Hot Cam and Decompression Cam?


10 replies to this topic
  • mountain-powder-slut

Posted January 14, 2011 - 11:12 PM

#1

I just got a 2001 426 WR. It came with Hot Cams. My friend has had a 426 and now has a 450. He recommends putting a decompression cam on it. Can I put one on already having Hot Cams on it? Thanks

  • Birdy426

Posted January 15, 2011 - 10:20 AM

#2

First, do you have hot cams intake and exhaust cams, just the intake, or just the exhaust? Depending on what hot cams exhaust camshaft you have, you may already have the auto-decompression feature your friend recommends. Hot cams originally made a non-autodecomp cam for the 426, but very quickly came out with an auto-decomp cam. Do you have to use the compression release and go thru "the drill" to start your bike, or do you just kick away? If you just kick away, you already have the autodecompresion feature. The grind on the 03/04 450 exhaust cam is very similar to te ho cams 426 cam, so you won't see a performance increase between the two (or even between either of those and a stock 426 cam that's "YZ Timed"), so if you already have auto decompression, there's no point in spending any coin on a "decomression" cam shaft. If you don't already have the auto decompression feature, it is without a doubt the best mod you can do to your 426. Shop around and pick up whichever cam shaft you can get the best price on (lately, that's been the hot cams unit). If you go OEM, you should consider if you want the YZ or WR cam timing (as with the auto-decomp mechanism, you can't switch cam timing or the auto-decomp feature won't work). YZ timing gives you a bit less down low (not much) a bigger hit inthe mid, and a bit more overrev on top.

  • Col Psoas

Posted January 15, 2011 - 06:08 PM

#3

First, do you have hot cams intake and exhaust cams, just the intake, or just the exhaust? Depending on what hot cams exhaust camshaft you have, you may already have the auto-decompression feature your friend recommends. Hot cams originally made a non-autodecomp cam for the 426, but very quickly came out with an auto-decomp cam. Do you have to use the compression release and go thru "the drill" to start your bike, or do you just kick away? If you just kick away, you already have the autodecompresion feature. The grind on the 03/04 450 exhaust cam is very similar to te ho cams 426 cam, so you won't see a performance increase between the two (or even between either of those and a stock 426 cam that's "YZ Timed"), so if you already have auto decompression, there's no point in spending any coin on a "decomression" cam shaft. If you don't already have the auto decompression feature, it is without a doubt the best mod you can do to your 426. Shop around and pick up whichever cam shaft you can get the best price on (lately, that's been the hot cams unit). If you go OEM, you should consider if you want the YZ or WR cam timing (as with the auto-decomp mechanism, you can't switch cam timing or the auto-decomp feature won't work). YZ timing gives you a bit less down low (not much) a bigger hit inthe mid, and a bit more overrev on top.


+1:thumbsup: I don't think there's anything life to add :smirk:

  • mountain-powder-slut

Posted January 15, 2011 - 07:24 PM

#4

First, do you have hot cams intake and exhaust cams, just the intake, or just the exhaust? Depending on what hot cams exhaust camshaft you have, you may already have the auto-decompression feature your friend recommends. Hot cams originally made a non-autodecomp cam for the 426, but very quickly came out with an auto-decomp cam. Do you have to use the compression release and go thru "the drill" to start your bike, or do you just kick away? If you just kick away, you already have the autodecompresion feature. The grind on the 03/04 450 exhaust cam is very similar to te ho cams 426 cam, so you won't see a performance increase between the two (or even between either of those and a stock 426 cam that's "YZ Timed"), so if you already have auto decompression, there's no point in spending any coin on a "decomression" cam shaft. If you don't already have the auto decompression feature, it is without a doubt the best mod you can do to your 426. Shop around and pick up whichever cam shaft you can get the best price on (lately, that's been the hot cams unit). If you go OEM, you should consider if you want the YZ or WR cam timing (as with the auto-decomp mechanism, you can't switch cam timing or the auto-decomp feature won't work). YZ timing gives you a bit less down low (not much) a bigger hit inthe mid, and a bit more overrev on top.


Yes I have to go through the drill and use the compression release to start the bike. I am not sure if I have the intake or exhaust hot cams or both. I will yank out the box...I think he gave that to me.

+1:thumbsup: I don't think there's anything life to add :smirk:


Ya no doubt! Thanks Birdy! B)

  • mountain-powder-slut

Posted January 15, 2011 - 07:55 PM

#5

It is an exhaust cam. YZ426S1-AE and there is also a number 4001-1E....if those mean anything to ya.

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  • Birdy426

Posted January 15, 2011 - 08:16 PM

#6

neither number hits on the hot cams website, so they must be old and no longer available.

As I said in the previous post, the auto-decomp cam is by far the best mod you will ever do to the 426. Not only is starting easier, flame-outs are eliminated. Swapping to the 4035-1E hot cam or the OEM 03-05 YZ426 exhaust cam will not change your power perceptibly, but will certainly increase the fun factor. Adding the intake cam will make a huge difference.

Apex racing sells intake and exhaust hot cams for 250 a set on e-bay ( http://cgi.ebay.com/...sQ5fAccessories ), or the exhaust only for about 130.00 ( http://cgi.ebay.com/...sQ5fAccessories ). Probably the best prices you will find, and their service is top notch. For reference, the OEM camshaft is about 220 bucks from several on line parts houses.

  • mountain-powder-slut

Posted January 15, 2011 - 11:32 PM

#7

neither number hits on the hot cams website, so they must be old and no longer available.

As I said in the previous post, the auto-decomp cam is by far the best mod you will ever do to the 426. Not only is starting easier, flame-outs are eliminated. Swapping to the 4035-1E hot cam or the OEM 03-05 YZ426 exhaust cam will not change your power perceptibly, but will certainly increase the fun factor. Adding the intake cam will make a huge difference.

Apex racing sells intake and exhaust hot cams for 250 a set on e-bay ( http://cgi.ebay.com/...sQ5fAccessories ), or the exhaust only for about 130.00 ( http://cgi.ebay.com/...sQ5fAccessories ). Probably the best prices you will find, and their service is top notch. For reference, the OEM camshaft is about 220 bucks from several on line parts houses.


Ya my buddy says the auto decomp cam is the best mod as well. Thanks for the ebay link! What does the intake cam do? I am not sure I want to lose any on the low end. I like the tight steep gnarly trails...so I should probably go with the WR timing right? I appreciate your help a LOT Birdy! :smirk:

  • Birdy426

Posted January 16, 2011 - 12:31 AM

#8

The hot cams intake cam changes the powerband a bunch...a big hit at the mid range, and the bike revs so much quicker past that...not great for woods and gnarly hills, but lots of fun here in the so cal desert!

The hot cams exhaust cam grind for both the YZ-F and WR-F is very similar to the stock YZ-F timing and profile. As you already have a hot cams cam (without auto-decomp), you have that grind already, so if you like the power characteristics that you have now, stick with hot cams auto-decomp exhaust cam (P/N 4035-1E) or the 03-05 OEM YZ450 cam. If you want less hit and a much more linear powerband, then go with the 03-05 OEM WR450 cam.

  • Shred Jesse

Posted January 16, 2011 - 05:16 PM

#9

Quick question for you all, along this topic:


I've got a 99 wr400. I'm pretty happy with my bike, although a smidge more power would be nice. I don't want a ton more though, as it can be a bit much in the thick woods already. I just would like a bit more power on wheelie capability in third!

I'm already considering going to a 13.5:1 piston soon just to make sure the engine is extra fresh. I would like the auto-decompression stuff on my bike, but not entirely certain I want to go advance the timing to get YZ spec. Can I get a hotcam with the decomprses for my bike, and leave the timing retarded (WR spec)? Will I notice any difference minus the fact I won't have a kicking routine anymore?

  • Birdy426

Posted January 16, 2011 - 09:56 PM

#10

No...hot cams has only one grind, and it's very close to the YZ spec. If you want to maintain the WR power characteristics, go for the 03-05 WR450 cam from Yamaha. A bit more pricey these days, but it sounds like what you want. With the WR spec cam, no, you won't notice any difference other than starting and no flame outs...

  • mountain-powder-slut

Posted January 16, 2011 - 11:34 PM

#11

The hot cams intake cam changes the powerband a bunch...a big hit at the mid range, and the bike revs so much quicker past that...not great for woods and gnarly hills, but lots of fun here in the so cal desert!

The hot cams exhaust cam grind for both the YZ-F and WR-F is very similar to the stock YZ-F timing and profile. As you already have a hot cams cam (without auto-decomp), you have that grind already, so if you like the power characteristics that you have now, stick with hot cams auto-decomp exhaust cam (P/N 4035-1E) or the 03-05 OEM YZ450 cam. If you want less hit and a much more linear powerband, then go with the 03-05 OEM WR450 cam.


Well I haven't ridden the bike a whole lot yet (just up and down the road) since Idaho winters make it a little tough. I can't wait though. I guess maybe I will wait to ride it in the spring and see what I want to do. Thanks Birdy...you have been a tremendous help! :smirk:




 
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