TRX250R.ORG
General => Lounge => Topic started by: 250rLaeger1 on August 01, 2013, 10:43:10 PM
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I was looking at CP industries web site and noticed that the 309 cc up to 363 cc sphinx has the exact same specs as the smaller puma of the same size... can anyone tell me the difference in the 2??
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The port layout is going to be a little different between the 2. The reed cage will be different (sphinx uses 250r and puma uses cr500). Puma is going to be a little more costly to build. I would bet that power between the 2 setups (same cc) would be very close in hp/tq. I have yet to see any of the smaller puma cylinders run.
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Dose the Sphinx use a standard style TRX250R exhaust manifold?
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It uses a cp manifold but it has the same od as a 250r manifold. So you can use any 250r pipe with the sphinx. The puma you can get either the large manifold or the oem od manifold.
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I think the Puma is for drag motor applications (it allows for larger displacements) whereas the Sphynx is more of an all-around design.
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Puma's can be set up for a variety of applications. From MX to drag.
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sphynx cylinders come with more drag style port timing just like pumas. both can be setup to your needs from a real builder
pumas cost more because you have to do more internal work and get new reeds and then it moves the carb back about an inch also
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Motofool, what do you mean you have to do more case work? Yo have to bore the cases for both right? Is there something else you have to do for the Puma. And as stated, either can be setup for what ever your needs are.
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Motofool, what do you mean you have to do more case work?
On the Puma's the cases have to be filled with epoxy before machining the cases. When done the builder usually makes a cut across the top to make sure no epoxy is above the surface.
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On the Puma's the cases have to be filled with epoxy before machining the cases. When done the builder usually makes a cut across the top to make sure no epoxy is above the surface.
is this on all the puma's, even the smaller bores like the 293cc?
would there be any benefit to use the smaller puma over a sphinx?
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The pumas have a larger skirt O.D. Because they are designed to run 85mm and slightly bigger the spynx does not have the extra meat in the skirts since its not designed for the larger pistons.
so the cases do not have be cut as large but if you were to start with a raw puma cylinder it could be cut with the thinner skirts but then you are limited on future bore sizes if you were to want more cc's
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So the cases don't need epoxy for the sphynx? I thought I had seen that they did.
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It would depend on the size of each setup your going to do, and each builder does it a bit different GO OVRIT, but the smaller Sphynx's should not require any epoxy,
i would not choose a small puma over a sphynx because the of reeds and pushing the carb back fitment issues and such. and air velocity of the larger reeds can make a difference.
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I have not done any sphynx cylinders yet so I can not comment much on them,but I agree with motofool on the smaller bore puma not being the prefered setup. I do think if you are building a 78 bore sphynx for drag racing a puma might be a better choice. But I have not done one to backup that statement just my thoughts.
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if your comparing 2 different cylinders of the same bore size, i cant think of one situation where i would choose a smaller reed cage. i guess maybe trail riding a smaller one might be ok but otherwise im taking the larger one every time. hek my ktm 500 has larger cage than cr500 but still i think the ktm could be alittle bigger or atleast open the reeds slightly farther another 2mm or so.
(http://i1081.photobucket.com/albums/j357/doddledo/IMG_20130420_163358_zps477594fa.jpg) (http://s1081.photobucket.com/user/doddledo/media/IMG_20130420_163358_zps477594fa.jpg.html)
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Does the intake volume not have the same effect as the carb size as far as what rpm range makes power? Would too large of an intake cause the velocity through the carb make for hard tuning? Or is the amount that the reeds open limited to the size of the carb? Not questioning anything posted, just wanting to learn.
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i dont know about calvins cylinders but on oem production cylinders its probly a safe bet the intake is too small for good power. if the spynx and puma of the same bore size im taking the one with bigger intake. if you dont need to move a ton of air volume then the smaller one would probly work fine
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Calvins cylinders are designed to use the biggest bore suggested. If you are going smaller then you are just spending extra money to be safe. A good example is my 89mm saber. Can't go over 87mm on the Puma and don't need to race. The 431 is fine but the 478 will be the ultimate dune machine. Yeah, I gotta buy some snowmo intake. You also need to increase the stinger size on the motors over 400cc.
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intakes/reed cage size is a funny thing, normally you can go bigger and help upper HP but not always, velocity does matter and some of the banshee cylinders actually worked out better with smaller reeds, the Cheetah cylinders I believe had this issue
along with the small DM's
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seems theres a connection between intake, trans, exh ports. chapter6 blairs book. perhaps the cheetah design had a miscalculation that put the intake grossly too large for the rest of the engines state of tune