Hoca 4 valve
 

Does anyone have any experience with the Hoca 4 valve cylinder head for the gy6 150cc?

4 valve heads arent popular, people such as my self, prefer the big valve, big port head, with a camshaft selection.

Alright cool, speaking of cams, which is gonna be the best bang for my buck cam? Probably staying 150cc, possibly going up a little but nothing major I don't think.

I had a hoca 4V and thought it rocked

There are decent and better 4 valve head manufacturers. I'm not sure which is the preferred maker though.

A lot of people don't use them due to price. You can have your 2 valve head ported for much less.

Tom at Syc Powersports (sponsor here) really likes the 4 valve. Pretty sure he also has his ported too.

They should move a lot of air without needing a really high lift cam. Therefore valve float wouldn't be as much of a concern at higher RPM like the 2 valve. Valve float has been a problem for me a couple times until I bought a nice set of American made springs from Tom. (If you don't know what valve float is, the valve springs are too weak to fully close the valve at high RPM. And with the valve not fully seated, the piston makes contact and normally bends or breaks it causing engine damage)

The only reason i have not done the 4 valve is due to cost. For the price of the head, I can get a sled or ATV engine and do a conversion with a lot more HP than the 150 could ever produce. That's just my opinion though.

Excatly, the price for a 4 valve head, then u need a matching piston, its gets very pricey, i rather bore the engine and put a stroker crank in for that price.

Cool, I appreciate all the info guys. I'm just running through all my ideas trying to find out what's gonna work best for me.

The 4 valve head will out perform any 2 valve head. It comes with a sport cam good through all rpm ranges. However on some of the heads you will need a piston with 4 valve reliefs and it comes with a longer timing chain for which you will have to split the case to install. It is possible to replace the chain using a chain breaker than threading the new chain through but is tedious and should be left to someone who has done it before. Hoca used to make a great head however as of late not such a great head for the money.

Hey Tom, how much better is it going to flow than a 2 valve head? I am looking at running between 5-10 psi of boost and if its not a considerable difference, I think I will stick with a 2 valve.