I asked a very knowledgeable friend of mine about this. He said:
The heat marks are caused by the heat treatment process used by Honda.
They induction harden the pin bore, and the integral pin area.
This is in effect "spot treatment" that heats and thus hardens only those areas that need it, the rest of the forging is left ductile to increase fatigue strength.
Its very normal on an NSR flywheel.

You may well be able to get away with just replacing that bearing.
It is starting to look as though the failure of that bearing is indeed reasonably common. See this thread.

<Rant>
As an aside: after being on this forum for approx 18 months I am starting to understand how things work here.
If you look at the list of services provided by NSR-World at the bottom of the performance page you will see that they provide a crankshaft rebuild assessment fee of £25, so I doubt that many of the "senior" members here will offer up any advice.

I guess the moderators put a lot of time into this site and it is possibly fair enough to shut down topics like this with a post that says "This is what our £25 assessment fee is for"?
Perhaps it is 'not really allowed', to give advice on this matter in this forum, as it potentially eats into the moderators cash supply?
But HEY!,... this is a forum
Sometimes I feel as though if this forum was a TV channel, it would pay per view. That is fine, as long as it is stated up front.

I fear that this is probably another example of some of the "mysterious" rules that exist in this forum, but are not mentioned in the "sticky's". Hopefully not.
I just wish that issues like this were made very obvious and transparent by stating them in the sticky's for all to see. Especially for the new members.
This has the potential to be an excellent forum, and I think that not having things like this mentioned up front in the sticky's really doesn't help this forum.
</Rant>
Sorry for the rant, but just trying to help,.. actually.
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[color=#808080][size=9]Yes,.. I too know how to waste Time and Money,...


Last edited by TuckerBag on Wed Nov 23, 2011 7:27 pm; edited 1 time in total