125-200cc is this true?

[razornpc]

ive heard from a couple people now that your supposed to drill a hole in the front of your weisco piston on the 125/144 engines to help with the wear caused by the exhaust bridge.

anyone ever do this? is this why im hard on pistons? am i crazy? should i have used the search option a few more times?

 

[HuskyDude]

Never heard of that before...

 

[rajobigguy]

I don't think I'd want to be drilling any holes in the exhaust side of a 2T piston, that would expose exhaust gas to the crankcase and contaminate the intake charge.

 

[dirt-dude]

I think I read about drilling the piston in the instruction sheet
that came with the weisco pistons. I didn't drill it though, I think
it was only applicable to specific years. I'll see if I have any of the
instructions laying around to clarify.

 

[dirt-dude]

http://www.wiseco.com/PDFs/Manuals/MSeries.pdf

 

[surfer1100]

FYI The OEM 125 pistons come with 2 holes on the exhaust side, and the Fast By Ferracci GP piston I'm running has 4 lubrication holes on the exhaust side.

 

[dirt-dude]

The new one I have in the box already has the holes, I assume the
one in the bike at this time likely has the holes too, being I had them
both at the time, I would have checked them after reading the
instructions.

 

[Darkside]

way back in the old days of air cooled 2st. I had a YZ250 ported by an engine builder and he told me to drill a small hole in the piston right where the bridge is. He said that the exhaust bridge is a hot spot and a small hole will help get oil and fuel to the bridge to help cool it since on 2st the mixture feeds from the crankcase.

 

[2whlrcr]

Yes, you are crazy.

 

[razornpc]

http://www.wiseco.com/PDFs/Manuals/MSeries.pdf

well ther you go, looks like i should be drilling some holes.

 

[Joe Chod]

They used to have the 4 hole FBF pistons on ebay for real, real cheap in FBF Store.hard to find as they were listed as "pistions" (must be some Italian code)

 

[ARod2000]

The last topend I did was a wiseco piston and I called my dealer/race friend Gerald at Upstate Cycle. Gerald said that was more important for the older engines way back in the 70's and 80's. I didn't do it but I will say I now need a topend. I don't keep exact hrs of my bike but it seems kinda short. Moral of the story, I'm trying to find a vertex piston now. If not vertex I'll go OEM but I won't use wiseco again. btw, I don't know if vertex or OEM has the holes drilled.

 

[razornpc]

ive got an EG 144 so i have to use weisco

 

[rajobigguy]

http://www.wiseco.com/PDFs/Manuals/MSeries.pdf

OK now I understand what were talking about. Yea I could see where this would add some cooling and lubrication to the exhasut bridge. I still think that there is some potential for minor HP loss but if it increases the durability of the machine then it might be worth the cost.

 

[Picklito]

way back in the old days of air cooled 2st. I had a YZ250 ported by an engine builder and he told me to drill a small hole in the piston right where the bridge is. He said that the exhaust bridge is a hot spot and a small hole will help get oil and fuel to the bridge to help cool it since on 2st the mixture feeds from the crankcase.

I had a 1980 YZ250 with a bridged exhaust port and had to drill the holes to make it live.

 

[PC.]

The Wiseco pistons for my Yami comes pre drilled. Its hard to see with the glare, but the holes are there

 

[pvduke]

It's a very common practice. Esp. on forged pistons.
If the directions say do it, do it.
Been using Wiseco products for decades. Never had an issue with their stuff....ever.

It's a forged piston so warm it up good first before flogging it.

 

[MOTORHEAD]

YES! You really need to drill your pistons on the exhaust bridge.

I do it to all pistons that are run with exhaust bridges.

Some times I'll do it like the 285 pistons in pix from PC, if I see a need.

 

[Darkside]

Originally Posted by Darkside View Post
way back in the old days of air cooled 2st. I had a YZ250 ported by an engine builder and he told me to drill a small hole in the piston right where the bridge is. He said that the exhaust bridge is a hot spot and a small hole will help get oil and fuel to the bridge to help cool it since on 2st the mixture feeds from the crankcase.

I had a 1980 YZ250 with a bridged exhaust port and had to drill the holes to make it live.

Funny, My bike was a 1980 YZ250 too.