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gildnernorth101

auto decompression cam for 426

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looking for a little input on a decompression cam for a 426 . How does it work? Is it worth the money? Does it make starting that much easier?

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After riding a 426 for a couple of years, I never really felt the need for it. My 426 started first kick every time. I guess auto decomp would have made it more of a no-brainer affair but if it ain't broke don't fix it. So I didn't.

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stop thinking and do it. I did it on my 250f and am going to do it on my 426. ALthough both bikes start first kick or two.. then cam just makes it easier. It will not affect the amount of kickes needed...just make them very easy. I hought about it for my 250 for monthes and wish i didnt. Once you have it the old way will feel like something from the stone age. there is a sticky for this if you want some more info

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It is the single best mod you can do to the bike. The benefit is much more than just ease of starting. If you stall the bike with the brakes coming hard into a corner it most likely will fire right back up under compression...without the auto-decomp cam you will just come to a screeching halt. Also, the new cam will increase the low and mid-range power.

When starting the bike with the new cam you just kick it...no dinking around going to TDC then pulling in the release lever, moving the kickstarter a bit, letting it back up, and then kicking. Just kick. You can start it with flip-flops.

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Here is the thread form this forum. I did the 450 DCM in 2003 and I don't regret doing it at all. This is a bit if reading but it is worth the time.

http://www.thumpertalk.com/forum/showthread.php?p=3706078#post3706078

Also, more on the 450 DCM

http://www.thumpertalk.com/forum/showthread.php?t=60381

Bill

In particular, read the last two pages of the thread in the second link.

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Is this mod hard to install and what is the approx. price? and what happens to the decompression lever. does it stay on the bike or can you remove it?

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After riding a 426 for a couple of years, I never really felt the need for it. My 426 started first kick every time. I guess auto decomp would have made it more of a no-brainer affair but if it ain't broke don't fix it. So I didn't.

:applause:

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You need to remove the decomp lever.

You will then need to plug the hole that the arm goes into on the cylinder. I bought a billet plug from the TT store and love it. DO not, whatever you do, buy the plastic yamaha plug from the 450 as they are prone to falling out.

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i just installed the hotcams auto decomp cam on my bike, its very easy...straight swap, just make sure you get the timing marks lined up right and that you check clearances after becuase you will have to reshim.

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You need to remove the decomp lever.

You will then need to plug the hole that the arm goes into on the cylinder. I bought a billet plug from the TT store and love it. DO not, whatever you do, buy the plastic yamaha plug from the 450 as they are prone to falling out.

In fact, you can leave both the manual lever and the shaft in the head on the bike if you like, although there's no reason to. You can also just remove the lever and cable, and leave the shaft in the head to plug up the hole. If you do that, be sure the coiled return spring is back in place on the shaft.

Another option is to use a steel or brass 18mm cup plug in place of the shaft and seal.

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Worth the cash.:applause: I put the Hot Cams intake and exhaust cam on my bike. Can't tell you anything about the install. My mechanic buddy installed it for me while he was living with me.

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Today was my first ride on my 01 since I did the cam mod. It is great not thinking about the decomp lever. It does seem to hit the rev limiter a little quicker than before, but not a huge difference in power for me.

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This may be a stupid question so pardon my ignorance but what is the difference between a hotcam and the oem 450 cam? I presume they both give you auto de-compress? This is all very interesting because i just bought a '02 426 and as such am still getting the feel for 1/8th off t.d.c. Nothing like getting half way through a kick start and being stopped half way ending with a bruised foot.

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The O.E.M. cam's sprocket has a slightly different pitch and the cam chain appears to ride bit high on the sprocket. The lobes of the 450 O.E.M. cam are thinner, also. The Hot Cams item is specifically made with a matched drive sprocket and cam lobe width. I used an O.E.M. cam in 2003 and I am completely happy with mine. The Hot Cams guys and gurls seem happy too. Your choice.

Bill

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Another point is that the OEM 450 cam was made for a head that is physically different than the 426 head in so far as height, valve angles, etc. The OEM 450 timing marks do not line up with the 426 head correctly when the cam is actuall y timed right, and it requires a special timing procedure because of that. This is laid out in the instruction, and is neither complicated or difficult, but it is different.

The Hot Cams product was made and marked for a 426, and so can be installed "by the book", in an ordinary manner.

If it were me, I'd use the OEM cam, and I'd buy it from TT OEM.

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