To drill, Or not to drill?

A

AyEss

Hii everyone...

Question: To drill? or not to drill?
2 stroke pistons i mean....

Drill holes matching the exhaust bridge, or not?

Buying a 2018 KTM SX 150 for a VERY GOOD price this weekend, Because it needs a top end rebuild and barrel re-plating.. Which isnt a problem...
The reason why i ask is.. The seller stated barrel needs machining and re-plating, because the exhaust bridge is cracked...
And ofc, I know this is the purpose of piston drilling....

So what do you reckon?
Piston drilling worth doing? or not so much of a big deal?

cheers
 
SRAD97750

SRAD97750

Moderator
Staff member
I can rememeber drilling one of my KTM pistons per the instructions included with the piston.
Not sure if it applies to your model though. It's for lubrication purposes as far as I remember.
-BIG DAN:thumb:
 
A

AyEss

yeah bud.. I know its to help lubricate the exhaust bridge.

My question was more of, Would you say its worth doing? or not such a big deal?
 
Photostar

Photostar

Hey, so I'm kinda new to this, but couldn't drilling affect the piston's integrity? Or am I totally off base here? Might be worth weighing the pros and cons carefully..
 
SRAD97750

SRAD97750

Moderator
Staff member
If done correctly it won't effect the integrity of the piston.
Some folks like the extra lubricant at the exhaust bridge and some manufacturers include instructions with the piston kit.
I have heard of bikes with current seizing issues run for longer with this mod done at rebuild, which is why I did it to mine.
Not sure if it added any life to mine, as it wasn't having seizing issues beforehand.
-BIG DAN:thumb:
 
Photostar

Photostar

SRAD97750:
If done correctly it won't effect the integrity of the piston.
Some folks like the extra lubricant at the exhaust bridge and some manufacturers include instructions with the piston kit.
I have heard of bikes with current seizing issues run for longer with this mod done at rebuild, which is why I did it to mine.
Not sure if it added any life to mine, as it wasn't having seizing issues beforehand.
-BIG DAN:thumb:
Click to expand...
Thanks for this!
 
jbird710

jbird710

I've run several CR500s in the last nearly 40 years and I never drilled any of my pistons. BUT, I have never been a pro or intermediate racer, my bikes all ran race gas mixed with synthetic 2 stroke oil, and I did top end tear downs more frequently than was recommended. I would think it depends on how hard you ride the bike and what extremes the engine operates would determine if it's really necessary.
 
Top