Re: minarelli vertical cylinders on puch derbi etc

Totally normal JBOT /

> LSLB RXb wrote:

> -------------------------------------------------------

> > ๐Ÿ‡ฎ๐Ÿ‡น๐Ÿ’ฆ Of the Loin wrote:

>

> > -------------------------------------------------------

>

> > I thought it was okay to have the piston be below the ports at BDC ?

>

> >

>

> > Jbot told me what that did to the performance but I have since

> forgotten

>

> nah maitland, itโ€™s the either way around. piston below the ports is not

> good

Lol ok

My fastest bikes have the piston below the ports. They are the holy crap Iโ€™m gonna die now engines. (edited)

Re: minarelli vertical cylinders on puch derbi etc

Tweaker trash /

> Graham Motzing wrote:

> -------------------------------------------------------

> I mean it's not ideal but it's not like the thing is gonna explode or

> not run. Just giving up a lot of power.

>

> I just emailed my tool guy and got the grinder on order. Yeah with the

> short stroke I can't have the piston sticking out 2mm at TDC so gotta

> port it down.

>

> > LSLB RXb wrote:

>

> > -------------------------------------------------------

>

> > > ๐Ÿ‡ฎ๐Ÿ‡น๐Ÿ’ฆ Of the Loin wrote:

>

> >

>

> > > -------------------------------------------------------

>

> >

>

> > > I thought it was okay to have the piston be below the ports at BDC ?

>

> >

>

> > >

>

> >

>

> > > Jbot told me what that did to the performance but I have since

>

> > forgotten

>

> >

>

> > nah maitland, itโ€™s the either way around. piston below the ports is

> not

>

> > good

Some people are into piston slap

Re: minarelli vertical cylinders on puch derbi etc

๐Ÿ‡ฎ๐Ÿ‡น๐Ÿ’ฆ Of the Loin /

I'm even more confused

Can someone state clearly what having your piston below the exhaust does?

There's no piston slap so I'm just curious

Re: minarelli vertical cylinders on puch derbi etc

Unless there is some magic benefit I don't know about it just reduces the time area of the port very slightly. It also cools the piston giving it a little more shrouding and contact with the wall.

It's probably has some sonic effect, whether that is good like anti reversion lip or bad like not getting clean transfer flow, I have no idea. In theory might be a bit more swirl and tumble coming off the transfers? I really don't know.

Re: minarelli vertical cylinders on puch derbi etc

๐Ÿ‡ฎ๐Ÿ‡น๐Ÿ’ฆ Of the Loin /

Yah like I actually dont know this is undiscovered country for me

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