Colortune, anyone used one lately?

iis_iis

iis_iis

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NSW
As the title says, have a problem motor here, thinking the colortune may be of merit in a well equipped workshop. Cost is noticeable in Australia. j.
 
yes, I have one and bought it 50 years ago, I have used it a bit in recent times but I found a dyno far more accurate, because the Colortune is only realy good (on a Lav) for setting the idle jet screw. They work realy well on car SU carbs which only has one jet.
CLEM
 
Hi Jon. I find them more useful as a comparator between cylinders, rather than as an outright mixture setting tool. As Clem said, most useful at idle.

Not truly necessary in the workshop, but useful for info gathering when you have a conundrum.
 
I tried one once, but I broke it before it could show anything meaningful. Not exactly a robust gadget.
 
I'm in the states and have just used the similar Carbtune that does a good synching job and is well made for a decent price. They also offer a version just for twins which is nice.

Morgan Carbtune - carburetor synchronizer for balancing motorcycle carbs

Carbtune motorcycle carburetor synchronizers;polycarbonate tool pouchs;for motorcyclists
www.carbtune.com
Of course, also check valve clearances, points gap and ignition timing, along w/ inspecting float level and slides/needles/new carb gaskets if needed. I used a Dell Orto rebuild kit
Also attached is a useful Dell Orto synching guide:
 

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TeddyG said:
I'm in the states and have just used the similar Carbtune that does a good synching job and is well made for a decent price:

Morgan Carbtune - carburetor synchronizer for balancing motorcycle carbs

Carbtune motorcycle carburetor synchronizers;polycarbonate tool pouchs;for motorcyclists
www.carbtune.com
Also attached is a useful Dell Orto synching guide:
Click to expand...
Colortune is a whole different thing, Teddy.
 
Glass-based, why it broke for me, see-through spark plug. It was years ago when I guess I was more ham-fisted.
 
Used one recently on a Guzzi 750S, wasn't really impressed. Would actually help to have more of them so all cylinders could be compared simultaenously, swapping from one to the other is just guesstimating...

Bike didn't run any better than before.

piet
 
Looks interesting to me, but from the above input, doesn't seem to work that well. I'm trying to determine how rich or lean my PHF carbs are after a rebuild, but I guess I need to ride it for a bit and inspect the plugs.
 
On a twin it's easy, I disconnect one plug and treat it like a single. You find the point it idles at its highest and smoothest, by winding it in till it's running poor and out to the same point and put it in the middle and with Dels add a tiny bit more richness with the mix screw. It's less easy with 3 or more cylinders. Then you ride it to see how it runs, looking at plugs these days isn't too helpful. There are pros here who know way more about this than my dumb arse. BTW I tried that colour tune gadget when I first bought my 3c as finding the correct idle mix on Muiltis is way harder.
 
Many thanks for the hands on reports, do like the technical basis and or merit, for the glass arpeture, seeing what is happening in the combustion chamber, which has been tested by my learned friends here.

Background for the post; Have a motor ( not Laverda ) with very low compression, so much so am unable to identify what cylinder with variable actual ignitable compressed air/fuel load, are igniting at all. Injected engine and the exhaust manifolds are almost impossible to test, or even measure individual cylinders with any certainty, as the motor does not start or if it does only a few cylinders, constantly stalls. Other practical issues including a very deep spark plug well. Thank you all. j
 
iis_iis said:
As the title says, have a problem motor here, thinking the colortune may be of merit in a well equipped workshop. Cost is noticeable in Australia. j.
Click to expand...

Hi Jon
I've got one but rarely use it. It's really only an aid to setting idle mixture. The thing isn't strong enough to put the engine under any load, like on a dyno. I used it on my Jota once. It was pretty simple to twiddle the idle mixture to get a nice blue flame, which is supposed to indicate a stoichiometric mixture. But I found that too lean. The transition from idle to small throttle opening wasn't smooth. The engine hesitated before picking up speed. I found the idle mixture needed to be a bit richer than a clean burn. That would be a yellow flame with the Colortune. In reality it wasn't any better than the old tried and true methods of setting the idle mixture. So for me, the Colortune is a solution looking for a problem.

Yours is a different issue though. Identifying a low compression cylinder. I really don't know how that would pan out. It would be an interesting experiment. Perhaps you've found a use for the thing. I'll dig it out and send it to you if you like.
 
Colourtune was meant for cars realy with one carb for four cylinders, and how hot/cold was the glass see through plug?

Nothing like a dyno and with temporary front pipes that each have their own lambda sensor port, plus a fourth in a very specific place on the collector box. (at the back facing full on gas flow in between the vee of the two outlets
CLEM
 
Dellortoman said:
Hi Jon
I've got one but rarely use it. It's really only an aid to setting idle mixture. The thing isn't strong enough to put the engine under any load, like on a dyno. I used it on my Jota once. It was pretty simple to twiddle the idle mixture to get a nice blue flame, which is supposed to indicate a stoichiometric mixture. But I found that too lean. The transition from idle to small throttle opening wasn't smooth. The engine hesitated before picking up speed. I found the idle mixture needed to be a bit richer than a clean burn. That would be a yellow flame with the Colortune. In reality it wasn't any better than the old tried and true methods of setting the idle mixture. So for me, the Colortune is a solution looking for a problem.

Yours is a different issue though. Identifying a low compression cylinder. I really don't know how that would pan out. It would be an interesting experiment. Perhaps you've found a use for the thing. I'll dig it out and send it to you if you like.
Click to expand...
There he is, could say you were not missed Cam, then being wrong was never so satisfying, a smile here, glad to see you once more. Funny how actual use differs markedly over a number of users with differing backgrounds. Does make clear expectations over ideal gains.

Damned civilised of you to offer the device for try out, may come to that, though will attempt at being more clever than have been, which is actually true, the difficulties of this motor have once more brought out imaginative plans and actions. Mind, while slow is none the less able to function at a good to better level, than the years would condemn. j.
 
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TeddyG said:
Since the motor's not running, I would imagine a leak down test would tell more about the motor's overall state
Click to expand...
Agreed, have the facilities to action a leak down test, matter of setting it all up and doing the test in safety.

Overall issue is what result post LD test, whatever it reveals there is the high probability of a motor disassembly to correct, have little appetite for a 30+ yo V6 motor manhandle and rebuild. Moreover, given this car has 10+ control modules onboard, when one stops, what then, the spares are not obvious. ECU et al are bespoke Japanese ND well made yet very obsolete semiconductors internally.

One obvious outcome, working on a Laverda motor is manageable here, car/elaborate electronics is not. Should have predicted this high possibility, yet failed to do so. Taken on a diesel motor swap in another van to sooth the dinged ego on failed V6. j.
 
By way of final outcome, not so much the colortune aspect. The motor with low compression and erratic behaviours, Japanese removed import, ie should have just run, somewhere a person had fitted the Gilmer belt drive cog on the crankshaft backwards. The actual crank to cams timing mark on this cog and woodruff keyway are about 20 degrees offset, the quad cams were closing the inlet valves around 40 degrees retarded to the piston tdc.

The Mazda Australian printed factory manual shows this cog, actually fitted backwards, cannot blame the person fitting it backwards, aware or no. Most probable removed to change the front crankshaft oil seal, looks new and not the usual orange viton seal of factory.

Perhaps of some interest here is the behaviour of my compression gauges, witnessed a "backwards step" as it came up to peak compression reading, on a successive series of compression strokes. Checked the gauge on my 79 Jota, the step was not nearly so obvious if at all. Also have old style complex dial face vacuum guages with the dial face colour zones and written sections "leaky valve" post a piccy later ( have a gig today ). My comp gauge has a schrader valve in the coupling, backwards steps are not easy to observe, as such.

Suppose a crank to cam shaft degree wheel ( have the opening and closing degrees in the factory manual ) would have unveiled the root issue. Wasted 10 days in avoiding the first principle approach, however. j.
 
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