YFM350 camshaft engine rebuild

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91warrior said:
megacycle has a .415 intake/ .395 exhaust cam called 252-x2. the .450 is the 252-x1. i would love to try that .415, and from what jason said, that cam would probably have exactly what i am lookin for, low end and torque. but curiosity has got me since i already have the .450 cam sitting in a on a desk brand new, and all i need to buy to swap it in is bearing. but if i could, i would trade even up for a .415 cam if i could.

now jetting for a different cam on an edelbrock would mostly consist of adjusting the acc. pump screw, maybe change the needle, and turn the needle to the right hight, right?

deadlast, got to www.megacyclecams.com then click on download catalog and then go to page 59 to see the cams they have for warriors and the .415 cam specs.
Click to expand...

I believe to change the main jet on the edel you have to change out the needle for a bigger one. Not totally sure on that.
Yeah if you want torque on the low end really .450 isn't the way to go. I think though you will get over that once you wick the throttle on the .450 .
 
I'm looking for more power overall and not just on the top end. I really don't push my bike to stay in the higher RPM"S... I don't what a bike that has to be in the 4000 + rpms to be useable.... I have not changed anything as of yet... My warrior has only the whitebros. R4 full exhaust and uni-filter and air box mod... It's jetted to a 152 main and thats it.. It will out run the raptor 350's and my friends piped and k&n filtered warrior.. I'm never happy with anything I like to tinker with it.. The 17/88 (whitebros. WB1905) cam came with my warrior.. The owner took it out because it was to much for him.. I beleive that cam was part of a packaged deal with the R4 exhaust and 152 main jet.. I think it was all a set... I don't want a bike that acts like a 2 stoke.. I'm to old to get hurt.. 47 years young... I just want more power to keep up with the newer bikes, but like to trail ride in the forest and climb hills... I like power up top but don't want a bike thats where you have to be to ride it...

The wiseco piston, z400 carb, cam 88 .390 webcam are the things I bought to get more power!! Ya!!!!! But have not installed any of them. I bought the big bear oil cooler setup for when I did redo the engine...
Don't get me wrong everything works as is, but I bought 2 cyclinders and wiseco pistons to do my warriors.. Both engines still have 116-122 psi. so the engines are running great.. I'm not sure about the 17/88 cam as you've seem to have had problems with them... I don't like the banshee (yfz450) traction problems on trail riding or the all or nothing power!!! I'm asking alot I know but want torque down low and Hp up top.. I'm never going to run this engine over 9000 plus so I'd like the power to peak about then... I don't think I'll ever stroke it either.. I have a bottom end I bought for the crank.. Chain kissed the case but it's sealed and the tranny is good as is the clutch... It was no stator or cover.. It's a backup if I screw up .

So i quess its just this.. I really don't want to keep trying lots of stuff... I want good torque down low and good Hp up top till 8000 rpm's plus.. The stock cam makes lots of torque and Hp down low but falls off arround 7000 rpms.. the 17/88 and webcams 84 make about 4 Hp (33hp) at 8400 rpm's Vs 29hp (stock) touques good at 8000 19 foot pounds.. But below 3600 the 84 looses about 6 foot ponds of torque.. So I'm asking people here who have tried the different cams which one would I be most happy with given the stuff I have because my wife forbids me to buy anything else.. Be happy with what you have.. HA, HA.. So guys my choices are 88 (.390), 84 (.430) or 17/88mc split duration and lift cams.. If I sell the last cam the I could send in the stock cam I have (extra one) and have them make it a 84 (.430) cam but change the lobe centers from 104lc (102-int 106-exh=104) to a 108 lobe center like stock cam gives more bottom end than the stock 84 grind but looses a1Hp on top end but broadens the power ban in both torque and Hp.. I've had many custom grinds done on camshafts for my 455cid pontiac engine.. 450hp 9.1comp.5400rpm motor... Takes a 77 transam with 3.23 gears running 28"tall steet tires to 112mph in the quater mile spinning the tire through 2nd gear Turbo 400.. 3950 pound car.. I know it's off the subject!!!! But it relates to the cam changing lobe centers..

So I could just send the 17/88 cam and have web regrind the intake to 84 grind from the 17 grind.. They said it's about 2 degress less and .01 lift But it would still be on 110 lobe centers with makes broader power less peak... It's like 80.00 plush shipping.. I could sell it for 80.00 out right on ebay use the money to send in my stock cam and have them grind it to a 84 on 108 lobe centers about 32 hp but more overall torque do to less overlap.. Higher cyclinder pressures with the less overlap.. This cam ground this way would have less overlap than the 88 (36 degress)

What does everyone think??????

29hp for stock motor
36hp for the wildest cam on stock stock motor..
I want the middle ground.
 
You want middle ground the .390 is it. period, done build the engine. Make sure and try and get around .040" of deck clearance for the most compression and squish that way you make up under 3600 rpm.
Out of all the cams the .390 had the best all around power. Most avarage HP and TQ. We all know that more all around power you have the fast the engine will be and more drivable. It may feel slower then say a big cam motor as it has the mid range hit but I wouldn't worry about it.
My .450 runs out of steam at 8500 rpm (that is peak hp) as well as my old .390. Another 500 rpm your at 4000 fps on piston speed which is the critical speed. I've taken this engine up past that many times though.
This is with a fully ported big valve serdi machined head.


**
Also I should say I was wrong before.
I adjusted my .450 to straight up cam timing because I was going to race a 550cc go cart and wanted the most hp I could get for racing.... Really took away something. Rode it tonight and going right back to 5 degrees advanced. It basically feels like the power band is narrower and a hair more very top end power at 8000 rpm to 8500. I really recomend advancing this cam to 5 degrees if used. So I was wrong about that sorry boys!!
I lost the race by the way. Really had no chance anyway. 50hp go cart against a 30hp warrior that weights a ton more. Just upset that the engine didn't run as good as before. Freaking cam timing.
 
My vote is for the .390.....it sounds to me like you wan the overall middle grounds cam and I think that that will be your best shot, the .430 will make you high rev more then the .390 cam.

Also sounds to me.......like you the one person on this forum that knows the most about cams in general! All great info and that for your input!
 
Thanks guy's I'll try the .390 cam..

What do you think about the old style suppertrapp mufflers???? I have one for my sons warrior, it's tunable, forest service approved and loud.. Does it make better power than the stock or other mufflers??? I have an FMF style (nock off) new one on it but it does not have a spark arrester..

So this is what I'm going to do on the GREAT Sujestions i've received from this forum: Rebuild the engine wiseco 83.5mm over bore, z400 carb and web .390 cam!!!! Sell the old supertrapp if it's not a good performance muffler and the web cams 17/88mc grind cam.. I'll use the money to get webcams to grind me a .430 (84) cam and change the lobe centers spread them out 108, like stock and try it also... I'll do a compairison against each other and see which one I like to ride with best.... Maybe the one I hate goes into my sons warrior Ha Ha Ha... I think I have the right parts to get some great performance out of the old warrior right?????

A side note I had a new klien tmx 36mm slide carb I was going to use , but I didn't think it would fit under the gas tank so I sold it... The throttle linkage cam out of the top of carb, not on the side as the others do.. Should I of keep it and tried it??? Would it of worked???
Thanks
Jerry
 
Olds style supertraps are Ok-ish. Best pipe for the warriors is the White Brothers E-series. Not my fav. pip but they say it gives you the best bang for you buck. Most people don't know that the stock muffler and head pipe on the warrior came so huge stock that an aftermarket pipe that will add huge HP numbers is hard to find. Many aftermarket pipes for the war dogs are just for sound/looks/ and very small HP adds. HMF makes a good pipe as well.
 
The old school supertrapps are pretty good. If yours is really loud you probably need to repack it, packing is only good for a couple years, or less if it gets wet. Once the packing breaks down it'll be louder and make less power. I have an old school supertrapp on my dr350 and it works great for me. They're actually pretty similar internally to the White Brothers E-series pipes. If you have one of those CZR ebay knockoffs, you'll be better off repacking that supertrapp and ditching the cheap thing, it'll probably break before long anyways.
 
yea i vote to on the .390 cam for you jerry. i think that will give you what your looking for.

on a side note, if you do sell that supertrapp, let me know, i really like mine and need one for my brothers.
 
Hi jason,
I thank you for posting and giving me some great sujestions in my posts!!! I've got some info you might be interrested in though..
I talked to webcams and found out that the .390 cam has only a .343 lift at the cam times the rocker ratio 1.14 = .391 lift at valve!!! the stock warrior camshaft I measured both the stock and web .390 base circle and heel to toe and found this...
stock 1.26 base circle.. 1.60 heel to toe ( top to bottom)=.34 x 1.14 = .3876 lift
Web .390 1.248 base circle. 1.591 heel to toe =.343 x 1.14=.391 lift

Stock cam as you said .341 lift at cam times 1.14=.388 and the web .390 .343 times 1.14= .391 lift.... So the cams really have the same lift just different durations and lobe centers placements..

Ie: stock 108 lobe centers with .388 at valve lift [email protected] duration
Ie: web .390 102-106= 104 lobe centers int, exh .390 valve lift and [email protected] duration..

It's only the duration that changes between the stock and web .390 cams and how they measure them at .50 or .40 which is very miss leading..
What do you think??? Call web at ask for the cam lift and what the rocker ratio is and see...
Thats
Jerry
 
crazy2jerry said:
Hi jason,
I thank you for posting and giving me some great sujestions in my posts!!! I've got some info you might be interrested in though..
I talked to webcams and found out that the .390 cam has only a .343 lift at the cam times the rocker ratio 1.14 = .391 lift at valve!!! the stock warrior camshaft I measured both the stock and web .390 base circle and heel to toe and found this...
stock 1.26 base circle.. 1.60 heel to toe ( top to bottom)=.34 x 1.14 = .3876 lift
Web .390 1.248 base circle. 1.591 heel to toe =.343 x 1.14=.391 lift

Stock cam as you said .341 lift at cam times 1.14=.388 and the web .390 .343 times 1.14= .391 lift.... So the cams really have the same lift just different durations and lobe centers placements..

Ie: stock 108 lobe centers with .388 at valve lift [email protected] duration
Ie: web .390 102-106= 104 lobe centers int, exh .390 valve lift and [email protected] duration..

It's only the duration that changes between the stock and web .390 cams and how they measure them at .50 or .40 which is very miss leading..
What do you think??? Call web at ask for the cam lift and what the rocker ratio is and see...
Thats
Jerry
Click to expand...

Hey Jerry.. no problem!! I pm'ed you back to.
I will post this link so everybody can see how much a warrior/raptor heads flow, both ported and stock. Shows basically that after .400" of lift that the head doesn't really flow any more air. No need to lift the valve that high.
Like I told you before that is really interesting as I thought the rocker ratio was 1:1 not 1:4!
http://www.geocities.com/kiwi_craig/GRAPH.htm


Also going to start to play more with cam timing. A good friend and me were looking the cam over and find that at about 7.5 degree advanced is about straight up. I know the cam is sitting lower and cam chain is basically longer because of the thinner gaskets I am using so I'm sure that doesn't help anything. I will report back more later after I drive it some more but for sure helps the bottom end not be so soft.
 
Thanks Jason,
By the way, that rocker arm ratio is 1.14 not 1.4 big difference there... anyway good luck with cam timming.. I have a 150cc gy6 engine (2 seater go kart) with a hot cam. I was going to shave the head to get more compression but changed my mind for just the reason you stated... Any time you change the distance from the center line of the cam sprocket to the bottom crank sprocket you end up retarding the cam (Chain slop).. You need a shorter chain.. This just why hot street cars run gear drives... Hot cams cause chain stretch ie: retarded timing..... Thats why there are so many different roller chains for v8's, But after a lot of abuse they will stretch anyways....
Watch that back lash on the chain.. check it forwards rotation and then check it backwards rotation and look to see it the cam stays stationary for a few degress in either direction... if too much slack in chain it will change timing on you when you let off the throttle (deseleration).. Just some of my thoughts... I had to geta custom timing chain on my pontiac engine because of line boring.. just enough to change timing a few degress between on and off the gas.. If you bracket race this is a few tenths and the difference between winning and loosing a race it's about 5 plush hp..

Jerry
 
The warrior motor makes like 19-20 HP stock on a good day...
And the wildest cam on the stock motor maybe makes 22/23 HP at max

Sounds to me like you want a little more power everywhere.. i would go with the cam you got already haha

The .430 is a midrange cam not a full on top-end cam... Honestly after puttin the .430 in mine i was slightly dissapointed as i was trying to build a completely top end power motor. IMO the .390 cam isnt even worth putting in.... been there and for the money its not worth it.

If you really wanted a good amount of power everywhere that you can actually use then you need to bump the compression up and do the cam at the same time.

All the parts you have already are good parts.. put the wiseco and the split duration cam in and you should have a good power at all rpm's. In reality all these cams are going to give you more power but none are going to be a huge increase... more or less just shift your power around from diffrent rpms ranges
 
DSWwarrior350 said:
The warrior motor makes like 19-20 HP stock on a good day...
And the wildest cam on the stock motor maybe makes 22/23 HP at max

Sounds to me like you want a little more power everywhere.. i would go with the cam you got already haha

The .430 is a midrange cam not a full on top-end cam... Honestly after puttin the .430 in mine i was slightly dissapointed as i was trying to build a completely top end power motor. IMO the .390 cam isnt even worth putting in.... been there and for the money its not worth it.

If you really wanted a good amount of power everywhere that you can actually use then you need to bump the compression up and do the cam at the same time.

All the parts you have already are good parts.. put the wiseco and the split duration cam in and you should have a good power at all rpm's. In reality all these cams are going to give you more power but none are going to be a huge increase... more or less just shift your power around from diffrent rpms ranges
Click to expand...

You had a hotcam stage 1 not the web .390 correct?
.430 has a ton of overlap.. While it is not as big as the .450 it is close.
 
After doing the big three mod, using a Yoshimera pipe I was impressed with the power gain, then I added a 4 degree crank key and the power gain doubled. A 20 dollar crank key gave me the same power gain that 600 dollars of aftermarket parts gave me. I would speculate that you need to do the other mods to get these results though.
 
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