PDA

View Full Version : piston questions?


kc 300EX
11-20-2001, 02:43 PM
What is the biggest piston you can put in a 300EX with out resleeving? is it a 77mm 305? (I think thats it??)


Also, I have no idea what +0.040" actually means
how much bigger than stock is that? does that mean 4mm, I really have no idea, and it mite sound dumb, but if you tell me I dont have to feel dumb anymore

Thanx
Guy400
11-20-2001, 03:03 PM
+0.040" means 40 thousandths of an inch. Converted to metric it equals 1.016mm. No reason to sound dumb, they're are many things we all don't know. How does a posi-traction in a Plymouth work? Who knows, it just does!!:D

Unfortunately I don't know anything about the 300EX.
quadfamily
11-20-2001, 10:25 PM
With a stock sleeve the safest overbore is .080" so I've been told. That's the size I got for my 300EX from Four Stroke Tech. I think the displacement is still under 300cc even with this size overbore though. I haven't installed it yet so don't ask me how i like it. Hey GUY660R, do you know the metric formula for figuring out displacement on our engines? This may sound dumb but does "pi" still work with metric figures?
Wheelie
11-21-2001, 09:11 AM
pi X R(2)=Surface Area of piston
SA X stroke=disp in mm
Then div. disp(mm) by 1000 to achieve cc's

Example: 400ex
42.5 is half of the 85mm bore

42.5 X 42.5 X 3.14=5671.625
5671.625 X 70=397013.75
397013.75/100= ~397cc
publicdrunkenes
05-12-2004, 11:39 AM
+0.040" means 40 thousandths of an inch. Converted to metric it equals 1.016mm. No reason to sound dumb, they're are many things we all don't know. How does a posi-traction in a Plymouth work? Who knows, it just does!!


my question is I got a .25 overbored stock honda piston. Now is that supposed to mean .025 or is it .25. Because that is a drastic change in displacement and i am trying to calculate the exact displacement.
Guy400
05-12-2004, 01:14 PM
Originally posted by publicdrunkenes
+0.040" means 40 thousandths of an inch. Converted to metric it equals 1.016mm. No reason to sound dumb, they're are many things we all don't know. How does a posi-traction in a Plymouth work? Who knows, it just does!!


my question is I got a .25 overbored stock honda piston. Now is that supposed to mean .025 or is it .25. Because that is a drastic change in displacement and i am trying to calculate the exact displacement. It would be .025" over because .25" is 1/4".