Piston mods

Tommyz125

Member
Oct 25, 2016
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Québec, Canada
I have opened up the window of this wossner forged piston to match the port , anybody did that here? Noticeable power gain?and is this skirt is to dangerously thin on the side? Thinnest part is 7mm, dont want to drop skirt in the crankcase.
 

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i dont think it is common variety mod and little have tried it but risky.
good luck:)

a cylinder head mod from @OConnor Racing will really boost hp for a very good price :D

http://www.kenoconnorracing.com/

http://www.blasterforum.com/threads/piston-boost-port.52561/

to save hassel of tiny pics

View attachment 29155 View attachment 29156
I have probably read all fhe stuff on internet and view every video of KOR , i have done the porting of the transfert port ...im in Québec canada and its too far from im to ship my cylinder head to be rechambered $$$ shipping , anyway the piston on the pic has like 15hr with the bore so is not slapping on the bore , that limiting the risk of piston failure... sorry for my weird writting my main languages is french, i hav'nt use english since high school 6 years ago hahaha!!!
 
i hav'nt use english since high school 6 years ago hahaha!!!

you're doing well enough for us to understand :)

your best way to get a rechambered head is buy one from ebayUS, have it shipped directly to Ken, or maybe he has a spare one ?
then only pay outrageous shipping one way to you, Ken gets good deals on shipping as a business, maybe drop him a message/email and ask how much shipped to you ?
best bang for the buck is a properly modified head !
 
you're doing well enough for us to understand :)

your best way to get a rechambered head is buy one from ebayUS, have it shipped directly to Ken, or maybe he has a spare one ?
then only pay outrageous shipping one way to you, Ken gets good deals on shipping as a business, maybe drop him a message/email and ask how much shipped to you ?
best bang for the buck is a properly modified head !
Good idea my friend il try it!
 
Salut Tommy, fellow Canadian here.
J'ai le meme probleme, il a etre quarante ans que je parlais francais tous les jour.
Pas beaucoup de francais ici en Nouvelle Ecosse.

My son has broken a few skirts on stock pistons, you are wise to cut carefully.
When you hear the slap sound, open it up and inspect.
We have caught several cracked but not yet broken pistons.
I do not thin the center web of the cylinder port at all, and I leave the piston to match with maybe a bit of radiusing to help flow. Much of the piston skirt strength is in that center web of the piston.

I agree with the head mod. You have some good snowmobile machine shops in Quebec that know how to machine cylinder heads, you could go to them, but it might be worth the extra $30 shipping to have Ken O'Conner do what is known to be perfect.

Besides Ken, Look at JoeAK47's old posts and pictures. My son is running a cylinder and head Joe did. It not only makes good top end power, the mid-range is still good. Joe knows his stuff and is worth learning from.

Steve
 
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Salut Tommy, fellow Canadian here.
J'ai le meme probleme, il a etre quarante ans que je parlais francais tous les jour.
Pas beaucoup de francais ici en Nouvelle Ecosse.

My son has broken a few skirts on stock pistons, you are wise to cut carefully.
When you hear the slap sound, open it up and inspect.
We have caught several cracked but not yet broken pistons.
I do not thin the center web of the cylinder port at all, and I leave the piston to match with maybe a bit of radiusing to help flow. Much of the piston skirt strength is in that center web of the piston.

I agree with the head mod. You have some good snowmobile machine shops in Quebec that know how to machine cylinder heads, you could go to them, but it might be worth the extra $30 shipping to have Ken O'Conner do what is known to be perfect.

Besides Ken, Look at JoeAK47's old posts and pictures. My son is running a cylinder and head Joe did. It not only makes good top end power, the mid-range is still good. Joe knows his stuff and is worth learning from.

Steve
Hey salut Steve, i greatly consider your invoice cause i consider you know your stuff well , from all the post you do i have seen you are playing with those blaster for a while! The snowmobile shop for the cylinder head is a good idea . I just leave the middle part between the window on the piston as it is stock. So you never seen completely broken forged piston?, they bend a bit before cracking ? Only cast can drop skirt?
 
Hey salut Steve, i greatly consider your invoice cause i consider you know your stuff well , from all the post you do i have seen you are playing with those blaster for a while! The snowmobile shop for the cylinder head is a good idea . I just leave the middle part between the window on the piston as it is stock. So you never seen completely broken forged piston?, they bend a bit before cracking ? Only cast can drop skirt?

I do use Wossner pistons on my KTM bikes and I like them.
I have had bad experience with Wiseco pistons in my Ski-doos, Sea-doos, and KTM.
Have never used one in a Blaster, but here is one I removed from a used Blaster:
181515_10150134020680803_4486083_n.jpg
You may need Facebook open to see the image.
Piston on left is typical broken skirt, one on right is forged piston "4 corner" seize.
It is caused from running the engine too hard before fully warmed up.
5 minutes of idling and an easy 1 mile drive is not warmed up enough, I can tell you!
The forged Wiseco expands faster than the bore and rubs near the pin.
Wossner pistons do not seem as prone to it. German engineering?

Even though it was the side of the skirt that breaks off, the center rib is needed for strength.
Avoid cutting it thinner. Inspect when you hear any slap noise.

Forged pistons will break, but typically scuff aluminum onto the bore before they break.
For racing they are a good choice, but not for recreational use. Wossners do seem better.

Steve
 
Mine have no sign of cold seize and i havnt warmed up real good before going WOT so maybe the wossner is less tighter fit or expand slowly compared to wiseco.
 
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