If you have the exhaust and the filter on you have probably got a lot more air flow than stock. this means you are likly running lean. A BAD THING You need to compenstate for the increased air flow by letting more gas in with the air, by rejetting. I would recommed that.
I have a jet kit and exhaust coming tomorrow i already have the filter. i waited to get my exhaust until i could get the jet kit too, to avoid the possibility of running lean. Also, have you rode it hard since you put the filter and exhaust on?(if you did) You might have noticed a little cutting out at high rpm's, caused by running lean.
Just my opinion.....go with majority

In case you didn't know running lean eats up the engine, from the inside out. Like cancer in quads

Jera '00 400ex

 

Jeaner, thanks. That makes sense, but according to White Bros. they say I don't need to rejet (according to the manual). Also the dealer said the 400EX is rich stock. Plus if I'm riding at 6000+ where there's less air (is that right?), less oxygen at least, wouldn't I be OK getting more air flow?? And it hasn't cut out when I near top speeds. And instead of rejetting for now couldn't I just remove some of the rings?? It has 12 now. That is if there's really something to worry about. Thanks again!!

 

padzz, are you really lookin for a cbr 600? i know a guy thAT HAS A 99 F3, did carbon fiber pipe , miles is 3500 ( around there )he is will ing to take $$ 4500 for it, he is gettin married . red and black, never turned on its side , it's a very nice bike. if you are serious about the bike i can get him to call ya or something.the bike is in marland, not sure how far you wanna go to get a good deal. just thought i'd let you know about that, ok. so your not gonna keep the 440? i put that dyno jet kit in my 400ex and could tell a difference , i am running a 170 main, with big gun complete system , k&n with outerwear, 36 tooth rear sidewinder, ac nerfs, i really want that 440 kit, but wb's said that 10:3:1 piston also requires race gas, so does the 11:1 , cam 2 here in pa is $ 4.00 a gallon, i really don't wanna go that route.

 

PADZZ2, do you want to sell your 440 kit?

 

Feara400...I already sent it back for a full refund. Total was $295.
Yes, I am serious about getting a CBR. The dealer here told me he'd give me his remaining one for $6,800 if I buy before the new year. That won't happen. Also I don't think I'd want a used one. It HAS to be an F4.

 

I didn't know you lived at that elevation, i live under 2000 in IL. if you din't notice any cutting out(except the rev limiter) you might be fine. do you plan to modify the airbox lid? or leave it sealed? I just installed my new white bros pipe and i already had the K&N filter. I went a head and drilled five 1.25 inch holes in the airbox so i would know when i rode where the prob was. sure enough i didn't have hardly any pull near open throttle(main jet) so tomorrow i have the day off i'm going to try and tackle this dynojet thing. i think it will make a big difference.

I personally think you should re-jet just to see if there is another level somewhere hidden.

I will have to agree it did still pull harder in the lower gears. I thought about adding six more rings but talked my self out of it afraid of loosing some low end pull.

once i get the jet thing acomplished i will let you know if the difference was really noticable. GOOD LUCK

Jera '00 400ex

 

Jeaner, yes I plan on leaving the air box sealed until I do rejet. Monday I'm hitting the mountains where the elevation is around 12000 ft. Believe it or not there's only about 3-6 inches on the ground. And this is in Utah, ya know the "greatest snow on earth". I am in the south end though.
Has anyone taken their 400 in the snow?? How does it do??
After my new pipe when I hit third the front tires pop up a few inches too. Didn't do that before. Still not sure about top end though. It's around the same. Fast.
As far as the rings go, how much are additional ones?? The more you put on the more top end tou get?? Hmm..Thanks, Drew

 

This is a new one. His girlfriend buys him a kit that increases hp, but HE doesnt want to do the required machine work. For $300 and the ability to spank some Banshees, your gonna send it back? Are you sure you know what a F4 is? They are really fast..

Have FUn

RoostKing

 

RoostKing...for one it was my wife. I didn't think it was necessary to spend over a thousand on me for x-mas.
I don't race it for a living. It's a toy, that's all. I like the new power it's got from the pipe etc. I don't think 600 bucks is a smart invesment into this toy. If I was loaded then hell ya I'd put it on.
And yes, I'm fully aware of what a CBR F4 is. Thank you.