Adjusting pilot on mk1 b12 using colourtune

[PaintItBlack]

After getting the dynojet kit dialled in on my b12, using an air/fuel gauge, thought I’d fine tune each carbs pilot screw using a colourtune, I’d had good results in the past doing this on my gs1000, 

before the colourtune tuning I’d settled on 3 1/4 turns out on each carb to get the air/fuel reading that I was after, around 12.5 at idle,

looking for that point with the colourtune, just before the orange flame turns to blue got very mixed results on each carb,

carb 1) 5 turns out

carb 2) 2 1/8 turns out 

carb 3) 2 3/4 turns out

carb 4) couldn’t get any trace of an orange flame even with pilot screw all the way out , so settled on 5 , same as carb 1.

this setup gave 12.5 on the a/f gauges and definitely felt better than with all screws at 3 1/4, but carb 1 and 4 it would seem , at 5 turns out,want a larger pilot,

does that seem a reasonable conclusion ? For the 2 outer carbs to want a larger pilot than the inner 2 ?

running pipercross dual pods, dynojet kit,stock pilot jets, carbs are very clean and balanced 

[PaintItBlack]

So no one got any thoughts then ?

nevermind, I got the colourtune out again last night, after the sun had gone down, was much easier to see the colour of the flame and make adjustments, 

numbers 2 and 3 ended up within a whisker of where I’d previously set them, the outer 2 were quite a way out ,

carb 1 now at 3 3/8

carb 4 now at 3 turns out,

can tell just by the way it revs that the bike is happier now,

quite a range of settings between the carbs, from 2 1/8 on carb 2, to 3 3/8 on carb 1 , but it’s really smoothed out that first 10% of throttle opening 

[Upshotknothole]

They usually came from the factory with different tuning for 1 and 4 vs 2 and 3. Also different length intakes going from the air box to the carbs. 2 and 3 run hotter and don't get as much air if you're running pods.

[TonyGee]

39 minutes ago, Upshotknothole said:

They usually came from the factory with different tuning for 1 and 4 vs 2 and 3. Also different length intakes going from the air box to the carbs. 2 and 3 run hotter and don't get as much air if you're running pods.

what tuning is that ?  all the jets are the same size in all 4 carbs, also the emulsion tubes,  and all 4 airbox rubbers are the same as well !!!!

Edited May 21 by TonyGee

[Upshotknothole]

3 minutes ago, TonyGee said:

what tuning is that ?  all the jets are the same size in all 4 carbs, also the emulation tubes,  and all 4 airbox rubbers are the same as well !!!!

I'm used to working on GSXR, not bandits. GSXRs had different length intakes as seen here.

They also had different size main air jets between the two inner and two outer carbs. Not a huge difference, but there was one.

[TonyGee]

1 minute ago, Upshotknothole said:

They also had different size main air jets between the two inner and two outer carbs. Not a huge difference, but there was one

yeah doesn't apply to the B12 though 

[clivegto]

9 hours ago, PaintItBlack said:

So no one got any thoughts then ?

 

Yea what's a colortune are you referring to the plug colour ? Yellow flames ? 

[PaintItBlack]

24 minutes ago, clivegto said:

Yea what's a colortune are you referring to the plug colour ? Yellow flames ? 

It like a spark plug with a window in it, so you can see the colour the fuel is burning at,

orange flame is on the rich side, bunson blue is leaner, just where it’s turning from orange to blue is where it wants to be, 

can be used to individually tune each carbs pilot settings 

[TonyGee]

18 minutes ago, PaintItBlack said:

It like a spark plug with a window in it, so you can see the colour the fuel is burning at,

orange flame is on the rich side, bunson blue is leaner, just where it’s turning from orange to blue is where it wants to be, 

can be used to individually tune each carbs pilot settings 

I have a colour tune with a 14mm plug thread, have you got the same but with a 12mm adapter on ? 

[Toecutter]

I personally wouldn't take colour tune for gospel these days. They were good years ago but with the fuel we have these days is it actually indicative of true burn colour? It's like plug chop readings, are they giving accurate results as per 15+ years ago? Or am I talking shite?

Edited May 21 by Toecutter
Predictive text ramblings

[TonyGee]

2 minutes ago, Toecutter said:

I personally wouldn't take colour tune for gospel these days. They were good years ago but with the fuel we have these days is it actually indicative of true burn colour? It's like plug chop readings, are they giving accurate results as per 15+ years ago? Or am I talking shite?

yeah you are probably right, but they do get you somewhere near the settings you are after. 

[Toecutter]

Yeah,  I had good results years ago using them mainly on old British bikes. I've long since lost/sold mine however. 

[PaintItBlack]

28 minutes ago, TonyGee said:

I have a colour tune with a 14mm plug thread, have you got the same but with a 12mm adapter on ? 

Yes, I’ve got a 12 and a 14mm colourtune,

was so happy with the results on the bandit that it prompted me to do my gs1000, hadn’t done it since I rebuilt the top end and added the 1085 kit, and again a noticeable improvement 

[PaintItBlack]

30 minutes ago, Toecutter said:

I personally wouldn't take colour tune for gospel these days. They were good years ago but with the fuel we have these days is it actually indicative of true burn colour? It's like plug chop readings, are they giving accurate results as per 15+ years ago? Or am I talking shite?

Maybe so , but they get you a lot closer than just setting all pilot screws the same, quite a difference in the settings on each of my carbs, yet it runs noticeably smoother and the air/fuel reading ended up about where I wanted it 

[TonyGee]

33 minutes ago, PaintItBlack said:

Yes, I’ve got a 12 and a 14mm colourtune,

was so happy with the results on the bandit that it prompted me to do my gs1000, hadn’t done it since I rebuilt the top end and added the 1085 kit, and again a noticeable improvement 

ah ive just got the one (14mm) you can buy a 12mm adapter but that takes the spark further away form the combustion chamber !!!  just wondered if it'll still run ok ? 

[Gixer1460]

2 hours ago, clivegto said:

Yea what's a colortune ? 

You've been around for a few months / years / decades, so I can't believe you've never heard of or about the Colourtune device! Its from the era before EFI when carbs were fitted to everything - only good for idle tuning but perfect visual feedback immediately on adjustment.

[clivegto]

1 hour ago, Gixer1460 said:

You've been around for a few months / years / decades, so I can't believe you've never heard of or about the Colourtune device! Its from the era before EFI when carbs were fitted to everything - only good for idle tuning but perfect visual feedback immediately on adjustment.

Never come across anything new fangeld like that in the sticks hear in North Yorkshire but live and learn. 

[Dezza]

How do you see the colour if the device is stuck down the spark plug well of an oil cooled engine? The colourtunes I have seen have all been aimed at the car market. Easy to see when used on a 1979 1600 Cortina.

[rodneya]

58 minutes ago, Dezza said:

How do you see the colour if the device is stuck down the spark plug well of an oil cooled engine? The colourtunes I have seen have all been aimed at the car market. Easy to see when used on a 1979 1600 Cortina.

There is a mirror attachment on the top that gives you a crappy view down the tube at a 90 degree angle from the plug

[Gixer1460]

9 hours ago, Dezza said:

How do you see the colour if the device is stuck down the spark plug well of an oil cooled engine? The colourtunes I have seen have all been aimed at the car market. Easy to see when used on a 1979 1600 Cortina.

If playing with carbs its likely the tank is off so looking down the wells should be easy enough + dark enough to see flame colour better? IMO the only engine they made sense with, was the original Mini's - plugs at front, directly behind the bonnet!