MS260 mysterious hole in cylinder - advice appreciated! :-)

[Ray1]

Looks like they have used a too big slot drill when they spot faced the rough casting to clean up the face prior to drilling and threading the spark plug hole. It looks a very cheap after market pot, i would be more concerned about it failing than the hole in the fin.

[Stubby]

Looks like they have used a too big slot drill when they spot faced the rough casting to clean up the face prior to drilling and threading the spark plug hole. It looks a very cheap after market pot, i would be more concerned about it failing than the hole in the fin.

 

If it was that the hole would be elliptical in the cooling fin as it is on a different plain to the axis of the plug hole .

[Ty Unnos]

Pretty sure my genuine 026 cylinder is the same. It has never been a problem.

[treequip]

Looks like they have used a too big slot drill when they spot faced the rough casting to clean up the face prior to drilling and threading the spark plug hole. It looks a very cheap after market pot, i would be more concerned about it failing than the hole in the fin.

 

wot he said:thumbup1:

[Ray1]

If it was that the hole would be elliptical in the cooling fin as it is on a different plain to the axis of the plug hole .

 

A photo with the plug out looking down on the hole would prove it either way.

[Bryapatch]

Some more photos, if it they help:

 

 

 

 

 

 

I have no idea where he got the pot, its safe to assume cheap. The thing i cant remember is whether the hole was there when i got the saw. Pretty sure i would have noticed when i first looked it over, but maybe not.

 

The hole is off centre as you can see from the photos, and is pretty rough, with a crumbly edge.

 

Thanks for taking an interest.

[eldon]

I can't see this hole causing concern but the casting seems quite a poor effort, read cheap.

If it works fine then as said alter mixture and just use it. I have seen many air cooled motorbikes work for years with cooling fin defects, snapped off etc. and never been a problem.

[Bryapatch]

Cool, thanks.

[wisecobandit]

Its cast like that on purpose I reckon.

To help clearance issues using a scrench or sparkplug socket to save fouling issues.

[spudulike]

The hole should be of no consequence, I did check an OEM 026 I have in the workshop and it doesn't have the hole but TBH, it is of no importance, it just leaves a small bit of the top cooling fin unsupported.

 

I wish this was the only thing giving me worries:001_rolleyes:

 

You pay £60 for a piston kit rather than £230 and this is what you get!