what cylinder heads fit rampage?

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Toyonka

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I'm on the market for a big bore cylinder head and came accross this kit, http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270654634516&ssPageName=STRK:MEWAX:IT It says that it will fit but the exhaust port looks different from the stock head. :confused: Now with the different types of cylinder heads out there, will this fit on a rampage?


btw: the reason for this head is because I want a cheap head to modifiy by porting/grinding to try and increase hp.
 
Yup, that's just a standard ole Zenoah head kit. It should bolt right on. The only time you really need to worry about fitment is if you have a CY topend with a 40mm boss. You have to have a crankcase that has that 40mm opening.
 
Is it just my bad memeory or are the Zen and Cy pin bearings different? I seem to remember haveing a prob figuring that out a while ago when I put a zen head on my cy bottom?
 
Demon....you said the magic word :D that was the next step in my plan. So what are some of the tips & tricks in porting a head? ;) Any guide lines to follow? I guess I'll practice on the old head before I mess up the new head. :) Or should I just start a new posting?
 
Trick is you don't have to go crazy with the porting, case match the cylander to the cases,match the gaskets to the intake and exhaust ports helps awhole lot just getting rid of the restrictions.


buy you a set of Dark Soul case matching templets from DDM and simply clean up the transfer ports and youll be amazed at how much that little bit yields alot more power.


use your old head and take your time then go to the new head.


Try eyebrowing the old head first cause its tricky, if you mess that up the heads pretty much toast!!


Good luck!! :p
 
A regular ole port like you would find for an extra $35 from DDM is what I call a "garage" port in that anybody can do it. There are really 4 steps to a simple base port job on these engines:


1) Matching the cylinder and case is the first thing I would do on a 2 bolt. When you move to a 4 bolt you will notice everything is almost lined up for you and you don't have to do anything. I have a billet Dark Soul 4 bolt case and it's already perfectly machined so you don't have to touch it.


2) Resurface the transfer and instake port: You would go in with a 1/8" and 1/4" inch cutting bit and resurface all 4 of the transfer ports. Then, do the same for the intake port. I use rounded cylindrical bits when doing this and also some ball cutting bits. The surface should be roughened after you finished. The reason for a rough finish is that it creates turbulance as fuel/air passes over it which atomizes the fuel better before reaching the combustion chamber.


3) Polish the exhaust port: This just lets burnt gases escape faster by reducing friction loss as gases pass over the rough surface at high velocities. This translates into increased CFM's.


4) Eyebrow the intake port: This can be tricky and I wouldn't suggest doing it without practice. If you don't know how the shape is supposed to be then you might need to save this till later when you see a head with it actually done. The eyebrows are basically two cuts above the intake port that extend from the top of the transfer port toward the middle of the intake port. This directs the fresh intake charge toward the intake port which helps push out the burnt exhaust gases. It's called "scavenging".


Now, there are a ton of other things that professionals like ESP and Oneill's do to get more power out of their engine which I won't get into cause it's a science and alot of formulas (intake & exhaust timing, etc) are involved.
 
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