Friday 7th January 2011

PH2: Ninja ZX-10R Powered Up For Launch

Revised cam solves pre-on sale engine prob for new Kawasaki

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Thank God for that. The recent recall that Kawasaki has had to instigate for the new ZX-10R will not affect peak power output, which in case you'd forgotten is 197bhp. I for one wouldn't have noticed a drop of a few ponies and I suspect most others wouldn't have done either, but it's the principle that counts.

The problem was to do with valve spring surge. Or what used to be known rather more brutally as valve bounce. At high revs the valve spring resonates which causes the valve to bounce on its seat with the result of a loss of power and eventually valve and seat damage. Kawasaki says it's changed the camshaft to prevent this surge from occurring

I'm looking forward to a go on the new ZX-10R which is apparently more than a match for the BMW SB1000RR. I remember the first edition of the ZX-10R and it was an animal. Extremely vicious power delivery that could easily catch you out. I rode one to Barcelona and back in company with all the other Japanese litre superbikes and came back with grey hair.

In theory Kawasaki could have done with the new ZX a couple of years ago so that it'd have been ready for BMW's first superbike. However, I doubt it wouldn't have made a huge amount of difference because I'm pretty sure that many people have bought the SB1000RR because it's a BMW, European and not Japanese; and not just because it's a brilliant bike. Anyway, the ZX arrives in UK dealers - a little delayed by it's pre-on sale 'recall' - at the end of this month.

[UnluckyTimmeh]

Sounds good Yonah!

Have you ridden the S1000RR? what did you make of it? Is it something I could ride everyday?

Cheers,

Tim.

[h4muf]

Nice "7" donor engine

[zakelwe]

I've only ever seen one BMW 1000 on the road, strange considering it got such good write-ups.

Check the exhaust out in the pic, flipping ell, they are ugly blunderbuss' nowadays. What happened to slim oval silencers? It all started to go wrong with the Ducati 999 tin of spam exhaust.

Regards

Andy

[UnluckyTimmeh]

zakelwe said:

tin of spam exhaust.

They'll have an Akro ready before you know it

[tonym911]

zakelwe said:

Check the exhaust out in the pic, flipping ell, they are ugly blunderbuss' nowadays. What happened to slim oval silencers?

Big pokey fours like this need to flow plenty of exhaust gas. Four-into-two systems are optimum for flow, but fashion dictates four-into-one. If you want to keep within the law (as manufacturers must) while delivering performance, you end up with big fat tailpipes like this.

[Castrol Craig]

UnluckyTimmeh said:

zakelwe said:

tin of spam exhaust.

They'll have an Akro ready before you know it

already are ready. and you only need the mid pipe & can, no matter what they do akrak cant get downpipes to match the stock kawak ones.

as for only s1000rr on the road...i know 8 lads with them on these forums alone!

[Vidal Baboon]

How did a different cam profile eliminate valve bounce? Would it not require stiffer springs?

[tonym911]

Vidal Baboon said:

How did a different cam profile eliminate valve bounce? Would it not require stiffer springs?

Maybe by removing the ability to rev to valve-bounce rpms in road use. As Yonah says, few mortals will get up to these levels anyway. Racers will presumably insert their own valvegear.

Edited by tonym911 on Friday 7th January 18:01

[tonym911]

IMO Kawasaki has always been a bit hamstrung by its own rather limiting corporate philosophy of outhorsepowering the opposition no matter what. This valvebounce thing may be a PR stunt.

[srob]

Vidal Baboon said:

How did a different cam profile eliminate valve bounce? Would it not require stiffer springs?

If you have a smoother back of the profile - if you know what I mean - so that the cam doesn't fall away so quickly after peak opening? In effect everything would be smoother so everything can keep up. Probably makes no sense to read, but I know what I mean

BTW, a top first article for PH2. Nice to get a bit of technical info and answer the ZX10 recall question - I wouldn't have known otherwise as I don't really follow modern sites any more

[Waynester]

I still think this is a missed opportunity by Kawasaki as even in the press the figures aren't significantly better than the BMW, in fact have they not RR both and the result being the S1000RR was more powerful??

I just think they had the chance to at least put daylight between themselves and BMW at least in the numbers dept as (unfortunately) the highest can attract those who think that is the be all & end all.

I'm not knocking the Kwak, I'm a fan of the marque with a KR-1, GPZ1000RX & ZXR 750 H2 in my garage.

We will have to see how it goes head to head, I for one hope it does the business.

[moto_traxport]

srob said:

Vidal Baboon said:

How did a different cam profile eliminate valve bounce? Would it not require stiffer springs?

If you have a smoother back of the profile - if you know what I mean - so that the cam doesn't fall away so quickly after peak opening? In effect everything would be smoother so everything can keep up. Probably makes no sense to read, but I know what I mean

Think you are referring to the "quietening ramp" on the lobe. Has got one on the lifting side and the errrr other to smoothly make contact and then after its lifted the valve it then smoothly drops it onto the seat.

On my race bikes I open up the valve clearances to max and what I lose in lift I gain in effectively slightly changing the cam profile by missing out the quietening ramps and having the cam batter the valve open. They rattle a bit more but produces a nicer engine to abuse.

[Castrol Craig]

Waynester said:

I still think this is a missed opportunity by Kawasaki as even in the press the figures aren't significantly better than the BMW, in fact have they not RR both and the result being the S1000RR was more powerful??

I just think they had the chance to at least put daylight between themselves and BMW at least in the numbers dept as (unfortunately) the highest can attract those who think that is the be all & end all.

I'm not knocking the Kwak, I'm a fan of the marque with a KR-1, GPZ1000RX & ZXR 750 H2 in my garage.

We will have to see how it goes head to head, I for one hope it does the business.

no one apart from paul bird motorsport (using frank wrathall) and mss kawasaki (using bsd) has had one on the dyno yet, akrapovic have had one for half a day but had a pre production one.

[martynr]

Oh why is it SB1000RR and not S1000RR?

Surely it was not a mistake, it has been written twice! If you have no idea of bikes, then why would you write about them?

[obscene]

SB1000RR ??? WTF ???

[tonym911]

Well done Col, your honeymoon period lasted approx 1hr 20mins.

[rhinochopig]

tonym911 said:

Vidal Baboon said:

How did a different cam profile eliminate valve bounce? Would it not require stiffer springs?

Maybe by removing the ability to rev to valve-bounce rpms in road use. As Yonah says, few mortals will get up to these levels anyway. Racers will presumably insert their own valvegear.

Edited by tonym911 on Friday 7th January 18:01

Valve bounce is not just an RPM issue. The 250 4ST of the eighties would wind up to 19000 rpm.

[tonym911]

It's an rpm and reciprocating weight issue. Small valves travel faster.

[rhinochopig]

tonym911 said:

It's an rpm and reciprocating weight issue. Small valves travel faster.

Partly but another factor is how the valve accelerates. To prolong opening times, the valve needs to open and shut as quickly as possible - open and shut too fast and it can contribute to valve bounce.

[tonym911]

Of course, if anyone knows all there is to know about these matters it's Kawasaki. I cannot believe that this so-called valve bounce did not manifest itself during the factory's engine testing programme. That's why I (perhaps cynically) wonder if all this talk of valve bounce was more about headlines to big up the 10's nutter bd power characteristics, and Kawasaki's reputation in that area, than reality.

Edited by tonym911 on Friday 7th January 19:25