/early 70's days the bikes were single ignition - but often had a second spark plug hole where you could add a backup plug - if one plug fouled you could move the wire to the other plug.  I remember hearing stories of guys who would not have a proper heat range plug to put in the second hole - and they would stick a plug in that hole that had too high of a heat range for the bike...they wrongly figured that since the plug wasn't hooked up to thec coil wire it wouldn't make any difference.  However - the second plug is still exposed to the combustion process, and the insulator of the spark plug still gets hot and holds heat ....and the second plug that had too high of a heat range could get so hot it would burn a hole in the piston.  (If I remember correctly the CZ had 2 sets of points, 2 coils and 2 spark plugs per cylinder).

Dave,
up, as to the Oilheads. In fact San Jose BMW does a twin plug conversion on the early models.
I'm going to pick up a used DR ignition box and coils on Ebay and see if I can get it to work with the Savage.
If all else fails, I'll use the second plug hole for one of those compression release thingies the guys use on big Harleys.

Armen, It would be interesting to see the results, it might  improve fuel mileage,and power.

One thing to keep in mind is that if it improves the flame travel, you will probably have to retard the timing to compensate for that. Otherwise, to the engine it will appear that the timing is over advanced. Especially if you have a bigger bore or higher compression piston installed.