2.25 bore Need some help plz

z24robinson

New Member
Oct 17, 2008
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i am boring my jug 2.25 over stock which i believe is about a 240cc plz correct me if im wrong. i wanted to know what ppl were running for jets if they have this same bore, i have a fmf gold series pipe with a pro circuit silencer. I have the carb that came stock on my blaster i dont really know what pe pj pcw or any of that stuff means (i just turn wrench's and experience what happens lol) i think i have after market reeds not very sure . i have tried searching the forums but im not very good at researching i would appreciate any help that is givin since im sure someone else has already discussed this . thank you in advance also should i look into advancing my timing since im goin alot bigger? thank
 
no its not to get 240cc you need to resleve it or buy a hole new cylinder
boreing it over will do nothing for power its just to clean up the cylinder from the damage of the last pistion that went boom
 
u lost me, sorry im not stupid i just get lost when having to type the right words, so putting a piston that is 2.25 over a stock bore is not gonna make it faster? im gonna go have the jug bored out, isnt that the same as sleving it>
 
No, boring a cylinder out is not the same thing as sleeving a cylinder.

What is the current bore size? Boring a cylinder is only to clean up damage and shouldn't be done all willy nilly as it limits the available overbores for cleaning up future damage.

If your cylinder is already 68mm (2mm oversize) then you don't have a choice but to go to 68.25mm

To create a 240 kit, you need a 72mm piston and the corresponding sleeve (which is special for big bore kits) or a bolt on replacement cylinder (vito's, la sleeve, or PB airsal kit)
 
ok i got ya now, i have a 66mm bore now which is stock so im told,,, i just order a 68.25 is that about a 220cc atleast lol
 
i want to go with a bigger piston so it will be faster i was told that 2.25 is the most i should go over with a stock jug
 
Boring the cylinder out to the max is NOT the way to get more power. You need to upgrade that stock carburetor, get the cylinder ported, and head rechambered.

68.25mm is the maximum bore size you can go with the stock cylinder. Once that bore is finished, you can't rebore it, only resleeve. Bore= $45 resleeve= $150 plus the sleeve.
 
do not do that it will not make it any faster instead just go over as little as possable and get it ported if you want more power
 
yeah man dont bore it out. if its running it doesnt need anything get a pipe and a filter. if it isnt running get a 66.25 and still get a pipe and filter
 
i dont think u guys understand what im sayin or maybe im saying it wrong. If i put a bigger piston and bigger jet with my pipe i have already and k&n filter will not make it faster ???? dont make sense what u guys r saying about keeping the piston at a stock size. when i punched out my 454 it did a hell of alot, i know that i have a track slip to prove that one. i understand why i should keep it as close to a stock for future bores, but i have like 3 jugs i can bore if i ever blow up my top end.
 
Over boring a single cylinder blaster motor will give next to no extra power. If you want more power get 240 big block kit, or a stroker crank, or a port, or best of all get it all.

Your 454 has 8 cylinders. Doing an overbore on each cylinder will add up. Not so on a single cylinder. You can't bore it out enough to make a difference. Least not on a blaster motor. Not sure about others.
 
wrong again, it is you that does not understand us,
boring that cylinder to the max only adds a few cc's, which adds very little power,
possible 1 horse power or 2, 5 max, maybe
the porting of these 1978 based cylinders is whats holding it back, not the bore size,
get it ported with head mod and double the stock 17 horsepower with matching mods....pipe, filter, reeds, bigger carb
boring it will not add a noticeable hp gain. period
this is not a chevy 8 cylinder big block, it's a single cylinder 2 stroke, even the unported true 240 kits like the vitos, will get smoked by a ported 200cc bike

understand ???? porting is where the horsies are, not the over boring coral
 
Make ya a deal. I have a cylinder out in the garage which is currently at 68.25mm fresh overbore (never been put together) back about a month ago from Ken O'Connor racing and a brand new wiseco piston kit.

You buy a piston for the top end you've got and I'll trade you my fresh top end and piston for that one. I'm out a bore job, but I'll gladly trade that for the cylinder life you're getting ready to throw away.

PM me if you're interested.
 
so this is what i have 68.25 piston fmf gold series pipe with a pro circuit silencer stock carb open airbox with a k&n filter what jets should i put in it to start??
 
300/290 do plug chop and work down if needed, prolly no lower than a 270
stock pilot and needle in the middle clip position
 
goin to pick up the cylinder tomorrow morning,would that jet be in a stage 2 kit? could i port it myself or should i have them do it at the machine shop? does porting the intake and exhuast hole make that big of a diffrence?
 
I think you should spend some quality time reading the stickies in the engine section and just general reading. There's tons of info here. Most everything has been explained several times over. Once you've done that and need some more info you could not find ask away.