revtothelimit - motorbike forum

IIRC they dropped the five valve heads for the model before the Big Bang.

My last real sportsbike, late model 5VY which I massively regret selling.
Quality WP rear shock, K-Tech SSK front - handled perfectly for me if a little wheelie prone.

I had a blue 1998 R1, R998RRT, it was mental, impossible to ride slowly, really easy to ride fast, only bike I've been able to deliberately and predictably rear wheel steer on tarmac.

The 03 had a useable midrange, the 04- were very revvy which isn’t ideal with 160hp, all models do seem to hold their value and owners seem quite loyal to them

I had one once and didn't get on with it (also had a 'Blade). It was peaky, revvy and a bit too coarse compared to the plush torquey ride of the "Blade. Great on a track but the firm suspension and wrist heavy riding position is murder on the road.

Nice looking bikes but cheap close up, mind you, mine was cheap.

Oh I should add after the 7R I bought a first gen R6. Night and day to 7R, it reminded me of my old KR1S. It only had two speeds 0 or over 130. Mrs M hated it and after a few too many near misses and the requirement for a new kitchen it had to go.

v8-powered wrote: Sat Jan 23, 2021 1:27 pm My last real sportsbike, late model 5VY which I massively regret selling.
Quality WP rear shock, K-Tech SSK front - handled perfectly for me if a little wheelie prone.

2011-05-30151109.jpg

Mine had a 4C8 Ohlins shock and standard front end but it was still wheelie prone. I have a feeling that no amount of suspension mods will cure that

Mine never wheelied, ever

In 3rd or 4th an R1 will happily wheelie whether you want it to or not. Especially true on the road where you really need to be careful because they will just wheelie everywhere.

Wide open throttle, max rpm, no stopping it unless you had a dud (or ride the rear brake).

Druid wrote: Sat Jan 23, 2021 4:35 pm

v8-powered wrote: Sat Jan 23, 2021 1:27 pm My last real sportsbike, late model 5VY which I massively regret selling.
Quality WP rear shock, K-Tech SSK front - handled perfectly for me if a little wheelie prone.

2011-05-30151109.jpg

Mine had a 4C8 Ohlins shock and standard front end but it was still wheelie prone. I have a feeling that no amount of suspension mods will cure that

IIRC the 4C8 had a slightly longer swingarm to 'help' minimise wheelies

I don't remember mine being "wheelie prone" it would wheelie off the brows of hills easily at over 120mph, but was never uncontrollable, and it would wheelie if you accelerated hard in first or second.

The only downsides of mine were the high seat, low bars and that it was a handful of you were tired.

I wouldn't say it was "wheelie prone" though it was definitely up for it, more so than say a soft old 'Blade. Bit like a Gixer thou without the grunt but any modern sportsbike is going to lift the front wheel if you give it some, especially on a bumpy road. Less so on a track, depending on the circuit.

I didn't keep mine long enough to dial it in, it was a buy-to-sell anyway but it could just be a combination of peaky motor and hard suspension.

You need to give more throttle, don't be afraid of the twist grip.

Taipan wrote: Sat Jan 23, 2021 10:38 am That stupid bluey coloured dustbin sized exhaust can kills the whole bike for me.

I think the exhaust is awesome, likes it’s a designed feature of the bike, a signal of intent. Reminds me of a Gatling gun for some reason. Up till then sportsbike exhausts looked like afterthoughts.

The exhaust also coincides with the start of the era when motorcycle noise and emissions started to get clamped down...it was the last of the days of 'traditional' looking exhausts innit?

Mr. Dazzle wrote: Sat Jan 23, 2021 1:02 pm
The Yamahas are 5v engines aren't they (are they still?) which probably explains why they've got loads of top end but less bottom.

Numpty question, why does the number of valves affect the top end/bottom end?

weeksy wrote: Sat Jan 23, 2021 8:09 am Say what you want about sportsbikes, this thing was a complete game changer in the arms race of the late 90s superbikes

There'd always be a space for one of these in my dream garage.

I do remember admiring them when they first came out at the motorcycle show and being impressed with the looks but it wasn't a Ducati 748/9** so that's as far as I got.

Even now ive never riden one.

Beancounter wrote: Sat Jan 23, 2021 9:20 pm

Mr. Dazzle wrote: Sat Jan 23, 2021 1:02 pm
The Yamahas are 5v engines aren't they (are they still?) which probably explains why they've got loads of top end but less bottom.

Numpty question, why does the number of valves affect the top end/bottom end?

Good question, Yamaha claimed it gave better mid range due to move inlet valve circumference, and FZ750s had the same top end as 16 valve 750s but better mid range when they came out, the FZ750 engine was also the most powerful 750 race engine at the time, but I think it was a bit of Yamaha 1980s sales thing as most of the following 20 valve engines were no more powerful than the equivalent 16 valve engines from other manufacturers.

You also have to take into account early 80s metallurgy, valves were made of softer metal than they are now, smaller lighter valves are less prone to stretching at high revs than big heavy valves, if you compare the valves from a GPZ1100 8 valve motor with those from a 16 valve GSX1100 motor you'll see the difference, the GPZ engine is more powerful than the GSX, but if you rev the knackered off one you'll need to regularly replace the valves, GSXs don't suffer from this.

I probably haven't explained this very well as it's a very technical thing, there are various 4 stroke tuning books that explain it better.

More valves generally also means more valve area, which is one of the big reasons they do it. The valves are circular, so if you imagine fitting circular valves into a circular cylinder head you can 'cover' more of the bore with a greater number of smaller valves.

That in turn means you have less restriction on gas getting jn/out of the cylinders. One of the limitations on engine power is how quickly and easily you can get the fuel in and the exhaust out. More valve area means you can shove it in/out more quickly so you push the revs higher and the peak power up.

5v doesn't intrinsically make an engine peaky, bit it does facilitate tuning for high peak power at peak revs, which has the effect of making the engine revvy. Chicken and egg kinda thing.

And just to add to that explanation a bit....El Grando Cheesy points out that the 5v Yamaha engine is intended to have more midrange.

That would seem contradictory to what I said about top end, but it's not. If you use a 5v head that allows better breathing at high revs you can potentially use that advantage to allow you to bias the design more towards mid range. I.e. you are less compromised at the top end so you can do more in the middle.

As with all these things, its always a compromise one way or another.