1075 over bore.

[imago]

What're the options for an over bore on a 1075 with 18mm gudgeon pins beyond the 'normal' 1168? Preferably low compression for the draw through and if I can avoid getting the meat of the block too thin that'd be good. I've had a search and I can't find anything definitive on it but it appears that I can go to 1230?

I have some barrels sitting and I'm thinking that while I'm at this stage it might be a good time to increase the capacity. Getting one of the custom barrels seems like overkill for what is essentially a road bike.

Edited September 7, 2023 by imago

[Duckndive]

1 hour ago, imago said:

What're the options for an over bore on a 1075 with 18mm gudgeon pins beyond the 'normal' 1168? Preferably low compression for the draw through and if I can avoid getting the meat of the block too thin that'd be good. I've had a search and I can't find anything definitive on it but it appears that I can go to 1230?

I have some barrels sitting and I'm thinking that while I'm at this stage it might be a good time to increase the capacity. Getting one of the custom barrels seems like overkill for what is essentially a road bike.

Max in a 1075 block is 3mm over which is 1166 cc  anything bigger needs sleeves 

You could use a 1135 "EF" block to go 1230cc.....but would need to open up the cases for the larger sleeves the 1135 block has 

MTC do turbo pistons in both sizes 

Edited September 7, 2023 by Duckndive
add text

[imago]

7 minutes ago, Duckndive said:

Max in a 1075 block is 3mm over which is 1166 cc  anything bigger needs sleeves 

You could use a 1135 "EF" block to go 1230cc.....but would need to open up the cases for the larger sleeves the 1135 block has 

MTC do turbo pistons in both sizes 

Thanks. Not worth the arse ache and expense then. I'll stick with the 1168. 

[bitzz]

2 valve? Is the Yosh kit still available?

The Wiseco kit uses soup can sized pistons and stock thickness rings, where the Yosh kit uses lighter pistons and 1mm vented rings from a GSXR. MUCH BETTER. (and Total Seal makes GSXR rings). Neither are "low compression".

Custom barrels/pistons (JL will make you 4 pistons for not much more than off the shelf) and you can hog it out to 4" if you wanted.

[rodneya]

Previous owner decided to go 4mm over on a 1150 motor and the sleeve and rings on No 2 relocated to the sump.

[johnr]

ive an 1170 yoshi kitted motor where the rod and piston from number 2 pot did that but instead of dropping down it just popped out of the front of the crankcases!

[Reinhoud]

14 hours ago, johnr said:

ive an 1170 yoshi kitted motor where the rod and piston from number 2 pot did that but instead of dropping down it just popped out of the front of the crankcases!

Photo?

[johnr]

i think the bottom end is still in the shed. ill take a snap.

 

[E T]

I have a set of low comp pistons if yer interested 

[imago]

17 hours ago, E T said:

I have a set of low comp pistons if yer interested 

Cheers, might be. If you drop me a pm with what they are and how much I can check. I'm not 100% on how low a compression ratio I need for the set up, so I can ask the question on the specs and see if they'd be suitable.