Ok, so I've got a few questions about my F3 that I just bought last weekend.

What are the stock jet sizes for a 1996 F3? I'm talking about main and pilot here as well...

I just finished tearing the bike down to its carbs yesterday, cleaning and rebuilding them and my pilot jets are 40 while the mains are what seems like 132.5 all around.

I read somewhere else on this forum that 135 outer and 138 inner is stock.
Here's the link too by the way:
https://cbrforum.com/forum/showthrea...ight=jets+size

What the hell is wrong with my bike? I'm pretty sure the carbs themselves are stock but wtf? Why would someone put specifically SMALLER jets on the bike?

It does have some aftermarket parts as well. Two Brothers slip on and a K&N air filter.

Here's why I'm asking all of these questions. From what I can tell, the bike is running too rich. When I'm below about 5k-6k and I wail on the throttle it momentarily bogs down the engine before speeding up again. After 6k, it pretty much performs fine. The problem isn't too bad at the moment, the bike is 95% driveable and it's really only noticeable when I'm running from a cold start. Once everything has warmed up for about 5 minutes, the bogging lets up a bit and I can drive around without worrying about it too much.

Here's some other things I know:
-The air duct solenoid works (clicks into position when I turn key to run)
-The fuel pump seems to be working
-I just finished cleaning and rebuilding the carbs (It runs a little better now)
-I am (presumably) the third owner of the bike. Second owner didn't know what he was doing and drove it probably 5k since 2004. Said he kept it up on service though. Riiiiight
-The exhaust smells rich rather than lean
-Bike idles fine
-Revs fine up to 4k and after 6k all the way up to the redline


You'd think if the bike were running too lean from the jets being too small and having a free-flowing exhaust and air filter that it would be parched for fuel on the upper end but run fine on the lower end.

I'm confused here...

 

Sounds like you've got a Dynojet Stage 1 jetkit in there. They're smaller than stock IIRC. If your problem is below 6k, it's almost always either a vaccum sync or pilot screw issue. Sync the carbs first, and if the problem persists, adjust the pilot a tad. Also, the pre-1998 F3's have a noticable dip in power between 5500k and 6k, but not something that would cause the bike to bog severely. Is this possibly your issue? I suspect it may be a combination of the two.

Overall, I can't quite figure out how you decided the bike was running too rich. If it's bogging when you crank open the throttle to let all that air in, shouldn't that mean there's not ENOUGH fuel getting into the mixture?

 

Thanks for the help johnny. I haven't looked into syncing the carbs yet and I haven't adjusted the pilot screws but that sounds like something I need to look into.

Why would a dynojet stage 1 kit have smaller jets and the same size in all four cylinders while stock had larger ones and an unequal dispersion of sizing?

Also, do you think that a stage 1 jet kit like that would be proper to compensate for the K&N filter and two brothers slip on?

I'm basing my assumption on the fact it's running fine on the top end and only bogging down at under 5k-6k. This is regardless of speed too. If I'm in top gear at 4k and open the throttle up, it still bogs a bit before picking up again. It's never a steady bogging, always only for a second or two before it picks back up and carries on.

I could be wrong though... I just think that if I were running lean that I would die out on the upper end.

In either case, I'll try syncing the carbs in a few days and see how that turns out.

 

The 95-96 F3's ran rich out of the gate. Dynojet found that reducing the a/f mixture across the board by shrinking the jets improved performance in a stock configuration. Stage 1 is fine for your config. I've got a stage 2 in mine with the full race exhaust, and it actually still runs a tad rich.