Hi all though id share this to help others trying to sort out fuel mixture problems ect.

If you have a keihn pkw carb and your plug is showing rich mixture black sooty, it may be worth replacing the center gasket which has the two security screws.

Other symptoms is now power band at all and the pilot screw makes no difrence when turned.

I had this exact problem and put new gasket in and transformed the bike.

What gasket are you talking about? I just looked at a parts diagram and the only 2 gaskets at all are the carb top and the float bowl. I know the floats themselves can get knocked out of whacked when removing/replacing the float bowl and that causes all kinds of weird issues.

I have a 2024 300 and its a real pain to start sometimes. A lot of the time. Last night I went to start it and it wouldn't at all. Put a new plug in it, still wouldn't. Old plug was very wet. Did the old full throttle, no choke routine and it finally started. I never had this problem with my 2020 300. The newer ones have a very long overflow spout internally that I have read causes issues. I can't help but wonder if it being so long is allowing it to overflow into the motor before it goes out of the carb.

Sorry, didn't mean to rabbit trail. So again, clarify which gasket you are referring to.

I just saw that this was posted in the Beta section. Supposedly Beta has some sort of mod for their Keihin versions that eliminates or modifies the long overflow spout I mentioned.

6 hours ago, honda65 said:

What gasket are you talking about? I just looked at a parts diagram and the only 2 gaskets at all are the carb top and the float bowl. I know the floats themselves can get knocked out of whacked when removing/replacing the float bowl and that causes all kinds of weird issues.

I have a 2024 300 and its a real pain to start sometimes. A lot of the time. Last night I went to start it and it wouldn't at all. Put a new plug in it, still wouldn't. Old plug was very wet. Did the old full throttle, no choke routine and it finally started. I never had this problem with my 2020 300. The newer ones have a very long overflow spout internally that I have read causes issues. I can't help but wonder if it being so long is allowing it to overflow into the motor before it goes out of the carb.

Sorry, didn't mean to rabbit trail. So again, clarify which gasket you are referring to.

NOT in the parts book ! Take the 2 x security screws out of the jet tower/jet block and underneath it there is a 'D' shaped plastic gasket with three small 'o' shaped bits attached , that is what he is talking about . Ebay sells them , they come in gasket sets direct from CHINA. SEARCH IN 'PWK GASKET SET'

6 hours ago, honda65 said:

What gasket are you talking about? I just looked at a parts diagram and the only 2 gaskets at all are the carb top and the float bowl. I know the floats themselves can get knocked out of whacked when removing/replacing the float bowl and that causes all kinds of weird issues.

I have a 2024 300 and its a real pain to start sometimes. A lot of the time. Last night I went to start it and it wouldn't at all. Put a new plug in it, still wouldn't. Old plug was very wet. Did the old full throttle, no choke routine and it finally started. I never had this problem with my 2020 300. The newer ones have a very long overflow spout internally that I have read causes issues. I can't help but wonder if it being so long is allowing it to overflow into the motor before it goes out of the carb.

Sorry, didn't mean to rabbit trail. So again, clarify which gasket you are referring to.

Edited 18 hours ago18 hr by Tr1AL

Thanks for the info. I have direct access to Parts Unlimited and Western Powersports, both who sell carb rebuild kits and neither show that gasket. I remember for years guys would talk about replacing a similar gasket on the Keihin FCR carbs and many swore they didn't exist. Now you can get them no problem.

So thanks again for the info. I ordered one and hopefully I will see a similar improvement