I spotted something called Gunsons Colourtune in Halfords today - you put it in a spark plug hole and it helps you tune the air/fuel ratio by changing colour. Looks quite good, has anyone used it before?

Pete

[Edited on 12/8/05 by scoobyis2cool]

I have one. They aren't perfect but you can get reasonable results with a bit of patience. Obviously not as good as taking it to a garage to have the carb set up properly though.

Used one on a GT 185 I had years ago. Found it when I was moving house recenly. Worked ok..ish.

Best tool for getting intial setting on twin SUs or DCOE Webers --- get each cylinder to as near ideal as possible then use a gas analyser to trim the emisions down turning each carb/venturi idele mixture adjuster screw an equal number of turns.

[Edited on 13/8/05 by britishtrident]

Thanks for the replies, looks like it might be ok for getting a rough setting but not for getting it spot on.

WRT gas analysers - I notice you can buy these in Halfords and they sometimes come up on ebay, would it be worth the extra money for one of these? There seem to be a lot of large professional ones on ebay but also a few of the smaller Gunsons type ones. Which to go for?

Pete

They are a bit average for setting up, but excellent for diagnosis, if you have 3 cylinders showing a nice blue flame, and one either white (lean) or yellow (rich), its a pretty good guess where your problem is!