Topic: honda Cm 400t hesitates at 5000 rpms

[mtd91]

I just got a 1979 honda cm400t.  It starts up great and runs good but when you try to go over 5000 rpms it misses and sputters but if you hold it wide open it will go past it and run fine after your past that point. So pretty much it only sputters at 5000 rpms    none before none after. This is puzzleing me.  The carbs are clean and both cylinders running good. If i choke it a little it will shoot right threw 5000rpm no prob witch makes me know that its a fuel shortage issue but why though?Where as i just cleaned the carbs.. Could it be an air adjustment?   Thanks in advance for anyhelp you guys give me.

[scunny]

could it be that giving it a bit of choke raises the fuel levels in the bowls due to vacuum.this would )possibly) aid in the transition thru to the main jet. ?

[mtd91]

Could be. I will check into that. But i was just thinking to myself that i should double check the air mixure screws just to be sure those are correct. Because the left cyclinders plug is a bit white at the tip  meaning its running lean so im assuming whatever thats causing that cylinder to run lean is why its doing this. I dont know. But i will check into the fuel level in the bowls and vacuum.

[mtd91]

 ok im bringing it to a buddys house next week to have him sync the carbs.  He said thats all thats wrong with it. Thanks for the help.

[scunny]

good luck, and have fun.

[BlindJoe]

I'd make sure there are no leaks at the carb manifolds too

[mtd91]

checked already thanks for the reply though.