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[color=#282828][color=#222222]After riding the bike with the exhaust cam rotated clockwise (12 pins), I couldn’t tear it apart fast enough because it had no low end or mid and the increased RPM's were pretty much useless. After tons of googling and research, I came across a couple pics that clearly show 14 chain pins between the cam dots and also 1 article that explains that the cam dots should not be used but to time them by viewing the cam lobes in relationship to each other and in a parallel line across the head. I also noticed that the Hotcams intake cam/sprocket is adjustable so that made me wonder if the intake cam timing is really what tames down a WR or makes a YZ a "fire breathing monster". [/color]
[color=#222222]So, I put the exhaust cam back to the location it was when I first opened it up and then rotated the intake cam 1 tooth clockwise. I’m at 14 pins and the lobes are parallel as shown in the m.bobbit.home.comcast.net (auto decompression upgrade) illustration and the sprockets appear to be exactly as shown in the YZ pic with the red screwdriver sticking up (random from the internet (allthigsmoto.com). [/color]
[color=#222222]Bike starts, idles and sounds great. Def much improved low end and mid-range but not as peaky as the 12 pin exhaust cam only move. Not so sure if it’s stronger than stock WR timing and now I’m really wondering if the WR and YZ cams are indeed different therefore no combination of timing will truly achieve YZ performance with stock WR cams. I have a stock 02 YZ muffler on the way and will test again with the stock uncorked WR muffler before I move any further. Please check out the pics and chime in with comments or thoughts. thanks,,,[/color]
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- The last pic there with the red screwdriver was a random YZ 426 pic I found on the internet. The top 2 pics are from my bike recently taken. I was just showing other examples of the same timing that does not jive with the rule of rotating the exhaust cam 1 tooth clockwise on a WR for YZ timing threads I've been reading everywhere. The bike basicaly ran like a turd at 12 pins and the exhaust cam 1 tooth clockwise so I did more research and came across that "450 auto decompression upgrade" article that clearly shows 14 pins and the intake cam clockwise 1 tooth and the exhaust cam where mine was when I first broke into the engine. It made me question if the intake cam should be moved and not the exhaust to make a WR run like a YZ. I've never ridden a YZ 426 but I got my ass kicked and headlight busted by a little kid on 1 when I was riding my 01 Husqvarna TE 610 so I know they rip. I’m really thinking the 2002 YZ and WR cams are not the same and simply rotating the WR cams does not achieve true YZ cam timing based on all of the combinations I've tried on my WR.[color=#282828] [/color]
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[color=#282828][color=#222222]I've decided that the WR's flywheel weight, wider ratio gearing and 20 or so extra pounds is 2 much for the YZ cam timing mod to overcome. The original 1 tooth (exhaust) clockwise method may very well be correct but the flywheel weight, bike weight and gearing is why it just didn’t hit as hard as a YZ? I put a lot of time into these post including pics, spell check, grammar not to mention a ton of prior/old post searching to have little to no interest from other members so I'll simply put it back to stock WR timing and go riding...[/color][/color][size=2]
[color=#282828]I guess I can't help myself.
My used eBay YZ muffler (stock) with a drd spark arrestor cap showed up so before I pulled the valve cover back off to put the cams back to WR stock, I threw the pipe on and took it for a quick spin. Needless to say, I am pretty sure that I'm onto the YZ cam timing because it is now explosive and crazy fast. Incredible throttle response and there may be slightly less low end now but you would never know because the mid comes on so fast and strong that its hard to determine if there's less grunt now. Only rode about 10 min without being geared up but hands down, 14 pins and the orientation like the above pics is what I was seeking all along. The stock uncorked WR muffler was the problem and explains why nothing I did before made much of a difference until now...
Edited by un chained, 21 May 2012 - 10:56 PM.[/size][/color][/color][size=2]
[color=#282828]After about 40 miles today, it has been confirmed. 14 pins, intake cam rotated clockwise, exhaust cam WR stock and it rips. I'm now convinced that all the other stuff about rotating the exhaust cam is garbage. Leave the exhaust cam alone, move the intake cam clockwise 1 tooth and hang on... [/color][size=2]