Serval Cat

[No Limit Powersports]

Here is a dyno graph from another reputable builder

 

Specs are

he degree it all out

 

187 exhaust

123 transfer

180 tripples

35 pwk air strikers

VFIII

160 cranking compression

.05 squish clearance

Shearer Inframes

All off the shelf stuff with no porting at all

 

he also did the same setup with the cpi inframe and it peaked at 8400 just like mine

[Snopczynski]

I saw a chart last night for a motor that was ran on the crank dyno last year. It was a 68mm cub with 2mm hacked off the base of the cylinder. Run with a stock head re-domed, and 4 mill crank. On the crank dyno it put down 85.5hp and 50ft lbs of torque with pro circuits and 30mm mikuni flat slides. The chart lines were a nice gradual rise like the one I posted for that 7mm motor. It had around 1,600 rpm of torque backup on it. The torque came on really early, and Dave said it was super easy to setup the dyno on it. It needed almost no adjustment, and it put down the same numbers run after run consistently. Turns out I also rode the bike that motor was in last year as well. I remember it being a wheelie monster and pulling pretty damn hard.

 

To give you guys an idea of hp readings on this dyno: My stock ported 350 beats quite a few mx and torque ported 350's we ride with on the drag hill. I put down about 66.75hp and 42 ft/lbs of torque on this dyno.

 

We have a really good running 4mm stock cylinder that runs almost a dune port duration (about 189-190 exhaust) That bike beats most 4mm stock cylinders bikes on the hill. It put down 72hp and 47ft ft lbs of torque.

 

I really think pro circuits and smaller carbs should be tested on this serval setup.

[Titan]

Here is a dyno graph from another reputable builder

 

Specs are

he degree it all out

 

187 exhaust

123 transfer

180 tripples

35 pwk air strikers

VFIII

160 cranking compression

.05 squish clearance

Shearer Inframes

All off the shelf stuff with no porting at all

 

he also did the same setup with the cpi inframe and it peaked at 8400 just like mine

wow andy that would be around 97 at the crank

[BigRed350x]

I really think pro circuits and smaller carbs should be tested on this serval setup.

 

So go buy a set and do the testing if you really want to see how it will do.

[Snopczynski]

So go buy a set and do the testing if you really want to see how it will do.

Im not gonna buy a serval until my motor needs rebuilt. I would buy one sooner if someone tested this stuff and had the results though.

 

Shane may get one next spring, so I am sure we will test that one.

[BigRed350x]

So go blow your motor up, THEN buy the serval and do the testing.

[Snopczynski]

So go blow your motor up, THEN buy the serval and do the testing.

Sorry, nobody has made me a deal that has seemed worth while to tear down a perfectly good running motor and put those cylinders on yet.

[2strokespirit]

We will be building a serval, hopefully 4mm and 7mm.... At this time it looks like 7mm, with pro circuits.... If all works out well, I will keep you guys updated if you are interested.....

I will be cutting the stock head for this setup... All setups for 93 pump gas.... Nothing "serious" :-)

Pro Circuits all the waaaaaay!!

[dajogejr]

Why build a 7mm out of a 4mm cylinder?

[2strokespirit]

Why build a 7mm out of a 4mm cylinder?

 

Why not?

 

I have a few 7mm cranks, haven't use them yet....

Edited November 20, 2010 by 2strokespirit

[dajogejr]

That's the only good reason I could see doing it.

You won't notice any more power 4 to 7, even if you take the time to match/fix the porting.

Obviously you'll have to run a spacer plate or cut domes....

Extra cranks is the only reason I'd see running one. You won't notice a performance gain...and if so it'd be so minimal the cost wouldn't be worth it.

[AKheathen]

well, one trend i keep seeing is the poer dropping off between 5-6k, but pretty linear torque from about 7-10k........omho, that's still kinda top-end torque motor...great for dune and even mx, but i think the idea of setting up 7 or 10 mill with cut domes can get a serval closer to what i'm interested. 1.5mm is a big change in duration..... i think some adjustment can get a set into a real torquey woods curve, building great linear power from under 5 k, and great off-idle comparatively. so, just as cubs have been cut down to make something similar to a serval, mabey a serval can be cut down, or port timings otherwise manipulated by stroke......i don't think the true nature of low-end is best served without the increased stroke.....so that's why i would do it.....

[2strokespirit]

For me its all about the low/mid grunt, everything on top is a bonus....

 

I agree for the guy out there that have to pay to build a 7mm serval would be almost a waste to make 5hp+ or so more, unless you know some people, because it will be lots of work and money for that extra few hp, 7mm crank, porting and maybe decking depending what durations you want.... BUT the torque curve will be even smoother and wider...

 

I do my own work, cut my own heads, porting etc.... there was something that changed my life "LOW AND WIDE" on a high transfer....

 

We are looking into decking the serval to keep the exhaust port low and the transfers under 130s, not sure what the deck height of the stock serval is or base gasket, but putting a 7mm in there with -1.5mm deck height will bring the transfers to about 130.7degrees... With 0.5mm shave of the bottom you should be in the 128s....

 

I also think with the extra 3mm stroke, pro circuits etc this thing will torque like a train... I will try my best to put it on a Dynojet with stock carbs and 33s, just to see what she make.....

 

For me its almost more fun building these things then riding them....

 

If it was not for the servals, I would have decked a 7mm cheetah cub....

 

Its all about the fun.....

[AKheathen]

sweet, keep us posted

[ltd.yfz]

For me its all about the low/mid grunt, everything on top is a bonus....

 

I agree for the guy out there that have to pay to build a 7mm serval would be almost a waste to make 5hp+ or so more, unless you know some people, because it will be lots of work and money for that extra few hp, 7mm crank, porting and maybe decking depending what durations you want.... BUT the torque curve will be even smoother and wider...

 

I do my own work, cut my own heads, porting etc.... there was something that changed my life "LOW AND WIDE" on a high transfer....

 

We are looking into decking the serval to keep the exhaust port low and the transfers under 130s, not sure what the deck height of the stock serval is or base gasket, but putting a 7mm in there with -1.5mm deck height will bring the transfers to about 130.7degrees... With 0.5mm shave of the bottom you should be in the 128s....

 

I also think with the extra 3mm stroke, pro circuits etc this thing will torque like a train... I will try my best to put it on a Dynojet with stock carbs and 33s, just to see what she make.....

 

For me its almost more fun building these things then riding them....

 

If it was not for the servals, I would have decked a 7mm cheetah cub....

 

Its all about the fun.....

 

Can't wait to see how it turns out.