Will not stay running

Unfamiliar with this exact model #, but if this is a 1 barrel tractor carb, float should be level when inverted (ie: float edge parallel with carb edge), Main jet screwed in until bottoms (lightly) then out 1 1/2 turns (just starting point, must be fine tuned while running), Idle jet bottomed then 1 1/2 turn to start, then fine tune. All final settings made while running and fully warmed up.

needs new gas lines and carb,go to ebay and get them it is about 25 bucks,or you can rebuild the carb and buy a new line and fuel filter,ethanol kills weed eaters,use non ethanol gas from a marina

I would suggest cleaning out the carbs and checking all your fuel lines, cause the ethanol nowadays in fuel eats lines and leaves junk in your carbs, then start with a pre set of 1 1/2 turns out on both jets, then once running you will have to adjust to fine tune.

Replace the pilot and main jets then really clean the carbs soak them in a good carb cleaner. When you re assemble the carbs make sure you have the air screws turned all the way in then one full turn out start from that setting.

Hello,
a good starting point is the low speed screw at 1 3/4 turns and the high side at 1 1/2 turns. Hope it helps

Sorry I thought the bike was a 1975 when in fact it is a 1982. I would suggest you check the points and make sure it is clean and adjusted properly. Regarding the carb, you can make 2 become 1 but if the parts will fit and bear in mind that air mixture will require careful tuning since it will not be the same as manufactured default. Back firing is often caused by faulty spark, plugs, coil or even bad ground to engine.Also before you consider doing any work on the carb, try to swap the points to a new one.(I assume it has a points engine due to the year of manufacture)

I believe that number is a Craftsman number. You need to know what kind of carb you have, either float-type or diaphragm-type. The float type has these pre-set: the main jet is 1.5 turns open. The idle jet has 1 turn open. The diaphragm type both start with 1 turn open. When you have it running you can go ahead and set it. Good luck...Lee

hi,fairly common problem with modified exhaust,start with the pilot screws,turn right in untill the screws are firm then back out 1 and 3/4 turns,this is a fairly standard rule of thumb that will get most things going,as far as the jets go,the original size would be a good starting point,but you should only need to go up 10-15 sizes to compensate for the exhaust mods(ie stock might be 127 may need to go to138 or 140 etc),the other thing that i would recommend is getting hold of a set of damped carb balancers these will enable you to get the mixtures and carb balance dead right,they are relitively cheap and easy to use and will have paid for themselves the first time you use them.(i regularly get 4-8 sometimes 10-11 extra hp over stock by tuning the carbs up properly).hope this helps

Standard jets for the CB 750 are 120's, popping and kicking are usually due to running lean which is probably why it runs great with the choke on as that riches it up. I've run 115's with no problem but 100's??? Maybe was trying for better fuel mileage when gas was $4.50 a gallon?