Love my Mark III - but how about a little more power?

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None of the ignition systems mentioned will do a great deal to increase performance over a properly set up Kettering points triggered system. The curve in a points based system can be varied to help produce the best possible results............a correctly engineered electronic set up which is programmable and used by the likes of Steve Maney here in the UK, though is quite different to the cheaply produced systems of the likes of Boyer and Tri-Spark etc etc, and is the ultimate set up for a Norton twin.
 
Carbonfibre said:
None of the ignition systems mentioned will do a great deal to increase performance over a properly set up Kettering points triggered system. The curve in a points based system can be varied to help produce the best possible results............a correctly engineered electronic set up which is programmable and used by the likes of Steve Maney here in the UK, though is quite different to the cheaply produced systems of the likes of Boyer and Tri-Spark etc etc, and is the ultimate set up for a Norton twin.
Click to expand...

A very broad statement. Based on .....what exactly?

As fitted to your Norton perhaps?
 
A very broad statement. Based on .....what exactly?

As fitted to your Norton perhaps?[/quote]


Fitting an ignition system with a curve that cant be varied to suit the specific application perfectly, is a bit like fitting a carb with fixed jets which cannot be changed. For instance a bike that has long duration cam and high compression pistons, will need a completely different ignition curve to a stock machine.
 
Jeff - Running the Altair here since August. It is not their "entry" into idle stabilization. They have had that in the Smart-fire for quite a while as someone else pointed out in an earlier thread about the Altair. It is a cheaper alternative to the Tripark and has the separate electronics box which is why I went for it (besides price). The Boyer was fine - this is just finer. Starting and idling much better and crisper throttle response are what I see.

Russ

(Not telling everybody they have to get one.)
 
Carbonfibre said:
A very broad statement. Based on .....what exactly?

As fitted to your Norton perhaps?
Click to expand...


Fitting an ignition system with a curve that cant be varied to suit the specific application perfectly, is a bit like fitting a carb with fixed jets which cannot be changed. For instance a bike that has long duration cam and high compression pistons, will need a completely different ignition curve to a stock machine.[/quote]

Great theory. But how does it work on real, not imagined bikes?
Have you ever seen one on a bike and working?
 
tricatcent said:
I have an 850 MKIII with a single MIkuni 34mm. I has a stock engine 8.5 compression, RH10 head (30mm), std cams, Lucas Rita, and a 22 tooth sprocket. It can go 95 MPH in third gear up a long steep hill. On the flat it can get up too 100 MPH really quickly, I don't find I want to go any faster even for passing. The engine is in good shape, everthing works right. It is faster than my friends 750 that has a PW3 cam in it and dual Amal 930s. quote]



Sorry to ask, but 930s are 30mm carbs and not generally fitted to 750s which came with 32mm, 932 carbs.
Fitting with a single carb will always strangle the top end power, but may give better low down throttle; i.e allow engine to drop to 25mph in top gear before stalling, if fitted correctly.
If you fit twin carbs, check inside the inlet ports on the cyl. head that there are no reducing sleeves fitted, if yes, remove them before fitting twin carbs.
Click to expand...
 
Bernhard said:
Sorry to ask, but 930s are 30mm carbs and not generally fitted to 750s which came with 32mm, 932 carbs.
Click to expand...

Thats a misguided statement - in the Factory Workshop Manual, ALL 750s except Combats came with 30mm Amal Concentrics.
 
Rohan said:
Bernhard said:
Sorry to ask, but 930s are 30mm carbs and not generally fitted to 750s which came with 32mm, 932 carbs.
Click to expand...

Thats a misguided statement - in the Factory Workshop Manual, ALL 750s except Combats came with 30mm Amal Concentrics.
Click to expand...

Unfortunately that isn't correct either, because 32mm carbs continued to be fitted to the majority of 750 models (with RH5 and RH6 heads) after Combat production ceased.
 
If you'd read my original version in Swahili, it said that the workshop manual noted that ALL Commandos before the Combat had 30mm carbs.

Something must have been lost in the translation....
 
Just like a programeable Elec Ign , a competant operator can map a mechanical advance unit by altering springs & weights .
However , unlike electronic , the curve isnt alterable in use.
Unless you have both Manual & Automatic Advance , which probly means youve fitted a Magneto .

For optimum output and responce , the ignition is ' mapped ' to the Camshaft & Carburation , etc .

Olde pictures show Joe Lucas spinning up the advance unit in the test machine & obseving with the stobeiscope .
This was std practise for Lucas Tecnitions .If they wernt at the Pub .
 
Fitting an ignition system with a curve that cant be varied to suit the specific application perfectly, is a bit like fitting a carb with fixed jets which cannot be changed. For instance a bike that has long duration cam and high compression pistons, will need a completely different ignition curve to a stock machine.[/quote]

Great theory. But how does it work on real, not imagined bikes?
Have you ever seen one on a bike and working?[/quote]

Not sure whether you have heard of someone in the UK called Steve Maney? The crank triggered RTD ignition he uses on Norton motors seems to work very well indeed, and cannot be compared to cheaply made systems like Tri-Spark, Boyer, Pazon etc etc.
 
Matt Spencer said:
Just like a programeable Elec Ign , a competant operator can map a mechanical advance unit by altering springs & weights .
However , unlike electronic , the curve isnt alterable in use.
Unless you have both Manual & Automatic Advance , which probly means youve fitted a Magneto .

For optimum output and responce , the ignition is ' mapped ' to the Camshaft & Carburation , etc .

Olde pictures show Joe Lucas spinning up the advance unit in the test machine & obseving with the stobeiscope .
This was std practise for Lucas Tecnitions .If they wernt at the Pub .
Click to expand...


Back in the day when car racers were still using Lucas distributor ignitions, it was very common to alter the advance curve to suit particular states of engine tune, and test machines for setting up distributors were often found in the workshops of people carrying out engine tuning work. Bottom end electronic systems cannot be programmed, and while they will work ok for bikes without any modifications, considerable power losses can be expected when they are used on modified machinery.
 
Hey Keith, It was a simple question, 90 odd replies ago,....
For $2,000.00 I'm sure you could get a pair of carbs, a cam and a $1,000.00 worth of Head work.
Do the work your self and she'll go like a jet.
AC.
 
Carbonfibre said:
Fitting an ignition system with a curve that cant be varied to suit the specific application perfectly, is a bit like fitting a carb with fixed jets which cannot be changed. For instance a bike that has long duration cam and high compression pistons, will need a completely different ignition curve to a stock machine

Great theory. But how does it work on real, not imagined bikes?
Have you ever seen one on a bike and working?

Not sure whether you have heard of someone in the UK called Steve Maney? The crank triggered RTD ignition he uses on Norton motors seems to work very well indeed, and cannot be compared to cheaply made systems like Tri-Spark, Boyer, Pazon etc etc.
Click to expand...

Funnily enough, I do know Steve Maney. I have a set of his barrels on my 850. My understanding is that you couldn't run the standard alternator as well as his ignition because of space issues.

Cannot be compared? Why not. Everything's up for comparison. That's why we are here talking about these things. Aren't we?
 
Personally , Id fit 34 Mk2 Amals and trash the stock filter & oil tank, put a big alloy one in and Filtron or similar ,or Ram Tubes & a air box .
Decent valve springs and Mr Axtels Cam, paying particular attention to the followers & includeing spacers on the rocker arm shafts .

If it had contact breakers , Id fit a BSA 36 Deg Advance unit and slightly tougher springs. AND decent TWELVE Volt ingnition coils .
 
Matt Spencer said:
If it had contact breakers , Id fit a BSA 36 Deg Advance unit and slightly tougher springs. AND decent TWELVE Volt ingnition coils .
Click to expand...

Why would you use a BSA advance unit? I have found a Norton looses power when the total advance goes beyond about 34 degrees on a low compression motor and less with high compression. A 10 to 1 motor likes about 29 at 4000 and 27 at 6500 with efficient ports. Jim
 
Jim, I am running 31 degrees of advance with a Pazon Sure Fire @ 4000rpm with a stock motor and Mk1 Amals with 240 main jets, doesn't seem to run out of puff right through the rev range and on the hills here in New Zealand, only thing was a bit of a backfire on the throttle off/downhill, but found a crack in LHS header which could account for this.
Have a set of JS Keihins arriving next week, at this stage the 850 doesn't have trouble passing like the original thread! That is the only thing I will have to compare to as haven't had it out against other Nortons at this stage
What are your thoughts?
Regards Mike
 
Original post: Nothing wrong with the bike ...BUT, Its the BUT bit, OK i am riding behind a Dodge Ram 500 Bhp 7 litre V 8, The driver see's me behind with my 50 Bhp 40 year old bike, when i start to over take i can see a big grin in his rear view mirror, He Slams open all 500 snorting mustangs and i seen to go into reverse :cry: dear members how can i cope :?: should i put on an extra carb,super spark kit? or what :?:
 
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