new mixture screws and colortune

[Mitch 570]

Hi, I have searched the site and only found a few bits of info.
My questions are-

1. Has anyone used a colortune on an st1100 and if so what were the results and your thoughts please?
2. I am also thinking of changing my fuel mixture screws to the knurled type you can alter with your fingers. Has anyone tried this or have any information relating to before i potentially waste my money and a shed load of time? At presant I cant find a 90 degree tool to adjust them as mine are cross heads and as you know there is less than just a little room to adjust them with the angles and stuff in the way.

I have attached a couple of photos to show the above. Any help or advise on this would be much appreciated.

 

[dwalby]

what is your goal? Are you trying to extract a few more HP, or is the bike not running right and you suspect the fuel mixture is set wrong? If the bike is running OK now, what's the real value of a few extra HP gain on a big, heavy, touring bike, assuming you can actually make it run better, not worse?

 

[Slydynbye]

From what I have gathered the Colortune won't work because of the depth of the plug hole. you might check that.
Those fuel mixture screws look interesting

 

[Mitch 570]

what is your goal? Are you trying to extract a few more HP, or is the bike not running right and you suspect the fuel mixture is set wrong? If the bike is running OK now, what's the real value of a few extra HP gain on a big, heavy, touring bike, assuming you can actually make it run better, not worse?

The bike was running a little rough stuttering comming out of corners. Its not ridden that often and I hadnt drained the carbs. An oversight on my behalf. As my wife is partially dissabled as a result of a biking accident, but will ride with me as a pillian, I wont take the chance. Ive done the tappets, stripped and fully cleaned the carbs, the float levels were all too high and all over the place, the mixture screws were between 1 and 1 1/4 the pilots are #40 and the mains #125. Ive done a carb sync and the next logical step in tuning and re sync. I just want a safe nice running bike. Im really not bothered about the HP. As you say its a touring bike.

 

[Mitch 570]

From what I have gathered the Colortune won't work because of the depth of the plug hole. you might check that.
Those fuel mixture screws look interesting

I must admit I have got this colortune and tried it. As you say it really didnt work very well at all. I thought I had some issue I wasnt aware of. The mixture screws though should let me adjust them so much easier as ive left out the rubber heat sheild just while I tune up then will rebuild and re sync one last time. I dont suppose anyone can suggest a taco idle drop tool that wont break the bank at all instead of the colortune???

 

[Brant]

Use of Colortune leaves fuel mixtures on the rich side. Best method for setting fuel mixtures associated with any and ALL carbs is the 'lean-drop' method.

 

[Brant]

Best fuel mixture adjustment associated with ALL carbs is the 'lean-drop' method. In other words, with motor at operating temperature, pick any of the four carbs and back out mixture screw a few turns. Slowly start in with screw until a constant engine/exhaust sound is noted. Stop at that point and back mixture screw out 1/8th turn and no more than a 1/4 turn. Do other three same way with idle adjustment kept at 1000rpm or less after each mixture screw adjustment.....THEN sync carbs. If cooling fan comes on during adjustment, shut motor off till it cools. This added electrical draw puts unwanted load on motor, causing a false mixture screw setting.

 

[Roger]

I had great success using Colourtune on my CX500 twin and my Kawasaki GT750 (a great bike that the USA never got?). I eliminated a flat-spot just over tick-over that made both bikes really pleasant just trickling along...

 

[Mitch 570]

It seems like there are mixed reviews with the colortune and works better on some bikes than others. I certainly had no luck on my ST though. Thanks to all for your feedback.