The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: nhmaf on April 16, 2008, 10:03:39 PM

Title: Do you use Colortune ?
Post by: nhmaf on April 16, 2008, 10:03:39 PM

I think that there are at least a couple folks out there who use the Colortune spark plug kit for adjusting their air/fuel mixtures on their airheads.
I've contemplated getting a kit to try and see if I can adjust the mixture better than I can "by ear" and spark-plug reading (plug reading isn't very accurate
unless one has fairly new spark plugs).   If you do use one now - or have in the past - I'm interested in hearing of your experiences (good and bad) with using
this to tune carburetted engines, and airheads in particular.

Many thanks in advance !
Mike

Title: Re: Do you use Colortune ?
Post by: airhead on April 16, 2008, 10:43:51 PM

I bought the kit way back in the early '70's, it worked well adjusting my Morris Mini's SU carbs.
However, I then got the 'Bug' and got big time into VW's. The thing never seemed to give me consistent results and I shoved it away in a draw for many years.
I resurrected it to try it out on Airheads, but as with the VW Airheads, results were inconsistent and I eventually shoved it back in the draw and rely on my ear. I've heard others have found this as well.. Might be something to do with the combustion chambers of the aircooled engines, or something else, but as far as I'm concerned, save your money!!


Bill.........................;-)

Title: Re: Do you use Colortune ?
Post by: Bob_Roller on April 16, 2008, 11:01:17 PM

I just tried mine last week, and with the electronic ignition ( '81 model year), the spark arcs from the center connection across the glass viewing area to the case of the Colortune 'sparkplug', not arcing inside of the combustion chamber, effectively shorting it out.

I tried insulating it with heatshrink tubing, and small diameter rubber hose, but I got the same result.

So unless you can solve this problem, in my opinion, it's useless on the bikes with the high energy ignition.

I'm going to use some RTV sealant on the rubber tubing next week, and see if it helps any.

So at this time I can't give you any opinion if it useful or not, I got it on eBay for $25US.

Title: Re: Do you use Colortune ?
Post by: airhead on April 17, 2008, 12:58:49 AM

Bob, I think you might have a problem with a short in the Colourtune or too large a spark gap. In actual fact, the stock points and electronic ignitions of our Airheads put out very similar energy's/voltages, It's just that the electronic can do it more consistently over more conditions.

I've tried mine on my '86 Mono, as well as a couple other later ignition types with no shorting across the glass.

Maybe try really scrupulously cleaning the glass and setting the spark gap on the unit as close to stock as you can. Here's a few pics of mine from different angles of the electrode. Gap is pretty close to 1mm.

(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi2.photobucket.com%2Falbums%2Fy22%2Fr65%2FIMG_2490Small.jpg&hash=d868f6d6a6e4c7d435d9dbee0e4c5e07ac506be0)

(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi2.photobucket.com%2Falbums%2Fy22%2Fr65%2FIMG_2489Small.jpg&hash=f6e8fe96f500e1ddeb25ecdb3d3b6ba3330d316c)

(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi2.photobucket.com%2Falbums%2Fy22%2Fr65%2FIMG_2488Small.jpg&hash=c4fbfdbe89b52c8adbfe7f2286f84ce97508dd82)

Bill.....................;-)

Title: Re: Do you use Colortune ?
Post by: Bob_Roller on April 17, 2008, 09:42:38 AM

I've got the gap set to .028 in, .71 mm, so I'll try cleaning the glass viewing window to see if it helps.