Pitster Pro Dirtmax Head WTF??

[NRG]

All the best for your next ride, hope you hit a tree, a wombat or something like that..........................>

Oh........oh....................just before i forget...................just wanted to say that i loved your latest youtube vid, the one of your "helmet cam" , ..........i mean "video camera ducted taped to ya head" LMFAOAUDP (must of looked real stupid!) but then again, its just what we can expect from you>>>>>> Keep em comin, A++

 

[matty06]

Mate, your setting a bad example for your company. No matter if someone says anything wrong you shouldnt react as your known as a leader of Dirtmax.

Also mate use english....LMFAOAUDP....what the hell's that mean?

the dam bikes a 187cc...what more has he got to prove?

throw us up a dyno mate no offence intended....just curious...

 

[SGONE]

cactus i measured the ports
intake- 26.8 mm
exhaust- 21.8 mm

measurements and pics are taken from a dirtmax avenger 150cc with dirtmax head

 

[daimojay]

Just me or does that look like a ported stock yx head? Any chance of some better pics of the ports? Is it the new one with the funky cam cover?

 

[SGONE]

Just me or does that look like a ported stock yx head? Any chance of some better pics of the ports? Is it the new one with the funky cam cover?

yeah it was ported when i bought it new i got some other pics ill put up... but yeah ported stock head is what im thinking cause they have only cleaned the exhaust making me think its a stock yx head..... their is not enough material to open the exhaust right up is what i've heard

 

[daimojay]

Hmm... not to say anything out of line, but that intake is worse then stock on the short side... why would you grid the floor down like that and make the short side angle higher...


Have u got a better camera by anychance >.<

 

[SGONE]

would not have a clue who knows what the chinks get upto motor was like that when it was bought from dirtmax .... pics are the best i could get with it mounted up in the frame
i have not run it yet so could not tell you how it performs

 

[themountain]

mmm...same shitty exhaust port as in all others...whats now so special about the dirtmax heads...lol ??...and SAGA..switch your camera on that little flowersign (macro)next time

 

[daimojay]

Yeah fair call. Certainly would have ported it differently if it where mine >.<

Hope she rips though!

 

[Cactus Jack]

cactus i measured the ports
intake- 26.8 mm
exhaust- 21.8 mm
measurements and pics are taken from a dirtmax avenger 150cc with dirtmax head

Thanks for that mate ... Yeah the exhaust port is still small ... as a comparison , bone stock Lifan 120 to 150 27/23 valve heads have a 25 mm exhaust port and even a bone stock Honda XR75 head has a 24 mm exhaust port with a 20 mm exhaust valve !!! A 150 cc engine with a 23 mm exhaust valve needs a bigger port than 21.8 mm ... for sure ...

Daimo's right ... when you port any head ... DO NOT touch the port floors except to gently curve and blend the short turn radius ... at high revs the gas wants to move up and flow along the roof .. Why they've opened the port all around on the Dirtmax head is to match it to the intake manifold they're using ... They shouldn't have touched the bottom of the port at all and moved the inner casting cores for the manifolds towards the top of the head OR moved the bolt holes ... The small exhaust port can be a good thing because you can move the port centreline toward the top of the head then match the header bore to it ... I do it with my XR's and it makes a noticeable difference .. OR if the pipe flange I/D is bigger than the stock port , you can simply "D" shape the port ...

 

[daimojay]

yeah, the only way u can really get away with touching the floor is epoxying.

all bout it in the porting thread. but yes agreed, the zorst ports are tiny. i opened the TBv2 one an absolute heap, and rounded D shaped the intake with a decent taper on the port, all the way from the start of the intake mani....


its almost like a dirty big tunnel ram haha, as the bend in the mani is hard to get too.

 

[minibiker57]

pitster pro and new dirtmax are the same frame but i dont no about the motor

 

[SEDUCE]

Why does The PisterPro GPX Engine have Dirtmax Stamped on the on the cylinder head?
Same reason Motovert and many other brands using the the YX150 engines, Beacuse......they are all produced by YX/Dirtmax.

Thats right............YX & Dirtmax are the same company!

YX makes engines and Bikes for a number of brands including Pitsterpro, Cinniworx, FMR, "Dirtmax" is their own brand.

YX/Dirtmax have developed a new cylinder head that has different inlet and exhaust port angles which flows better than the old YX stamped clinder head, this clyinder head is marked with "Dirtmax".
You can see the changes by looking at the inlet port angle, it slants to the front of the engine instead of to the rear.

Dirtmax have a lot more going on then you think, and are the one to watch....
look out for the Dirtmax 169 cc engine & a Four Valve head for the 150cc Avenger

YES they have some good fast riders riding for them to.
See you all out at the track and you will see how the Dirtmax goes