As mentioned in my dead (now living) '28 post the '28 gearing is pretty low so you can end up on the stop in 6th pretty easy which we're fairly paranoid about (and not without good reason), but surely if you change the ratio to say 15/41 thus effectively increasing the top speed by around 7% and reducing the likelyhood of running flat out you don't actually change anything at all, the engine is still under the same load at 120mph no matter what.
Thus if you changed the gearing to 15/38 you'd end up at about the same rev's in 5th as you had in 6th running 15/44 and thus the same dilema but in a gear lower?
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I think the point is that you would be going so fast when flat out in top you would need a runway length of road to get there, which means at all other times you'll be accelerating.

If you choose to hold your bike flat out in 5th for a while... you deserve to sieze!
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Dave Ett wrote:I think the point is that you would be going so fast when flat out in top you would need a runway length of road to get there, which means at all other times you'll be accelerating.

Ah ha, the penny drops.
Thanks Dave
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Oh come ON!?
If we are SERIOUSLY saying that you can't have an NSR WFO for more than a moment, then I'm selling all my strokers coz they are no use to man or beast.
Anyone accepting that should buy a Suzuki!!
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Of course you can, but the setup to allow this for a prolonged period may leave you with a compromise at other revs. That's the drawback of two strokes I think.

Maybe it's time to develope a variable airbox intake to allow for temperature changes, and linked to a detonation / gas temperature guage. That way you could jet for a hot day, and when it got chilly and damp, you wouldn't have to worry about siezing.

Off you go Matt!
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Honda jets the stock NSR rich, and prolonged high RPM in top gear on a stock bike is not going to be much of an issue.

When you start fiddling though, i.e. when racing (which is what the NSR is really all about) the whole point is to set the bike up for max power and to set the gearing up so that max power & RPM is achieved just at or towards the end of the longest straight, therefore there is never the nead to hold your 70hp+ F3 wide open on max load any longer than necessary.

Trouble with tuning a road bike is that it is almost certainly going to be a compromise at some point. At the end of the day, no NSR (or any other 250 2-stoke) is meant to be blasting up and down a motorway - where are the twisties on a motorway?!

Even a moderately quick A road should be enough to be up and down the 'box and NOT sustain max RPM in top for a prolonged period. If it is, then go find an even twistier B road, it's much more fun.

Remember, any tw@t can go fast in a straight line!

Fontyyy's question about gearing down to a 41 rear... well yeah, of course you will then be pulling the same speed in 5th instead of 6th - then you change up and drop the rev's back down 1000rpm!
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Hang on.
I'd bet my mortgage that most road riders just "de-restrict" thier bikes?
In simple terms, let the NSR breathe and perform like [say] an RGV - without the Jap regs strangling it.

This is a long way from a race set up and I just don't accept that an NSR cannot handle that?
Most road NSR's here put out the same low-mid 60's bhp that an RS Aprillia does, and you can hold them WFO until the gas runs out. [Yes, of course that was me!] I do NOT accept that the NSR cannot be properly set up to do the same.
It's a Honda - don't accept anything less than "bombproof"!
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Do the flat-slides have anything to do with it?
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No I was trying to make more of a point that an NSR (or RGV or RS or whatever) shouldn't even be on a motorway - same as whale shouldn't be in a pool, it's not their natural environment!

What I am saying though is that Honda only ever produced the NSR in 40-45hp form, and then made it safe! Exactly what Suzuki and Aprilia did for their 60hp UK spec' models. It will run all day long like it, in the same way, as you say, an RGV or RS. The problem is no-one other than Honda knows what the "safe" 60hp setup would be, so it's all down to individual tweaking, and that's where the problem lies. Even then, no one is going to stick with Honda's setup. I agree, a 60hp NSR should be bullet if set up correctly.

I rode my '21 flat out up to and back from Thruxton BSB one year, 200 mile round trip up and down the A303 (coming back wasn't quite so flat out as it was wet, but it was still 15 minutes quicker than the Ducati 888 SP4 and 30 minutes quicker than the CBR600F3 that I went with!) and it was solid as a rock, but it's not healthy for a 250! Normally I just stick to fun rides on twisty A and B roads.

I'm regaining confidence in mine again now, after 2 failures in rapid succession (both probably avoidable - one certainly!) and I am now running a pretty "safe" setting. It's not making quite as much power as it could, but I reckon the crank will go before anything else now as it's already on about 30k. It's getting thrashed in top more and more often, and you'll soon hear about it when or if it goes bang!
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Did Honda ever do a HK market NSR de-restricted as Suzuki did the VJ23? That would give us the Holy Grail settings.
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Not as far as I know. If there was a HK market NSR there would at least be something available in Chinese, if not in English. There are no "delimited" spec's or parts in any of the parts books. If you look at the RGV, the Japanese versions came with smaller carbs, different ECUs, various things, but if you look at the Honda list, there's only one type of everything for each model (subject to new parts superceeding old).
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Andy wrote:What I am saying though is that Honda only ever produced the NSR in 40-45hp form, and then made it safe! Exactly what Suzuki and Aprilia did for their 60hp UK spec' models. It will run all day long like it, in the same way, as you say, an RGV or RS. The problem is no-one other than Honda knows what the "safe" 60hp setup would be, so it's all down to individual tweaking, and that's where the problem lies. Even then, no one is going to stick with Honda's setup. I agree, a 60hp NSR should be bullet if set up correctly.

In my book this is such a big thing, even this forum is abound with "can I put pipes / cans / HRC cards etc. on with stock jetting?" posts. "No you cannot" is the only sane answer. Surely if you're going to attempt to derestrict the bike and potentially raise the power by 40% (think about that) a little more fuel may be required. So some base settings somewhere just above the middle ground in the HRC jet kit which is going to put it somewhere on the quite rich side with an oil pump would be a better place to start? Strangely enough this is where my '28 is.

HRC may never have published "safe" full power settings but you can bet your bottom dollar they've got them, they are in the jet kit and they are no where near the "safe" 40-45bhp strangled bike settings.
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