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| 150cc GY6 and Under Engine Tech GY6 and Smaller Technical Discussion Forum |
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#1
12-02-2016, 12:21 AM
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Hoca 4 valve
Does anyone have any experience with the Hoca 4 valve cylinder head for the gy6 150cc?
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#2
12-02-2016, 04:38 PM
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4 valve heads arent popular, people such as my self, prefer the big valve, big port head, with a camshaft selection.
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Hammer head Single seater know as herbie under construction Aluminum fuel tank, aluminum wheels, custom fuel/cargo rack, entire rewire, trail tech vapor, ported big valve head, a12camshaft, 12 gram sliders, straight intake, kirkey wide seat, front end extension. 4 point harness, welded cage. Hammerhead exhaust. Blade Single Seater Restore welded cage, engine build, new wiring harness/electric box, spun aluminum fuel tank. |
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#3
12-02-2016, 07:17 PM
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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.
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#4
12-02-2016, 09:07 PM
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I had a hoca 4V and thought it rocked
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2013 Trailmaster XRX 150 Type 86 stroker Taida 4V head with 23/22mm valves, forged 4V piston,Taida 62mm jug,forged Taida 8200 KDU stroker crank, Koso high-flow oil pump, Taida case half w/ oil cooler ports, Setrab oil cooler,TrailTec Vapor, Mikuni VM26-606, aluminum 30mm intake, Uni filter, aluminum stack, Hammerhead racing exhaust, MotoRio adjustable CDI/HO Coil, Iridium plug, Full Dr Pulley CVT kit w/ 16g sliders, JD's Mikuni slide kit 2014 Kandi 90B |
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#5
12-03-2016, 02:08 PM
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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.
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My Yerban assault vehicle: 2.2mm stroker crank, 62mm Nikasil cyl, Taida large vavle head, American made valve springs, ported intake manifold, TM 28mm carb, stock CDI, Bando coil, TK exhaust, stock CVT except for the 14g sliders, 13/40 internal gears, 16T drive, 31T axle sprocket, 22" rear tires, and ONE BIG POTATO CANNON mounted on top.......... |
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#6
12-04-2016, 09:00 AM
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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.
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Hammer head Single seater know as herbie under construction Aluminum fuel tank, aluminum wheels, custom fuel/cargo rack, entire rewire, trail tech vapor, ported big valve head, a12camshaft, 12 gram sliders, straight intake, kirkey wide seat, front end extension. 4 point harness, welded cage. Hammerhead exhaust. Blade Single Seater Restore welded cage, engine build, new wiring harness/electric box, spun aluminum fuel tank. |
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#7
12-04-2016, 03:17 PM
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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.
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#8
12-11-2016, 01:21 PM
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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.
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#9
12-11-2016, 02:21 PM
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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.
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