The International CBX Owners Association

I have a '79, with the Kerker 6 into 2's on it.

After a spirited 75 mile ride through the twisties in toolies Saturday, (LOTS of full throttle runs in 4th and 5th) I noticed when I got back (for the first time) that cylinder's 1 and 6 have more blueing on the pipes than the center 4 do. 2 thru 5 pipes are mostly gold, with just a trace of bluing. #6 is a fairly dark blue with little gold, and #1 is a very pretty light blue, and looks to me to be the leanest cylinder on the bike.

To verify, I took the plugs out of 1 and 6 to compare them before I rode it anymore. #6 looks normal to me, with just a trace of tan deposit on the very bottom of the porcelain part, just above where the center electrode comes out. #1 LOOKS leaner, as the porcelain was totally white - Didn't see any signs of any added metal (aluminum) on the end though, thank heavens.

I should add thet these pipes have been on the bike for several thousand miles, and they are actually LESS discolored than just about any other Kerkers I've ever seen - The discoloration is limited to the first 5 or 6 inches or so - Just the downward bends. By the time the pipe is straightened up, (pointing down) the chrome looks a normal color.

I figured just to be on the safe side, I'd back the pilot screw on #1 carburetor out 1/4 turn or so, but this turned out not to be possible. That one screw (the other 5 look fine) is all buggered up, with almost no slot left in it at all. Even after removing the alternator to get a straight-on shot at it with a brand new, correct sized screwdriver, I couldn't budge it - I think it'll have to be drilled and easy outed.

My neighbor thinks I'm worried about nothing, as he (correctly, I think) points out that a truly lean running cylinder would have a longer length of pipe discolored than any cylinder with a correct mixture. Can one glean ANYTHING from the discoloration on Kerker pipes?? - The color OR the length??

While here I should mention that my alternator has always slipped more than I like when the bike is cold, and it has to be up over a consistent 3500 to 4000 RPM's for a couple minutes before it begins charging normally. I noticed the clutch plates looked pretty worn when I had it out, and there are two "shim washers" between the driven plate and the spring - One thick one and one thinner one. Should I think about replacing the clutch plates, or would just adding another washer suffice for now?

Anybody got a high/low beam "button" for the headlight switch laying around?? Mine evidently took a hike during the "run" yesterday ;)

Thanks guys,

Don

Don:

I have no experience myself with the Kerker 6-2. Different exhausts react different to combustion temperatures, but I had the same happen to me on a SS Supertrapp.
In general, however, the following needs to be considered with the CBX:
Due to the fact that the carbs were angled towards the inside, the outside carbs have a significantly longer distance from air intake to intake valve. Honda engineering tried to compensate this by incorporating different length plenums in the stock airbox, but they always admitted that 1 and 6 were still slightly off. So even with a perfect sync your airflow losses are a little greater on the two outside intake tracts. This will be worse if the stock airbox is replaced by an aftermarket set which does not compensate for the difference in intake runners between carbs and cylinders. No 1 and 6 have the best heat dissipation due to their position which should make them run a little cooler(??) Some may call it an "old wife's tale" but it has been said, that a proper (slow) warming up procedure will prevent exhaust blueing. The old BMW Boxer Twins were notorious for turning blue headers if you would punch the bike too early.
The only remedy may be blu-ex.