Twin plugging anybody?

[Rob Farmer]

I've been over to Mick Barr (in Leicester) this morning to get a price for twin plugging my R80GS. Mick quoted me £60 for the machining of both heads and £65 for the extra coil which seems like a very good deal. He does a next day turnaround on the heads as well.

Micks on 01162 419316 Monday to Friday 8am to 7Pm if you're interested.

 

[Tarka]

Sounds very reasonable.
Apparently,the 800 is greatly improved by twin plugging,as it becomes so much more efficient.

 

[Rob Farmer]

Thats what Mick told me this morning, said it made it made them much crisper off the throttle.

 

[judge]

Well yeah that's all true but you don't want to stop there Mr.F there is a lot of potential there waiting to be released.

We don't really get off on better fuel efficiency and all that do we

 

[Global Rider]

Rob,

You do know that you have to limit the advance curve and alter the ignition timing when you twin plug.

Easy to do, but it has to be done.

 

[Rob Farmer]

Judge,

I've just picked up another 3 speeding points (now on 9) so clean running at low revs and fuel economy have suddenly become interesting

Global,

Mick told me that it was fine with the electronic ignition. Why do I need to limit the advance curve and alter the timing?

 

[cookie]

i think it's because combustion is so much better, that you don't need so much advance.

andrew sexton does a mod for the bean can timing unit.

 

[(RIP) Kaister]

twin plugs = better / faster flame front travel - so less initial advance needed.

less advance = more power ( slightly )

 

[thornley]

9 points, what a disgrace to this forum. Slow down young man and keep your eyes open. Dreadfull behaviour on the public high way. OOPs sorry thought I was on that other site!

 

[Global Rider]

Global,

Mick told me that it was fine with the electronic ignition. Why do I need to limit the advance curve and alter the timing?

As Motomartin said. The combustion process takes less time with two flame fronts at which point combustion will be complete far too early with respect to TDC. The same applies to ignition timing at idle, although that isn't as critical.

You can always rotate the ignition can to retard the ignition advance point, but then ignition timing at idle will be off. Not a good way to do it. BTW, you won't be able to use the S and Z marks on your flywheel for timing.

Even the BMW electronic ignition has mechainical advance. In fact a fully electronic ignition has a designed-in advance curve. Change the conditions and you still have to change the advance curve...not easily done unless it can be programmed (race bikes, etc).

 

[Global Rider]

Rob,

As for limiting the amount of advance, we slipped two layers of heat shrink tubing on each of the limit pins for the advance weights on a 1976 R100 RS and then changed the ignition timing at idle. I don't know what the inside of the electronic ignition can looks like. (haven't done my dual sensor mode yet) Maybe Frank Warner can chime in.

It worked perfectly and the RS gained 10 MPG. I think he said he was getting 65 MPG, up from 55 MPG at 60 MPH, but in your case... Just kidding.