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aj_yz426

yz426 hotcams ex cam only?

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Just bought a very clean '01 yz426, still has original tires, very little boot rub marks, etc. and 100% stock. Only thing the previous owner did was regularly change oil/filter and clean air filter. Never adjusted or checked valves.

I'm in the process of sorting through servicing suspension/seals, brakes, carb (did BK and jamesnow mod), oil, fluids, engine etc. since its been stored for a while.

It starts and runs very well (despite cold weather in Michigan now), but can hear noises from valve train and chain, maybe that's normal? Topend looks OK from what I can see, intake valves are just at the lower limit of spec and ex valves are 0.18mm (spec per manual is 0.20-0.25mm). Since I'm going to be changing shims and will have cams off, I plan to do the "DCM" mod and new cam chain I read about here:thumbsup:

Question is: I can't find a used 03-05 stock yz450 ex cam. I've skimmed the 36 pages on the DCM thread and can't find a definite answer from some one who has done just the hotcams ex cam with the stock in cam. I think it will be OK, anyone know for sure?

Thanks.

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Yes, you can use a Hot Cam on the exhaust side and a stock cam on the intake.

You might want to replace the timing chain while your at it. They are the weak link in the YZF and should be replaced yearly.

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trust me, l had a 2003 YZ450 cam in my 2002 426, then put a hotcams exhaust cam in it, and honestly there is no difference in power...dont bother with hotcams stuff l; reckon for the 426 as its a waste of $$$

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Yeah you won't see any more power from just the exhaust , you have to put the hotcam intake as well for that. But it might change the power spread a little. I just installed a hotcam ex cam in my bike yesterday. I started it and warmed it up and just cruised up and down the street, so I haven't really tested how it runs but having no starting drill is nice. It feels so weird to not have a drill anymore, but it's nice!

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Either the OEM 450 cam or the Hot Cams exhaust will have the effect of widening and flattening the power curve, adding to the low end, and smoothing out the peakiness somewhat. Two years ago, when the OEM cam could be had for $100 new, it was a far better deal, but with prices as they currently are, and with the refinements to the Hot Cams product, the aftermarket part may be a better choice, all around. If nothing else, it drops right in and the timing can be set without any special procedures, and the sprocket is a better fit to the chain.

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The stock exhaust cam new is about $200 here. I picked up a new hotcams on ebay for about $129 (plus I had an 8% off coupon). So the cost and the fact that I don't have to count links and worry about timing marks being off on the stock cam makes it a no brainer.

Thanks for the help.

To be safe I should torque the cam bolts to about 75 in pounds right (not the 86 or whatever in the manual)?

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To be safe I should torque the cam bolts to about 75 in pounds right (not the 86 or whatever in the manual)?

That's my opinion, yes. And, always seat the bearing cap by hand rather than drawing it down with the bolts, and run the torque up in 3-4 increments.

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Either the OEM 450 cam or the Hot Cams exhaust will have the effect of widening and flattening the power curve, adding to the low end, and smoothing out the peakiness somewhat. Two years ago, when the OEM cam could be had for $100 new, it was a far better deal, but with prices as they currently are, and with the refinements to the Hot Cams product, the aftermarket part may be a better choice, all around. If nothing else, it drops right in and the timing can be set without any special procedures, and the sprocket is a better fit to the chain.

Gray,

I have the hotcams exhaust and can't seem to find info as to whether or not there is an advantage to adding the hotcams intake cam into the mix. Any idea?

Thanks

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Supposed to be a minor boost in that. Don't know from personal experience.

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