Question on yfz450 pistons

[Fibe Industries]

I just wanted to now what commpresion piston you guys are putting in these and what cam work you have done

also check out my new site www.hstrial-aparks.homestead.com

[RiPPiNiTuP7]

most people i know are dropping in a 13:1.

[EvilJester400EX]

Most people drop in 13:1 pistons and do the "cam-mod" to their YFZ. You probably already know about this, but the cam-mod is when you boost your timing up one degree to get it back to YZ spec timing, instead of WR spec.

[Quad18star]

Hey Adam , how come your sites not working??? Also , are you gunna buy a 450???

[AlaskaSpeed]

Originally posted by EvilJester400EX
Most people drop in 13:1 pistons and do the "cam-mod" to their YFZ. You probably already know about this, but the cam-mod is when you boost your timing up one degree to get it back to YZ spec timing, instead of WR spec.

You are actually RETARDING the exhaust cam timing by doing the cam mod........JIM

[LapTraffic]

You are actually RETARDING the exhaust cam timing by doing the cam mod........JIM

Im no expert, Im just going by what they have said. The cams are the same between the WR and the YZ motors. The only difference is the exhaust cam is advanced one entire tooth on the timing chain on WR. The same configuration is used in the YFZ

I'm not sure what benefit this has, but Yamaha engineers obviously think it's the thing to do so they did it.

To get the cam timing back to YZ specs you do have to retard it from it's current position. What's interesting is that the timing marks are set up on the bike for YZ timing.

My wife has the YFZ and I did this mod for her. I will say the bike runs much better. And im not saying that from a 'more power' is better standpoint. It idles better, it lugs around better it snaps to life quicker, on just about every count the thing is a better running machine with the Cam timing mod.

These are just my observations.