Gunson colortune

[Atoll]

I note the Gunson colortune has different spark plug sizes. Which one would I need for an A7SS alloy head 1960? Thanks. 

[coater87]

 I would think it would be 14mm, but just measure the diameter of your spark plug threads to be sure.

 Or, you could always do the cheapy, cheapy, cheapskate thing and try to make your own like a 3 buck Chuck would. Just be careful you dont burn down the bike and the shed.

 Lee

[muskrat]

G'day Atoll.
There's 3 sizes of modern spark plugs used in motorcycles. BSA's use "B" which is 14x1.25mm. A lot of Asian bikes use "D" 12x1.25, then there's the "C" 10x1 often used in twin plug heads.
Cheers

[Atoll]

Thanks, guys 14mm it is then 

[Rex]

Sadly the Colortune kit is pretty useless on modern petrol. It never was up to much (IMO) but it's pretty much worthless now.

[Billybream]

Have mine, never had much success with it

[BSA_54A10]

I found it one of the best tools in the tool box and use it regularly, particularly on modern twins like A 65's
Even with the slop we get down here they work really well for idle & slide cut away.

I use one a lot  with chain saws that "just stop".

When you get yours, also get a small fuel tank, pinch one from a push mower or weed trimmer.
This will prevent you cooking the engine by running it for too long stationary while looking at the colours.

[muskrat]

G'day all.
Like Trevor I use mine quite a bit. I have an auxiliary fuel tank on the wall and a large pedestal fan in front of the bike lift. The only way I could get the twin Kehins set up on my A10 Cafe.
Cheers

[Atoll]

I had one back in the 80s that I used on my Ford escort which worked very well. Why shouldn't one work just as well on a bike?
Why the need for a remote fuel tank is it because the petrol tank on the bike prevents it being used by fouling it or other?

[kiwipom]

hi Atoll, so you dont run it too long and overheat the motor, Musky says that he uses a fan to cool the engine when he uses his, cheers

[Atoll]

hi Atoll, so you dont run it too long and overheat the motor, Musky says that he uses a fan to cool the engine when he uses his, cheers

Sorry I must be missing something here, you use a remote petrol tank to prevent overheating the engine?

[duTch]

 

...Sorry I must be missing something here, you use a remote petrol tank to prevent overheating the engine? ...

 When you not riding it, it's not moving through moving air to cool it.....maybe folks in cooler climes don't have this issue...I've ratted the heater fan from my old van to do the same when necessary, but haven't used it yet- the variable speed resistor is burned out, also have a redundant radiator fan for same, but haven't used that yet either- both run from 12V, so good in isolated areas

[muskrat]

G'day Atoll.
I do most of my tuning on many bikes with the tank off, balancing carbs etc. Better to have a good look at the colourtune. Just makes life easier and less chance of dropping a spanner on a tank.
 Just a two gallon tank on the wall and the fan will blow your freckles off if too close!
Best to have the tank about the same height as the bike tank so the head pressure is the same so the float needle will shut off flow at the correct level.
Cheers

[Atoll]

G'day Atoll.
I do most of my tuning on many bikes with the tank off, balancing carbs etc. Better to have a good look at the colourtune. Just makes life easier and less chance of dropping a spanner on a tank.
 Just a two gallon tank on the wall and the fan will blow your freckles off if too close!
Best to have the tank about the same height as the bike tank so the head pressure is the same so the float needle will shut off flow at the correct level.
Cheers

Thanks that explains it clearly, just what I wantd to know.

[BSA_54A10]

I had one back in the 80s that I used on my Ford escort which worked very well. Why shouldn't one work just as well on a bike?
Why the need for a remote fuel tank is it because the petrol tank on the bike prevents it being used by fouling it or other?

Firstly as already been said, no air = no cooling
Secondly a small tank means that you can not run it for a long time.
I use an old Victa mower tank. And even more handy they have internal filters plus a tap.
If you can't adjust the idle & slide cut away with a pint of fuel you should not be touching a bike with tools.
Even without a fan, the engine cool better without the tank sitting on top of the engine and it also allows better viewing of the colortune
Because a motorcycle engine is exposed, you really need to to the tuning in the shade to see white / blue-white flashes.