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CMaD

YZ cam or Hot cams?

25 posts in this topic

I am wanting to get more power out of my 03 WR450 street tard. Is it better to go with the YZ exhaust cam or get Hot cams intake and exhaust. Does the YZ exhaust cam make a good difference in power? and what about the Hot cams? I have the grey wire mod, throttle stop, air box snorkle and stock muffler mods done.

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I'd go with the YZ cam. It's cheaper and the e-start will still work.

The YZ cam makes a big difference.

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I'd go with the YZ cam. It's cheaper and the e-start will still work.

The YZ cam makes a big difference.

Thinks thats what I'm going to go with. Where can I get one for good price?

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I'd go with the YZ cam. To be honest, the most significant power gain you will see is from the exhaust. I have an '04 WR450, and the single biggest gain in performance was definitely the exhaust. Either a stock YZ can or aftermarket will do the trick.

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I have read here in TT that some people had problems with the e-start despite putting the YZ cam. Others say that the e-start worked just fine.

I am thinking of putting a YZ cam too and i don't know what is really happening.:ride:

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I'll throw in my $ .02..... go with the Hotcams, they cost more but they have the de-comp pin in the right location for the WR's e-starting.

I put the OEM YZ cams in my 07' and could not get the e-start to work very well at all, it would kick start just fine. I asked around and the common answer was the YZ ex cam had the decomp pin advanced vs. the WR, the result was an excessive, or early dump of compression that prevented the WR from e-starting. The e-start apparently revolves the motor much slower than kick starting and therefor requires a certain amount of compression to start... to little compression and it will not want to start with the button.

This is my own horror story, I have heard from many poeople here, like beezer, that are happy with the OEM cams... remember, just my $.02:excuseme:

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I'll throw in my $ .02..... go with the Hotcams, they cost more but they have the de-comp pin in the right location for the WR's e-starting.

I put the OEM YZ cams in my 07' and could not get the e-start to work very well at all, it would kick start just fine. I asked around and the common answer was the YZ ex cam had the decomp pin advanced vs. the WR, the result was an excessive, or early dump of compression that prevented the WR from e-starting. The e-start apparently revolves the motor much slower than kick starting and therefor requires a certain amount of compression to start... to little compression and it will not want to start with the button.

This is my own horror story, I have heard from many poeople here, like beezer, that are happy with the OEM cams... remember, just my $.02:excuseme:

In regards to the hot cams , do you think it is necessary to change both cams? Or could I get away with just changing out the exhaust cam?

I’m not greedy… I only want YZ level power:thumbsup: , so maybe this bad info but I thought it was only the WR exhaust cam that is not to YZ spec.…. thus big gain can be had with only the exhaust cam replacement.

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In regards to the hot cams , do you think it is necessary to change both cams? Or could I get away with just changing out the exhaust cam?

I’m not greedy… I only want YZ level power:thumbsup: , so maybe this bad info but I thought it was only the WR exhaust cam that is not to YZ spec.…. thus big gain can be had with only the exhaust cam replacement.

Hotcams has a pretty good tech support / info dept. Ask them about it but keep in mind they are in the business of selling cams.

The earlier WR's and YZ's had the same intake cam so they were only changing the exhaust cams. The 07' and newer WR and 06' and newer YZ's have different intake cams as well... I replaced both intake and ex. with 06' YZ OEM cams. I have to admit that the performance gains were more than noticeable, it really woke the motor up. I spoke with a trusted motor builder here in WA about my e-starting issues and he also rides and races an 07' WR. He told me that the ticket is to just install the YZ intake cam and a higher compression piston and that the exhaust cam really has no effect on the newer model WR's :ride:

I made a decision to go back to the WR cams but in the process I thought I would try the setup he described less the hi-comp piston... something was not right, the cam chain kept trying to jump teeth with the YZ intake and WR ex. cam installed ;) It could have been a botched up install but I don't really see how that could happen...

You should get information from a more knowlegable source than I. Greyracer or William 1 might be able to chime in here and shed some light on the mix/matching of WR and YZ cams.

Good luck and I have a set of 06' YZ cams, with just 3 hours on them sitting in my shop... for sale in the TT classifieds section :p

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the e cams and yzf cams have slightly different de-comp pins. It does effect the starting if you switch them around.

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The 07' and newer WR and 06' and newer YZ's have different intake cams as well...

I checked and the 08 WR and the 08 YZ have the same intake cams.

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Recently sold my '03 motard. Ran amazing with the YZ cams. Cheaper, and it ran better than a 450 I rode with the Hotcams. Never had any trouble with the e start.

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2008 YZ450

Intake cam 2S2-12170-00-00

Exhaust cam 2S2-12180-00-00

2008 WR 450

Intake cam 5TJ-12170-00-00

Exhaust cam 5TJ-12180-30-00

They are different. I have an 07WR with 06YZ cams in it, when I changed them I didn't measure anything but there was deffinitely a big difference, you could actually see visually that they were different. The bike makes more power now, noticeable but not huge. My bike also has 07 YZ exhaust, JD jetting , and all of the usual WR free mods.

I would say it is a little bit more reluctant to start with the E-start now but it does still start. When I kick it starts very easily. (which makes me wonder why I have E-start, which makes me wonder why I have a WR)

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On my 06 WR with YZ exhaust cam it does make a big difference in power and it does take more revolutions to start with E-Start. However I always use E-Start even at 9000 ft with no problem. The blue/white wire mod helps and 50% of the time it starts like a KTM (instantly). I have a 72 starter jet instead of a 65 (stock) and that helps.

The YZ exhaust cam has the same lift as the WR cam. Hot cams have a more radical cam which has higher lift than Yamaha cams so Hot cams would seem to wear the valves and springs faster......just food for thought.

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The YZ exhaust cam has the same lift as the WR cam. Hot cams have a more radical cam which has higher lift than Yamaha cams so Hot cams would seem to wear the valves and springs faster......just food for thought.

OK, so that means the YZ cam has more duration than the WR?

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OK, so that means the YZ cam has more duration than the WR?

no the timing is just advanaced .

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no the timing is just advanaced .

Thanks, but do you know if that's done from the mapping, rotated CDI, or the gear index on the cam?

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Thanks, but do you know if that's done from the mapping, rotated CDI, or the gear index on the cam?

The cog on the cam is pressed on the shaft with the lobes advanced a bit. Both cams are made from the same cog and shaft.

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On my 06 WR with YZ exhaust cam it does make a big difference in power and it does take more revolutions to start with E-Start. However I always use E-Start even at 9000 ft with no problem. The blue/white wire mod helps and 50% of the time it starts like a KTM (instantly). I have a 72 starter jet instead of a 65 (stock) and that helps.

The YZ exhaust cam has the same lift as the WR cam. Hot cams have a more radical cam which has higher lift than Yamaha cams so Hot cams would seem to wear the valves and springs faster......just food for thought.

That's interesting. What is the blue/white wire mod? Haven't heard of it before.

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That's interesting. What is the blue/white wire mod? Haven't heard of it before.

You can clip this wire and it apparently disables the input from the start button to the CDI... or so I have read. Anyway the CDI now thinks your kicking and allows the bike to fire instantly, versus the programmed 2-3 dead revolution when e-starting.

There seems to be no ill effect to this mod at all, I did it about 6 months ago and it works! If you are jetted correctly the bike will fire instantaneously:thumbsup:

On my 07' it's in the same 6 pin connector as the grey wire. For your 06' do a search, it's probably in the performance mods index, if it's not, it should be... it's one of the best free mods I think:thumbsup:

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