magnum race cam

[johnnynonails]

has anyone ever used a stage 2 magnum race cam in there 400ex?
i just bought 1 from atvs unlimited,i should of asked what make it was,but i didnt. you see that many cam pictures on ebay that say,this maynot be the picture of your cam,but you will be sent the correct 1.
gunna have to press the cam flange of my stock cam and put it on the new one ,easy job ?
any input on these cams would be great,as ive never heard of them for quads,thank john

[F-16Guy]

I remember reading somewhere that the Magnum Stage 2 cam requires shortened valve guides and possibly hardened rockers. I would hold off on the install until someone can verify that.

Swapping the cam flange isn't dificult, just make sure you don't put any pressure on the ears.

[johnnynonails]

thanks i think its wise to hang back and wait.it came with very very basic instructions,no mention of hardened rockers or shorter guides needed.john

[johnnynonails]

ive found this info
1 check piston to valve clearance,provide the necessary clearance by removing material from piston,minimum clearance intake .050 exhaust .080
2check valve to valve clearance,it may be necessary to remove material from the valves or sink valve seat height in head.
3check the valve spring retainer to valve guide clearance at maximum lift.remove material from top of valve guide to provide a minimum of .030 clearance
4check for valve spring coil bind at maximum valve lift,clearance at every coil should be at least .015
5be certain that the cam and rocker arms rotate freelyin head or block,remove material from head or block or rocker arms where necassary.

what does all that mean in english ?. john

[F-16Guy]

That means that the cam has so much lift and duration that it is possible with some engines that the valves could contact the piston, the valve spring retainers could hit the valve guides, and/or the cam could cause the valve springs to compress so much that they bottom out and bind. Those are probably generic instructions, so there may be some parts that don't apply to the 400ex.

The 400ex is a pretty mild engine with lots of piston-to-valve clearance, so even with an off-the-shelf aftermarket piston, there's not much chance of the valves hitting the piston. What I would be more worried about is the valve guides needing to be shortened and what material the cam is made from. If it is a reground cam where the lobes are built up with beads of weld and then machined down to spec, you'll need to have the same thing done to your rockers (typically called hard-facing or hardening). If the cam is machined from a piece of billet steel, then it may be compatible with the OEM plating on the rockers.

[F-16Guy]

http://www.exriders.com/vbb/showthread.php?threadid=289651

[johnnynonails]

thanks for the link
the cam looks like a 1 piece construction, as u can see the cast marks on the lobe sides,same as marks on the shaft,were it hasnt been milled.

it looks wise to get hd valves and springs,and can you buy shorter guides,or could i just nibble a bit off at home ? thanks john

[johnnynonails]

just got an email back from atvunlimited.and there stating you can run stock ex rockers,valves and springs,without any modification,the plot thickens. john

[jdog75]

wow im stumped with this im putin the same cam in my 400 now with my rebuild and dont have money for the valves or springs dont know what to do but they say its safe to run it with stock everything in the head so i dont kno what to do

[jdog75]

plus do you think a 416 11:1 could handle that

[johnnynonails]

im running a 440 kit with it,so anyone with more info would be great

[F-16Guy]

Originally posted by johnnynonails
just got an email back from atvunlimited.and there stating you can run stock ex rockers,valves and springs,without any modification,the plot thickens. john
Well, the cam will be the last thing to install if you do a piston too (which is highly recommended), and it is easily accessible, so you could just install it and use a breaker bar to turn the engine over slowly by hand and see if you get any binding in the valvetrain. Aside from that (or more detailed information from the manufacturer), you'd have to clay the piston to check valve clearance and also find out what the maximum lift is for the stock springs and guides.

[johnnynonails]

simplest answer for me to do is,just pop the cam in and turn it by hand first,get a feel for how its turning or binding.thamks for all your help.i'll report back with more info when its done.john

[togup]

I had a magnum stage 2 and run it for years in a 440 and i never had any problems , it really woke it up. save up some money and buy a hot cam swap them out see if there is a difference.

[johnnynonails]

are you saying you had no set up issues togup ?

[togup]

Originally posted by johnnynonails
are you saying you had no set up issues togup ?

sorry so late replying but no I had no problems at all ,I recently tore my engine down to build a stroker and could not find any thing worn or damaged in fact im using the same head and valves but I did change to a stage 3 Hot Cam.

[johnnynonails]

hi,well im stuck.is the flange that holds the cam wheel on the cam pressed on? .i cant get it off the stock cam to switch it over to the new cam.
and with it being christmas time,all the machine shops are shut down for 2 weeks.
ive had it sat in a vice losly,and tried hitting it througt the vice, heated it up and tried that,but the little buggers still on the cam.
and ideas ?. thanks john

[jdog75]

Originally posted by johnnynonails
hi,well im stuck.is the flange that holds the cam wheel on the cam pressed on? .i cant get it off the stock cam to switch it over to the new cam.
and with it being christmas time,all the machine shops are shut down for 2 weeks.
ive had it sat in a vice losly,and tried hitting it througt the vice, heated it up and tried that,but the little buggers still on the cam.
and ideas ?. thanks john

im rebuilding my engine as we speak and im going to run the same cam and i had to press the old flange from my stock cam off and the press it on the magnum cam

[togup]

Originally posted by johnnynonails
hi,well im stuck.is the flange that holds the cam wheel on the cam pressed on? .i cant get it off the stock cam to switch it over to the new cam.
and with it being christmas time,all the machine shops are shut down for 2 weeks.
ive had it sat in a vice losly,and tried hitting it througt the vice, heated it up and tried that,but the little buggers still on the cam.
and ideas ?. thanks john

yea I had that problem , i took it to work and pressed it off ,alot of local auto shops have those presses check with them it will probably be cheaper

[dariusld]

I just bought a new flange. I figured just a couple dollars since the machine shop was going to charge me something.

Edit found an old thread


Originally posted by dariusld
Putting my bike back together after taking it apart. I had to put my new flange on my new Hot Cam. I really didn't want to have to find some place to have it pressed on and I didn't want to spend the money. So I took a piece of plywood, 19mm socket with extention, a jack, and my 5000lb truck and wa-la you have a hydralic press. I know I shouldn't of done it this way but it worked. I threw the plywood under my truck,put the cam on top of that, put the socket on the flange, the extention on the socket, and lowered the front end of the truck on top of all of that. And slowly but surely it pressed into place. I had to buy a new flange to do it this way, but that would be $20 I'd be paying to the machine shop anyways and I got a new flange. I'm not saying for you to do it this way, but I did it and the cam doesn't have one scratch on it. And the flange doesn't move at all and everything is lined up.

There is also that freeze and heat method. But I couldn't get it to work.

[johnnynonails]

found a guy today who pressed off the flange and put it on the new cam,put it all back together,checked all clearance (about a dozon times) before spinning it by hand,all looked good,so i turned the key,and wham she fired 1st time,ran it for 15 mins at a few thousand revs to run the cam in,( had a fan heater blowing cold air over the engine as it stood still).i havent had time to take it out yet,but its all good upto now.
would like to thank every one who helped me out on the cam swop :) . john

[F-16Guy]

Awesome. Let us know how it runs!

[chronicsmoke]

Old thread but good info a somewhat unknown and considerably cheaper cam..


just got an email back from atvunlimited.and there stating you can run stock ex rockers,valves and springs,without any modification,the plot thickens. john

I've been running mine like atvunlimited said, with stock valves and springs with no ill effects..

[cheater13]

How's it compare to a Webb cam?

[chronicsmoke]

How's it compare to a Webb cam?

Well I've always assumed it was kind of between a HC Stage 2 and 3 (like the early HRC cam in a 04/05 450r)

I was curious so I checked for the specs on here.. Great info in this thread; http://www.atvriders.com/vbb/showthread.php?224516-Cam-Cams-Camshafts-(400EX)-information

LIFT DURATION
IN EX IN EX
stock............... .316, .302, 234, 238

XR400.............. .326, .321, 240, 244
HRC................. .350, .339, 254, 256
GT Thunder....... .350, .345, 256, 256
WB Track.......... .350, .345, 256, 256
WB All Around.... .345, .335, 240, 248
WEB 450/451..... .350, .345, 256, 256
WEB 479........... .378, .378, 250, 250
WEB 463/9i....... .385, .370, 272, 270
Hotcams stg 1... .354, .354, 246, 246
Hotcams stg 2... .354, .350, 254, 248
HC stg 2 (old).... .348, .349, 254, 254
Hotcams stroker. .358, .354, 262, 257

Magnum on E-bay .350 .345, 256, 256 <-- numbers off the $80 magnum cam on E-bay

Seems to have the same specs as the GT Thunder and White Bros Track cams

[RNL]

Boy that stock cam is weak.

[chronicsmoke]

haha for sure, those numbers are tiny compared to any of the aftermarket cams

[RNL]

haha for sure, those numbers are tiny compared to any of the aftermarket cams

Sure is, no reason honda couldn't at least put the Xr cam or a hotter cam right from the factory. Be such a better performing quad.