Performance upgrades for 250s

[Mr. Peanut]

TYGA Performance make a kit
http://tyga-performance.com/site/pro...089a5df7d73b34

And there's a guy selling them in NZ
www.dsracing.com

As much as I would like a 600, I'm thinking of upgrading to a 400 and modding the hell out of that. Twin intercooled turbos, Nitrous, adjustable suspension, Carbon Fibre fairings, the works. I plan to make/install them myself (at least try to). That'll be cheaper and I don't want a trained mechanic or specialist spoiling my fun

Yeah, and I can get them too, and a discount

[Bangbug]

Keep it serviced, lubed and keep the hp you have. Lose weight.
If you have l8 80's early 90's gear it is pumping good hp from the factory. Leave it the f**k alone. LIke people who change performace factory sparkplugs and shit........ yeah! engineering companies with millions didn't know about the 7yt4 f548 sparkplugs (or woteva), bet they put in the wrong ones.
Rant rant RANT!
Get some better tyres too

[Mr. Peanut]

Most machines are built to a price, not a standard. Sometimes simple upgrades can make a lot of difference.

[Coyote]

Yeah, and I can get them too, and a discount

O rly? By how much?

Still a dream to do all that at this stage. Got to get the 400 first. And to get the money for it I have to tidy up the RGs (which I plan to do these holidays). I'm looking into getting a 400 from www.nilin.jp but they haven't emailed me back about shipping to NZ. Otherwise emoto might be the best people to deal with, it shouldn't cost a hell of a lot more (I'd hope) and you have the insurance that the bike will be compliant. In saying that, LTNZ say you only need a paper saying it was once legal in Japan which will mean it'll be fine here... I think. LTNZ have always wanted to remain an enigma

[Coyote]

Make your project an XV400

Or Turbo a pocket bike, then sell it as a Moped/learner license bike.

I prefer the 400 sport style. If I was going for a cruiser I'd go for a GN250

It's been a dream of mine for a while to do up a pocket bike. I was inspired by whitetrash pulling apart his motor in his bedroom, and there were only 12 bolts holding it together. Plus if it goes bang, you can buy another motor pretty cheap. Only problem is finding a small enough turbo and fuel injection system. Nitrous kit is easy to make though: http://www.diy-nitrous.fsnet.co.uk/index.htm

[Mr. Peanut]

5%, more if I really like you...

[Coyote]

5%, more if I really like you...

Well cheers. Won't be doing anything for at least 6 months, I remember planning only to take a month to fix the ol' CBR (which was just a broken crankcase sidecover, dented tank and cracked fairings) but it took 5-6 months to get onto the road due to a panelbeater I had to rely on. "It'll be done Friday"..."No next week"..."Next Monday"..."Tomorrow"...etc. This is where my ambitions of doing it myself came from And now I've got 2 bikes to fix

I'll be picking up Jamezo's bike next week and then the fun will begin. Complete tear down, Kro style

[xxblackbirdxx]

dont even bother, performance gains will be hardly noticable, you might be a little better and happy but that happiness will disappear when you get beaten by a 400.
The other guys have got the right idea. save your money for that bigger bike. The cheapest way to get more power is to upgrade to a bigger bike

[R6_kid:Me]

In my honest opinion, if a person wants to 'upgrade' their 250 then let them, their choice, their money, in the end it may be their loss, it might not be.

However, if i was back at the start of the graduated licence system and had just got my 6L, had money to spend, and wanted to eventually ride quick here is what I would do.

First of all, good rubber. Depending on how much you ride, and how you ride, you'll want Dunlop GPR70's or GPR100's. The only other decent substitute i know of is the BT45/92/96 range from Bridgestone. Talk to a reputable shop or person that you can trust to find out what will suit you best (helps if they have seen you ride on the open road but this is hard to find these days with shops)

Sweet, got the rubber sorted. Now what? Suspension. Get it looked over and sorted. Even if it didnt need it having fresh oil and new fork seals will give you piece of mind. If you're rear shock is screwed, then look for an alternative. Most 250's use similar mounts to their 400+ equivalents so if you are heavier than the average 50kg Asian that your bike was designed for this could help you. However suspension is about geometry and messing with it too much could send you a cropper. If you can get Shaun Harris to look at your bike and see what he says... he is your best resource with regards to suspension here at KB. New springs may be needed, or perhaps a rebuilt shock, maybe some spacers, either way your bike will be better off from being looked at by a professional.

Now, sprokets and chain. Generally you won't need your top end, and to be honest what you really want on a 250 is pulling power. Get your rear end geared down. That means going UP teeth on the rear sproket. Where possible avoid going DOWN teeth on the front, because if the turn is too tight your chain will wear quicker. Generally 2-3 teeth up on the back will be plenty if you want some more go. Chains should be kept lubed (not excessively), checking the state of your chains lube every 200km and checking the tension every 400km is suggested from most factories.

Brakes. Most bikes you guys are riding are coming up to 15-20years old. Get your brake calipers cleaned and serviced. New seals will do wonders for your braking power. Keeping your pads in check will too. If you think you need more stopping power then try fully sintered pads, but in many cases, factory product is best. If your brake discs are warped or worn below spec then the first thing you need is new discs... doesnt take a rocket scientist!

Other general maintenance such as keeping clutch and throttle cables well lubed is also wise as this will help to keep your riding trouble free.

Keep your bike clean! I use Formula One Wheel Gold. This stuff will obliterate brake dust and built up oil/grease like a turps soaked cloth, but without the harshness. Keeping dirt out of tight areas will help keep everything in top condition, some people i know strip their bike of all its fairings, and remove the wheels every 6mths to do a thorough clean. I'd suggest doing this before you start riding lots in summer.

[R6_kid:Me]

Bearings/Bushings. Steering head, wheels, swing arm pivot. Get them checked. If they need replacing then do so. This will keep things rolling, turning and pivoting that much better - helping to make you quicker and more confident!

Now, the stuff you've been waiting for - POWER. Im no expert but the basics that everyone should know are FUEL, AIR, COMPRESSION, COMBUSTION.

Good fuel lines and a clean tank will help insure your fuel gets where it needs to smoothly. Having a fuel filter helps keep the stuff going in to your engine clean.

Carbs. They need to be balanced as well as tuned. Having bigger jets will allow more fuel mixture but may cause your bike to run rich - a good mechanic can tell you what will and wont work, its all relative though.

Exhaust. There are some exhaust systems available for 250's but the main thing you will get are end cans. Letting your bike breath more will help it run better, but generally a little more top end will mean a little less low end. With an open pipe your bike will want to blow a bit more exhaust through, so you should open up its throat (air filter) with a hi-flow filter, or if you dont care, no filter (not recommended). Of course, now you have more air going in, and more air allowed out, so you can let the carbs give the engine a bit more gas to burn. Again its all relative, and generally you'll need a mechanic to do the work for you.

An end can will cost between $200-400 and most likely be second hand. Not sure on the availability of hi-flow style filters for 250's but ask around and you might find something.

If you are really crazy then you can go and get your engine head planed for a little more compression, maybe get some more aggressive cams, but as everyone has said - The CBR/FZR/ZXR range came from the factories pretty worked so its wise to leave the mechanicals as is.

If you did the air filter and exhaust modifications i'd expect between 2-3hp increase. But it varies, and yep sometimes you even go backwards... the benefit, your bike sounds better and has a bit of an induction growl.

To be honest, if you want to go faster, losing some weight is an obvious choice. If thats not enough, once you've learnt how to handle a 250 properly (i.e have some decent skill) maybe a two-stroke 250 will be up your alley.

There is a long road ahead of you in the life of motorcycling. Once you can 'ride' there are soooooo many things to learn how to handle, it gets mind boggling at times. The faster you go, the more you have thrown at you, the more things your bike will do unexpectedly, faster than before. Take your time and process everything you experience, if you dont understand, ask someone that you respect to tell you what they think, no-one will knock you for asking, trying, and learning, but you sure as hell will get knocked if people tell you and you dont listen.

Essentially, the best things for you to do is to make sure that your bike is in tip-top shape, and keep it that way. Get your suspension setup, run the best tyres and brakepads you can. Listen to your mechanic and look after your bike. At the end of the day its what lies between you and hitting the wall - so look after it.

[Mr. Peanut]

Yeah yeah... BUT WHAT ABOUT TURBOS!!!?
(really good info R6)

[R6_kid:Me]

cheers man. Turbos... hmm, maybe on something like an inline or v-twin. Very expensive, and with these little engines you probably wouldnt gain back much over what you lost in decompressing the engine so you could run the turbo. Not to mention the lag.

There is a story of a guy that had a ZXR/CBR turbo'd. It ran, and apparently had 60ish HP, but blew its lid after 70km of riding... and i bet it was an expensive 70km of riding.

[Coyote]

cheers man. Turbos... hmm, maybe on something like an inline or v-twin. Very expensive, and with these little engines you probably wouldnt gain back much over what you lost in decompressing the engine so you could run the turbo. Not to mention the lag.

There is a story of a guy that had a ZXR/CBR turbo'd. It ran, and apparently had 60ish HP, but blew its lid after 70km of riding... and i bet it was an expensive 70km of riding.

Oh gosh, that's knocked my ambitions to make a turbo'd VFR :S

Then again, part of the reason for me thinking of the project is cause I wanted to make it work, that would be the challenge

[SimJen]

cheers man. Turbos... hmm, maybe on something like an inline or v-twin. Very expensive, and with these little engines you probably wouldnt gain back much over what you lost in decompressing the engine so you could run the turbo. Not to mention the lag.

There is a story of a guy that had a ZXR/CBR turbo'd. It ran, and apparently had 60ish HP, but blew its lid after 70km of riding... and i bet it was an expensive 70km of riding.

Jamie Bezzina (tuning god) in Australia did a FZR250 and got 100hp from it.
Was a little bit of info about it in Rapid magazine ages ago.
It'd be like riding a hand grenade
If you want performance in a 250 then get a two stroke. I did many thousands of km's on my derestricted NSR250SP but it was lovingly fettled by me on a regular basis. Not all two strokes are well looked after, and that is why they start to have problems.
A heavy ass 250 four = 150kg dry whereas an NSR with decent chambers and a little weight reduction can be 120kg dry. The two strokes almost always have better suspension due to being used in sports production racing.
Brakes are often better too, the NSR has 4 pot brakes from an early fireblade, while the CBR250's often have sliding 2 pot calipers on a heavier bike.

[avgas]

Derestrict kit may/may not contain the following (dependent on bike):
- Speed derestrictor
- RPM derestrictor (for the old ignition unit)
- Carb components and cleanup (needles/jets, also in some case baffles are removed)
- In some cases a computer upgrade
They guys in Japan do the best stuff - but unfortunately most of it is in japanese. Every time i had it done, she was allready altered on the bike from Japan.
Those crazy japanese