Piston wash patterns

[huskihl]

View attachment 176212

Cleaned up a touch

Do the ports crack open flat? Even or staggered from one side to the other?

 

[Deets066]

Would less muffler outlet help with short circuiting? I’m not a pro porter, just wondering.

It wouldn’t make much sense to spend the money on a custom piston, then grind the port to 80% only to close off the muffler.

 

[Deets066]

Do the ports crack open flat? Even or staggered from one side to the other?

Pretty sure they are flat and even. Gunna double check next time at the shop though

 

[Fruecrue]

The exhaust port itself is very wide. 79-80 percent of bore

Real hard not to lose a bit with that port width, especially if theres long duration.

 

[huskihl]

View attachment 176226 View attachment 176227

Pretty sure they are flat and even. Gunna double check next time at the shop though

One transfer could be pointed up a little and maybe the exhaust is pulling it out.

 

[Deets066]

One transfer could be pointed up a little and maybe the exhaust is pulling it out.

Very possible

 

[Deets066]

Real hard not to lose a bit with that port width, especially if theres long duration.

174 duration. I know a lot is goin out, muffler is soaked even at a lean tune

 

[Stump Shot]

Make three reed valves to go over the holes in the muffkin cover might get you what you need when you need it.

 

[Deets066]

Make three reed valves to go over the holes in the muffkin cover might get you what you need when you need it.

 

[Stump Shot]

I ain't smoking nothing. Lol

 

[usmcbuckwild]

Make three reed valves to go over the holes in the muffkin cover might get you what you need when you need it.

That is pretty damn ingenious. Can even use different tension reeds to fine tune flow and pressures.

 

[srcarr52]

View attachment 176213

Thoughts?

I would check the exhaust side entrance angles.

 

[Deets066]

I would check the exhaust side entrance angles.

View attachment 176322

Headed there shortly, will definitely check that

 

[Deets066]

I would check the exhaust side entrance angles.

View attachment 176322

Good call Shawn

 

[bwalker]

View attachment 176211

Easy to see where the squish band is. Looks like short circuiting out the exhaust

How are the roofs of your transfer ports aimed?

 

[bwalker]

About a year and a half 390 husqvarna

Looks rich, but you definatly have even flow from your transfers.

 

[Deets066]

How are the roofs of your transfer ports aimed?

 

[bwalker]

Here is a Yamaha Banshee piston. Shows very small wash with a sandblasted appearance on the sides and intake due to detonation. Also the underside of the crown shows death ash. This engine is actually a twin and the Mag side cylinder blew a crank bearing, probaly from deto.

 

[tree monkey]

looks rich

 

[RI Chevy]

What oil did you use Ben??? LOL