Need help with windowed piston and bdc

[Jaycee236]

So this might sound stupid but i think i went a bit high on my window on my piston and when its bdc it clears my exhaust port fully but then a small portion of the window is visable at bdc. To me that seems like a problem because isnt it suppose to be expelling exhaust at bdc not sucking in air? Thanks guys.

g2 reed valve 66cc chinadoll

 

[Greg58]

That shouldn’t hurt it, the reeds will prevent back flow to the carb. The reeds will be closed before the piston reaches bdc.

 

[Venice Motor Bikes]

So this might sound stupid but i think i went a bit high on my window on my piston and when its bdc it clears my exhaust port fully but then a small portion of the window is visable at bdc. To me that seems like a problem because isnt it suppose to be expelling exhaust at bdc not sucking in air? Thanks guys.

g2 reed valve 66cc chinadoll

Post pictures so we can see exactly what you're talking about

 

[Jaycee236]

Post pictures so we can see exactly what you're talking about

 

[Jaycee236]

Dont mind the cylinder its an old one im not using. This is bdc. The window is slightly exposed. Is that okay to run?

 

[Mossy]

It won't keep it from running with a reed... a reed setup only cares about the transfer and the exaust... You could trench the intake to the transfer and the window works both ways...

 

[Venice Motor Bikes]

Dont mind the cylinder its an old one im not using. This is bdc. The window is slightly exposed. Is that okay to run?

As long as you're using a reed valve, it will be OK.

 

[Jaycee236]

As long as you're using a reed valve, it will be OK.

Yeah but we all know that the g2 reeds sometimes dont fully sit flat. Ive had brand new ones that end up open just a hair once seated. Doesnt effect idle or throttle but i thought it might now considering the window is high. But i guess if you both think im good then im good lol

 

[Mossy]

Yeah but we all know that the g2 reeds sometimes dont fully sit flat. Ive had brand new ones that end up open just a hair once seated. Doesnt effect idle or throttle but i thought it might now considering the window is high. But i guess if you both think im good then im good lol

You want to file the surfaces flat on everything... The cage has flash also... It's a miracle any of those engines even run without fussing with them

 

[Mossy]

6m bolts surfaces filed... The casting flash on the cage...

 

[Larry Trotter]

Pretty sure the window in the piston should not be on the exhaust port side.

 

[Jaycee236]

Pretty sure the window in the piston should not be on the exhaust port side.

Never said it was

 

[Larry Trotter]

does this not say exhaust port?

 

[Larry Trotter]

View attachment 112165
does this not say exhaust port?

 

[Jaycee236]

View attachment 112165
does this not say exhaust port?

It literally says the piston clears the exhaust port at bdc. When the piston is bdc it means its all the way down lol once it hit bdc i looked over on the intake side, the picture i sent was the intake port. I could have worded it better i guess