Are Twin Plugged Heads
- Thread starter GT3North
- Start date
I wouldn't. There's other stuff you can do before doing all that stuff.
Try some new Siebenrock pistons and barrels.
How much performance do you want out of your 30 year old airhead?
Someone who knows better than me will be along to tell you what's what, but I wouldn't go down the twin plug route.
Try some new Siebenrock pistons and barrels.
How much performance do you want out of your 30 year old airhead?
Someone who knows better than me will be along to tell you what's what, but I wouldn't go down the twin plug route.
I have a twin-plugged R100RS. It is quite the most awesome engine I've ever had the pleasure of owning. Smooth from 1000rpm. Good mpg. Great performance.
I've also a twin-plugged R90S with Siebenrock pistons and barrels. What could be better?
I've also ridden (test-driven) a R100GS PD with twin-plugs and again, that was like riding a 3 or 4 cylinder bike for smoothness and response. I didn't buy it because it was too scruffy (for me, it looks great actually). It's still for sale on ebay, so you could go and test drive it yourself? https://www.ebay.co.uk/itm/285024428310 oh, you are in Canada.
On pure cost-benefit (will you ever save the petrol money to pay for the conversion) then no. But on ridability, flexibility, smugness, this is all priceless.
I've also a twin-plugged R90S with Siebenrock pistons and barrels. What could be better?
I've also ridden (test-driven) a R100GS PD with twin-plugs and again, that was like riding a 3 or 4 cylinder bike for smoothness and response. I didn't buy it because it was too scruffy (for me, it looks great actually). It's still for sale on ebay, so you could go and test drive it yourself? https://www.ebay.co.uk/itm/285024428310 oh, you are in Canada.
On pure cost-benefit (will you ever save the petrol money to pay for the conversion) then no. But on ridability, flexibility, smugness, this is all priceless.
I had my R100R twin plugged years ago. I should have kept that 'bike. Had it done by a German firm, they also wanted the points canister so that they could alter the degrees of advance curve.
Ran much more smoothly afterwards .... yes a noticeable difference
Ran much more smoothly afterwards .... yes a noticeable difference
Shows what I know.
Mr Moore is quite disparaging about twin plugging from what I recall.
I thought it only benefited very low rpm running and was generally abandoned years ago?
Obviously it is commonplace on modern bikes, but is fitted for entirely different reasons and is much more sophisticated.
Obviously it is commonplace on modern bikes, but is fitted for entirely different reasons and is much more sophisticated.
According to a top guy at Cosworth .... if the spark plug is in the correct place to start with then not much point in twin plugging.
If not then twin plugging will be of benefit. They had done much experimentation!
Was talking to the guy at the NEC motorcycle show a few years ago .... in the BMW hospitality suit I might add
If not then twin plugging will be of benefit. They had done much experimentation!
Was talking to the guy at the NEC motorcycle show a few years ago .... in the BMW hospitality suit I might add
Didn't twin plugging begin in WW2 aviation as a way of ensuring better flame spread in monster V12 engines and as a precaution in the event of German U boats cutting off supplies of high octane fuels and additives from the US?
I can see why it might be attractive as BMW increased the size of their engines from the original R50 and R60 airheads. The bean counters probably stopped any such expensive investment for the bigger airheads. Then they eventually did it when they developed the oil cooled boxers?
Whether it's worth it for a private individual, well your pays your moneey etc. However, there are other ways of improving performance as pointed out above.
I can see why it might be attractive as BMW increased the size of their engines from the original R50 and R60 airheads. The bean counters probably stopped any such expensive investment for the bigger airheads. Then they eventually did it when they developed the oil cooled boxers?
Whether it's worth it for a private individual, well your pays your moneey etc. However, there are other ways of improving performance as pointed out above.
According to a top guy at Cosworth .... if the spark plug is in the correct place to start with then not much point in twin plugging.
If not then twin plugging will be of benefit. They had done much experimentation!
Was talking to the guy at the NEC motorcycle show a few years ago .... in the BMW hospitality suit I might add
The thing with airhead heads, is that the plug is very much not in the right place. It's on one side of a hemi head - long flame path.
dogshome
Registered user
I've not ridden a twin plug bike, but I do have Silent Hektic multispark electronic ignition. They say it makes "more power from the cellar" and I'd agree with that. 860 conversion (without the best combustion chamber shape) will trickle down to 1500RPM and happily work it's way back up when pottering about in the low gears (I have high 3:1 gearing). It also took some backing out of the idle screws and leaning of the mixture. I didn't have much flicker using a strobe with crank powered bean can, but the timing with crank source is rock solid.
This also is not a cheap option, but I imagine combined with twin plugs it would be quite awesome at the low end. I'd always do the 650 - 860 upgrade first as that has a huge effect. The SH ignition just makes it nicer. With a big budget and a 1000 needing new valve guides etc, I would definitely do it. AND fit Siebenrock pistons, SH igniton, blueprint and suitable cams. Hell, alloy rods, slide carbs and the full magookle
Modern engines with vertical ports, advanced fuel injection, 4 valves, a central plug and multiple (smaller) cylinders have no need for dual plugs. They also have multispark built in. We are riding pre-war VW Beetle engines with 2 cylinders lopped off after all ~ish!
This also is not a cheap option, but I imagine combined with twin plugs it would be quite awesome at the low end. I'd always do the 650 - 860 upgrade first as that has a huge effect. The SH ignition just makes it nicer. With a big budget and a 1000 needing new valve guides etc, I would definitely do it. AND fit Siebenrock pistons, SH igniton, blueprint and suitable cams. Hell, alloy rods, slide carbs and the full magookle
Modern engines with vertical ports, advanced fuel injection, 4 valves, a central plug and multiple (smaller) cylinders have no need for dual plugs. They also have multispark built in. We are riding pre-war VW Beetle engines with 2 cylinders lopped off after all ~ish!
Guys, thanks for all the advise and opinions.
I have already purchased a Siebenrock power kit and was going to pick up a set of refurbished heads from BMW2V.com as my heads are both missing a couple of fins, so I was just
looking at the duel plug option. In for a penny in for a pound I guess I at this point as I'm only going to build it once. Its a tempting option for sure.
I have already purchased a Siebenrock power kit and was going to pick up a set of refurbished heads from BMW2V.com as my heads are both missing a couple of fins, so I was just
looking at the duel plug option. In for a penny in for a pound I guess I at this point as I'm only going to build it once. Its a tempting option for sure.
Twin plugged my '83 R100RS, runs smoother and never have any pinging. I fitted the twin plug Wedgetail ignition. Get almost 5mpg better fieul economy. Has light smoothing of the inlet ports by Jim Cray. Very pleased with how it runs.
I used two twin outlet Dyna coils, Bike starts better too.
I used two twin outlet Dyna coils, Bike starts better too.
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