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Discussion Starter · #1 ·
History...having just bought this '83 CX650 a scant 3 weeks ago, I've put over 1,000 km on the bike - going no where in particular - and loving every km! The bike sat idle for about 9 months prior to my purchase. I did take the bike to a Honda dealership to have an oil change, air filter, new tires and a general inspection. A pretty good bill of health given by the mechanic - who asked that I call him if ever I was selling the bike (which I took as a pretty good sign). We had a good discussion and the mechanic was extreamly helpful on a number of fronts, as has this web site been helpful - thank you Chopper Charles.



So, like the Yamaha V Star I purchased 5 years ago, it too had also sat idle for a time prior to purchase. I learned from that lesson that it would be OK to pour in a few oz. of carb cleaner fuel additive for the first couple of tanks (being careful not to over-do it), and again, it cleared up a minor starting difficulty to the point that it now starts like it's a new bike. Hard to believe for a 27 year old! Great sounding exhaust notes at both at full throttle and completely backed off. I live for the downshifting! I pull the plugs for good measure. Beautiful tan, with no deposits or electrode/tip erosion at all. They are the recommended plugs to begin with. Nonetheless, I replace with the same recommened plug, gap at 25 thousands, which is in the tolerance per the on line shop manual, and I can't tell any difference between the old and new plugs. All good so far. Stupidly I throw the old plugs away.



I have started to notice a slight gold/blue hue appearing on the top end of the exhaust pipes. Hummm...maybe it's due to the carb cleaner additive I added? Maybe it was the new spark plugs? Having read a few posts here I believe I've got a slightly leaned out carb setting - which supports the extreamly good mileage I've been getting. Expecting to grab a flat screw driver and give the 'ole low and high speed jets a 1/4 turn to open...well, what a surprise. No easy access to the adjusting screws on these carbs. I've referenced the on line "500" bike manual hoping that there would be little if any difference between it and the 650's ('cause I can't seem to find a dedicated 650 manual - is there one?). So, I'm somewhat uneducated here and could use some guidance. Is there an easy way of adjusting these jet settings? I gather from what I've read that I need to pull the carbs? Gosh, tell me this isn't so.
 

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The golden hue could be partly due to the gas additive. What brand did you use. General consensus is that Seafoam is one of the better ones, with Techron also being good. The OEM pipes on these bikes are double walled, one tube inside of the other. They generally don't blue or golden to the extent that single wall pipes do.



I have read that a golden color is attributed to a rich mixture, while a blue color is lean. I cannot attest to the validity of this statement personally.



Your carbs should be essentially the same as a 500, with the idle mixture screw in the same spot. Maybe the PO has broken the screw off flush with the body. That happens more often than expected. These screws only adjust the mixture at idle and do very little at speed. The "jets" you are referring to are a fixed plug with a appropriate sized hole milled in the middle. They can only be adjusted by changing them for a different sized jet. You mentioned your plugs were a nice tan color when removed. This is the best indication of a proper mixture being burnt. I would probably not worry too much on the pipe color, if you feel the need, I would turn IN the mixture screw 1/4 turn and then recheck the plugs after a ride.
 

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Bluing and Golding are both caused by a,"Lean" mixture just the way the different metal/alloy of pipe brands reacts to the extra heat caused by the lean mixture.



Note:Single skinned down pipes are more affected than OEM double skinned pipes.





HTH
 

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Discussion Starter · #4 ·
Blue Fox...the additive was STP brand. I've never seen the brand you're referring to, but I will look around should I need this again. As for whether the pipes are original equipment, I can't say. Is there a tell tale sign or stamping? I can only say they look to be what I would consider original, but I've got no foundation to stand on here. I'm not certain if I'm happy (or not) to learn that a carb adjustment is as difficult to do as it is. Kind of sounds like the Honda mechanics were pretty stead fast in their engineering to not allow an easy adjustment, so they must have had their game plan pretty much sorted before manufacturing...and they did have a couple of years experience behind them by 1983. I'll leave things for now and see where we go.



Shep...& Blue Fox...as for the contoversy between what gold and blue actually mean (rich or lean), I'll bow to your greater knowledge on this. I'm seeing both colours appear. And no, I'm not under the "Molson Effect".



Shep...my darling mother came from Yorkshire (Middlesborough). I've been there a couple of times. Beautiful riding country in those Moors!
 

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