bore size on tri-z?

[twgranger]

I was wondering what size bore pepole have on their tri-z? mine is in the shope getting the topend redone and he said he is boring it. and how do you know what sizi piston is in it? the old piston in it has a #25 on top. so does that mean it was bored 25 over before? and the bigger the bore does that mean more power?

[J.D.]

#25 should mean a .025 overbore. I'm about to do mine .010 over with a Wiseco Pro-Lite. With small overbores like .010 and .025, you won't notice a power increase.

[TRI-Zbrian]

correct me if im rong but at 80 i think i herd it makes it a 265 or something like that dont quote me on that i just seem to remember that from some wares, i could have just made that up in my head tho im pretty tired right now so dont hold me to it.

[TRI-Zbrian]

also boring a machine out never realy gives you any type of a power increase even at 80 over you have to remember that its 80 thousanths of an inch over u wont feel any power gains at all what you want to do is
DG pipe
DG silencer
shave the head
boysen power reeds
38mm flat side carb
port n polish
yamaha rench report cylinder mods (second boost port)
clamp on air filter

there is more but i cant think of the mods right now cause im tired.
also please forget the mith that the more your machine is bored out the more power you will have, i have seen alot of people that think like this and they will take a machine that is on its std bore and puncg it out 80 over cause they think they are going to get a huge power increase but think about it now when the motor pops u have to resleave it cause its punched out all the way

[TRI-Zbrian]

www.quadpit.com/mags/1985/3-4w-action/yam-wrench-report-tri-z.htm

go to this site it will tell u every thing u need to do.

[twgranger]

ok :?

[TimSr]

Displacement = .7854 x bore x bore x stroke (all numbers in mm)

The bore and stroke for most machines are listed on Wiseco's web site.

.010" =.25mm

Pistons are always marked in mm so you have a .25mm overbore which is .010"

Ive ran all the way through from stock to .080" , resleeved, and ran it through again on mine, and I can safely say that boring it to the max will give you no "noticeable" improvement.
Boring is not a performance modification, and its purpose to is remove defects in a cylinder, and to make an egg shaped cylinder straight again. You always always bore the minimum necessary to achievce these.