Are any of you running CPI cylinders puma?

[jhtrx250r]

I was wondering if any of you are running one of the CP cylinders Puma, sphynx,sabertooth
and if so what pipe do you feel makes the most power/torque?Any info on the subject would be great.

[morse250r]

in frame or out of frame ? shearer is the only on making pipes for them right now they use a bigger flange

[derby]

The ID of the puma exhaust is pretty close to the stock honda exhaust flange ID. To run the standard 250r pipes you just have to machine the OD on the flange down. For inframe pipes I have heard most people run the esr trx 5 or trx 11 depending on what you do with the bike. I also heard that the duncan hi-rev was pretty impressive. I have a few different pipes that I plan on trying. I think I am going to dig up and modify the CT whale pipe to see how it does first.

The sphynx should be able to run any currently made 250r pipes.

The puma is still on the back burner for an inframe pipe with shearer, but there is currently and out of frame version available.

The sabertooth has an inframe and out of frame pipe designed by shearer.

[Buttermilk]

Nate McCoy of McCoysperformance.com has ran the inframe pipe for the Sabertooth on a 431cc Puma (dyno session) and it performed within 2 horsepower of an out frame pipe for the Puma.

www.mccoysperformance.com

Give Nate a call, he'll steer you right. He's built a few of them.

The Puma and Sabertooth will perform best with a pipe made for them.

The Sphynx can use any of the 250R pipes already out.

I have been talking to Nate McCoy about building me a 431cc Puma and I will be running an inframe pipe. Plans are to either run the Sabertooth inframe pipe or have Shearer custom make one to Nate's spec's.

Regards,

[jhtrx250r]

I should have been more specific, my cylinder is the sphynx, with a power valve.

I am currently running a lrd pipe, v force reeds and a 39mm pwk, I ride mostly dunes and XC, The current set up runs pretty smooth and pulls hard on the top, but i was looking to see what others where running, and trying to figure out how to get more bottom end.

thanks for all your help

[derby]

I personally like the trx6 pipe for bottom to mid range. I have only run it on the stock cylinder. Did you buy the bike with the cylinder already on it? Unless you specify to a builder that you wanted a XC setup. I would not have chosen the sphinx for a XC cylinder. That cylinder is not cast as a low end setup. You might be better off with the pro-x cylinder. You could try another low end pipe but it may not help your problem. Just guessing but your port timings are going to be too high for lowend and a lowend pipe will not give you the compensation you are looking for.

[Buttermilk]

Is your Sphynx ported or is it ran "out of the box" with no changes to the port timing?

The Sphynx has some pretty aggressive port timing as cast. If you are looking to enhance the bottom, then you may want to consider decking the bottom of the cylinder and lowering the port timings.

I highly recommend that you give Nate McCoy a call at 1-530-476-2222 and talk to him. He can set that cylinder up to do what you want. He's an honest, standup guy that will treat you right.

[jhtrx250r]

Thank you for the info, the funny thing is my machinist told me the the exact same thing yesterday, (decking the base to lower the port timing), he said if we need to go that route it would be no problem.

He told me to first try adjusting my power valve by increasing spring pressure and adjusting my pipe out for bottom end ( it is currently all the way in)

I don't really want to loose any top either, It is a real fun cylinder set up to ride, it also put out some pretty good numbers on the dyno 54 rear wheel HP with current set up.

I should be at the dunes the 14th of next month and will try adjusting the PV then.

I can let you know how it works out.

[derby]

How do you deck a cylinder that does not have a removable sleeve?

[dunatic]

u can do it, it just requires the use of an automated mill. takes some time to setup the program.

[cdrookie]

chuck it in a lathe...

[Buttermilk]

Is that a 310cc Sphynx?

With a powervalved Sphynx, I'm a bit suprised that you feel your lacking bottom end. Of course, two strokes don't really have much "bottom end" power compared to a 4 stroke. You just have to ride them "on the pipe" to get the benefit of the power.

You may want to seriously consider a different pipe as well. I've personally had excellent luck with the ESR pipes. Never have tried a LRD though....

My oem cylindered 265 put up numbers of 56.4 hp/ 34.6 tq using a ESR11 pipe and has more bottom, mid, and top power than my old setup using a Sparks TT pipe (my engine build is listed in the dyno section....).

I would really think that Sphynx has got more power in it too.

Do you know what the compression is, and what kinda squish you are running? Sometimes changing things by as little as 0.010" can make big changes in the power.

As an example, I was at 51.4 hp, with ~209psi compression (15.9:1 UCCR) with ~194E, and ~128T port timings with the squish set at ~ 0.040". I raised the cylinder 0.010" by using a thicker base gasket, with no other changes and the HP went to 55.3 on the dyno.

This accomplished 3 things for me:

1. Raised the port timings ever-so-slightly (by just less than 1 degree).
2. Dropped my compression ever so slightly (15.2:1 UCCR)
3. Relieved the squish and resulted in a less efficient combustion chamber that ultimately put more heat into the pipe (by taking some of the heat from the combustion from the less efficient combustion chamber with a greater squish) thereby causing the pipe to work better overall (scavanging, return pulse, etc.). On a two stoke, what your after is not just the first initial combustion cycle, but the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th iteration of that combustion cycle, hence the reason you need some heat in the pipe.

So, if you deck the cylinder, make sure you also factor in other things as well.

It took me a year and a half to get my 265 from 40 hp to 56.4. And several trips to the dyno.