downgrading hi-comp piston to a lower?

[ny300exrider]

say i have a yfz with a built 60hp motor with a 13.5:1 piston in it along with a wr crank,cams,etc,etc,etc...would it be possible to swap out the piston for something with less compression like a 11 or 12:1 without doing any other major work? if so what would i be looking at cost wise to do the "downgrade".

im a recreational mx rider and have the chance to get a SICK yfz but i definitly dont want to be running race gas and i have no need for such a hi comp piston as i dont want to deal with reliability issues. i know my stuff about quads but never was into doing motor work so i honestly am not too sure about it....sure its a dumb question but hey...gotta learn somehow


thanks!

[Ride1Rob]

With a 60hp motor you can't be concerned about reliability. You surely won't get much ride time on a motor that built :ermm: . If you want a reliable bike that's not the bike to get.

[ny300exrider]

yeah i hear ya man...its just that this quad is so hard to pass up...things beautiful. heres the engine specs....no way i could "tone it down" a bit to make it like pump gas and not need constant rebuilds?

Cylinder|Head: port and polish
Bore & Stroke: wr crank/ stock bore
Displacement: 450 cc
Cam: hot cams intake and exhaust
Carburetor: 172 main, 48 pilot
Air Filter|Box: Pro design filter and billet adapter
Pipe|Silencer: full hmf sport
Clutch|Plates: barnett
Gearing F|R: 14/38
CDI|Killswitch: pro design
Cooling: yamaha
Other: cam mod/ oil mod/ 13.5:1 piston

[ohsobad_chevy]

60 HP with those mods is highly doubtful. Just my 2 pennies. ;)

[Ride1Rob]

I think it's safe to say that from the mods that I see your not pushing 60hp. Normally motors that big have oversized valves and the head is modified to help maximize them. Also the Hotcams are very tamed compared to motors with that much hp (Webcams, Crowers, etc....)

[ny300exrider]

thats actually what i figured...not uncommon for people to overexaggerate their hp alil bit..

now after reading those motor specs, would i be able to tame it down to a pump gas drinking, reliable motor without dumping alot of $ into it?

[Ride1Rob]

Based on the mods u have that motor can be pretty reliable. Just get rid of the hc piston and you'll be fine. I have the same mods and I'm around 52hp.

[ny300exrider]

thats what i like to hear!...now correct me if im wrong but since it states "stock bore" i can just have a mechanic swap out the 13.5:1 for something like a stock bore 11 or 12:1 piston without needing to hone the cylinder and all that right? ...is it basically swap out and go without any other mods?

i really appreciate the help!!

[Ride1Rob]

Yeah, just swap them out. Check your cylinder to make sure the nickasil is good.

[ny300exrider]

thanks so much ride1rob...i hope this trade works out now!