maybe moving from 125cc 2 stroke to a 400cc four stroke, thoughts?

beasty6 said:
I can't stay with the mito for much longer, it's gonna blow up at some point, just trying to keep up with my friends I'm having to full throttle it :(

As the zx6r b1h has a meaty midrange compared to the other 600's would it take a restriction better?

A friend of mine has a 2001 yamaha r6 restricted fine and that still goes like stink!
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my srad 600 ran like poo with the kit in, my srad 750 was better
 
cyclops12 said:
All the main fun power on those older 400's was at the top end of the rev range.

Some bikes take restriction better than others and even though they would both be 46 bhp the 600's mid rage would make it a better choice imo.

As for double restricted power I forgot about that, even so I think i'd still go for a 600 of sorts over a restricted sports 400.
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The V4's have a pretty decent midrange, arguably better than most 4-pot 60
0's I've ridden at least, the FZR/ZXR yeah were very 'peaky' but the V4's were a lot better in that respect.
 
I'll agree the VFR400 has great mid-range, felt like a 600 the one I had when I was younger.

Liked to get hot in any sort of traffic and not exactly frugal on fuel but was a nice alternative while my FZR400RR was undergoing rather lengthy insurance repairs (paintwork took forever :mad: ) Very tall first gear as well, good for at least 60mph from memory.

Would say the engine seemed bullet-proof, build quality wasn't bad so there may still be some out there in reasonable condition. Did feel pretty heavy and even with carb mods and an modified exhaust system it actually made less power than the virtually standard FZR. Didn't feel that way though. And it sounded like one of Joey Dunlops onboard TT videos :D Obviously I can't say what one would feel like with a restriction kit on, if fitting it involves getting the carbs on and off that's a bit of a fun job needing a mallet to get them back on :rolleyes:

May feel quite small compared to a 600 so depends what you feel comfortable with too. Would say you'd get a lot more bike for your money with a 600 especially if you decide to keep it once you can unrestrict it.
 
SKILL said:
The V4's have a pretty decent midrange, arguably better than most 4-pot 60
0's I've ridden at least, the FZR/ZXR yeah were very 'peaky' but the V4's were a lot better in that respect.
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Funny both you and tl45 saying that, I only rode the VFR out of all the 400's from that time.

Done a swap for a couple of hours with a bloke I knew, his VFR and my RGV and I can say hand on heart that I had to ride it like my 2t to make it go ie wring its neck:D

It hit 135mph ok (on clocks) so don't think it was restricted in anyway, maybe his wasn't a great example even though it wasn't that old:)
 
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beasty6 said:
What dose the restriction consist of? If i was to go to a track day, can I easily remove it?
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think they put something on the throttle stop? not sure,stop you twisting it fully

on the small 125's it used to be a washer welded in the exhaust and different carb jet if I remember correctly
 
cyclops12 said:
All the main fun power on those older 400's was at the top end of the rev range.
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Right, but they don't make huge power to start with so they don't need much in the way of restriction. An RVF400 only maks 52bhp, so it's going to need barely any restriction to take it to a 47bhp limit.

600 sports bikes also make all of their power at the top of the RPM range, they just make more of it.
 
If I remember rightly the rvf 400 was a bit of a pig to work on. Worth bearing in mind if you're a home mechanic
 
The old 33bhp restrictors from a few years ago used to go in the intake manifold. They had to fitted and certified by an approved fitter, and also re checked if the bike changed owners.

The V4 requires some patience, tis quite fiddly to work on, a good 1/4 drive socket set is an investment if you intend to work on it yourself.

Don't get to caught up in bhp figures, they actually mean very little and don't tell much of the story. BHP is quoted as a maximum, not an average figure, it can sometimes only be made in a window of 20 or 30 rpm at some place in the rev range you don't get to very often.
 
My 33bhp restrictor on the Kawasaki ER6n was a little plug-in cable to some pre-existing cables under the seat and a torx-screw on the throttle body. Took me less than 2 minutes to take it off :)

The actual genuine screw and cable kit costs £10 from a main Kawasaki supplier who'll sell it to the public, they even include instructions and a certificate!
 
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I already have a lot of tools, so working on anything won't be a problem :)

I've seen the RVF400 are quite expensive, but i belive I would get that money back or even more when or if I sell it on.

I've just seen the full tyga race exhausts and the HRC ignition box and intake box, I can see this being tinkerd with, time to play!
 
You could also go the NC30 VFR route, fundamentally the same bike (except forks iirc), last time I looked they were cheaper but still the 'classic' in terms of only going up from there.

Working on them isn't that hard, bit fiddly but nothing major really, hardest bit is the carbs but once you've got the knack of doing it it's not bad.

With mods, the tyga exhaust is nice but also Graeme France does/did some link pipes/cans for a shotgun setup that looks and sounds as nice for less than half the cost iirc (I got my tyga as part of a race bike + spares package, 'bargain' :p). Ignitech CDI's are nice as well, although you won't see much difference (I mostly used it to remove the speedo without faffing around with resistors and raising the limiter for the race bike).

Best mods I made was suspension/brakes though, nitron rear shock and new springs/'compression emulator valves' (early model vfr forks) transformed the handling especially being quite heavy, whilst upgrading to cbr1000 front brake calipers was just insane (did that first and had to beef up the forks as the tyre was rubbing the radiator under braking :D)
 
beasty6 said:
I've just seen the full tyga race exhausts and the HRC ignition box and intake box, I can see this being tinkerd with, time to play!
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'HRC' looks like an innocent collection of letters but can lead to excessive spending :p
 
james1985 said:
The old 33bhp restrictors from a few years ago used to go in the intake manifold. They had to fitted and certified by an approved fitter, and also re checked if the bike changed owners.

The V4 requires some patience, tis quite fiddly to work on, a good 1/4 drive socket set is an investment if you intend to work on it yourself.

Don't get to caught up in bhp figures, they actually mean very little and don't tell much of the story. BHP is quoted as a maximum, not an average figure, it can sometimes only be made in a window of 20 or 30 rpm at some place in the rev range you don't get to very often.
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While that's true, a RVF 400 at 9krpm is making 40bhp, and over the next 6krpm goes on to make another 10bhp.
An FZR 600 of the same era makes 40bhp at 6krpm and by 9000rpm is making 75 BHP.
An RVF 400 weighs 165kgs dry
An FZR 600 weighs 181kgs dry.
Power to weight ratio of an RVF400 is 315bhp per tonne.
Power to weight ratio of an FZR 600 is 414bhp per tonne.

If he gets another 9 BHP with a tuning kit on the RVF if that's the way he chooses to go, gives the RVF 363bhp per tonne, which is a significant difference.
 
I wouldn't buy a 400 because you will soon be wanting / needing more engine.
A 600 is a very good compromise and can be better than the bigger bikes in some circumstances.
2 mates of mine bought RVF 400s after passing their tests and both changed them out within 2 months...one for a TL1000R that he still rides now (10 years on) and the other for a 900 ninja.
 
I personally had a NC30 and loved it, the power wasn't great but it saw me through my restriction period well and because its such a low/small bike it really handles well and gives you good confidence as a new rider in corners etc. perfect stepping stone between a 125 and a 'big bike' imo.
 
Right so I'm looking for a RVF400 but if i got a zx6r b1h, can the police pull you over to check if the bike is restricted? I do t fancy have a zx6r then having it chocked up so much that I will look a tit lol
 
beasty6 said:
Right so I'm looking for a RVF400 but if i got a zx6r b1h, can the police pull you over to check if the bike is restricted? I do t fancy have a zx6r then having it chocked up so much that I will look a tit lol
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There isn't a single model of ZX6-R that is legal for a class A2 licence since they all start with more than double the restricted power. Any insurance company worth their salt would know this. You'll effectively be riding unlicenced.

Sandycheeks said:
I wouldn't buy a 400 because you will soon be wanting / needing more engine.
A 600 is a very good compromise and can be better than the bigger bikes in some circumstances.
2 mates of mine bought RVF 400s after passing their tests and both changed them out within 2 months...one for a TL1000R that he still rides now (10 years on) and the other for a 900 ninja.
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This is irrelevant since your mates obviously didn't have class A2 licences which the OP has.

A bike for a Class A2 licence needs to have no more than 94 bhp to start with, must be restricted to 47 bhp and have a (restricted) power/weight ratio of no more than 0.26bhp per kg.
 
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