I don't think there ever was a GENUINE 400cc "race" bike out there (at least not in the sense your talking about). There are GENUINE 400cc street bikes out there. And there are GENUINE 400cc street bikes that have been raced, but there never was a GENUINE 400cc race bike. Hell for that matter the NSR250's everyone on this site talks about aren't even GENUINE race bikes, there just street bikes that some people race.
Now the Honda RS250, Yamaha TZ250, Aprilia RSV250 are GENUINE race bikes
now if you want to come onto the forums and troll for agruments about 250 vs 400 just come out and say it _________________ Charles Gallant
whoknows wrote:just wondered why all the two stroke guys seem to try and disprove bhp figures for some of the GENUINE 400cc race bikes out there?
It's usually because they're A: not genuine and B: bull
Some of the 400's you see claiming 90 odd bhp would seem to be in a better/higher state of tune than current MotoGP bikes cc for cc, and that from a 17/18 year old engine design...! _________________ NSR300R - Why did i ever have a 250...
I will take someone seriously who claims 75~80hp from a GENUINE 400, but when they start claiming figures more akin to a 600 then I will laugh at them and promptly tell them they are full of sh*t.
What's on your mind?
Bear in mind I don't like bore-strokes (this is NSR-WORLD after all) and I don't suffer fools gladly, and there are people here who make bikes go fast for a living, so don't try pissing down any of our backs and tell us it's raining!
Over to you... _________________ Andy.
NSR-WORLD.COM
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Mainly because 60-70bhp 250's can keep up with them
Mid to high 70's bhp? Maybe, that's what the fully kitted ones made back in F3 days. Low 90's bhp? No. _________________ Please do not PM me technical questions, if you can't find it on the Forum start a thread
Honda claimed 75ps from a full TT-F3 NC30. Honda are pretty close with their figures so maybe around 72-73rwhp. Cant say Ive seen many full F3 NC30's though mind.
Taking that into account I can see the possibility of a 80hp+ ish V4 given the full works. Cant see much more than that though. _________________ If I have to take the carbs off once more...
No No No No I can’t......... Oh okay then I agree with fontyyy There said it... LOL I would have thought the bikes making serious power would wip the 250's all the time..
However there are some serious People out there with some seriously clever old duffers working for them..
I would have thought it would have been disproven by now if not true, they send there engines to the USA for teams out there; it’s a long way to come for being wrong!!!!!
However, I still prefer a stroker... And I see your after bits for yer 125 what ya got what ya doing?[/img]
Last edited by rc46 on Thu Jun 21, 2007 4:51 am; edited 1 time in total
I share info with a G-Force Engine Developments in the USA, and if anyone knows a thing or two about V4 Hondas it's Mike Norman. Now, he's getting high 70's rwhp out of 400cc, and over 80rwhp on big engines (428cc~450cc). The amount of work (and money) to achieve these figures is shocking. Mike has left no stone unturned, and has broken many engines in the search for big numbers.
An 800cc GP bike is making in excess of 200hp, so it should be more than possible to make a 100hp 400cc. Especially given the fact that the parts weigh less so you can (theoretically) spin the bits faster. Honda redline the NC30 at 14,500rpm, which just so happens to be 20m/s, the standard for mean piston speed. Well, with modern materials we can safely go higher than this. Probably up to 16,500~17,000rpm without astronomical expense.
Let's just say that we're making 28ft/lb of torque at 14,000rpm (peak power), this would give us (28*14000)/5252 = 74.6hp. Now if we could keep that 28ft/lb but at say 15,000rpm then we'd get (28*15000)/5252 = 80hp.
Sounds easy when you're just saying it, but if you can get the ports to flow the extra air/fuel mix, and an efficient combustion chamber and ignition, then there's no reason why it can't be done.
A grand prix 250cc stroker can make over 100hp and still be rider friendly, so with good engineering (and non-standard parts) a 400cc boiler would be right behind it.
There used to be a link on the old Bemsee front page to some details regarding the (then) new Superbike 400 class saying the BDK FZR testest over 78bhp on a DynoPro dyno and was thus banned from the class.
The link is gone now but someone else posted about it on the forum as well.
No doubt the 400's have some monster power compared to the average 250 out there (in DP F250), but there are very few (Alan? MJ?) properly kitted 250's and the 400 boys are spending monster money, you're looking at £2.5k for bits alone to build an engine like Dean's FZR has got and you aren't going to put it togeather in the shed either.
That would buy an NSR, get it race preped and in a normal lowish state of tune (mid 60's) easily.
Monkey has bought a ram aired CBR400 to come and play in F400 next year, we should be giving it a bit of a shakedown at Donington track eve on the 3rd July, I'll report back how much quicker than my '28 it is, it's going to be quicker for sure, his old non ram aired track bike had a little bit more zip than it. _________________ Please do not PM me technical questions, if you can't find it on the Forum start a thread
Interesting reading. I was heavily involved in the 400 scene a few years back and actually saw BDK's 90bhp FZR being run on their dyno and the resultant dyno graph on the screen, impressive to say the least! I've also seen that motor in bits and it isn't a big bore, trust me.
One interesting thing though is the amount of work they had to do to get it there, even the crankcases had to be modified as they weren't strong enough to hold together properly with that horsepower going through them, the motor has to be pulled apart after a weekends racing if it is wanted to be kept up to 90bhp otherwise it tails off to mid to late 80's but apparently it is reliable if left untouched, it just looses the edge, bit like a two stroke i guess.
I think in the end though horsepower figures don't mean that much, its what happens on track and i think everybody knows that.
As for people with 400 big bores, that is just cheating and it does go on but i can guarantee BDK don't do it, they have had loads of motors pulled apart over the years at race meetings by officials and none of their motors have ever been found to be illegal.
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I would have thought the bikes making serious power would wip the 250's all the time..
