cbr400 nc23 Please Help Bigger main jets?

[cbr400]

hi i have s/steel downpipes into a very wide car exhaust pipe bent and shaped to fit into a viper end can-....which says on the end ---for track use only -- which is going to be polished off very soon lol
my bike has flat spot at top end it wants to go more.. but dont,, im sure its fuel starvation as far as i know my jets are standerd ....what size are standerd jets and what is a good size to upgrade to, but mainly were do i buy the jets i cannot find them for sale anywere on the internet iv'e heard about a graeme bloke on here who knows a lot about cbr400, rr, nc23, E registration but if someone can tell me were to buy them from i'd be very grateful as my neighbour has the same bike and he also wants bigger jets as he has removed every baffle from his exhaust....

thanks james and dan

[petrolhead19]

1. clean looking bike mate
2. graeme france is deffinatly the man to talk to if you want to find out what size you need. but i think you would be good with 118 jets thats what most ppl use with ss systems and what im going to be putting on mine seen as ive just put an ss system on mine.
3. here is the site were you can get the main jets from, they do them in all sizes £3.57 each http://www.wemoto.com/bikes/Honda/CBR_4 ... pan/88-89/
there under "fuel section"

hope this help mate

Adam

[cbr400]

1. clean looking bike mate
2. graeme france is deffinatly the man to talk to if you want to find out what size you need. but i think you would be good with 118 jets thats what most ppl use with ss systems and what im going to be putting on mine seen as ive just put an ss system on mine.
3. here is the site were you can get the main jets from, they do them in all sizes £3.57 each http://www.wemoto.com/bikes/Honda/CBR_4 ... pan/88-89/
there under "fuel section"

hope this help mate

Adam

i have ordered some main jets i dont know what size they are but graeme seems to know what i need so il leave it to them cheers for info m8

[cbr400]

told GF racing graeme france my bike has a 4 into 1 exhaust system and that its highly free flowing and he sent me 112's ??
is this correct size

[Wozza]

I'm pretty sure Graeme will have sent you Dynojet jets, is that correct? Size 112 Dynojet jets are equivalent to around 115 standard Honda jets. 118 sounds big to me. The popping is due to excess fuel combusting in the exhaust, possibly because of running rich, not a symptom of running lean unless I'm mistaken. A little bit of popping when off the gas is not unusual. Graeme has sent you the right jets to get you in the right area - to adjust your fueling further you need to get the bike on a dyno to get a reading of the air:fuel ratio over the rev range.

Just to check - is your airbox standard/unmodified, standard filter? Standard needles and heights? Trumpets? Float heights? Pilot screws? Carbs been cleaned recently? You need to make sure everything is clean, working and set to standard to help diagnose a problem.

[GF Racing]

To much fuel is just as bad as to little fuel - get on a dyno and see what your fuel air ratio is ... if you don't like my advice / jets simply send them back (undamaged!) for a refund - its fine.

Exhausts need to be tuned lengths of the correct bore - take a look at the last Honda CBR400 NC29s - tiny down pipes - making great power - the tuning harmonics of exhaust systems is some science ... both 2 and 4 stroke.

Yes you have Dynojets - and these flow considerably more fuel than like for like Honda CV jets.

A 118 Dynojet will not work in a CBR400 ....

[cbr400]

ok well it will have to do as im not taking it apart again this will be the fourth time it will just have to stay like it now sorry if i came across rude in my post yesterday so i deleted it.... i was just well and truely P***** off because i really thught the new jets were going to sort it out ...

does anyone know why my bike holds back until getting to medium revs then goes like stink ...if i wind the throtte back slowly it will go fast but if i wrench the throttle back fast bike just makes a booorrrrrrrrr sound before picking up and absolutely ripping my head off i have just no bottom end sluggish until it get going...power all top end

[GF Racing]

Can you put up a picture of your headers especially where they combine under the sump ... plus how long is your end can and its actual bore size ?

Cheers

Graeme

[cbr400]

Can you put up a picture of your headers especially where they combine under the sump ... plus how long is your end can and its actual bore size ?

Cheers

Graeme

Will do mate just trying to find something to use to get the photos onto my pc

[cbr400]

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