www.zxrworld.co.uk

just fitted a ramairbox to my zxr400l ,now down long straigths on the race track it only revs to 12k it use to go to14500 i have flat slides with 114 jets have tried 122 and 130 and no better ,it has standard h cams and mild porting and kit type exhaust

try takeing the fuel filter out before the pump as it sounds like fuel starvation to me ! also if flatties have no other mods i run 145 mains ! there is also some small filters behind the needle valves that can block ? you have to bear in mind that flatslides use considerably more fuel than cv ?

Filters are all good when i take box lid of it revs out fine i have 30mm stacks on carbs

which ram-air box have you fitted ? kit ? kit copy ? rmkd ? etc ..

i'd try asking whoever made it what their recommended starting point for setup is.

having said that.. if it revs out under load with the lid off, then logic say's its running rich with it fitted .. so try smaller jets.. ?

I've never used flatties, but i had an H1 on CV's with beet exhaust that plateau'd @12k.. was rich at the topend.. smaller jets, modded airbox (stock) and tweaked ignition (ignitech) moved peak power up to 14,700, and it would happily run into the 15,250 limiter

has anything else been changed at the same time ? cams/ignition etc ?

its a rmkd copy and nothings been changed i could go to 110 jets, but they should be far to small, ? How would i tell if its to lean

Dyno ? ? ? ?

What mains do you guys use with flats and ram air box

Are they original SP with a round main or aftermarket kehins with a hex main.
Around 140 for round main or 120 for hex.
This is also dependent on main air jet size & float level
Regards,
MB

The flatslides had the 9mm long hex ones, i have put in round cv type because thets what i had would this make a difference

mitchpaul wrote:The flatslides had the 9mm long hex ones, i have put in round cv type because thets what i had would this make a difference

" Does a bear toad in the woods ? "

I think Mori has the answer for you,
There may be a chance that you main jet is clearing the fuel level???
Regards,
MB

Just ring Roger, his number will come up on a google search easily enough if you havent already got it ..

I'm sure having made the airbox he'll be able to give you an initial setup

my main air jets are 200s ? is this ok

Yes, What is the needle code? try it with the long hex jets, my jetting runs from 118 to 122 mains depending on atm pressure/track.
I run 118 at Wakefield, 120 at Eastern Creek & 122's at Phillip Island. Check your float levels, do not deviate from the manual.
Regards,
MB

You can really feel/hear when you have them on song