Hi everyone. I'm new to this site and in need of some help. I've just bought a CBR 900 F with a cbr 1000 F motor in it. It's been street fightered with a mono shock rear suspension , rentals etc etc. My problem is that it has no air box and a 4-2-1 micron exhaust and subsequently running very bad. My question is , have you got any idea of what size jets I might need to get it running properly or any other advice ? There is no room for an air box so would k & n's help or foam cleaners ? Thanks

 

I see you found us !
Start here
https://cbrforum.com/forum/cbr-1000f...jet-kit-37559/

and this one:
https://cbrforum.com/forum/search.php?searchid=1538046

then use the "search" button, but I suspect the lads will be along in a bit so help will be at hand.

 

Welcome Fred!

If there's no air filtering at all I wouldn't even run it mate as you'll be up for a new motor real quick. I'm not just talking about the rocks, dust and other nasties either. If it's got no filters and a free flowing pipe it'll be running seriously lean and this will kill it if left.

As it's got no fairing you'll have to put some pod filters on for sure, then start dicking with the jetting.

Has it got a jet kit in it already? The stock carbies don't have adjustable needles so if it hasn't got a kit in you'll need to put one in I'd say.There's no magic solution I'm afraid. Stick some pods on, see if it runs at all and go from there.

 

Thanks for the advice guys. Now looking for a stage 1 dynojet kit and K&N's lol. As soon as I can I will post up some pictures. Great site and great help !

 

There's a couple of guys on here with fightered cbrfs. Off the top of my head I can't remember the names though.

Do a search and PM them as you might get a starting point as far as needle heights and jet sizes go. At least then it'll run and you can fine tune from there in the usual way: Ride, fiddle about, ride, fiddle about, swear, drink beer and so on.

 

You should write a book on carburetor work. Those are the exact steps that I always take. LOL..

 

Ha I had my carbies off completely 4 times and the tops off half a dozen to get mine running right when I put the V&H and drop in K&N...

Always leave the drinking beer 'til after I've done for the day though...too easy to f#ck something right up when you've got a buzz going .

 

Not me! I just keep right on trying. Diaphragms upside down, springs flying, jets in the garage floor drain, vacuum hoses routed to god knows where.
Then there's all the fuel.... and cigarette smoking.

 

Thanks for the replies and encouragement guys. Just wondering what the difference is between a 1990 and 1996 dynojet kit for a cbr1000f as that has been suggested. Thanks