Looks too loose to me ..

**Chaz** · 09-16-2017, 10:45 AM

I think the center hole has a problem ...

**AZMIDLYF** · 09-16-2017, 10:50 AM

Loose is fast right?

Looks like it is getting a little more use than the others as well...

**Chaz** · 09-16-2017, 10:57 AM

Maybe I can fix it ....

https://i.imgur.com/LiObFIk.mp4

**AZMIDLYF** · 09-16-2017, 11:14 AM

One of the easier remedies for you I guess...

**vnemous** · 09-16-2017, 11:22 AM

Im sure you have a tighter fitting slug for that bore

**Chaz** · 09-16-2017, 09:08 PM

Originally Posted by vnemous

Im sure you have a tighter fitting slug for that bore

That link is a short video . I haven't got a handle on a good place ( besides slow loading you tube ) to load vids .

Link : https://i.imgur.com/LiObFIk.mp4

Besides the torque from the increase in displacement . The port window's get much wider even when sticking with Mercs conservative port width / bore ratio ..

**AZMIDLYF** · 09-16-2017, 11:09 PM

Bore/port width ratio reasoning?

**NICE PAIR** · 09-17-2017, 08:48 AM

Originally Posted by Chaz

Maybe I can fix it ....

https://i.imgur.com/LiObFIk.mp4

3.999999 liter ???

**JPEROG** · 09-17-2017, 09:56 AM

Originally Posted by NICE PAIR

3.999999 liter ???

You are pretty close...
Joe

**Chaz** · 09-17-2017, 11:12 AM

Originally Posted by AZMIDLYF

Bore/port width ratio reasoning?

For any kind of ring life 70% of bore diameter is considered the end of the road .
A stock 300x works off of a 64% ratio @ 2.330"
To bore one of these out "bigly" would bring the port width ratio down to 60% which would leave a lot on the table .
It's been pretty much relized that the most critical width area is in the first 30* of the ex ports opening .. that's why you will see people going to an Opti - elliptical window , which is easier on the rings and skirt life .
Anyway ..

Going out to 2.500 brings you back in line @ 64%
And even going to 2.600 brings you in @ 67%
As a side benefit , having a lot of meat that needs to be cleared out of the port , lets you contour the radius to ones own liking ... well OK , more twords what the windmill liked ..

Nice Pair :
3.999999 liter ???

As Joe says ... Close

Chaz = thinking , after taking a quarter inch of material out of each hole ... Pppffftttt these things can go out another eigth inch ... easy ...

**H2OPERF** · 09-17-2017, 12:18 PM

All these years us rude boys have been trying to turn them into mercs now u merc nuts are trying to turn them into rudes..Looks nice but need some omc tractor rods in there lol...

**Markus** · 09-17-2017, 12:46 PM

Good that you caught the intruder piston before you put the head on.

**AZMIDLYF** · 09-17-2017, 03:52 PM

OK Chaz, thanks for taking the time to explain it. Again, I was over complicating things by thinking bore size/port velocity interaction. The 30* fact or initial port exposure always did seem to me the most critical time to get things headed in the right direction though.

**Chaz** · 09-17-2017, 10:54 PM

Originally Posted by H2OPERF

All these years us rude boys have been trying to turn them into mercs now u merc nuts are trying to turn them into rudes..Looks nice but need some omc tractor rods in there lol...

I don't know nuffin boutz where dem pissons had be .. Jus like Liberty City , I din-do-nuffin ..

I would had use a tracker rod .. but I cooden fine a shorty skroke crank to fit my blok ..

Markus
Good that you caught the intruder piston before you put the head on.

So 10 years ago, Todd D gives me a set of billet head that had most of the chambers cracked . They sat on my shelf for a few years . A local OMC guru borrows one , redesign's the chambers and takes it to "my" CNC guy . They reprogram the bolt hole pattern and run off a bunch of sets .
Some time later , I take "my" head to the "use ta be" my CNC guy and say run me a set , but with the Merc bolt pattern ... Wait , I gotta get permission from the OMC guy first ....

LOL .. so I guess you could say , I gotz OMC / BuRP heads too ...

AZMIDLYF

OK Chaz, thanks for taking the time to explain it. Again, I was over complicating things by thinking bore size/port velocity interaction. The 30* fact or initial port exposure always did seem to me the most critical time to get things headed in the right direction though.

That one was easy . I wish I could claim it , just another step in two stroke evolution . Shame that most of the world has given up on them , no telling where they would be by now ...

300x on the left .... 300xs on the right ...

**AZMIDLYF** · 09-18-2017, 12:28 AM

Both stock sleeves? If so..wow that is a startling difference. Aside from the obvious size difference and the naked eye observation, is the X exhaust port opening sooner and closing sooner than the XS?