1980 cb750 bogs down full throttle at 6k rpm

[wossie]

I have a 1980 cb750F that bogs around 6k rpm when full throttle. I have pod filters, stock pipes, and the main jet is 126 (stock is 98). I have no problem getting it to redline in first or second gear at 3/4 throttle or half. Its fast and very responsive, but when I give it wide open throttle in 3, 4, 5 the bike starts to jerk and loss speed, especially around 6k rpm. After pulling hot plugs, it looks like they running normal. Carbs are clean. I think its running too rich, but I don't really know. Any one know what the air cut off valve does and if this would effect the bike as described? I've replaced one, Its very hard to replace the other 3.

[woodsrider250-2]

Bike would be running fine w/ airbox/paper filter.....These carbs are real sensitive to this.  Main (secondary)is way too fat go back to stock.  This jet only works the last 1/4 of the throttle, and that's IF your slides are openening all the way. Change PRIMARY main from the stock #68 to a #75.  That'll be as good as it gets, and this is a good mod even on a completely stock bike (primary jet came too small from factory).  Well, as good as it get's without getting special needles that will really help w/ the pods (needles out of the $100 dynojet stg III kit).

[wossie]

I feel like I might have special needles in there. They have 6 clip position settings. I'm sure as you might of guessed, I bought the bike like this and I'm back tracking through the carbs to fix this problem. Do you know any specifics on what comes in the Dynojet stage III kits? Having a hard time figuring out what jet sizes they recommend.

[woodsrider250-2]

Definitely aftermarket if they have ANY clip settings.

I'd go back to the jet specs I just posted.  The needle has A LOT to do with getting the pods to work better.  Your bog isn't coming from the big jet...Most likely your not even getting onto that jet currently.