First hand colortune review

[whiterabbitt]

thanks for the input, I cant wait to use this new toy, right after I use my new carbtune pro that came in the same package.

btw I recieved my order in just 7 days. morgan is an awesome company imo.

[koolaid_kid]

Just a couple of observations:
First, it seems like this complements but does not replace using some method (plug chops or a sniffer) to tune the main jets.
Second, since the correct way to tune a carb is top down (mains then needle then pilots) how would you tune the mains? On my GPz I used the highest idle method to get it running, then tuned my main jets using my sniffer, then the needles, also using the sniffer, then the pilot jets.
So, would you use the ColorTune first, then tune the main jets (most use plug chops, then get back to the shop and use the ColorTune again?

[TheCafeKid]

Just a couple of observations:
First, it seems like this complements but does not replace using some method (plug chops or a sniffer) to tune the main jets.
Second, since the correct way to tune a carb is top down (mains then needle then pilots) how would you tune the mains? On my GPz I used the highest idle method to get it running, then tuned my main jets using my sniffer, then the needles, also using the sniffer, then the pilot jets.
So, would you use the ColorTune first, then tune the main jets (most use plug chops, then get back to the shop and use the ColorTune again?

This is only true (the top down tuning) of the vacuum type carbs. The mechanicals you generally tune from the pilot circuit up, (and this is because you have control over the air and fuel to the pilot circuit independent of eachother) and a colour tune is a handy tool, but plug chops will tell the real story with the engine under load and dealing with that constant load and throttle position. With the CVs, the fuel for the pilot circuit is metered by the pilot jet, but that jet is fed by the main...so that all goes hand in hand. If the main is too small, obviously the pilot jet will not get enough fuel fast enough, nor will the needle circuit, and if the needle is wrong, that circuit can't feed fuel to the system fast enough or soon enough or both.

It's been my first hand experience, as well as Steve's (we both had a go at it at the same time) that the colourtune is rather useless on the CV carbs. There was no colour change while adjusting the screws. It was either on (blue flame) or nothing. And I'll jump the cliff and assume this is because what is being ignited is a pre-mix of fuel and air from the pilot fuel and pilot air jets (the only thing that screw adjusts is how much of that pre-mix is being fed). And since the slides don't quite function the same while revving the bike in the garage vs on the road, I'd assume it's pretty useless there as well. Highest idle method seems to work quite well for me in tuning the pilot on the CVs. Anything beyond that is wasted fuel and adding to poor mileage.

So I guess what I'm saying to YOU George, is your sniffer is probably a better tool than a colourtune in your situation.

By the way, my friend, you have a PM

[posplayr]

This is only true (the top down tuning) of the vacuum type carbs. The mechanicals you generally tune from the pilot circuit up, (and this is because you have control over the air and fuel to the pilot circuit independent of eachother) and a colour tune is a handy tool, but plug chops will tell the real story with the engine under load and dealing with that constant load and throttle position. With the CVs, the fuel for the pilot circuit is metered by the pilot jet, but that jet is fed by the main...so that all goes hand in hand. If the main is too small, obviously the pilot jet will not get enough fuel fast enough, nor will the needle circuit, and if the needle is wrong, that circuit can't feed fuel to the system fast enough or soon enough or both.

It's been my first hand experience, as well as Steve's (we both had a go at it at the same time) that the colourtune is rather useless on the CV carbs. There was no colour change while adjusting the screws. It was either on (blue flame) or nothing. And I'll jump the cliff and assume this is because what is being ignited is a pre-mix of fuel and air from the pilot fuel and pilot air jets (the only thing that screw adjusts is how much of that pre-mix is being fed). And since the slides don't quite function the same while revving the bike in the garage vs on the road, I'd assume it's pretty useless there as well. Highest idle method seems to work quite well for me in tuning the pilot on the CVs. Anything beyond that is wasted fuel and adding to poor mileage.

So I guess what I'm saying to YOU George, is your sniffer is probably a better tool than a colourtune in your situation.

By the way, my friend, you have a PM

Having tuned my 1166/ported/4:2:1 with a WB LM-2, I can only imagine the difficulty in trying to use anything else in seeing what the AFR is doing. For a known configuration where you are just moving around a bit, maybe ??? but anything else would be difficult at best.

[koolaid_kid]

Thanks for the PM.
bwringer borrowed a colortune and tried it out on my GS (CV carbs). We abandoned it after testing cylinder #1 because the readings were just not right.
I never worked on VM carbs, so I can't respond to that. The only experience I had with them was my 78 750E, and they were the reason I sold the bike after only a year. I could not stand the bog when I whacked the throttle wide open. My RDs (very simple slide carbs) would point to the sky, the GS just bogged and finally started accelerating. But that's just me, the CVs don't do that.

[koolaid_kid]

Having tuned my 1166/ported/4:2:1 with a WB LM-2, I can only imagine the difficulty in trying to use anything else in seeing what the AFR is doing. For a known configuration where you are just moving around a bit, maybe ??? but anything else would be difficult at best.

That is why I chuckle when people talk about plug chops. It is kind of like trying to fell a tree with a sledgehammer versus an ax. You will eventually get the job done, sort of, but it has to be painful and time consuming at best.

[chuck hahn]

Heres the link i checked out while learning a bit about it..also you can google the colortune instructions if youn wish..

http://www.gadgetjq.com/ctune.htm

[TheCafeKid]

Thanks for the PM.
bwringer borrowed a colortune and tried it out on my GS (CV carbs). We abandoned it after testing cylinder #1 because the readings were just not right.
I never worked on VM carbs, so I can't respond to that. The only experience I had with them was my 78 750E, and they were the reason I sold the bike after only a year. I could not stand the bog when I whacked the throttle wide open. My RDs (very simple slide carbs) would point to the sky, the GS just bogged and finally started accelerating. But that's just me, the CVs don't do that.

That's because the CVs have basically a secondary like a 4 barrel carb on your muscle car. With the mechanicals, the slide is actuated by your hand more or less. (of course there is the cable actuating the throttle rod/linkage, which lofts the slides) so when you whack the throttle open, the slides go from zero to WFO instantly. The motor isn't prepared for this obviously, and the vacuum is dumped for as long as it takes to catch up. Some versions of mechanicals tried to aleviate this with "accelerator pumps" which shot a squirt of gasoline down the intake to make up for the fact the motor wasn't drawing air across the jets fast enough to supply fuel, or that's my basic understanding anyway. They work to a point but are kind of fiddley and can make tuning a bit more tedious.

CVs have a set of "butterfly" valves and the slide. The blade valves are linked directly to the throttle, but the slides require vacuum to lift, so when you whack the throttle on these, you open the butterflies WFO but the slides still act as a partial restriction so the vacuum isn't dumped all at once. Then they lift as vacuum allows/requires, and you go faster. Theres some hesitation but not nearly as much. Which makes them a more user friendly street carb, IMO. They're not as on/off as some of the mech carbs can tend to be, which makes maintenance throttle with a less than perfect throttle hand a bit less exciting in the tight stuff.

They both, IMO have their drawback as far as tuning goes. Mechs for me are much easier to dial in for hot-rod applications, since you have independent control over every aspect of each circuit. The needle is a pita as the throttle control arm must be removed to change the clip position, requiring a sync every time you do it. But they're easier to sync because they don't effect each-other like the CV carbs do, as they don't share sync adjusters.
If you know, or at least have an idea of where you should be, ballpark-wise, they can be quite easy to tune for pods and pipe/ performance mods. But if not, like any carb, you're just shooting in the dark. A wide band would be awesome to have but many of us aren't so lucky

The CVs on the other hand are fairly easy to dial in for stock applications, but god help you if you try to jet them by hand for performance upgrades. Its simply a waste of time and effort. A jet kit is, in my humble opinion, absolutely necessary. And from there dial them in is less cumbersome, but still requires patience and understanding of how the circuits, because they rely so much on each other in these, relate to one another.

But, this is all just my opinion from personal experience.

[chuck hahn]

On the right side youll see the manual download link....

http://www.autoexpertproducts.com/colortune-14mm.htm