F.A.S.T. Racing 4 mil Serval Cub

[crazycanuck]

The suspense is killing me, if one of them is a cheetah cub, not on alky nor oof drag pipes I might be back on the Cheetah cub band wagon!!

 

End my suffering Andy!

 

Great discussion so far guys.

 

By the numbers i would guess the 112 hp run was either a 10mm cub on gas or a 4mm on meth. From what ive read Andy does all his testing with alcohol, so my uneducated guess is a 4mm on meth and oof's....?????? OR a 7mm cut down to match a 4mm long rod crank.......

[No Limit Powersports]

Its all in that other post i started. Basic setup thought 140lbs compression, 91oct fuel, .045 squish stock flywheel, +3 timing, stock drivetrain

 

 

 

I think its great that you guys did the testing i just dont think you gave the test the proper chance to see real results. CPI's or shearers are absolutely not going to like the boyseen reed or small carbs that you guys put on there and thats why i think that the pc came out on top in the test it likes the intake setup that didnt flow near as well.

 

 

 

Its funny that you ask. As I have seen so many people say that cubs just dont have any bottom end most of the time because of either the way there built. Or most likely because when they do hit they hit so hard that nobody wants that in the trail anyway. Dont get me wrong a serval setup like i think a serval should be setup (pump gas) is a killer setup but a cub can make the power and then some.

 

Here are 3 graphs, the lower one is the 421 serval, the other two are different motors not servals. Ill let everybody speculate for a little while what they are before i tell.

 

 

The Blue line is a 421 cub drag motor were talking ported, alky, oof pipes the whole nine yards. so yes drag port timings can make bottom end its just not as easy and it will make big power everywhere.

 

The green line is a 535 pv cheetah you can tell right where the powervalves open completely and how low the power comes on. The motor is gas, inframes, and in a duner chassis, cause thats exactly what it is a duner.

 

The cub feels way faster cause the power hits hard from the bottom but has the "comes on low power" as the easy riding serval and then crushes it up the face of the curve. The cheetah feels alot like the serval just way faster from bottom to top and it should its a lot bigger motor. My point is that making bottom end does not have to come from very low ports, small carbs and small reeds its just not as easy to get. I will say that when i started i liked higher port timings on my drag motors as it was the easiest way to make power but more power can be made from bottom to top with a lower port its just alot harder to find. Both of these motors have 40mm+ carbs shearer pipes and big high flowing reeds and dwarf any serval graph to date, BUT the are not pump gas low compression motors. Both of them are higher compression more timing motors that will not run on pump fuel and alot more expensive to build. Making big numbers from bottom to top like this is not nearly as easy or as rideable as a serval is but it can be done. Most people would not like riding this much power in the trails or woods and complain about no bottom end when in fact its just too much everywhere, if thats possible .

[beebs]

Excellent write up Andy. I was thinking that one was a 421 cub on meth. Also proves that a properly ported cub is well worth the cost, if thats the power a person is looking for.

[dick turpin]

I know it sounds like a rant...but I understand the dyno issues (We have a DynoJet 188) and even I find the results to be a little misleading.

What are your A/F readings? A pipe can look good vs. another pipe if the A/F readings are lean. The smaller pipe might favor the lean condition.

Dynojet dyno's AREN'T different from one to the next. (using the eddy current brake will show different results from a non eddy current run) but in the inertia mode it will read the same as mine. (That's why the DynoJet is the industry standard)

I was expecting to see improved results from the previous posted advertized results. All you have shown is that your motor (which thanks to your eddy current run style looks low anyway) seems to like the PC's. Nowhere is there anything that says the carbs are even close to the right size. (You didn't try a bigger carb?)

The eddy current mode is used for diaing in your jetting at different RPM stages. Final dyno numbers are more often done without the eddy current in use. (80% of chassis dyno's don't have the eddy current feature) So why not just list runs that compare with others, so we can compare results. (Yes I know runs made in one area of the country under different weather conditions will very the results) But they will be ALOT closer than the eddy current results and cause less confusion.

 

I really don't get what your saying?

 

So a guy post's his results using an eddy current brake and your saying there misleading figures. The figures using the eddy will be much more accurate than inflated figures off a Dyno jet.

The only reason "dyno Jet think they are the industry standard" is because they give out higher figures than a dyno using an eddy brake. People like to think there pushing out high numbers when if fact there not that high at all.

Stick two ATV's together one showing 75WRhp one dyno'd with an eddy and the other not, guess which one will be spanked lol.

I feel he's done it the correct way using an eddy brake dyno to get really figures.

If people don't understand that they shouldn't really comment on the low figure they think there seeing.

 

By the way the inlet track is way to long to use a single carb manifold for the peak power RPM.

[camatv]

welp just as i have been saying for a few YEARS NOW IF YOU WANT bottom end AND hp YOU NEED A PV MOTOR now that said most people cannot handle that kind of HP and tq in a chassis and with a shorty swing arm its going to be very HARD TO RIDE they can be detuned on gas and will drop about 10-15% OR you can back the timing way out of them on alky ( the way i like to control them)

 

bottom line is this..

 

servals NEED large chamber pipes they are VERY efficent and no matter what you do carb reed comp wise trail pipes are going to hold them back..

 

CUBS WILL WHIP A SERVAL in a drag race similar frame similar rider....

 

i saw the serval andy did it wasnt any thing spectacular in the frame/ chassis depart ment BUT i dodnt see anyone PISSED off after ridign it and mad that it had just too much top end to ride!! and was like a cub.. to me the power looked smooth enough to jump ride play race and goof off on.

 

 

i cannot believe that those kind of graphs can be posted AND some of you STILL dont believe it!!!

 

another thing with the PV's you can TUNE the open / close times.. HINT HINT>>

[camatv]

wonder if nate will put those SLP's on a serv.

[252wheelieking]

Why did this thread die? It was good, so im assuming a mid to top pipe, high flowing reeds & 33-35mm carbs is a better set-up for the serval.

[camatv]

it died because of what i said.

 

not much debate in a dyno graph of an "old pv" cylinder..

 

id personally love to see a rebirth of a smaller cc large bore pv jug like a 73mm stock stroke pv cheeta.. the larger bore would like to rev and the pv's would make all the bottom you would ever need. plus the short stroke would allow higher rpm stability.

[252wheelieking]

it died because of what i said.

 

not much debate in a dyno graph of an "old pv" cylinder..

 

id personally love to see a rebirth of a smaller cc large bore pv jug like a 73mm stock stroke pv cheeta.. the larger bore would like to rev and the pv's would make all the bottom you would ever need. plus the short stroke would allow higher rpm stability.

 

That makes alot of sense. I was wondering how the stock stroke cheetah would perform. You just gave a me a good idea, so the purpose of the serval is to make similar power @ a cheaper price tag?

Edited October 18, 2011 by 252wheelieking

[camatv]

welp lets look at it like this.. from what i understand:

 

the cheeta is partial owned by trinity and is the reason for the inflated price i dont know how long the "deal is set up for" i'm not sure what if any castings of cheetas are even being produced and its a shame because of the greatness of that design..

 

the cub was a great selling cylinder and brought the banshee back as far as i'm concerned.. so then what? you market a "super cub" bigger bore ( and more design problems that the cheeta had solved with the larger bore cyls) thats the BBD for a lil while.

 

then you do a DM and DMX and other larger more $$$$ cc cylinders that are the next BBD

 

THEN you realize the amaxing success of the "cub" so you derive a serval for the trail and custom porters that want more to "play with" then that sells well but kinda fails in preformance unless done right ( and whay not its a custom cylinder that really needs a completely differnt setup from what is the "norm" takes a lil time) but i think its mostly figured out but far from really pushed to the max.

 

THEN you release the wompus a "look alike" stock cylinder cub and is available in mucho larger cc motors and market that as a

street killer and develop the stock looking head with replaceable domes.. NICE!

 

all marketing and development of a product line i like it its keeping this industry exciting and to think its all from one company..

 

i'd love to see a re release of a PV cheeta in a more better price range and using externaly adjustable rotax powervalves ( like a trex has) but i feel if that happend it might push a lot of "serval" buyers into a differnt cylinder and would probably hurt the sales of the serv. with extrnally adjustable valves you can "dial" in the lkinda power you want for the day you can keep them copmpletely closed for tight traisl and technical stuff where you dont want a hard hit of top end that breaks loose traction then with a simple twist you can have bottom end with a brutal midrange lil more twisting you can lightswitch the powerband to a high rev hard hitting exciting drag style top end.. all in the same motor.. without the screwey head gasket blowng or special heads that the super cubs need... think about it

[252wheelieking]

welp lets look at it like this.. from what i understand:

 

the cheeta is partial owned by trinity and is the reason for the inflated price i dont know how long the "deal is set up for" i'm not sure what if any castings of cheetas are even being produced and its a shame because of the greatness of that design..

 

the cub was a great selling cylinder and brought the banshee back as far as i'm concerned.. so then what? you market a "super cub" bigger bore ( and more design problems that the cheeta had solved with the larger bore cyls) thats the BBD for a lil while.

 

then you do a DM and DMX and other larger more $$$$ cc cylinders that are the next BBD

 

THEN you realize the amaxing success of the "cub" so you derive a serval for the trail and custom porters that want more to "play with" then that sells well but kinda fails in preformance unless done right ( and whay not its a custom cylinder that really needs a completely differnt setup from what is the "norm" takes a lil time) but i think its mostly figured out but far from really pushed to the max.

 

THEN you release the wompus a "look alike" stock cylinder cub and is available in mucho larger cc motors and market that as a

street killer and develop the stock looking head with replaceable domes.. NICE!

 

all marketing and development of a product line i like it its keeping this industry exciting and to think its all from one company..

 

i'd love to see a re release of a PV cheeta in a more better price range and using externaly adjustable rotax powervalves ( like a trex has) but i feel if that happend it might push a lot of "serval" buyers into a differnt cylinder and would probably hurt the sales of the serv. with extrnally adjustable valves you can "dial" in the lkinda power you want for the day you can keep them copmpletely closed for tight traisl and technical stuff where you dont want a hard hit of top end that breaks loose traction then with a simple twist you can have bottom end with a brutal midrange lil more twisting you can lightswitch the powerband to a high rev hard hitting exciting drag style top end.. all in the same motor.. without the screwey head gasket blowng or special heads that the super cubs need... think about it

 

I agree with what your saying because if I could get a motor that was that universal I wouldn't want a serval. I think a small cc cheetah is my type of engine. You have good bottomend because of the PV & still got the mid & top of the CUB. That's my ideal motor, but for now the closest thing to my riding style is the serval from what I've read. If I rode a 400 PV cheetah I might like that better from what im understanding about them. The only thing is the price tag.

Edited October 19, 2011 by 252wheelieking

[lms1977]

I too wanted a pv motor but the price was way higher

[gusto]

Anyway to see these graphs again? This was a great read.

 

has anyone since this tested PCs on a serval? 

[Ayesully810]

3 hours ago, gusto said:

Anyway to see these graphs again? This was a great read.

 

has anyone since this tested PCs on a serval?

I plan on picking up a completely stock bike to mess around on this spring and summer with just PCs. I loved mine when I had them

[gusto]

Same here. Regret selling mine.