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ghunter

Looking for a definitive answer about exhaust cam for my '04 WR450

6 posts in this topic

Ok, I've searched this site and several others looking for definitive answers to two questions:

 

1. Is better to change the stock '04 WR450 exhaust cam timing and if so will it impact the e-start? If this is preferable, do I just re-index the cam and check valve clearances again, or is there some crazy WR's-only procedure?

 

2. Is it better to run a stock '04 YZ450 exhaust cam and if so will it impact the e-start? If this is the preference, its just a cam swap and clearance check, right? Or do I need to index this cam according to the number of teeth the WR cam was showing?

 

When I say better, let me explain my riding style and location a bit: I ride (not race) in SoCal deserts, mainly Mojave, from Jawbone to Butterbredt and in Cal City. I'm an older guy, about 205 lbs. with no gear, and have made all the free mods (except changing cam timing), have an aftermarket full exhaust and air filter, suspension tweaked for my style, JD jetting , Quickshot, 46T rear sprocket, and recently rebuilt engine (oil plug wasn't seated completely...what a mess).

 

Anyway, I'm looking for more overall power and could lose a small amount of low-end if the mid and top end power was dramatically improved. I'd prefer an all-over increase, but its really on those long straights where I wish for another gear. I ride with a buddy who has the same bike - we bought them from the showroom on the same day, 1 serial number difference - but his is stock. I'm heavier, and need more power to really pull away in those straights. 

 

I'm sorry for pulling this up from the past, as many folks are now on newer rides, but mine is in perfect condition so I saw no need to replace it. Just feeling the need for more (easy to produce) power but it seems there are no definitive answers to all the forum posts I've read. Many swear the YZ cam is the way to go, but some have e-start issues where some don't.

 

Thanks in advance!

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Regarding your first question, no, you cannot simply retime the original cam. Retarding the cam to "YZ" specs would also retard the decompression event to the point where you have no cranking compression, after which it would not start. The decompression pin can be shortened to correct this, but that's a time consuming task, and a lot of trial and error.

I would recommend either the '03-'05 YZ cam or the '06. Search some of the more recent postings regarding this swap. Most of the details have been ironed out if the process now.

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Having gone through this before on numerous WR's I would just go buy Hotcams and be done with it.

 

Otherwise the bike will never e-start right.

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Having gone through this before on numerous WR's I would just go buy Hotcams and be done with it.

 

Otherwise the bike will never e-start right.

:thumbsup: That's what I did.  Got the YZ cams for the WR.  E-start works great, bike has much more power, very happy with it :ride: 2007 WR450

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