People with race cams come on in...

[jasonp]

Alright, I want to some the poeple with high compression pistons and cams.
After thinking about it and thinking about how big the bore is and short stroke on this bike I'm starting to relize with my setup this engine will really never be a power monster down low at low mid rpms. It just doesn't have the stroke to do it. So now I'm begining to think about some high rev cams that will go work better with this type of engine right now. I'm just thinking about going all out and going for the Megacycle 252-x1 race .450 cam. The only thing I'm really neverous about is loosing all the torque and power down low. I guess it's all a trade off isn't it. The Web .430 is more in the middle with a little less lift (which when you get in the .400's I don't think your gain a whole bunch even with a ported head cfm wise) and a little less duration and overlap. So will have a little more lower mid range power less top then the .450 cam. So I'm not sure as of yet... Help me out, give me your opinions.
Thanks guys!

 

[dave76]

The megacycle cam served me well, and you won't lose the low end, the increase in compression made up for that.

 

[jasonp]

Thanks for the reply dave!

 

[jasonp]

When and if I do put one of these cams in I'm going to get a DID timing chain.. where did you get yours?

 

[yamarider]

I ordered mine from the powersports shop's Parts Unlimited catalog, I think it was about 30 bucks.

 

[dswwarrior350]

With my current set-up (12:1 compression and .430 webcam) I have more power than stock everywhere, after upgrading from a wiseco and hotcam i make more torque and midrange power than i did with the hotcam, also on top end it screams and winds forever.

 

[jasonp]

I bet!!! It's got to just sing with this type of bore/stroke and the way the head is setup.
You know I wonder if alba is actually getting away with using a 12:1 piston (it sure looks like a JE 12:1, but I've always heard it was custom made) because there using such a big cam to bleed off dynamic compression.

 

[dswwarrior350]

ive still be throwing the idea around of getting a .450 lift cam, but im worried about clearence issues and if ill really gain anthing, what i should go do is get my head ported, with all my work a port job would really benefit me.

 

[jasonp]

DSW I completely agree. Duncan racing did mind and they did an unbelievable job with it. Plus they have a SERI machine do the valve seat cuts so it's super acurate and it's been proven that by a good machinest that you gain a alot of flow with out hurting anything just in that area.
Also they cleaned up the combustion camber and looks like they worked it over quite a bit. The only thing I didn't like is they didn't flow bench it... basically what loren told me is that they take a couple of good warrior heads and they port them different ways and such also using a computer program to aid them in the port design and combustion camber design to help produce the best hp and they flow bench the hell out of them... Once they get somethign that they like they load that model into the computer that way the can copy that design and port work over and over again. Just what I was told.... Still wish they would have benched it.
I've heard of people running 12:1 compression pistons with this setup JE piston though.

 

[dave76]

You know Jay if you look at the Warrior cam lobe it actually does have more lift before 0.50 lift, thats probably why some manufacturers measure at 0.40 istead of 0.50. This proves the Warrior has very fast opining rates and slow closing rates, it's actually a nice ramp on the closing side of the cam lobe. This does create a bit of overlap, and hooked to a sniffer machine you'd probably see a high HC at idle. The more overlap you have the more cylinder pressure gets bleed down at idle. So a 12.1 piston would probably run fine until you drop the hammer and it heats up a bit.

 

[kawfox9]

with a stock 350 except hmf s/o and uni air filter and airfilter vents would i benefit from a cam......if so what kind??

 

[jasonp]

Megacycle 252x-2.. 415"/395". or maybe a Web .390". Is the biggest I would go with a stock piston.. Even these small cams will bleed of dynamic compression and you'll lose a little bottom end.

 

[kawfox9]

what about hotcams...are those good for stock quads.....i am just trying to get more power for a good price

 

[dave76]

what about hotcams...are those good for stock quads.....i am just trying to get more power for a good price

Not worth the price your going to spend for it because you'll want to upgrade someday. Not to say the stock valve springs suck on a stock cam let alone one with more duration. Your best bet is Web, Powroll, or Megacycle, and replace those valve springs.

 

[jasonp]

You know Jay if you look at the Warrior cam lobe it actually does have more lift before 0.50 lift, thats probably why some manufacturers measure at 0.40 istead of 0.50. This proves the Warrior has very fast opining rates and slow closing rates, it's actually a nice ramp on the closing side of the cam lobe. This does create a bit of overlap, and hooked to a sniffer machine you'd probably see a high HC at idle. The more overlap you have the more cylinder pressure gets bleed down at idle. So a 12.1 piston would probably run fine until you drop the hammer and it heats up a bit.

You know dave and I've always questioned alba's JE pistons, meaning are they actually 12:1 pistons, ? But they get away with it because there using such a large cam and still run on pump gas? Makes me want to try running a 12:1 with a massive cam and see what happens.
Also just a little something I read today that I found interesting. The most important valve event is intake closing because it effects when or where the cam will make power because of reversion. Reversion is the ram air effect into the motor or I should say the oppsite of that, it's gas moving backward through the intake. A later closing intake valve will have more reversion and then also take longer in the rpm to make power because there is more gas acutally moving backwards through the intake at low rpm on overlap.

 

[dave76]

[quote:bwj48k4v]You know Jay if you look at the Warrior cam lobe it actually does have more lift before 0.50 lift, thats probably why some manufacturers measure at 0.40 istead of 0.50. This proves the Warrior has very fast opining rates and slow closing rates, it's actually a nice ramp on the closing side of the cam lobe. This does create a bit of overlap, and hooked to a sniffer machine you'd probably see a high HC at idle. The more overlap you have the more cylinder pressure gets bleed down at idle. So a 12.1 piston would probably run fine until you drop the hammer and it heats up a bit.

Reversion is the ram air effect into the motor or I should say the oppsite of that, it's gas moving backward through the intake. A later closing intake valve will have more reversion and then also take longer in the rpm to make power because there is more gas acutally moving backwards through the intake at low rpm on overlap.[/quote:bwj48k4v]

Thats were a good exahust comes into play with proper back pressure, at high RPM it'll act as a vaccuum sucking that cylinder plus mabe a little of the fresh charge too. Too much back pressure will reverse this effect and no back pressure will not create that vaccuum.

 

[jasonp]

I remember talking about backpressure in school.. I guess it's a big myth. Wanting backpressure that is. It's wanting as little backpressure as possible so the engine doesn't have to work to push the exhaust gas out of the engine. Pipe length and diameter play a huge role in this area, nothing to big which makes the gas move very slow (you want fast with out restriction) through the pipe and ruining your pressure/sound wave reflection pulling the exhaust gas out.. . nothing to small to create to much backpressure and something in correct length so the pressure/sound wave doesn't go out the back of the pipe. It got so techinal that I thought my brain was going to explode.

 

[snafer100]

i just ordered a powroll 390 cam with springs, what all is involved in installing these? IE to is it possible to do this with the engine / head still in the bike? also will i NEED a new chain or not?

 

[warriorcliff77]

You will need to remove the head and get yourself a valve spring compressor tool. (looks like a big clamp). While you're at it, get yourself some new valve seals. If you're gonna go through all that work it's cheap insurance to replace the timmng chain as well. Keep in mind you will also have to pull the flywheel.

 

[jasonp]

No you don't need to pull the head. No you don't need a new cam chain. Borrow a valve spring compressing tool from Napa or somewhere close and you'll be just fine.
If you do replace your cam chain which honestly I bet it's not worn all that much.. spend the money and buy oem. I put a DID one in and the links and pins are smaller then stock... what a joke.