www.zxrworld.co.uk

Hi,

I have current engine and wish to tune it for formula 400. Its got SP Cams and been blueprinted. Last dyno run output was 68bhp. Apart from that nothing else has been done to it. Please bare with me as I am new to engine and dont have full understanding of all the different upgrade's available. I just ride it

I probably will put it into a tuner (any recommendations?), I hear people talking about over sized pistons, larger bore (what’s legal limit?), stainless steel valves, fine I guess a tuner will give me the direction on those. However RAM Air puzzles me, this I guess is something I can do myself. I was planning on the BB Plastics kit. But can someone explain how it works. I have an L3 Model.

Do I need the bellmouths? these fit straight onto the carbs, Do you fit this inside the ram airbox and then connect to carbs? Then close up the airbox and install. How much effort is required to install? is it a case of remove old airbox? I cant really see from the pictures as to how the bellmouths and the ram airbox fit together?

I also read about flat side carbs? Do these work with the ram air and where do you get them? Why they so good?

What sort of power should I be looking for plus reliability from a tuner and ram air, bellmouths etc.

What is this bb-plastics air dam? Is it worthwhile? dO i really need it?

Really appreciated..... Once I have this sussed, Im going to ask about total loss....

J

johnboyjim wrote:Hi,

I have current engine and wish to tune it for formula 400. Its got SP Cams and been blueprinted. Last dyno run output was 68bhp. Apart from that nothing else has been done to it. Please bare with me as I am new to engine and dont have full understanding of all the different upgrade's available. I just ride it

I probably will put it into a tuner (any recommendations?), I hear people talking about over sized pistons, larger bore (what’s legal limit?), stainless steel valves, fine I guess a tuner will give me the direction on those. However RAM Air puzzles me, this I guess is something I can do myself. I was planning on the BB Plastics kit. But can someone explain how it works. I have an L3 Model.

Do I need the bellmouths? these fit straight onto the carbs, Do you fit this inside the ram airbox and then connect to carbs? Then close up the airbox and install. How much effort is required to install? is it a case of remove old airbox? I cant really see from the pictures as to how the bellmouths and the ram airbox fit together?

I also read about flat side carbs? Do these work with the ram air and where do you get them? Why they so good?

What sort of power should I be looking for plus reliability from a tuner and ram air, bellmouths etc.

What is this bb-plastics air dam? Is it worthwhile? dO i really need it?

Really appreciated..... Once I have this sussed, Im going to ask about total loss....

J

Dynotech in Basingstoke provide the best reliable tuning package for ZXR400's. Multi championship winners Tel 01256 881711

Some clubs run manufacturers overbore which is +.5mm, some run no overbores, Bemsee run a 2% tolerance which works out at +1mm overbore, get these from Dynotech.
Use stailess valves, they're much more reliable and don't stretch.
As for internal tuning, I'm really not going to go into it here as it's way to complicated to explain it, besides I'm no expert on it although I do undersatnd it. But, you'be be looking at setting squish by modifying barrel/piston height, increasing compression by skimming the head, porting the inlet and exhausts ports, cutting valve seats etc etc.
Ram air box is sealed with a funnel to the front above the radiator in the case of the BB plastics box, air is forced in giving more valumn to the cylinders.
Don't need bellmouths but they will give more top end power.
DO NOT bother with flatslides, they're a pain to set up and on a well soretd bike will only give 1 or 2 more bhp over cv carbs. They will however give you better drive out of corners due to the way they work. Everyone I know that has tried them didn't get on with them and changed back to CV's.
BB air dam is a form of fairing infill, it directs all the air through the radiator and more directly into the BB air box, not many people I know run them, they may or may not help with power.

Depending which dyno you go to, you'll get 81+ bhp will a full Dynotech tune on their dyno (not a high reading dyno). That will equate to about 74bhp on the trackside DynaPro dyno.

Hope that's a start for you,

Greville

You could allways try

Hodson Engineering he tunes a sweet motor and has a few engines running in the superbike 400 and where doing very well last year

I think Greville will agree hes pretty good at tunning a zxr

Hodson engineering 01732 463658 ( if you dont ring you will never know )

Its allways good to shop around

Simon Lowes 85
M.R.O Superstock 600
http://www.sloweracing.co.uk

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sloweracing wrote:
M.R.O Superstock 600
http://www.sloweracing.co.uk

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You making a comeback then

thought that was a tuned bike you got

Excellent replie, thanks. this site has some valuable advice and difference of opion. always good.

I think I might just get the ram air with bell mouths to start, keep CV carbs, get that setup and see what I have, then look latter in year '08 at a tuner.

Many thanks chaps!!!

My 600 is totally standard mate 117bhp on S.D.C performance dyno

As for the 400 class no chance of a come back mate been there done it 600 is a lot more fun and less work

Put bike in shed change oil take bike to circuit thrash the pants out of it take home put in shed change oil take bike to circuit thrash the pants out of it ( seee my piont )

Cant do that with a competive 400 i know

Good luck next year mate

Just be doing a few races here and there mainly there ( Brands ) unless it doesnt clash with my carp fishing
http://www.britishcarpchamps.co.uk/venues/berners.html

But would love to do a full year next year in the superstock class as i think i could be there at the front certainly after my champion of Brands leading the B final all weekend and being pipped by 1000cc shame i couldnt get a steering damper because i think i could have won a the second race

Good luck see you soon
Simon Lowes #8
Superstock 600