revtothelimit - motorbike forum

A tricky-ass all the way from the USA double shoulder socket to be precise,27/32mm.

For the sole purpose of loosening the ridiculously tight front sprocket nut on certain Kawasakis.

I hope it works as well as the pretty packaging.

Doesn't one have a chap who pops over to one's chateau to do it for one ?

Yorick wrote: Thu Jun 10, 2021 5:02 pm Doesn't one have a chap who pops over to one's chateau to do it for one ?

But then I couldn't buy crazily priced tools for a one(or two) off use.

Ohhhh shiny

I feel like making it green is a bit redundant It won't fit many other bikes anyway.

Mr. Dazzle wrote: Fri Jun 11, 2021 2:12 pm I feel like making it green is a bit redundant It won't fit many other bikes anyway.

Attention to detail boi. Makerz need to generate the wantz.

I feel your pain, I remember trying to get the front sprocket off of my ZX9R and ended up chiseling and using a dremel

Daft question possibly but whats the reason for the extra recess?
What does the nut look like and why does it need the extra bit?

demographic wrote: Fri Jun 11, 2021 6:43 pm Daft question possibly but whats the reason for the extra recess?
What does the nut look like and why does it need the extra bit?

Didn't you get the memo?

Yorick wrote: Fri Jun 11, 2021 7:21 pm

demographic wrote: Fri Jun 11, 2021 6:43 pm Daft question possibly but whats the reason for the extra recess?
What does the nut look like and why does it need the extra bit?

Didn't you get the memo?

Nope, to me it just looks like the kind of thing that should be designed out of existence but I assume there's a good reason that I'm unaware of for them making it like that.
Thats why I asked.

demographic wrote: Fri Jun 11, 2021 6:43 pm Daft question possibly but whats the reason for the extra recess?
What does the nut look like and why does it need the extra bit?

You can see the double flange in the pic by rossm. The 27mm part usually rounds off before the nut loosens.

Skub wrote: Fri Jun 11, 2021 7:40 pm

demographic wrote: Fri Jun 11, 2021 6:43 pm Daft question possibly but whats the reason for the extra recess?
What does the nut look like and why does it need the extra bit?

You can see the double flange in the pic by rossm. The 27mm part usually rounds off before the nut loosens.

Ahh, dodgy connection so the pic wasn't showing.
Or rather, by the time it showed I'd moved down the page.

Still looks like the kind of thing that should be designed out of existence mind.

Is this the nut in question? This is what Google reckons an H2 sprocket nut is anyway...



From looking at it I think its actually meant to be just a 27mm nut. Its probably forged in a number of steps (like lots of nuts and bolts) so the second larger flange isn't necessarily meant to be a flange at all. Its just a natural consequence of taking a peice of metal from a billet to a big nut in a few steps.

Just a guess though.

I get what you mean Daz,but there is a definite two size thang to the Kawasaki part and if you just use a 27mm socket,it's not a good tight fit and the chances are you won't get many bites at the cherry before it rounds off.

Pic of the o/e part.

The world has gone mad. Firstly Kawasaki for designing such a proprietary piece of crap when a simple deep hex nut would suffice. Then the makers of the 'Kawasaki green anodised' socket for making the damn thing in aluminium (or aluminum if you're a Septic) even if it is 7075-T6 grade. It needs to be an impact socket made in chrome-vanadium, FFS.

Unless it's an aluminium nut of course, which isn't unheard of in motorsport. We had a complete set of aluminium spanners for just such occurrences.

Probably a but stupid on a road bike if it is, but isn't this the bike with a £1200 fuel pump?

Thinking about it I bet this particular tool is just ally for cost reasons. Machining that tool from a solid lump of 7075 would be pretty cheap, forging it from steel (or even machining it) would be significantly more expensive. Especially when you consider the cost of the forging tools and how many you actually expect to make. Youd bank on the fact it doesn't get used very much and he ce you can live with the fact it's more delicate.

IME of designing stuff for high performance OEMs this weird shit often creeps in. Its generally a case of a late change that was the path of least resistance...I dunno, something along the lines of the crankshaft ends up being 2mm longer for legit reasons and the only way to package everything is to have an odd nut somewhere. Generally you try to avoid these things but on a lower volume special you often just end up living with the pain of one odd bit cause it's less expense overall.

Oh and BTW, the yield strength of Chrome Vanadium steel is gonna be somewhere in the range of 500-700MPa, maybe a smidge higher.

7075 in the T6 condition is gonna be more than 500MPa too, so there's not much in it. 7075-T6 is stronger than many kinds of steel.

Its also softer and less stiff, which make it easier to machine. So you will often see it made into low volume high strength stuff. That softness also makes it less suitable for sockets cause it dents more easily, but as I said you'd rely on the fact owners don't take the front sprocket off much.

Oh, and another thing to consider is that to get 7075 to be 500MPa you need to heat treat it to the T6 condition...treated T6 bar is an off the shelf product. You would also need to heat treat CV steel to get it to be 500MPa plus, but crucially heat treating it would then force you to either do machining in the hard state (£££) or post machine heat treat it, which brings in all sorts of problems with movement during the heat treat process. With aluminum even the heat treated stuff is soft enough to machine fairly easily.

I've not looked, but I expect the raw material cost of a 7075-T6 bar is a fair bit higher than untreated CV steel, but when you throw in all the other costs of making a low volume tool as above it balances out.

I guess my point is, its not a stupid design

Mr. Dazzle wrote: Sat Jun 12, 2021 3:35 pm Probably a but stupid on a road bike if it is, but isn't this the bike with a £1200 fuel pump?

That's Ming's ZH2.

Skub wrote: Sat Jun 12, 2021 4:24 pm

Mr. Dazzle wrote: Sat Jun 12, 2021 3:35 pm Probably a but stupid on a road bike if it is, but isn't this the bike with a £1200 fuel pump?

That's Ming's ZH2.

Couldn't remember which of you had which bike.

No big bike is really "high volume" in automotive terms. High volume is >100,000 a year!

Mr. Dazzle wrote: Sat Jun 12, 2021 3:35 pm Unless it's an aluminium nut of course, which isn't unheard of in motorsport. We had a complete set of aluminium spanners for just such occurrences.

Probably a but stupid on a road bike if it is, but isn't this the bike with a £1200 fuel pump?

Thinking about it I bet this particular tool is just ally for cost reasons. Machining that tool from a solid lump of 7075 would be pretty cheap, forging it from steel (or even machining it) would be significantly more expensive. Especially when you consider the cost of the forging tools and how many you actually expect to make. Youd bank on the fact it doesn't get used very much and he ce you can live with the fact it's more delicate.

IME of designing stuff for high performance OEMs this weird shit often creeps in. Its generally a case of a late change that was the path of least resistance...I dunno, something along the lines of the crankshaft ends up being 2mm longer for legit reasons and the only way to package everything is to have an odd nut somewhere. Generally you try to avoid these things but on a lower volume special you often just end up living with the pain of one odd bit cause it's less expense overall.

Come off it; you're trying to defend the indefensible. All it needed was for Kawasaki to use a standard deep 32mm nut and then anyone could remove it with a standard 32mm impact socket and a windy gun. Instead they decided to go for a two-stage 27/32mm nut which necessitates a special tool to remove. Other than deliberately making it awkward for anyone to remove that fancy nut, tell me how that can be justified? To me that smacks of forcing Joe Punter to book their bike into a Kawasaki service centre when they need a new chain rather than being able to change it themselves.