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Puma 250R's

39823 Views 123 Replies 28 Participants Last post by  bubba297
Anyone got any dyno numbers to post on the new Puma's yet?

If you do, what crank/rod/piston combo are you running?

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We havent dynoed mine just yet, still waiting on a intake manifold for a 48 lectron. But mine is 431cc, it is 85mm bore with a 4mm crank with a ktm 132mm rod, using a polaris piston..... my 370 pro x nate built did 77hp on the dyno, so im excited about the puma!
I thought your Puma had already been dyno'd at ~90hp or so.....

I am wanting to put one together using the 137.5mm rod on an 85 bore and 76 stroke. But I gotta wait a bit more.....

Part of me still want to do a smaller motor with a powervalve, but I like the idea of the 431cc Puma. Even a Saber is tempting.....
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nope, the PUMA that made in the mi 90's was Sherear's....... I havent dynoed mine yet, but to go out on a limb, im not sure id do another one....the same work goes into this thing as a big saber...... but the port layout is a bit different in a ood way on the puma, so we will see..
are all the bigger cp cylinders for the R such as the pumas,sphynx,sabers all drag orientated? or can you set them up as a duner such as trails ?
you can set them up for anything with some extra work....
Probably what I really need for my application is a power valved Sphinx..... That would probably suit my needs better.

Unless the Puma can be had in a power valve cylinder (last I heard it wasn't available with a powervalve - has this changed?).
QUOTE (SandTrix @ Jun 12 2008, 10:50 PM) index.php?act=findpost&pid=2658430cc hondas dont need a powervalve

I might be wrong, but I don't think I am, but I do think any two stroke cylinder can benefit from a powervalve if it is set up correctly, particularly if you are trying to enhance the bottom/mid power coming out of corners.
I think what he meant was a 430cc single popper makes enough "extra" torque as it is, for that light of a vehicle. You prolly would have enough torque to get you off the corners that you would never miss the power valve, and to be honest a power valve could really hurt you if it started hanging up in the middle of a race.
buy my rotax R motor and you try riding it out of a corner. if you need more grunt than that ill eat some crow.
LOL, I rode this rotax.....its got GUTS!
Buttermilk, it is pretty amazing the grunt and bottom end power the big hondas can make. You and I can surely differ in opinion, but from the few big hondas ive ridden I cant imagine needing a powervalve in dirt on knobbies unless you were purely trying to calm the power down a bit. Which in my opinion is doing nothing more than taking away some power. The big hondas are able to turn 16/36 gearing with a good size paddle tire. I see no reason a 430cc puma or larger wouldnt do the same. I dont believe you would find a knobbie style power to even half harnass the power it would produce. I would think a 370cc prox style motor would be all you would want on a flat track. It has been many years since I raced any flat tracks though!!!!!!!!!
Sandtrix, I appreciate your views on big single cylinder Hondas. However, we don't run knobbies, we run flattrack tires on oval and TT courses. Coming out of the corner on these tracks is quite different that coming out of the hole on a drag race. A lot of the time your engine rpm is dictated by how tight and twisty the TT course is and this sometimes means that coming out of the corners you're really not in the best part of the power, no matter what gear changes you make, especially when you take into consideration the gearing you need on the longest straight.

As you are well aware of, I'm sure, the 4 strokes make real good torque down low (most of it is in the lower rpm's). The 4 stroke power is very tractable and makes for very good corner speed and excellent corner exit speed (corner exit speed is where it's all at in this form of racing in my opinion... as most passes are made coming out of the corners....)

What I think could be done with a power valve is hopefully make more power/torque where it would be beneficial particularly on tight technical tracks. Most flattrack/TT bikes would be overkill with 90+hp unless the track is a big 3/8 mile oval (they don't run those much anymore...)
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Here's an example of what the small 265R has to face. Granted it's more a best case (ain't too many thumpers putting out this power in the flattrack/TT ranks).

If you're coming out of the corner at 6500-7000 RPM, that 4 stroke done run off and left you......


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I think any good big honda will make that 4 stroke you just posted a dyno of feel like a moped, regardless if its coming out of a corner at Kellyville, the little sahara flats, or up olds hill.
hey.......... I've seen that little moped dyno curve somewhere before. LOL

Nates was feverishly working at getting a 399 puma together at Stans yesterday so we could go to the dyno tomorrow night but I dont know if its gonna happen!
It should happen, he got the last piece he needed today to get it done....Poor guy has been to hell and back with that thing!
QUOTE (blasterman88 @ Jun 19 2008, 12:16 AM) index.php?act=findpost&pid=3140It should happen, he got the last piece he needed today to get it done....Poor guy has been to hell and back with that thing!

Nate said it made some really good power on santrax's dyno ...
What kinda numbers did Nate get?

I'm gonna have to call him I guess...
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