2002-2004 Yamaha YZ 125 Apex Cylinder Head Review

[@dalecarmine6604]

Thanks Mark, good review. Tell us about the Athena top end sometime.

[@markswartmx56]

Other than the fact it uses an oddball inner head gasket, it seems pretty unremarkable. This one was in really good shape so I got lucky there. It was on the bike when I got it so I can’t really say if it is any different from stock. I wish the guy had gone with a big bore instead though haha!

[@808tainment]

What needle position, pilot jet size and main jet size did you go with? I have the same setup, fmf pipe, vforce, and sx/xc dome

[@markswartmx56]

Hi Daryl - I’m just running the settings that FMF had on the jetting chart on their website. Pretty close to stock really. I think I’m at the middle clip too. If you have a good setup I’d love to give it a shot though.

[@billzadventures856]

"if you think its going to turn your 125 into a 150 its not" - hey i was wondering, what do you mean by that? which bikes are 150cc that your referring too? thanks for the review

[@markswartmx56]

I just meant like a KTM 150 or a big bore YZ 125. Funny thing is I actually ended up doing a 134 kit on that bike and I wasn’t impressed at at all, sort of messed up the character of the power, didn’t feel like it revved quite as high and it also didn’t gain much punch. I wouldn’t do that again. Thanks for watching!

[@billzadventures856]

@@markswartmx56 have you rode the ktm 150? (sounds like you have) did you like it better for the track? or do you prefer the yz? and was the power difference that much noticeable? thanks!

[@markswartmx56]

@@billzadventures856 I actually haven’t ridden one. But I spent a season on a late model YZ 125 which is a 34 HP bike, so I could only imagine how cool another 4 HP on top of that would feel with a 125 chassis and feeling. I really need to get a ride on one sometime just to see if it is everything I think it would be!!

[@billzadventures856]

@@markswartmx56 yeah you do because thats why i was wondering when you said that. i was like yeah its extra HP with the the ktm but its mid range and on most tracks that are tighter you want the better bottom end coming out of turns that the yz offers...ktms are a little boggy out of corners if you dont stay on it on it is my understanding....i think you rode the better bike that day...if it was a wide open cali track or a place they have long stretches then yeah i would want more top end. anyway, nice talkin 2 ya, have a good one!

[@deantarus3548]

What did you do for jetting?

[@tristanbooth-dz2dq]

Hey mate I was just wondering if the 2002 cylinder head fit the 2000 can’t seem to find any

[@markswartmx56]

I think it fits 02-04? You should check with Apex, they are very knowledgeable I'm sure they could get you a good answer. If I were doing it all again I don't think I would invest the money in this.

[@mototodd]

Do you really need all those clothes in down there?

[@markswartmx56]

Huh?