Genesis of the Jota: Part 2 - The Slater Jota

dja982 said:
If your valves are not closed at tdc it's not going to fire anyway.
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well, this is what mr. otto thoughts, and is still common on driving schools, even mechanics belive that..... but if any otto engine would spark and have valves closed at TDC the power would be like 100 years ago...
 
hochkoenig said:
well, this is what mr. otto thoughts, and is still common on driving schools, even mechanics belive that..... but if any otto engine would spark and have valves closed at TDC the power would be like 100 years ago...
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WTF have you been drinking? 

Where's the compression going to come from with valves open?  You are obviously mixing up the compression stoke and the exhaust/inlet stroke...  Not much has changed in Nicolaus Ottos' principle.

I suggest you re-think your comment.

piet
 
sfcpiet said:
WTF have you been drinking? 

Where's the compression going to come from with valves open?  You are obviously mixing up the compression stoke and the exhaust/inlet stroke...  Not much has changed in Nicolaus Ottos' principle.

I suggest you re-think your comment.

piet
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I was actually talking about the valve overlapping
 
Yes overlap is when they are both open at the same time, around tdc exhaust, NOT tdc compression. The picture of checking the combustion chamber volume was I would think simply demonstrating. The plug hole has to be the highest point of the chamber so the bike would have to be tilted. Then you have to remove the fluid mix from the chamber afterwards, tip the bike upside down like we do a bicycle? It is generally done with the motor on a bench, and I do it at assembly, without the cam chain even fitted on twins, on a triple you would leave the cams off.
 
hochkoenig said:
I was actually talking about the valve overlapping
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if any otto engine would spark and have valves closed at TDC the power would be like 100 years ago...

Oh... yeah...

Do you happen to be female?  My wife sometimes says "this", but means "that"... :D

piet
 
Paul Marx said:
I always overlap valves a bit when I dismantle a head.
Keeps them sealing properly.

Paul
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How do you overlap them, Paul?  With a hammer?  ::)

I only lap them... :D

piet
 
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Hi Sock..Wonderful picture and fond stroll down memory lane for sure.

Anyone know why the very big rear sprocket? Looks like 45+ teeth. Wheelie contests or dyno pulls?
 
sfcpiet said:
if any otto engine would spark and have valves closed at TDC the power would be like 100 years ago...

Oh... yeah...

Do you happen to be female?  My wife sometimes says "this", but means "that"... :D

piet
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okay, maybe i should behavior like your wife and tell you are right. your laverda spark at TDC, valves are allways closed at TDC. Happy now?
:-*
 
Hochkoenig this is not a stab at you, merely trying to get you to understand that compression ratio is checked with both valves closed and the piston at the top. Nowhere in the article did it mention ignition timing advance. Please do a bit more study on how a four stroke motor works instead of getting offended.
 
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