CR250 2002 Top End questions- OEM or Weisco?

[macscr125]

is there any place i can get my wiseco piston for my 03 cr250 already drilled? if not what size drill bit do i use to drill the holes?

 

[dirtbike_madness]

I noticed on **** there are some weisco piston kits on there, and in the picture it shows the holes drilled. I have yet to contact the seller and ask if they are coming pre-drilled. One question that I have not seen answered....

Do you still want to drill an OEM piston the same way?

 

[macscr125]

my wiseco kit had the picture with the holes drilled on it and i got it from e-bay and when i got it today, no holes were on it.

 

[dirtbike_madness]

Well, that answers that question! I'd send it back and have him drill it! Just kidding!

Anyone? Drill the OEM on not?

 

[Thumpdaddy]

I drilled the Wiseco last weekend. Just follow the instructions as to location. It says to drill a hole between .060 and .090 so if you use a 5/64 it is right in the middle. Take a slightly larger size drill bit and chamfer the holes with a light hand twist and then use a scotch brite very lightly to make sure there are no burrs. The first hole should be .375 down from the bottom of the lower ring groove and the second hole .300 down from the first hole. You pencil the location on the piston through the exhaust port. It is no big deal to do. Hope this helps.

T-Diddy

 

[pace]

Just a tip that might seem obvious, but it doesn't hurt to mention..

If you do decide to drill the piston, don't bother installing the rings until after you've marked the bridge location and drilled the holes. Also.. the piston skirt has pretty good surface hardness, and the drill bit may be reluctant to bite initially. Take it slow, as you'll be cryin' if the drill bit wanders across the skirt.

 

[dirtbike_madness]

Anyone drill the OEM? Or, with the OEM you don't need to drill? I promise, this will be the last time I ask this if someone would please let me know!!

I would lean towards OEM if I don't need to worry about drilling. But if both should be drilled, then...

 

[jmossbarger]

Whether you drill the OEM or the Wiseco is the same question. Its the same for both pistons, you can do it, but its not going to cause a failure if you don't.

I wouldn't worry about it.
Joe

 

[dirtbike_madness]

Thanks Joe!

 

[mladewig]

I am in the process of replacing my piston. The new piston is a 'Wossner - High Performance Piston' and does not mention anything about drilling oil holes.

Should I drill these holes or rather just install the piston as is? :fft:

 

[jmossbarger]

Not knowing the details on the Wossner piston, I would probably drill holes. Its insurance just in case Wossner didn't get the shape just right.

What made you buy the Wossner? Where did you get it? That's not a name you see much in the states.

Good luck!
Joe

 

[mladewig]

It was by pure accident I got a Wossner piston. I originaly ordered a Wiseco but supplier only had Wossner in stock. The quality looks excellent and has a ceramic coating which makes me a little hesitant to drill holes. There are slight differences between this piston and my oem piston. I will take some pics of it...