New member, same old problems

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Wilco

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Aug 3, 2009
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Hi guys, I have a 72 roadster, which may be a combat, but I dont know how to confirm this. it has the 32mm (single) carb and black barrels, and the engine number 202022, is in the area of combat production. Is there any way to confirm exactly what it is? Id like to figure it out, as the tappet clearances are different, and I assume the timing is to?
I have had a 'mechanic' (old bastard with a shed full of old bikes) adjust the timing and tappets but to me the head noise is louder than before, and the plugs seem to foul up worse. I am running NGK BP6ES, and still experimenting with the different fuels, 91,96 & 98. I am told using avgas at 5 to 1 helps to keep the plugs clean, but i dont have access to any.
Any help appreciated.
 
Wilco said:
Hi guys, I have a 72 roadster, which may be a combat, but I dont know how to confirm this. it has the 32mm (single) carb and black barrels, and the engine number 202022, is in the area of combat production. Is there any way to confirm exactly what it is?
Click to expand...

Hello Wilco, and welcome to the forum,

The first standard production Combats supposedly started at serial 200976, so yours could certainly be a Combat model.

Combat heads had their gasket face planed to increase the compression ratio and the heads normally have a 'C' stamped on the top to denote Combat, you will probably have to remove the headstady to find that C mark if it's there?

Combats would normally be expected to have black barrels and a front disc brake, the twin carbs are no longer fitted to your bike, but they would have been 32mm originally. Internally a 2S camshaft would have been fitted. However after all this time, any parts could have been changed?

Valve clearances for a Combat would be 0.008" inlet and 0.010" exhaust, standard models were 0.006" IN, and 0.008" EX.
The factory recommended that the Combat's ignition timing should be retarded 2 degrees from standard when using low octane fuel. The standard plug was a Chamipon N7Y (modern equivalent is N7YC)
 
The correct NGK plug for a combat is BP7ES. BP6ES is too hot, yet your said it is fouling...something wrong, maybe the carburetion. The old saying is don't worry about tappet noise unless you don't hear it - within reason.
 
I am the guardian of a 72 combat in canary yellow. 202 ... means your born on dating was Jan/Feb 1972.
Hearty Welcome to you mate!
When you crack the throttle if it feels like your being ripped from the seat, you have confirmed you own a combat.
What carb is on it? It could be set up wrong.
I had a rich plug on the left side and found the main jet holder vibrated loose.
Not something found in Amals trouble shooting brochure.
Make sure the air slide is fully open if applicable.
Replace the plugs.
If an Amal close the fuel idle screw fully gently and open 1 1/2 turns to get things going.
Warm up and see how it responds.
Idle can be adjusted slightly from there. Small increments 1/8-1/4 turns at a time not @ 1/2 turns.
If an Amal they respond to gradual increments.
Just how I manage my yellow peril.
Kepp us posted you'll eventually get it right w/ the volume of help the board has to offer. We all asked these questions at one time :roll:
Marshal
 
Thanks guys, Ive gained more useful knowledge in this one thread than I have in the last couple of years of trial and error!

It seems first I need to find that "C" marking on the head, so I can tune it properly.
The carb is a right hand 932. I will start with using BP7ES plugs (just because i have some new ones already) and adjusting the fuel idle screw as suggested, thanks marshal. Could a poorly set fuel idle screw be the source of the fouling? is this what you refer to illf8ed?

L A B, if 26 degrees is correct for low octane fuel (91?), then is 96 or 98 octance correct for a 28 degree timing?
I have been using all types of fuel, and found the only oddity is that on a hotter day, the engine will run on after the ignition is turned off when using 91.
the timing is set to 28 buy the way.
 
Wilco said:
if 26 degrees is correct for low octane fuel (91?), then is 96 or 98 octance correct for a 28 degree timing?
I have been using all types of fuel, and found the only oddity is that on a hotter day, the engine will run on after the ignition is turned off when using 91.
the timing is set to 28 buy the way.
Click to expand...

If you grade your fuel by the RON octane system in NZ, then the reccomended grade for Combats was 100 octane (97 for the standard models)?

However, Norton released a service bulletin (N3/2 - May '72) stating that 97 octane fuel could be used in Combats if the ignition timing was retarded to 26 deg. BTDC, and 250 main jets fitted (95 octane for the standard models with 240 mains, but no timing adjustment) . And stating that "Do not use fuels lower than the alternative ratings and setting given above" [26 deg.] . "A small power loss is to be expected utilising the changes recommended."


(100 RON octane is approximately equivalent to 96 US octane rating, and 97 RON is approx. 93 US rating)
 
L.A.B., could you tell me what octane grade - EU rating - is required for a Combat ? (non retarded ignition timing).
 
So does this mean I should use an octane booster ? (the highest grade overhere is 98)
 
I removed the head steady this morning expecting to find a "C" stamped in the top, but I did not. Instead, there was an "O" ! What does this mean?

Also, I assume that adjusting the fuel idle means pilot jet screw?
 
in my view c on the head is not that important as i beleive that model all had ss camshafts which are 8 and 10 a noisy tappet is a happy tappet, i sugest you contact your local norton owners club which is active in NZ i am a member What part of the country are you in?
 
arent the recommended adjustments for standard roadsters 6 and 8? and the timing is also different?

I have a new problem to add to my collection, a leaky fuel tank! The paint has been bubbling at various places, especially in the right rear corner, and yesterday I brushed off a paint flake only to find that was all that held the petrol in :O !
I fear my tank is slowly breaking down and requires some work in a few areas. Does anyone know a product or a process for lining the tank against leaks and protection from the new petrol?
 
Wilco said:
arent the recommended adjustments for standard roadsters 6 and 8? and the timing is also different?

I have a new problem to add to my collection, a leaky fuel tank! The paint has been bubbling at various places, especially in the right rear corner, and yesterday I brushed off a paint flake only to find that was all that held the petrol in :O !
I fear my tank is slowly breaking down and requires some work in a few areas. Does anyone know a product or a process for lining the tank against leaks and protection from the new petrol?
Click to expand...

My bike came with a fiberglass tank, and I coated it twice with this product from a company here called Caswell. The tank lasted almost two days before the fancy coating started peeling off the inside of the tank. I replaced the tank with a new steel one, and it weeps just a bit on the left rear corner, and the paint is bubbling around the filler neck. I blame both instances on the ethanol the US has mandated be added to all gasoline - about 10% currently. Ethanol is a pretty strong solvent, and will dissolve things unaffected by gas (petrol)

If NZ hasn't fallen for the ethanol trap, I think any of the epoxy sealers would work for you.
 
is your tank fibreglass or steel if glass our fuels will react against the glass and will need to be lined i sugest you get hold of dave seale at euroglass in christchurch, all the 72s that i have encountered have had ss camshafts as standard and an ss cam requires 8 and 10 tappet clearances.
 
BillT said:
The tank lasted almost two days before the fancy coating started peeling off the inside of the tank. I replaced the tank with a new steel one, and it weeps just a bit on the left rear corner, and the paint is bubbling around the filler neck
Click to expand...
"so, you highly recomend the sealer and pakistani roadster tank then :?: :wink:
BillT said:
If NZ hasn't fallen for the ethanol trap,
Click to expand...
No the tree huggin lesbian running the country got arseholed out last election I :idea: believe
 
possm said:
i sugest you get hold of dave seale at euroglass in christchurch.
Click to expand...

cheers possm Im in chch, i'll do just that.
Who do you recommend for paint? I had the tank done by a shop in town a few years ago, called JT or JP, cant remember which, and I was not happy with it. I need someone with a solid reputation instead of picking a name out of the phonebook.
 
My favourite painter is a guy named shurk if you hsve been around a you would have heard of him, he is off the road due to a crash but will be painting again in about 7-8 weeks, when on deck he works for bill stevens painting halswell junction road, he knows his stuff but like most long term painters a bit slak
 
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