new motor same knock

[WICHOL98]

i have a 79 cb and the og motor had a knock at low rpm and piston #4 didnt worm up at all and i got a different motor and the same piston does the same thing what could it be i replaced the og warness cus it was all hacked up there is spark but idono if there is fuel

[Rod_Knockin]

well now that you changed the motor I guess you can cross that off your check list. Did you use the same carbs? Since you dont seem to be shy about doing big things first rebuild the carbs paying special attention to the low speed and idle jet passages.

[WICHOL98]

the motor was easy to take out im more scared to mess with the carbs where can i get a rebuild kit for them

[Rod_Knockin]

they can be found many places online. I didn't need rebuild kits. I just took them apart and cleaned all the passages if you take out the metering jet make sure you count the turns open first so you can put them back in the same spot. Really the only place you need to mess with is in the float bowls. Dont separate the carbs. A can of carb cleaner is all I needed. I did replace the bowl mounting screws with ss socket heads because the phillips head screws strip to easy.

[gonebiking-2]

Try www.babbitsonline.com and www.cmsnl.com for all the carb parts you need - if you need them. When playing around with the mixture scews under the float bowl, remember to turn the screws in all the way - dont overtighten, then turn them out one and a half turns.