Is my 93' 250 restricted??

[t3mp0r4ry nzr]

Hi there, just a quick question. Have heard something about 250cc jap imported bikes being restricted in power at some point and Im not too sure on the details. Would my 93'cbr 250rr be restricted at all being a jap import??

[N4CR]

Yes. Restricted to 45ps or 45hp? one of the other. At the crank, I think it's PS.

After riding a restricted bike I see what they did, they tuned em more for torqueier midrange but they are dead in the top end compared to mine which is unrestricted (91zxr250c1). 91 cbr250rr I rode was quick like mine and the 93 I rode a while back was all midrange as well.. similar thing. Weird but I suppose tuning for torque and not max hp is the way to get around it eh...

They all have speed limiting (180kmh indicated) 93 onwards and some 92's as well. Mine definately don't but all cbr's do. Most zxr 92 onwards do as well but my 91 does not... but some others do. Mine might have been delimted in japan before it came here.

Production was stopped in 1994 for all inline 4 250's and some were registered in 95 due to time taken to ship out. From memory they didn't make any in 95.
Stopped due to the fact that there was no point in making power restricted 250's with 4 cylinders and much more complicated shit when other, less complicated engine types could get a similar power output without restriction.

Hope that helps. If you want speedo destriction go get a little 'mod box' that plugs in or do a resistor mod to change it. Plugs into a cable off your speedo. Ask a local bike shop they can help. Get the electronics part of the cbr manual and see what is the limited. Private message hdt_boy he has destricted his cbr (old one) and it worked.

Good luck.

[Mr. Peanut]

Production was stopped in 1994 for all inline 4 250's and some were registered in 95 due to time taken to ship out. From memory they didn't make any in 95.
Stopped due to the fact that there was no point in making power restricted 250's with 4 cylinders and much more complicated shit when other, less complicated engine types could get a similar power output without restriction.. :Punk:


They called them Two-Strokes :finger: and the proverbial 10...

[N4CR]

Umm go look carefully you will find restricted rgv's as well, the SP models were not.

And no I'm not meaning two strokes I'm meaning v/ptwin and 4 strokes and shit like that. NSR's died out 96 or so, aprillia stopped in 04. Only offroaders and mabey some obscure 2 strokes still being done nowadays... 4 strokes are still being made. Funny huh?

Emissions are the key here too.

[t3mp0r4ry nzr]

midrange power on a 250?? huh is that possible :blah: haha. Ok, next question or simpley confirmation: to restrict the power honda probabley fitted smaller carbs to reduce the air into the engine,correct? is it feasible to chuck fit larger carbs to it, if so, from what model would I want to source them from and would it be worth it. Basically I want to justify tinkering with it, because, well I like to tinker and modify. BTW, the top end is pretty good as is with a debaffled muff and airbox, the speedo has indicated 170 on a couple of occassions and thats without pushing it too much, heaps of revs left too!
thanks for your indepth reply

[N4CR]

Okay it probably is power restricted as most get to 180 indicated easy enough but stop like hitting a wall due to speed limiter. Yeap they might have put in flow restrictors in the carbs which I think is one of the things kawasaki did.

By more midrange I mean 'more pronounced' lol there ain't much on a 250 hehehe.

[R6_kid]

midrange on a 250 4 is generally 11k-14k, then 'top' is the bit between 14-17.5k/18k wherever the power drops on the dyno chart.

After riding a ZXR250 rather 'extensively' but not so much as N4CR, it becomes very apparent that when riding twisty roads if you arent riding at 11k+ you arent pushing the bike to its max.

Now this is only for crazy people that practically ride these bikes balls out, and it is rather dangerous... just that 250's tend to get away with a quite a bit more than larger bikes when it comes to brown pants moments.

Best way to find out if your giving your bike the thrashing it deserves then go to the track and go 95% (last 5% is generally where crashes happen for newbs) of your max and see how much the bike is straining (e.g running out of revs). Pukekohe is a bit long for 250's but you will soon find out what your max speed is as you generally enter the back straight at 100kmh and have approx 800m of straight.

[N4CR]

Pukekohe is a bit long for 250's but you will soon find out what your max speed is as you generally enter the back straight at 100kmh and have approx 800m of straight.

Mmm mine runs out of dial... how does that help me :P
I should stick a 400 speedo on and see eh.. calculated it to 198k indicated before. Good shit, poor bike.

I heard the litre boys can top out 300k along there.. is that true?

[Mr. Peanut]

Umm go look carefully you will find restricted rgv's as well, the SP models were not.

And no I'm not meaning two strokes I'm meaning v/ptwin and 4 strokes and shit like that. NSR's died out 96 or so, aprillia stopped in 04. Only offroaders and mabey some obscure 2 strokes still being done nowadays... 4 strokes are still being made. Funny huh?

Emissions are the key here too.

Ha-ha, I made you think... :nya:

[imdying]

The SP (1997- VJ23) RGVs were only JDMs, and all restricted :( Damn near doubles in hp when derestricted though!

[N4CR]

The SP (1997- VJ23) RGVs were only JDMs, and all restricted :( Damn near doubles in hp when derestricted though!

I heard otherwise but mabey you are correct. I heard normal ones were restricted but the SP/limitedish ones were not as they are race(ier) than normal ones. If that makes any 'cence'. Interesting they were JDM only though, woulda thaught they would have exported them like Aprillia for racing etc. I'd love to go check out the bike yards over there, bet there are some gems and rare shit we never heard of over here!

[imdying]

Totally... check out the 'Bike Trader' magazines from Japan. They're about the size of the Auckland Yellow Pages, and they come out every week!! If you're in Chch, hit OAB for a look at one.