Boring Stock Sleeves

[Filip]

Hey, anyone know the maximum amount you can bore a stock 75mm sleeve before it becomes too weak?

 

[Jan_P]

Well since no one else Ill try ..
Most of the engineering aspects has no fixed answer digital 1 - 0
It is a complex engineering situation pressure heat transfer lubrication how the bike is used.
The designers from the beginning made a reasonable design
Involving testing and adapting after feedback from the market
Changing that for more power or other use
In my view reduces lifespan and perhaps causes a stop rather soon.

I saw some in the 70 ies buying a cheap bike and tuned them .No success stories
No warmup and skipping oil changes did not help

I suppose bore out and drive carefully is a working solution .But if it is hot rodding
and more power
My guess more power can be found safer cheaper on newer design.
Perhaps not an answer ...here are people on the forum that has done it so perhaps they can come in

 

[Filip]

Thanks for the reply! In your experience would 1mm be too much on the stock sleeve?

 

[RustiePyles]

Thanks for the reply! In your experience would 1mm be too much on the stock sleeve?

+1.00mm is 4th oversize for an XS650, so yes you can bore OEM sleeves over 1mm.

 

[Jan_P]

Thanks for the reply! In your experience would 1mm be too much on the stock sleeve?

I see that RP was quicker post it nevertheless

I am not really Qualified to give advice on this .But just to think out loud
Not checked it but the Pictures of the sleeves
And some Measurements there
--> https://www.xs650.com/threads/replacing-a-cylinder-sleeve-how-to.52354/

Ca 4 mm thickness of the sleeve and if I get this right the 1 mm is ?? Diameter or Radius
If diameter going from 75 to 74

4 mm going to 3.5 mm Does not make me feel so nervous but again there are better Qualified here.
I can se situations I myself would consider it since a machining can be simpler than replacing the sleeve.
saving costs

Radius ?
4 mm going to 3 mm Again .. there are better Qualified here. But I would consider it in some situations
having been in the " Last Owner Low Budget Segment " not implying that you are so.

My first guess is it can work. But lets wait for others

 

[GLJ]

To get to 750cc and above you have to replace the liners. There are pistons to get you to 706cc.
https://www.cruzinimage.net/category/item/itemgenre/motorcycle/yamaha/pistons-yamaha/page/2/

 

[650trader]

I used to sell a 6th. OS piston kit ( about 700cc ) and never ever had a problem.

Mike Lalonde Yamahaxs650.com