I will lock the topic if the kind of blatent trolling I've just removed continues.

Personal abuse of members WILL NOT be tollerated here, be warned!
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Please do not PM me technical questions, if you can't find it on the Forum start a thread

Look if he wants to have a cry over the information that others have provided freely in an effort to educate him, then just let him... I don't see how being all mod Nazi on the thread is going to retrain him.

fontyyy wrote:I will lock the topic if the kind of blatent trolling I've just removed continues.

Personal abuse of members WILL NOT be tollerated here, be warned!

I dont think I have abused anyone, especially personally. As I said I wanted to get answers, and got jokes and other bla-bla

imdying wrote:Look if he wants to have a cry over the information that others have provided freely in an effort to educate him, then just let him... I don't see how being all mod Nazi on the thread is going to retrain him.

Information? Please tell me where you see any information.
Educate me? Thats even more funny, please tell me where was the education part (maybe I should pay for it)

NSR-lizard wrote:

Neal wrote:I am sure that nsr125 use a 16mm gudgeon pin. ?

And...?

So does an NSR150!

So what small end bearing do they use on the Tyga 300 cc kits?
Surely that is a NSR150 piston with a 16mm pin. Standard NSR150 s/e bearing is 16/20 x 19 wide, but NSR250 s/e bearing is 15/19 x 17?

The nsr300 has it's own pistons that use a 15mm gudgeon pin . So for us it is a straight forward fit .
If you have a conrod small end made for the 16mm pin and wanted to use these same pistons you need to use the xyz bearing .

My Problem is this:
I have a set of 308cc Polini barrels and heads.
I managed to source piston kits for these, but they are actually NSR125 big bore kits.
So, the gudgeon pins are 16mm. Is there any way that I'll be able to use this on the 250 bottom end?
Option I have at this stage looks like I have to get 2 NSR125 rod kits and then get a set of big end bearings to fit the crank (25/31 x 16).
Unless one of the MC18 cranks that I have has a 24mm big end crank pin.
I was hoping to use the MC21 crank though.

Neal: Is there anywhere(in South Africa) I can get the center main bearing for the MC21 crank?
TBR engineering replaced the outer mains, but he couldn't source the center one.

If you have a mc18 crank with the loose seal in the middle then the pin is 24mm and I think I saw a rod that may work . It all depends on the space that you have for the front cylinder . The Nsr 150 rod is 5mm longer than a stock 250 rod and I assume it is the same as the nsr125 .
For mc21 bearings you need to talk to Andy .
Are those barrels nikasiled ? If it was me I would go bigger with the piston kits available or go the 300 route as there is history and set up info on them . The Polini stuff has not been spoken of here so everything will be new and untested . So for 308 headaches rather go all out or do the common 300 conversion .

I have a list of rods and pistons that may work but I have to find it first .

Good luck

Thanks for the info Neal.
The NSR125 rods are 104mm between centers, but the big end size is 31 ID and the small end 20 ID.
So those will work on the Polini pistons I have. I'll just have to see about the MC18 crank, though.
These Polini barrels are indeed nikasilled, but I may have to have them re done. I'll have to check the piston clearance...
I was hoping to get some info on the 300 setup and use that as a basis for the 308 setup.
I was also thinking about contacting Dr Neels for a set of pipes, but all this is on the back burner at this stage, as I'm still collecting parts and info for the rebuild.
And by re build, I mean a complete rebuild of the hole bike and not just the engine...
Everything is still in boxes so there's still a lot of work ahead.
I was hoping to get the engine done first and then build the bike around it.

Yes i actually forgot about the 125 rod - you can get them on the net , same as the crm125 .
If it was me with those barrels i would go straight to 180 or 190 kit because 308 is too much of a headache when you can get all the 300 stuff off the shelf .
The DR is a very busy man and if he agrees to do your pipes you have to be prepared to wait and he needs the rolling chassis too as he makes the pipes on the bike .
Can you put some photo's of those barrels up ?

If you do go the whole way and bore out those barrels i am sure you could get very simaler results as the rz400 i posted about . That would be expensive to get there but it will pull
like a tractor .
Let us know how it goes cos i am liking the idea of having a 380cc NSR !