Big bore with CP high compression piston

[lixno]

I have a 03 YZ450F, which i have turned into supermoto. I am thinking of upgrading the motor a little bit (already have WB Carbon Pro full system, JD jetting and open air filter K&N style).

My first thought since i don't want to spend a lot of money, was to buy a big bore kit from Cylinder Works or Max Power at 478cc.

As far as i can see these kits come with a standard compression piston.

So, do you think that a higher compression CP 13:5 with the big bore kit will work better or not? I am thinking that it might require other cams or head porting...

Also has anyone installed a CP piston with a Cylinder Works cylinder (i see that CW comes only with Vertex pistons)?

[yz450fcranker]

get yourself a stroker crank and a high compression cp piston and get your cylinder remade to fit the big bore piston its like putting a perfectly nice cylinder back in that already works maybe porting and cams will also give you some power but not as much as a stroker 500cc

[lixno]

get yourself a stroker crank and a high compression cp piston and get your cylinder remade to fit the big bore piston its like putting a perfectly nice cylinder back in that already works maybe porting and cams will also give you some power but not as much as a stroker 500cc

I know that a stroker will give me more power, but as i mentioned i cannot afford right now the extra $ for it.

Also a stroker isn't as reliable as a simple big bore cylinder at 478cc...

[beezer]

I put a standard bore 13.5 CP piston and Hotcams in my 03 450 dirt tracker and the thing really runs sweet.

[lixno]

I put a standard bore 13.5 CP piston and Hotcams in my 03 450 dirt tracker and the thing really runs sweet.

Thanks for the info! Did you try the CP piston without the cams first?

[beezer]

No I did both at the same time. I think you needed one to work with the other.

[lixno]

I have done a lot of search in this forum about High Compression pistons. I see that a lot of guys have installed 13,5:1 CPs or Wiseco's in stock motors (cylinder bore and cams) and noticed power gains.

Do you think that there is any difference with the bigger bore?

(Gray, i would appreciate a lot your point of view:thumbsup:)