Need help running.
 

Ok guys. Got me a 91 cbr f2 and I love this bike. She starts right up and pulls great, however at high rpm in higher gears (5th&6th) she acts up. 6th gear completely falls on it's face. I know I'm getting fuel and spark. Carbs are synched and no vacuum leaks anywhere. Almost at my witts end with it. It does have a different exhaust and jets are 138 across the board. Idk if I'm getting too much fuel not enough air or what. It does have stock style air filter. Any help is greatly appreciated.

Have you got stock sprockets on

No I we -1/+5 . But the problem arose before I changed sprockets. I thought it was the carbs but after synch the problem persists

Made progress
 

Ok so a buddy of mine suggested removing the snorcle from the air box. ( he thinks I'm getting too much fuel) I took it down the road and it was a lot better. But if I get on it it starts to break up a lol bit, but nowhere near as bad as it was. No longer dies in 6th. Maybe I need more air to the air box???? Not sure but I'm so close to fixing the problem

Sounds like time for a carb teardown & cleaning. A carb sync is not a cure-all.

Also need to make sure that the petcock is flowing as it should. I and others with an F2 have had issues with the stock vacuum actuated device,

Right on. I've torn down an cleaned carbs so I'll go ahead an order a f3 petcock. To my understanding I should just be able to plug the vacuum line and be ok as long as I turn fuel on an off.

I did find that it was a fuel problem by playing with the choke as I was going down the road (not recommended). It was the only other way I could think to make sure it wasn't something else

Honda PN 16950-MAL-603. I believe Honda stuck with the vacuum actuated valve till '98.

Petcock
 

Ok I found one on eBay. There's no vacuum port. Just to make sure, I don't need a fuel pump for those petcocks do I.

No...nothing changes except that now you do not need vacuum to allow fuel flow. You will need to get a cap for the vacuum port on the #1 carb.

You'll have to get into the habit of turning the fuel off when you park the bike.

Woot woot!! New one should be here Saturday. PN matched up, so here's hoping for closure