YZ exhaust cam vs Hotcams exhaust on WR450


60 replies to this topic
  • yz426weelieking

Posted February 20, 2008 - 07:39 PM

#41

Are you guys that are having problems shimming the valves??? I have a 01 yz426 and i was thinking of changing my exhaust cam so i dont have to use the decompression lever, it all sounded good till i started reading your posts, i might just go for a 03 yz exhaust cam, any feedback???

  • tweav

Posted February 28, 2008 - 12:23 AM

#42

I'd really like to see a dyno test of all of the cams . wr vs. yz vs. hot cams vs. graves or any of the above. I think it would be a great test with proof, someone with a dyno needs to try it or have already done it

  • Speedracer747-400

Posted February 28, 2008 - 08:33 PM

#43

Are you guys that are having problems shimming the valves??? I have a 01 yz426 and i was thinking of changing my exhaust cam so i dont have to use the decompression lever, it all sounded good till i started reading your posts, i might just go for a 03 yz exhaust cam, any feedback???



Installing an 03 YZ450F exhaust cam w/auto decompression is one of the best mods you can do to the 98-02 YZ400/426F. You can get an oem Yamaha cam for $102, no need to waste money on the Hotcams unit. You will need to check and most likely adjust the valves, but this is part of normal maintenance on the yzf motors.

Original 450 decompression cam mod thread(All 106 pages)
http://www.thumperta...ead.php?t=60381

Instructions
http://www.thumperta...078#post3706078

  • Storbeck

Posted March 09, 2008 - 05:42 PM

#44

Sooo... any news on this. Looks like at least two people on this thread (albertabigdog and SJMC Don) were going to try the 06 YZ cams on thier WR.

I'm probably going to order some 06 YZ cams for my WR tomorrow, but still interested in hearing any feedback from somebody who's already done it.

Still snow on the ground here in Wisconsin so won't be able to try it for a few months.

  • dirtysouth

Posted March 10, 2008 - 12:54 AM

#45

Posted a reply to someone elses thread relative to this subject a while back and have since got some more info from the Yamaha shop owner here in town that might interest you...He rides an 07 YZ and one of his buds (salesman) rides an 08. They ride together and the conclusion that they have drawn (and has him trying to tune DOWN his 07) is that the cams have changed in 08 and the '08 bike is less "rowdy" due to that fact for the most part. They have the 07 down for potential re gearing now but he is complaining of how abrupt the power is on his 07 compared to his buds 08. They ride trails a lot so there is his reason for modification. But to your questions...go with the 07 I and E cam :thumbsup: and BAM! you've got power. BTW he already put a bigger flywheel on his 07 and thats not enough downtuning for him. He has been troubled runnin the trails with his bud but on wide open straights he is clobbering the guy. '06 cams will give you plenty juice over WR but I might disagree with this and go '07 if you are going. His explanation, although speculative, is that the YZ riders on the circuit were having trouble with the power coming on like it was so Yamaha switched it to flatten out the power curve. I might say this is the way to go but '06's stuff should be good too. Shew, after all that these guys are talkin about I would actually go '08. Good luck and happy trails:ride:

  • wRrooster

Posted March 10, 2008 - 02:33 PM

#46

I experienced a huge power gain in low RPM's going with the YZ exhaust cam. So much that I can now pull a taller gear up hills that I would be bogging down in at the same low RPM's with the WR cam (without changing my jetting). I can't say that I noticed a whole lot in the higher RPM's, but I didn't need a big gain there anyways.
Its by far the best $100 mod you can do to a WR!

Why bother with Hotcams, when you know you can get the power with a realiable Yamaha part?

  • erickdj

Posted April 15, 2008 - 01:52 PM

#47

Sooo... any news on this. Looks like at least two people on this thread (albertabigdog and SJMC Don) were going to try the 06 YZ cams on thier WR.

I'm probably going to order some 06 YZ cams for my WR tomorrow, but still interested in hearing any feedback from somebody who's already done it.

Still snow on the ground here in Wisconsin so won't be able to try it for a few months.


so, did anyone actually do a cam swap with the 06 or 07 cams? results?

  • SJMC_DON

Posted April 15, 2008 - 02:03 PM

#48

so, did anyone actually do a cam swap with the 06 or 07 cams? results?


My 06' YZ cams are sitting on my shop work bench... calling my name now for 2 weeks :thumbsup:

I did however ride my buddies 07 WR with 06' YZ cams in it the other day and something must be wrong... I thought the bike was an absolute sloth off idle with no low end grunt at all... it pulled harder in the mid... I asked him if his gearing was stock and he said yes... the only thing I can see that he may need to improve is that he still has the stock exh with just the pea shooter removed...

I am keeping my fingers crossed but if I get similar results I will be pissed:foul:

  • erickdj

Posted April 15, 2008 - 02:44 PM

#49

My 06' YZ cams are sitting on my shop work bench... calling my name now for 2 weeks :thumbsup:

I did however ride my buddies 07 WR with 06' YZ cams in it the other day and something must be wrong... I thought the bike was an absolute sloth off idle with no low end grunt at all... it pulled harder in the mid... I asked him if his gearing was stock and he said yes... the only thing I can see that he may need to improve is that he still has the stock exh with just the pea shooter removed...

I am keeping my fingers crossed but if I get similar results I will be pissed:foul:


oh $h1t, that's frightening. is there maybe a possibility that he got the timing slightly off? let me know when you decide to install those cams. I'm VERY curious to see if the swap/upgrade is worth the time and $$$.

  • Storbeck

Posted April 15, 2008 - 07:26 PM

#50

I put 06 YZ cams in my 07 wr450F running an 07YZ exhaust and all of the free mods a while ago. Used the JD jetting for 06/07 yz450.

Unfortunately I can't tell you much about how it runs, the only riding I've done on it so far is on a frozen lake. All wide open high speed with super tall gearing. I can tell you it made a big difference for that type of rideing, but really have no idea what it will do in something more normal.

The day after I got it all buttoned up with the new cams, I went riding on the lake and sunk the bike while crossing a preasure crack. Fished it out and tore it down that day, still don't have it completely back together yet because I've been busy with other things.

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  • erickdj

Posted April 15, 2008 - 09:11 PM

#51

I put 06 YZ cams in my 07 wr450F running an 07YZ exhaust and all of the free mods a while ago. Used the JD jetting for 06/07 yz450.

Unfortunately I can't tell you much about how it runs, the only riding I've done on it so far is on a frozen lake. All wide open high speed with super tall gearing. I can tell you it made a big difference for that type of rideing, but really have no idea what it will do in something more normal.

The day after I got it all buttoned up with the new cams, I went riding on the lake and sunk the bike while crossing a preasure crack. Fished it out and tore it down that day, still don't have it completely back together yet because I've been busy with other things.


I'd be interested to know how it would run under "normal" conditions.

  • SJMC_DON

Posted May 05, 2008 - 08:26 AM

#52

Well - I am finally getting around to installing my cams and I have yet another TDC question...

So I understand from this thread that we are to use the third "I" on the rotor for TDC... when I have my rotor at TDC (supposedly) my timing marks, or dots on my cams are not in line with the top of the head as shown in my manual.

I set the piston stroke to TDC according to the two dots, or dimples on my cams... this is actually an 1/8"+ CCW from the third "I"... my plan is to install the new cams exactly as the original WR cams were found with the two dots, or dimples to the outside and level with the top of the cylinder head and the rotor in the same position (1/8"+ CCW from the third "I")....

I know this is probably as clear as mud, but has anyone else experienced a similar situation.

The bike is an 07', been riding hard for a year and 3 mos., no issues at all:excuseme:

  • erickdj

Posted May 06, 2008 - 09:30 PM

#53

I can't wait to hear about the results of this mod.

  • rufusz

Posted May 07, 2008 - 01:22 AM

#54

Are you guys that are having problems shimming the valves??? I have a 01 yz426 and i was thinking of changing my exhaust cam so i dont have to use the decompression lever, it all sounded good till i started reading your posts, i might just go for a 03 yz exhaust cam, any feedback???


I've installed an HotCams exhaust cam to a 02 yz426 and it works great. Definitely on of the best mods to a 426, starting is now easy, but I would prefer a remote hotstart also, but don't have the budget for it right now :eek:

  • woodybepierced

Posted May 17, 2008 - 07:43 PM

#55

Word, just put in the new 03 Cam in my friends 99 WR 400 and when we were checking the valve clearance we came up a little high in numbers. Now, reading the awesome pdf we had, that the average was .1mm - .2mm thicker shims. We came up with putting in .3mm thicker shims. We just got a little set off by the large shim adjustment and we were wondering if anyone else may have had to make such a large shim adjustment after making the cam mod?

Thanx for your help!
-Brian!

  • SJMC_DON

Posted May 18, 2008 - 07:27 PM

#56

Word, just put in the new 03 Cam in my friends 99 WR 400 and when we were checking the valve clearance we came up a little high in numbers. Now, reading the awesome pdf we had, that the average was .1mm - .2mm thicker shims. We came up with putting in .3mm thicker shims. We just got a little set off by the large shim adjustment and we were wondering if anyone else may have had to make such a large shim adjustment after making the cam mod?

Thanx for your help!
-Brian!


I had the opposite in that I had to increase clearance :thumbsup:

Just REALLY rode the bike today for the first time since the cam swap. It was tight and technical riding never got out of 3rd gear really... It's actually stronger in the bottom but not like hard hit I had anticipated,,, more grunt, tractor type power and this may sound weird but 1st gear seems taller and more useable :rolleyes:

I have some jetting to figure out still because the bike does not really like e-start now but it fires on first kick and while I did not open it up today I did have a few occasions to really roll it on about halfway through the RPM range and it definitely pulls harder with these YZ cams.

Still holding out on final grade till the next GP on June 1 that will be the true test or opportunity to see just how drastic the performance gains are.

  • elcubeo

Posted March 18, 2009 - 06:49 AM

#57

Lol if anyone is still out there looking at this after 3 years::::

This is a retraction, correction, apology in response to my previous post. In my defense I was uneducated and very upset when i wrote it.

Here is what I have learned:

I did in fact use the wrong timing mark. I am (was?) an idiot. the TDC mark should look like a single small RADIAL notch, as in, draw a line from the center of the flywheel to the outside edge. It is positioned closer to the edge of the flywheel than the ignition advance timing mark, which looks like a wide letter H.

Hotcams corrected the decomp pin length problem for me. The original one was way way too short, and barely popped the exhaust valves. Now with a 14:1 JE piston, it kicks over like there is no spark plug in it, its awesome to start. The electric starter had to be replaced because of the previous escapade, but all is well again, and the starter will still fire the bike even with a nearly dead stock battery. Magic Button :)

The piston to valve clearance with my JE piston measured .045" intake and .060" exhaust. I removed the head and checked it with clay to be sure this time! I have found this to be sufficient as I have proceeded to kick the crap out of this engine since my last post. 1200 miles so far!

Performance?
Well with the high comp. piston and the head porting, exhaust, and camshafts this thing smacks the rev limiter like that's its only job. I am very happy with the power, its still stock cc and hasn't lost a drag race yet :banghead: It's almost too much to race enduro's with because it beats the pee out of you, but i just need to grow a set and ride like the tough guy i think i am.

Good luck all!

  • erickdj

Posted March 18, 2009 - 09:28 AM

#58

It's almost too much to race enduro's with because it beats the pee out of you, but i just need to grow a set and ride like the tough guy i think i am.

Good luck all!


I've found out that these bikes do wear you out quite a bit once the performance is boosted beyond their stock power. Mine has all the free/cheap mods, full 06 yz exhaust, and both 06 yz cams. It has beautiful power, quite awesome to feel it pulling like that, but it does give you a good workout to stay on the bike. It's funny that before I added the cams, I would ride the wr over the yz when I wasn't feeling too good, and now the wr kicks my butt too. As good as the wr is though, it's still not quite the wild ride that the yz is.

  • superbad

Posted June 12, 2009 - 12:10 AM

#59

So did anyone figure out what the best cams to use are for the 07 WR450 or if you need to use the intake cam also? I never saw a review of the 07 with the 06 cam setup reviewed. Any imput would be appreciated!

  • rcmx67

Posted October 13, 2010 - 10:03 PM

#60

Too bad this thread moved on. There was a lot of usable stuff here.




 
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