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what to try next?

Butch Davis

CB750 New member
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New guy to the forum, Just purchased my 74 CB 750 from the original owner, he was a wonderful guy in his 80s that just had a hard time letting it go. He would start the bike often but it had not been ridden for years. I have had the carbs rebuilt and syc. replaced the plugs and coils and wires and all full lines and filters. The bike starts up and idles just fine. When you attempt to ride the bike and put it under load it pops and misses badly. I am not sure if I am dealing with a spark issue or a fuel issue, I have ordered a new petcock to make sure if I am getting a good fuel flow. any ideas on what to try next would be great. The bike looks like it did in 1974 complete with windjammer. I have attempted to put the bike back in its original state.
 

pidjones

CB750 Addict
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Put on a new fuel line with a filter that you can see through. No telling what rust from the tank is making it into those newly - cleaned carbs (requiring another cleaning).
 

ricerocket71

CB750 Enthusiast
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I agree drain the tank make sure it is clean and put new in-line filter on her, also pop the float covers off and make sure they are clean also, no telling what you will find. good luck
 

MotersickleBum

CB750 Enthusiast
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i think it's a fuel issue. i've had many bikes that did the same thing and i had to rejet them. on one bike someone put too big of main jets the others needed more gas because of intake pods and headers.... does it have aftermarket intake pods? has it been rejetted? check petcock by opening up the line and see if how much fuel flows.
 
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chuter

CB750 Member
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You state that you have rebuilt the carbs, new spark plugs, new coils and fuel lines and filters. Have you replaced the points and condensers? Many an ignition problem has been mistaken for a fuel problem. Put in new points and static time them and I bet you will find your problem. Better yet put in an electronic system and you won't have to worry about ignition problems again. Chuter
 
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