Serval Cat

[BasicBajaX]

And I am just going by what Forcefed's description is of these new cylinders. From his feedback I think thats the direction I want to go...

[SonOfSand]

Damn, took the initiative to be one of the 1st to lab rat this cylinder (payed full price-fyi) stimulated the HQ economy with several builders, reported everything I could with pics, & am getting crucified over a set of carbs & reeds.

 

Not looking for a pat on the head ... nor do I want one ... but how about maybe buying a set of Servals & setting it up how you see fit ... or you can donate some 28's & a set of Boyesons.

 

I'm done here.

 

(thanks Rog & Daj - talk to ya'll l8r)

 

 

ForceFed, you have had me hanging on you're every word. I have almost purchased a cub several times but have been reluctant too due to the nature of the power, now I am so glad I did not. The testing you have done on the cat has me very excited, I am only a dune guy, and want more low and mid with out losing any top end. I Love my HJR 4 mil stock cylinder, do you think I could love this even more?

 

regarding Snop, could you expect anything more from a guy who keeps an avatar like that??

[Snopczynski]

Hey, when a world reknown motor builder flips off the camera, you have to post it up somewhere.

 

You guys are gonna lose top end with a serval cat if your running cylinders that are ported with an exhaust duration of more than 188 degrees right now. With the right matched pipes to that setup that motor is never gonna peak over 9,000 rpm because it only has 188 degree exhaust duration. However, your going to make a ton more power down lower in the rpm range, and the bike is still going to feel eye blinding fast. You cant throw a set of mid-top pipes on a low-mid cylinder duration and get mid-top power out of it. Its only going to do what the port durations will let it do. Those dyno charts Andy posted up proved that, the motor only made power to 8,450rpm with a set of CPI pipes on it. CPI pipes are designed to peak later in the rpm range than 8,450rpm. You have to match the pipes, carbs, reeds, timing, and compression to the porting. The porting that comes on this cylinder from the manufacturer doesn't want to make power up over 9,000rpm. That is well under where all these bolt ons that have been tried so far will shine the most. I feel there is still power being left on the table with these cylinders, put the right parts with it, and its going to be amazing.

 

 

A good majority of the parts being used so far for testing were known at one time as industry leading drag race parts, even some are still used as drag racing parts today. When cpi pipes came out years back, they were the top production drag pipe that you could buy. When you build a drag motor on gas, you use at least 35mm pwk carbs. When you need to flow a ton of air in a drag motor you use vforce 3 reed cages. When you build a motor thats not designed to rev to 9,500 rpm+++++ then you dont use the same parts that you would use in a drag motor. You cannot fully benefit from the operating range of these bolt-ons, and your leaving power on the table because the efficient areas of the pipes, carbs, and reeds are all outside of where this motor operates. Bigger carbs that never flow 100% on this motor because of the rpm it can achieve will also cost you throttle response and intake velocity down low because they are way too big. So there is Torque and HP there that is not being used yet. This cylinder doesn't have a drag duration, it doesn't even have what most motor builders would consider a dune port duration (190-192 dgrees). It just wont simply make max hp where a cpi is designed to make max hp, or even a fatty, or T5 pipe for that matter. There is also more midrange torque and hp left to be made with this thing with a pipe thats designed to come on sooner down low.

[dirtydownunder]

haha man i just cant catch a break, i get a serval last month, get taxed hard at customs, these cylinders are now on special and now i found out the T5 is the worst pipe for it .

[ltd.yfz]

If i had the money I buy these now!

[kingsley]

How well will the FMF Fattys work on this motor?

 

Dirtydownunder.... How much tax did they slug you?

[Forcefed]

Boyeson ports - extra transfers & tripple exhaust is where the 35mm carb makes for a GREAT choice for this cylinder. The flow potential of a cub over a stocker is the key. So, you were right a 35 does belong on a cub

 

As far as the V-Forces ... they work flawlessly ... why can't a "drag" reed respond accurately at 4K anyway ?

 

The dome design lends itself to a pretty crucial factor as well ... something that was, um ... not discussed in any great detail.

 

We finished up this build with the CPI inframes ... Peter & Paul are Even Stevens - lol

Edited October 22, 2010 by Forcefed

[87sheerips]

I rode a MM bike in LS with these cylinders. Broad powerband and a perfect amount of power for a trail/duner. Excellent platform!

[Snopczynski]

I hate to say it Jeff, but you may have to throw the standard logic out the window when it comes to these cylinders. Having triple exhaust ports, more transer ports, etc. these do not work on the same level compared to stock cylinders. Ive heard that there are dyno runs on these without any extra porting still making power in the high 9-low 10k range. Your theory on small carbs, low port timing pipes, etc. may not make for the best setup after all. Im not saying by any means this is the final/best testing, but it does give a broader range of testing.

 

Some testing from McCoy

http://forums.atvdragracers.com/topic/9435-cerval-cub-testing/page__pid__80415#entry80415

You dont ever throw standard logic out the window when applying it to two stroke motors. I am sure this motor has power at 9-10k, but I seriously doubt it makes more power in that range un-ported, because of the durations. No one has tested anything low-mid for carbs, reeds, or pipes on this setup yet, and everything that guy at McCoy said verified what I told people here on this forum. CPI is a better mid-top pipe than a T5. McCoy's increase in Compression and more timing translated to more power as well.

 

The situation we are dealing with on this setup is like comparing a diesel motor to a gas motor in 2 of the same pickups. One is more centralized around hp (gas truck), and the other is more centralized around torque (diesel). Now, if you have ever driven a diesel pickup, you know that you mash down on the gas in one of those things and they take off like a bat out of hell, but they dont rev up as high as a gas truck does. A 5.7L Dodge Ram Hemi pushes around 375hp. My Cummins 5.9L diesel pushes 325hp. So if the Hemi makes that much hp, then why does the cummins make a superior tow rig, and why did it take off and accelerate way faster than a 5.7L hemi? The answer is.....................

 

Torque

 

My Diesel Packs 610 ft/lbs of torque vs the Hemi at 400 ft/lbs of torque.

 

Here is another scenario, my cousin has a 4 mill stock cylinder motor with a single lectron, pc pipes, mid reeds, high compression, and exhaust ports that are lower durations than stock. He makes about 61hp on the crank dyno. My bike is a stock bore, stock stroke ported 350 with a tiny bit higher exhaust duration than stock, pc pipes, twin 28mm carbs, mid reeds, etc..... I push about 66.75hp.

 

When he and I drag race he takes me off the line by alot, and then I catch up to him further down the strip and we always finish dead even with each other. Now why does his 61hp bike hang with my almost 67 hp bike? The answer is...............

 

Torque

He has almost 4 more ft/lbs of torque in the midrange of his motor rpm than I do. His bike launces hard off the line.

 

Everyone is interested in hp this, and hp that, when with this setup we should be watching torque. I have 42ft lbs of torque in my motor setup, my cousin runs about 46 ft/lbs.

 

The idea I have for the Serval cat is more torque. We bolt on pipes that make Torque, and carbs that make torque, then reeds that make torque, more compression that makes torque, and more timing that makes torque. The end result would be slightly more hp, but a ton more torque. As a low-mid guy I dont want more hp, I want to see more torque, because the bike is a lot funner to ride when it accelrates so fast that it tries to throw you off. I still stand by that there is hp and torque being left on the table with this setup. I think smaller carbs, pc pipes, mid reeds, some race gas domes, and advanced timing is what will make this setup more fun. Like I said, we have re-sleeved cub motors putting out 94hp and tractor like torque with pro circuits, 30mm carbs, mid reeds, high compression, and advanced timing.

 

I like the Serval cat cylinder, I would just set it up way different than what everyone else has done.

 

I have a motto: lots of hp is fast, but lots of torque gets you there faster.

[Forcefed]

Sounds like you need a 4 stroke

 

It all boils down to ones specific riding situation - imo

 

Torque gets you there (& these have tons the way the have been setup thusfar) HP keeps you there !

 

Oh, & you don't have to run racegas to have compression or FUN - the masses are wanting pump fuel anyway.

 

Here's a couple more pics of the build we did here in this thread.

 

.... & yes ... I'm aware it's just a gauge.

 

I'd bet the build you have in mind would pull stumps out of the ground - can't wait to hear about it.

 

Edited October 22, 2010 by Forcefed

[No Limit Powersports]

Testing is the key here and we want to test more setups unfortunately we do not have the time to do all setups. You have to keep in mind that this is not a stock cylinder this is a triple transfer triple exhaust big intake motor with low port timings. This is a new school of thought making a low-mid motor so testing is what is going to have to happen. Nate tested with many different pipes and many different timing/dome combos and even stock carbs and stock reeds. In the pipe world on every motor that we have ever tested the t5 is so far from a top end pipe it isnt even funny when compared to a true top end pipe like the shearer. I was actually surprised that Nate said that the motor did not come on as soon with them as they did a shearer as well. I do agree that more compression will make for broader tq curve but the low timing does not surprise me with this port layout.

 

Comparing two bikes together and attributiing the ability of one to "come out of the hole faster" to the port timings is far fetched. There are a million variables completely unrelated to port timings that this could be attributed to, like bike weight, suspension setup, clutching is a big one, rider weight, rider ability, tires would be huge one... Now im not saying that a higher port timing can make more low end power, nor that a lower port timing motor cant rev because I have been proved wrong and tested this myself many times. Post some dyno graphs of your low end motors so we can see. I will say that I have tested and seen a lot of nicely done port jobs on stock cylinders setup for dune riding, and this is as nice smooth of power as I have rode.

[Snopczynski]

Almost 200 psi is a lot, that ought to get the job done.

 

Like I said, my experience isn't just based of stock cylinder bikes. We have some re-sleeved cub motors running around with lower port durations.

 

The T5 is a mid-top pipe (considered by most as a dune pipe), not a top end pipe (drag pipe). The T5 is not considered a low-mid pipe by any means, even though people on here keep referring to them as such. The pt mids and pc's service up to about 8,750rpm, and the T5 is designed to peak much more than that (around 9,500 rpm). As a mid-top pipe the T5 sucks, cause the cpi's will devastate them all day long.

 

I agree that this is a new setup. Basic rules of the cylinder are unchanged though. What every low mid motor guy wants is low durations that move in air in large quanities, and move exhaust out in large quanities. Nothing has ever changed there regardless of the cylinder design.

 

As far as the statement about hp keeping you there, that is true! However, Torque backup is what allows you to let off the throttle and go right back up to where you were. Which is what we need for the trails and idiot holes in Oregon.

 

As far as the setup on my cousins bike, he weighed 30 pounds more than me at the time, he runs the same shocks, the same swingarm length, and the same front end as me. He also has the same exact tires and rims as I do. Chassis Setup wise our bikes were identical at the time of the drag race, the only difference was in the motors, and I run a dyna ignition (custom curve programmed) with a dyna coil. I attribute his coming out of the hole harder due to the fact his motor makes more torque than mine at a lower rpm. Thus created by his 4 mill crank, lower port durations, and single carb setup.

 

I still stand by my opinion that there is un-claimed hp and torque being left on the table across the rpm with not running low-mid power range parts on the setups being tested and ran. I can vouch for things like vf3's being taken off and replaced with mid tension reeds on stock cages, and that adding 2hp to the MIDRANGE RPM of a motor (without making much of a noticeable number difference on the top end).

 

I have dyno sheets for my setup right now for twin carb and single carb. A little has changed since the dyno session, but its right for the most part. I cant get a hold of the sheets for my cousins 4 mill or for the cubs right now. They are on the builders laptop, and its just not an easy thing to get a hold of.

[No Limit Powersports]

Well only testing will see. I still agree that there is power left on the table as i know that i will be able to improve on this setup. I will however agree to disagree that the pc will ever be a pipe of choice on this motor as i just do not see that small of a pipe ever being able to keep up with a cylinder that flows as well as this one does. I hope that I am proven wrong as my ultimate goal is to improve the sport and offer the best combination available.

 

I will try and get it back on the dyno in the near future for some more test. If your interested in getting a setup together shoot me a pm and we will set you up.

[Snopczynski]

Well only testing will see. I still agree that there is power left on the table as i know that i will be able to improve on this setup. I will however agree to disagree that the pc will ever be a pipe of choice on this motor as i just do not see that small of a pipe ever being able to keep up with a cylinder that flows as well as this one does. I hope that I am proven wrong as my ultimate goal is to improve the sport and offer the best combination available.

 

I will try and get it back on the dyno in the near future for some more test. If your interested in getting a setup together shoot me a pm and we will set you up.

As far as inlets and outlets on pc pipes, they are the same size as a T5 or SB CPI Inframe pipe last time I checked. Pipe design is based around back pressure, expansion chamber, and scavenging. The pipe and the exhaust durations on a 2 stroke motor are effectively the camshaft of a 4 stroke motor. They determine how the powers comes on, and how much of it you get.

 

I dont know how to say this any other way then I dont think the pipes, carbs, and reeds are well matched to that motors durations that everyone is testing. I know the motor can make 90+ hp with pro circuits, mid tension reeds, and 30mm carbs. We already have a re-sleeved and dropped duration cub motor doing it. Its as simple as that! I read in one of these posts either here or in that link that this motor is identical to the cub if you change the porting. So effectively we have already done a serval cat motor by resleeving a cub motor is what I am gathering here. I have already dyno tested the setup with a 7 mill crank and it makes 94hp with a ton of torque, and good torque backup on a 50/50 race gas motor. The thing launches hard, and pulls wheelies with a +6 swingarm, its an awesome handfull of a bike because of the midrange torque and HP it makes. Can you imagine riding a 94hp low-mid built bike? Its awesome!

 

Im not sure anyone else in here is on the same page as me as to what I would like to see the motor do. It seems like everyone interested in this setup making maximum hp, and anything else it does is just an added bonus as long as it doesn't have the power characteristics of a cub motor. For me, I want to see it make a lot of hp, but also a lot of torque, and maintain a good torque backup curve so you can throttle out and back in as needed for obstacles, hill climbs, jumps, etc........

 

Here is a chart for my motor, notice the 1,500rpm of torque backup on it. My setup is a little different now, but fairly close still.

numbers

graph

[No Limit Powersports]

I understand how a 2 stroke pipe works, not claiming to be an expert pipe builder but it is a important part of building a motor, no need to explain. The characteristics of a PC or any other low-mid pipe in there inherit nature of design IMO, will never be the pipe of choice for this motor. If you think that you can make another 10 peak hp out of this cylinder by using a low-mid setup then i guess I fail to understand your logic. You say your looking a motor that is basically a tractor but you come back with "I know the motor can make 90+ hp with pro circuits, mid tension reeds, and 30mm carbs"??? I hope that there is better setup and i guess im a little confused at what you are looking for. You said that you did it with a 7mm cub, lets see that graph and let me compare it to one our cubs. I honestly dont want to compare your dyno graph to the serval that we built because its comparing to different breeds to each other which would not be fair for you. I know that you think your logic is the best possible setup, and it may be, but until you can test it lets lets leave it at that, "theory". I hope this continues to grow as a discussion and not an argument because i do not want to steer away from the good of the thread.

 

Have you ever ridden a big motor. I can assure you that i can show you a bigger motor that will make more power from top to bottom than any stock stroke stock cylinder that you have ridden. Maybe that would be something for you to consider. The problem with a motor like that is who wants 120+ hp in the tight trails, maybe you, but for the most it would be too much.