Go Fast(er) Bits!!! Where to start?

[.produKt]

Righty...

I've had my kawasaki zxr250a for 3 weeks now, and im used to the power :(

And i dont like that, im looking for that unpredictable lil burble of torque and POWER that'll leave one arm flapping behind me as i approach any - km/h :D:D

Unfortunatly, my kawa has 60,000 km's on it, and on wednesday it'll be sent to the doct0rz for a camchain replacement, de-carb and de-sludge, oil change and a K&n Air filter stuck in.
So thats the heavy maintainance taken care of now for the GOFAST(er) bits..

Where do i start?
i was thinking of a higher voltage coil, and those sparkplugs with the 4 firing points instead of one. And the major tune of gettin it dyno tuned :)

Have a suggestion? and no im not wasting my monmey trying to polish a turd either, and i certainly cant afford a bike with lower km's and more power, so the mods have to come with a tiny price tag :(
Feel free to suggest anything! (for those that dont know thier kawa's, its already got a ram air system) :cool:

[kickingzebra]

Basics, Clean and gap spark plugs, make sure air filter and carbies are clean, well balanced, wash it, and paint it red. Other than that, torque and 250 4s just don't really go in the same sentence.

[R6_kid]

ram air on the 250 is a myth mate. How do i know, i built one from scratch, and there is nothing connecting the airflow to the airbox, the intake is on the lefthand side. Bottom line is it's a 250, so there isnt much worth doing to it, unless you have a massive budget - which you've already said you dont.

You may be able to de-restrict it via a limiter in the speedo, but i dont know much about that. Only thing i can think of is getting a more open exhaust system such as a DIC or BEET. Then it needs to be tuned to the pipe, that will give you 1-2hp extra max. Main thing about 250's is to keep them in good shape, so get the valves done - will cost between $250-400 depending on how much work needs doing.

You wont see a 250 four cylinder, four stroke getting much more engine performance than they come with, unless you want to cash out on lighter pistons, rods and a lighter flywheel, and custom cams etc. But that would cost thousands and in the end isnt worth it.

Like we say to everyone, get the best tyres - GPR70's seem to be the bizzo at the moment, and get your brakes and suspension in tip top shape. Then learn to ride the nuts off of it. If you cant do that already then there is no need for extra power.

The only realistic solution for more power is a bigger bike or a two stroke.

[onearmedbandit]

The only realistic solution for more power is a bigger bike or a two stroke.

Or go turbo and nos!! :lol:

[R6_kid]

haha yeh, but he did mention a smallish tiny budget.

just to show you how it all works produckt i have attached 3 pictures of my old bike when it was in pieces.

first pic is of the airflow created by the fairings and k-ras/k-cas

second pic shows where the air intake for the engine actually is.

third pic: red arrow shows air intake port, blue shows the connecting flange. I found that it seemed to run better minus the flange but i may have just been imagining.

Note however that there is no entrance at all in to the airbox(the black plastic bit on top of the engine) which is where the air from the hoses is directed. It simply puts 'cool air' behind the radiator to help keep the bikes temp down a bit while being run continuosly at high speed.

[Buster]

Take all the lights off, throw the speedo in the bin, and go on a diet. All that wont cost ya a cent.. unless you get pulled over, or crash.

[.produKt]

wow, now i think somehow i've bought a lame misleading bike :( *sob
Ahh well, now that i know that kawasaki have done a poor job of thier acclaimed 'ram air system' all thats left to do is improve it :D

[R6_kid]

yeh, i had a spare left hand fairing and was gonna put a subaru scoop on the side to force more air in. The hard part is getting the velocity vs volume right because you want to make sure you are pushing the air in, otherwise you might as well take the air box off and get it tuned to run without it.

That's bad for the engine though, and it's also a real arse to tune.

[Sniper]

Mate, there is not alot you can do to the bike that will make it much faster, They are pretty will tuned from the word go.

[.produKt]

I'd drop a 2smoka in it if i had the time money and paitence.
Ahh there are soo many ideas floatin round, Im suprised noone has suggested lightening the bike, or getting a set of lighter rims or this that and the other bloody thing. Btw which side of ferry road is wilsons road?

[Sniper]

Lightening the bikes a great idea, but how do you plan on doing it?

The thing with buying a zxr/cbr 250 is both are really the fastest of 250's cause they come out of manafactures like that, bar changing carbs, plugs and pipe, there aint a shit load you can do.

BTW, why a 2 stroke in a 4 stroke bike??

[.produKt]

Was just stirring shit bout chuckin a 2smoka on it :P :sweatdrop :crazy:
As with reducing weight, i do have a contact whos able to press CF to most custom shapes based on his mould library.... Now to find his phone number :sweatdrop

[cowpoos]

I seriously doubt you can ride the bike to it's limits mate...why not just get out there and ride...practise your cornering...Etc...

Zxr250's are neat lil bikes...handle really well...just ride it till you can get ya full and then upgrade...your pissing against the wind if you think your gunna find much more HP in one of those bikes...

[sefer]

haha yeh, but he did mention a smallish tiny budget.

just to show you how it all works produckt i have attached 3 pictures of my old bike when it was in pieces.

first pic is of the airflow created by the fairings and k-ras/k-cas

second pic shows where the air intake for the engine actually is.

third pic: red arrow shows air intake port, blue shows the connecting flange. I found that it seemed to run better minus the flange but i may have just been imagining.

Note however that there is no entrance at all in to the airbox(the black plastic bit on top of the engine) which is where the air from the hoses is directed. It simply puts 'cool air' behind the radiator to help keep the bikes temp down a bit while being run continuosly at high speed.

Funny, but I never thought the k-ras refered to the hoses at all, but to the fairing air intake. That's where the k-ras sticker is located after all (at least on my old zxr250C anyway).

[metric]

I seriously doubt you can ride the bike to it's limits mate...why not just get out there and ride...practise your cornering...Etc...

Zxr250's are neat lil bikes...handle really well...just ride it till you can get ya full and then upgrade...your pissing against the wind if you think your gunna find much more HP in one of those bikes...

I think I can see where produkt is coming from - given that he's under 25 y/o it's probably going to take ages to get his full licence

why not just ride it for a while, then sell and buy a two stroke? I got nailed at the lights by some young guy the other week who was on a 2 stroke... can't remember what it was but it was pretty f'n quick

[.produKt]

Im bit of a tinkerer. I think the old zxr has 46 hp @ 12,000rpm's?

Heh it'll be funny to dyno it, to find its making more than standard anyway :P

[metric]

but thanks all, these are some good ideas for me too...

I need to get a wof & service done on my bike, and I'm going to have it for another three months at least - quick & easy top 3 improvements from those listed above?

am thinking as per what kickingzebra said: Clean and gap spark plugs, make sure air filter and carbies are clean? would this be covered by a service?

[onearmedbandit]

Sparkplugs and air filter yes, you'll have to request a carbie service though.

[Coyote]

It's not worth it. Once you sell the bike you'll realise it was pretty quick already. Just enjoy the 18,500rpm redline untill your full licence

I miss my old CBR

[R6_kid]

Im bit of a tinkerer. I think the old zxr has 46 hp @ 12,000rpm's?

Heh it'll be funny to dyno it, to find its making more than standard anyway :P

you'd be lucky mate. The standard number i have heard is 45, and there is debate as to whether that was crank or wheel... my R6 is said to have 120hp at the crank, and gets 98hp at the wheel in good nick... when i got it done it has a meesily 92.6hp thats with a race can, K&N and a dynojet kit too.

tristank's ZXR250C came in at 36hp but needed a tune, so might get 38-40 out of it if your lucky. And his is in good nic, opened up zorst, carbs tuned to the zorst, and had valves etc done too.

Basically if you want more speed then get a two stroker. I was lucky because i was only on a top of the line 250 for 6mths... before that i only commuted. Tristan has been on his for ages now, and is just waiting it out til his full. If you want, get on an FXR150 for a week - then tell us your ZXR is'nt enough for you :bash:

p.s get out in the twisties, keep it above 12k rpm and you shouldnt have any problems with power... if your a good rider it will be a hard task to get past you, otherwise you got lots of room to improve.

[Ixion]

By far the most effective tuning for a 250 being ridden by a learner is to spend time and money upgrading the nut that holds the handlebars.

Which has the extra benefit also, unlike other approaches, that maybe youget to stay alive, and the bike stays unbent.

[stanko]

Come out to Ruapuna and run in the Streetstocks you will be up against RG150's and buckets. A fast 100cc bucket (not me) will probably kick your ass. You will learn so much. Boy will you be suprised how much there is to learn about your current bike. There is a have a go day at levels on 13 may

[Rashika]

By far the most effective tuning for a 250 being ridden by a learner is to spend time and money upgrading the nut that holds the handlebars.

Now that is FUNNY, but oh so true!


Come out to Ruapuna and run in the Streetstocks you will be up against RG150's and buckets. A fast 100cc bucket (not me) will probably kick your ass. You will learn so much. Boy will you be suprised how much there is to learn about your current bike. There is a have a go day at levels on 13 may
yeah, sounds like a damn good idea. Ya might find that the bike is going plenty fast enough, and get a chance to see how it stacks up with you riding it on an open track, against other similar bikes. You should have been out there yesterday, was loads of fun watching the blokes :Punk: Maybe one day I will do more than watch...but I'm a little chicken really.

[aff-man]

ok first of all the way to make your bike faster is ride the nuts off it.... where are you changing gear?? You should be changing between 11000 and 14000 rpm normally or at about 16000 if you are going hard... They are little screamers so do get put off by the noise the make. The bike rides smoother when changing at about the 12k rev mark as well.

Air induction is a joke so unless you make some significant modifications to the air intake system there really is no way to improve power there. Good plugs a can and a good air filter will help you on your way. With these you might be looking at about 40hp at the rear wheel. Ok the next suggestion doesn't really improve the power of the bike but if you get really good tyres you'll find you'll be able to go much faster round corners and use the bike to it's full potential. You shouldn't need to do to much till your running full tap with the bike cranked way over and then thinking you need some more.

If you want a more powerfull bike , and although i hate to say it, get a 2 smoka. An rgv or nsr will be the bussiness and you can get 300cc kits for them as well as quite a few tasty after market bits...... but then it is a 2 stroke.

So in summary= change bike or just ride it harder

[CBobR]

Agree with all the trackday recommedations, but if you are a tinkerer you might be interested in this CBR250 that someone in Oz has stuck a turbo on: http://www.cbr250.com/cbr250/forum/topic.asp?TOPIC_ID=31272&whichpage=1
Not much info in that thread but a couple of nice photos.

My CBR is heaps of fun, I'll probably never sell it so I would like to try to turbocharge it myself oneday just to learn more about engines. It will still be way slower than my 600 but I think it would be a fun experience.
Good luck (and go the trackday!)

[_intense_]

IMO, dont worry to much about making your 250 gofaster, they're such small motors, VERY highly tuned anyway, is it really worth working it that much harder with more air/fuel/power? Save you coin for a bigger bike if speed is all you want. by all means lovingly care for her and retune her and fit all the good bits, like i did mith my CBR250 (a far superior bike imo :Pokey: ) Its all been on this forum before: http://www.cr-x.org/cbr250/forum/default.asp and im reminded of the dude who got 55/58 horses out of an RR which leaves the factory putting out 45hp. It lived for about three hours if i remember rightly.