E: Engine Ignition Advance

[Dave Hulstone]

I think he does. No doubt he‘ll be on in a minute.

 

[Martyn Goodwin]

I think he does. No doubt he‘ll be on in a minute.

Amal Mk 1 concentric 30 mm

 

[Dave Hulstone]

There you go. I was wrong. Got my cams confused with with my carbs.

 

[Martyn Goodwin]

There you go. I was wrong. Got my cams confused with with my carbs.

And a Mk1 (alleged!) cam

 

[Dave Hulstone]

I thought you were chasing speed?

 

[Bill Thomas]

I was out yesterday, On my old Comet, Down by the coast,
And after all these years am starting to think 30mm is too Big ?.
Which is hard for an old racer !.
So many older people out doing 25 mph and all over the road, Like they have never been out before.
I guess like me, They are out in case we get "Lock Down " again,
And the Sun was out for a few hours.
I think it would be brave of me to have a 26mm carb ??, Not sure ?.

 

[Dave Hulstone]

These are strange times indeed Bill. People getting about under the speed limit due to lack of practice. Not sure a drastic measure like fitting a 26mm carb to your Comet is the answer though. We will get through this, I hope.

 

[Martyn Goodwin]

Does Martyn use Mk2 Amal ??, If He is some people use a 105 needle jet, I have found 106 for me, U.K.
I know He says use a bigger main jet, But the petrol still has to go though the needle jet.
And being hotter out there, I would have thought it needs to be rich.

From memory my needle jet is a 105. I know for sure that the main is a 230. I also use one of my shim kits (see the advert in OVR) to fine tune the needle position. I have it half way between the middle and lower (rich) groove. Oh also use a Spares Co foam air filter and my exhaust is essentially a straight thru pipe that ends next to the rear axle.

 

[Bill Thomas]

Strange how some people can run 105 needle jets, Others 106 !.
Better NOT say what I think of air filters, But I don't live in AUS'.
Mine is Mk2 Cams Mk2 Amal 30mm Carb' , 9 to 1 piston, On a Rear Cylinder Head !,
Open Exhaust, Armours , Stainless.
50 mph 3000 rev's, and the World is a Super Place !!.

I have been watching too many youtubes of Royal Enfield Him ar lion, !! .

 

[Gordon Ryley]

Hi Brian. From my experience they make for a more efficient combustion allowing for later ignition timing, like 28 degrees btdc , resulting in more power out of your engine. For years I had to run my twin spark head with one plug replaced with a decompressor to help my starting as I was using a bth, giving me a 4 - 32 ignition curve from memory. I fitted a Grosset electronic ignition designed for a twin spark set up giving me a 4 - 28 ignition curve, fitted 2 plugs and the power gain was massive. I was getting a bit of pinging under load so after talking to David Dunfey I adjusted it to 2 - 26 and gained even more power.