Why Big Bore kits are a No in my book

[Trigger]

I refuse to fit or rebore for such kits for the reason in the picture. Bryan has mentioned it before but, today I had a chance to take a pic of what can happen to a liner if past OEM spec. Yes, I know my camera is shite but the crack is under the red straw 

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[Bryanj]

Thats why the only ones i considder are those that come with thicker liners, more expensive to fit because of the cost to bore the block and maybe cases but safer

[Tomb]

That looks like quite a thick liner and it still cracked

[andut]

That's an interesting post Trigger !

I stripped my project 400/4's engine a few weeks ago to find a set of 54mm Yoshi big bore pistons installed (have since contacted the original owner who told me that he had Dixon racing fit the Yoshi kit and do a bit of head rework back in the 80's)  The pistins and bores now mic up to just about max clearance and are a little oval, so I figured the only option is Cruzinimage's 54.5mm big bore kit - would you avoid that on the 400 ?  I guess the only other option is to look out for another set of barrels or new liners if they're available anywhere ?  Any recommendations ?

Thanks in advance !

Andy

[Colonial-Clive (yindi)]

I ran a 605 kit on my 500/4 back in the 70,s and have just put a 600 kit in my 550, I've been lucky and not had any problems with them.

[matthewmosse]

Hmmmm I think I'd still give them a shot if I had a spare set of standard bits to go back to  ( which I do ) but its a valuable heads up and thanks for sharing it. Moot point at the moment as I've neither the time or cash to finish my project but I live in hope.

[Trigger]

That's an interesting post Trigger !

I stripped my project 400/4's engine a few weeks ago to find a set of 54mm Yoshi big bore pistons installed (have since contacted the original owner who told me that he had Dixon racing fit the Yoshi kit and do a bit of head rework back in the 80's)  The pistins and bores now mic up to just about max clearance and are a little oval, so I figured the only option is Cruzinimage's 54.5mm big bore kit - would you avoid that on the 400 ?  I guess the only other option is to look out for another set of barrels or new liners if they're available anywhere ?  Any recommendations ?

Thanks in advance !

Andy

A lot of Yoshi kits came with the upgraded liners, if it has the upgraded kit fitted you should get away with 54.5mm. But if not, I would look around for a set of barrels with bad fin damage and take the liners from the damaged set and put in your set. You need to know if your barrels have been altered to take a thicker liner or will still take STD liners.

[andut]

Ok thanks Trigger, would you happen to know or be able to measure the od of a std liner  ? 

[Trigger]

Ok thanks Trigger, would you happen to know or be able to measure the od of a std liner  ?

Just in from the workshop and only have 500,550 and 750 STD liners on the self, have some 400 engine but they are awaiting to be stripped. I have the measurements of STD liners on a scrap bit of paper somewhere, must be another member who has a engine apart.