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underground-mpyre

Let's talk about Pro's & Con's of Hotcams.

25 posts in this topic

So after finding out that Wr450 exhaust cams(and other hot cams ) have a auto-decomp lever that will fit into a 400/426f, I have decided to go that route rather than fighting with the decomp mechanism on my 426.I just want to kick and go, but it isn't that simple with the 400/426f. Especially in the woods. I have worn myself out to get the timing just right in soggy mud for it to start. 

So, most of you already know that this is my first dirty and thumper and would like to be able to really enjoy this bike. So if I go with the exhaust upgrade cam, might as well do the intake too, is there a down side to this swap? Pro's& Con's of riding it with Hotcams on these thumpers?

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I am speaking from experience on diesels and performance gas engines...

But in my experience a "Hot Cam" gives up low end power in favor of higher top end power.

It can pay off for some people and their riding style though if they tend to hang in the mid-upper RPM band.

It might not work so well for people who idle around, hit lots of technical sections, ride in loose terrain where wheel spin is a fun sucker.

This is all me talking out of my ass as I work on big rigs all day. I have built performance engines (AMC, VW, Cummins,etc) but haven't messed with a bike yet.

2014 WRR R.I.Pieces

2012 WR450F ECU, GYTR tuner, Q4, MSR rad guards , Cycra Pros, and a growing wish list...

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I am speaking from experience on diesels and performance gas engines...

But in my experience a "Hot Cam" gives up low end power in favor of higher top end power.

It can pay off for some people and their riding style though if they tend to hang in the mid-upper RPM band.

It might not work so well for people who idle around, hit lots of technical sections, ride in loose terrain where wheel spin is a fun sucker.

This is all me talking out of my ass as I work on big rigs all day. I have built performance engines (AMC, VW, Cummins,etc) but haven't messed with a bike yet.

2014 WRR R.I.Pieces

2012 WR450F ECU, GYTR tuner, Q4, MSR rad guards , Cycra Pros, and a growing wish list...

 

This is exactly what I have experience personally (wr450) and seen (CRF450X)

It seems that HotCams cam profile and timing (Stage two specifically) is designed to give you increased power, and lots more acceleration, as they push the power increase into a much smaller rpm range. There is a very noticable 'hit' in the power, and a reduction of the low end across the board.

 

Hotcams makes 

Stage one ( a 'torque' cam): pushes all the power down to 2000-6000 rpm

Stage two (a 'race' cam) slightly less power from 2000-5000, and much more from 5000-8000

Stage three ( a race cam for high compression and port work motor) 5000-100000 

 

They don't seem to make a 'more power' cam, that widens the entire power band.

 

I would stick with changing to the wr450 exahaust cam only, and not the intake, as from what I have read the 400/426 intake cam is actually more agressive than the 450 cam

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This is exactly what I have experience personally (wr450) and seen (CRF450X)

It seems that HotCams cam profile and timing (Stage two specifically) is designed to give you increased power, and lots more acceleration, as they push the power increase into a much smaller rpm range. There is a very noticable 'hit' in the power, and a reduction of the low end across the board.

Hotcams makes

Stage one ( a 'torque' cam): pushes all the power down to 2000-6000 rpm

Stage two (a 'race' cam) slightly less power from 2000-5000, and much more from 5000-8000

Stage three ( a race cam for high compression and port work motor) 5000-100000

They don't seem to make a 'more power' cam, that widens the entire power band.

I would stick with changing to the wr450 exahaust cam only, and not the intake, as from what I have read the 400/426 intake cam is actually more agressive than the 450 cam

Hey Kah, what do you think about higher lift cams with a similar duration to stock? Would the valves be kissing pistons if it was any higher than stock specs?

2014 WRR R.I.Pieces

2012 WR450F ECU, GYTR tuner, Q4, MSR rad guards , Cycra Pros, and a growing wish list...

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Hey Kah, what do you think about higher lift cams with a similar duration to stock? Would the valves be kissing pistons if it was any higher than stock specs?

2014 WRR R.I.Pieces

2012 WR450F ECU, GYTR tuner, Q4, MSR rad guards , Cycra Pros, and a growing wish list...

 

Don't know.

Remember too that the WR head is really restrictive. The center valve port is no bigger than the diameter of a sharpie pen....that's why mine is ported to the moon, and all three ports are WIDE OPEN.

It's pretty good with the HC S2 cam, but my 450X with porting and the R cam blows it away in all respects power wise. Much much wider power band.

 

1236716_10200681478659586_640779056_n_zp551144_10200681474459481_1787908149_n_zp

 

All I know is, my 450 X STOCK cam has more lift and duration in the profile than the WR hotcams stage two cam

The '02 450R cam in my X is insane. Someone needs to make something like that for the YZ and WR motors....!

Edited by Kah Ran Nee

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I am in the process of removing the manual decomp cam in my WR426.  I am just waiting on the parts from the TT store, specifically the HotCams exhaust cam for the 426.  This is what I read here on TT:

  • HotCams makes an exhaust cam with auto-decomp, that offers no performance gain over the stock cam.  This cam has the correct gear pitch for the 426 timing chain, keeping things from wearing out. http://www.hotcamsinc.com/ProductInfo.aspx?item_id=566
  • The OEM exhaust cam from a 2003 WR450 provides more low end than the 426 cam (either OEM or HotCams) and is autodecompression.  The downside of this cam is that the gear pitch is different, increasing wear on the cam gears and the timing chain.
  • You cannot go between WR and YZ timing with the auto-decomp cam.  Pick the cam for the timing and leave it there.

I asked a few days back if anyone had issues with durability of the OEM WR450 cam/chain due to the gear pitch difference, but there was no response.  I went with the HotCams just to be safe, although I wouldn't have complained about more low end grunt.  

 

One thing I JUST realized is that the exhaust cam part number is the same for both the WR and YZ426.  I just read an old TT posting and the timing of the HotCams is neither WR or YZ, it is their own timing.  I might guess it is inbetween?

Edited by Pooley

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Remember too that the WR head is really restrictive.
 

 

The fuel injected (2012+ ) heads supposedly have larger ports.  The cams in these engines are lower lift than previous engines.

 

I bought a set of 2008 YZ cams for cheap.   I'll report how they work when I install them.   I'm trying to change one thing at a time, so it might take a bit until its their turn.   My WR isn't exactly hurting for power, there are higher priorities right now.  I'm hoping that I can tune out most of the low end loss with changes to the FI map.  I'm also hoping for a little less engine braking.   It would be nice to be able to hold 3rd gear higher on steep hill climbs and hold 2nd gear forever, not have to downshift. 

 

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One thing I JUST realized is that the exhaust cam part number is the same for both the WR and YZ426.  I just read an old TT posting and the timing of the HotCams is neither WR or YZ, it is their own timing.  I might guess it is inbetween?

 

 

Ya, I have been looking on a few sites and seems the exhaust cam is the same for the WR and YZ.

 

But if maybe hot cam on the exhaust side might not show any difference if I leave the intake cam stock(way in if I am wrong). I really just need the decomp gear on the exhaust cam.

Edited by underground-mpyre

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Are all Hotcams from the same company or should I use discreation when looking for a perticular brand?

 

I am kinda worried what Pooley said about the stock Wr450 cams have a different pitch and might want to go with a Hotcam made for the 426f, thoughts?

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I have had (3) quality control issues with Hotcams, and Ken had (1), all with YZ spec hotcams set for 2007-2011 WR450

 

I would not use them again.

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I have had (3) quality control issues with Hotcams, and Ken had (1), all with YZ spec hotcams set for 2007-2011 WR450

I would not use them again.

I've had one also. Decompression pin was not long enough.

However they are dirt cheap for a new cam.

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So I am at a loss then? I would really like to have a decomp exhaust cam for the quick kick start. Supposedly Pooley has brought up the gear pitch on the Wr450 cam isn't the same for the 400/426f and the Decomp pin wasn't long enough and quality issues with the Hotcams. Where am I at on this, I dunno.

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Hot cams should be able to provide the right cam with the right decompression pin. I just had to return it once.

Measure the pin and email them before you put it in. Might save some time.

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Okay the pin you see is the decompression pin. You can even measure it with a metric ruler if you wish. The measurement shown is for a 07-11 WR450.

 

cam_zpseccc0663.png

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This picture is a stock pin height and a Hot cam that is not high enough. So you can likely just look at the pin and see.

cam2_zpscddfbc8e.png

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Oh wow, that is a difference! I assume I need it to be the length of the bottom one.

 

Timing is the same for the Wr and Hotcam? Drop in the Hotcam and line up the timing dots and go, right(after I shim it up)?

 

I appreciate yours and everyones help with these.

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