2015 ec300e

[(F5)]

Many race bikes run the pins over the boost port. There's no twist if it's central. Probably little like that.
Does the piston manufacturer specify your bike?

 

[(F5)]

Hmm, followed that ebay link, strangely one pic is Vertex and the other Woosner. My Woosner is several years old and measured good enough for me to put it back with the same rings after a crank rebuild a couple of months back.

If Vertex list that kit on their website, I'd run it and not worry. I've run pins over open boosts before. Wouldn't do it over transfers.

I've done it over exhaust as a younger lad. Less said about that the better but it didn't end well.

 

[Desert Silver]

Well, the guy who sold me the piston kit called S3 in Spain and they told him that that's the way the 16 and up are made. I also talked to one of the Factory supported Gas Gas riders at the Costa Mesa Endurocross and he told me he's seen the pistons that way so I guess I'll put it in and not worry. Thanks for the feed back.

 

[Jacob 'Berg]

The last piston I installed into my 2011 250 had the some ring pin configuration over the booster port. I have 40+ hours on it with no issues.

 

[Desert Silver]

Yeah, everything I've bee finding out is this is normal. I just goes against everything I've ever been taught about 2-smokes. Installing it now and hope to have it running before the weekend. Thanks guys for all of the input. I really appreciate it.

 

[gasgasman]

Blow- by will be the same as running a single ring piston.

 

[Desert Silver]

Blow- by will be the same as running a single ring piston.

Yes, but the main reason for running a single ring is less friction which allows the engine to rev higher thus producing more HP.

 

[uawelder]

I just bought a Wossner for my 18 Beta 300RR. Beta changed to a domed piston from flat piston this year. I don?t think $300 for a top end kit is fair, this one cost $150. Here?s some pics. Checked measurements w/ an od mic all were spot on. Received a flat top pro-x that was claimed to be for an 18. It?s measurements were sloppy at best compared to the Wossner w/ skirt .02mm oversized from diameter listed on box. This Wossner is a class act with good machining inside to lighten it up. No machining inside of the pro-x.

 

[uawelder]

Note the placement of the ring pins on the pic from my previous post. That was the whole point that my previous post was supposed to have made. Sorry, long day.

 

[Desert Silver]

That's the location of the original ring locating pins. I found that the 2017 KTM 300 has the same ring pin location so I went with it. The proX is a cast piston so there's a lot less machining required in comparo to a forged piston. I'm in the process of doing heat cycles for the break in. I didn't put the ground wire that uses one of the bolts to hold the coil and the Electric starter wouldn't work. Fixed that today and now the button works. lol