1985 yamaha 200

[Walkerallen]

ok guys i need help FAST and asap. so me, my dad, and my brother are suppose to go riding this weekend. so i got all the bikes out of the garage to make sure they were ready to ride. my brothers xr100 is perfect, my 225dx was perfect. and then the bike that always has carb problems starts acting up again. it starts and idles perfectly, takes off great then half way through every gear it just starts cutting out and bogs down. so i pulled the carb apart and cleaned all the jets and still the same problem. took off the tank cleaned it along with the pet cock and still the same problem. anybody know what my problem could be?

[puggerton03]

air filter, plug?

[Grizzlypeg]

If you unhook the fuel line from the carburetor and open the petcock, does it flow freely? That will help eliminate the tank, screen, petcock.

Hook up a clear line to the carb drain, lift the line up alongside the carb and open the petcock and carb drain. The line will fill to the level of fluid in the carburetor. See that it fills to around the parting line of the carb bowl. That willl tell you if its filling with fuel properly.

[Walkerallen]

the carb is clear, new plug, the pet cock is clear. it smokes like a bat outta hell, and i run synthetic oil. could it be that the valves are not seating all the way?

[Walkerallen]

oh and by the way, without the baffle and the air box lid and air filter, it sounds badass

[thestud25]

Have you checked to make sure that you have proper valve adjustments? If your intake valve is too tight that could cause some issues. Does it back fire through the carb, or backfire at all? I would get the valve specs and some feeler gauges and check that. It is pretty simple. Make sure you are top dead center though.

[Walkerallen]

if you let off the gas it pops, i wouldn't say through the carb, i think it pops because the baffle is removed and it doesn't have enough back pressure.

[200XMichigan]

Play around with the air mixture setting, the the needle is old it might be a hair out of factory settings. Sometimes I have seen a few that want to be way off, one actually had new cheap Chinese jets. Pretty lousy kit. New plug and a clean air filter, then I would look at the settings. And valve adjustments, cam chain tension, if the Yamaha has an adjuster. If it smokes that bad though it could just be getting worn out. Try some thicker 15-40 diesel oil, I wouldn't run synthetic in something that's so worn out it smokes. Is the gas just old? That can make them smoke like crazy.

[Walkerallen]

gas is brand new, along with the filter and spark plug. is the air fuel screw on the botten of the carb in the back or is it the flat head on the side? it started smoking when i over filled it with oil. i know i know rookie mistake, but that was 4 years ago. i wouldn't think that it would still affect it.

[MonroeMike]

The idle mixture screw is on the bottom.

[Walkerallen]

how does the idle mix screw affect the bike while your riding it? i understand that the idle mix screw is for idling.

[thestud25]

The air adjust screw should be on the side, and yes it typically is a flat head. Tighten it all the way in, then back it out 3 full turns. Fire it up, hit the throttle. If it bogs, your ratio is off and needs a half turn to a turn out. Try that.

[MonroeMike]

Mine's on the bottom, as in the manual. They show it might be on the side also.