Carburetors
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How do you clean the carburetor on a 1979 Honda CB 750 K?

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January 04, 2008 1:46AM

first remove gas tank and seat for easy access. READ ALL INSTRUCTIONS BEFORE STARTING. to save on carb cleaner do only one carb at a time first remove gas tank petcock and drain gas. most likely there is rust in it. trust me it will be your worst nightmare. clean petcock filter and inspect tank for rust, this most likely is your first problem. second, if you don't ride at least once a month aways turn gas off and let motor run until gas is used up in carbs. this might be hard on pistons but old un-leaded will ruin piston and vavles even faster. gas tank cleaning instructions will be at end nex't remove battery box and air cleaner housing wires attached to battery box should only fit one way, but you might want to tape and mark for later assembly now loosen all four clamps in front of carbs, don't remove clamps, only loosen,and unless the rubber is cracked and need replace don't loosen clamps from motor. [this will keep them in place when you re-install carbs]. then remove all 4 drain lines from carbs and leave in frame. now pull carbs loose, it might take a little extra help[big screwdriver] now that they are off place rags in holes to keep trash out of motor. now you can easily remove throttle and choke cables at this time DON'T separate carbs from linkage and brackets nex't you'll need about 10 steel coffee cans,9x12 bake pan,pipe cleanerscarb cleaner,and synthedic steel wool carefully remove bottom float bowls over newspaper or large clean surface and try not to break any gaskets unless you plan on buying a carb re-build kit place screws in one can,gaskets in another can. remove drain screws from bowls and place rubber 'o' rings in gasket can.[carb cleaner will destroy gaskets and rubber rings and seals] now place drain screws and bowls into separate cans label cans carb1,2,3,4, don't mix parts. fill can with bowls with carb cleaner until bowl is submerged carefully remove clip from float and place float and float jet in cleaner. nex't with large screwdriver unscrew brass jet housings and place in cleaner and let parts soak while you dis-assemble top of carbs. [ REMEMBER, DON'T PLACE RUBBER IN CLEANER] in 1979 you should have vaccum carbs remove screws and carefully remove. now inspect rubber diapham for cracks and holes. if rubber is good a little oil will soften them up. if they are bad or you cracked the gasket YOU WILL HAVE TO BUY A NEW CARB RE-BUILD KIT after this remove all top of carbs parts and place in separate cans and submerge in carb cleaner DON'T MIX TOP AND BOTTOM PARTS AND WATCH FOR SPRING JUPPING AWAY if you need to remove carbs from brackets and linkage, carefully don't mix parts it's best to use 9x12 pan now and soak all carbs at one time and let soak take pipe cleaners and clean all hole to remove all dirt and rust, with air compressor or canned air blow out all holes to make sure everything is clean, all other parts can be cleaned with steel wool.after cleaning take spray carb cleaner to remove any lint from pipe cleaners and steel wool and let dry after cleaning reverse dismantling and start re-assemble. after carbs are done replace choke and throttle cables remove rags and use alittle vasilene on rubber and carbs will slide on easier replace air filter box and install new air cleaner. then replace battery box and wires almost done, use small gas filter DON'T USE CLEAR GLASS FILTER, THEY ARE JUNK make sure gas flow arrow is going right direction. to clean gas tank get a hand full of marbles or ball bearing and go to the car wash.take alittle water and marbles put in tank and shake like heck this will loosen alot of the rust. dump out marbles and using engine cleanig or tire cleaning setting stick sprayer in tank and go and watch the grud come out rinse until water looks clean. use clean rags to soak excess water on the internet or local cycle savage a two part liquid gas tank liner. the three part cleaner system is not bad but the two part is better replace gas tank and your ready to go honda's won't run if the battery is bad and if the battery is good but low charge don't start car to jump off, your riding lawnmower has less amp and won't blow your fuses if you need pretty pictures and step by step mechanic instructions i recommend Haynes motorcycle manual #535 it covers all cb750& cb900 dohc fours from 1978-1984 I hope this helps superdave