Decompression removal

[mrcribbs]

So I've read here, there, and every where differing opinions on removing the stock decompressor from the cam on the 400EX's.

I'm in the middle of installing a CRF timing chain and thought about doing this. (This was very popular with the XR400 guys back in the day)

I've read where guys post that their 400EX wouldn't start after removing this - not sure I understand why. All the threads I have read end abruptly with no further discussion.

I'm assuming all will be fine if removed, correct?

[jman7290]

Not sure about removing the mechanism from the cam, but if you remove the plunger and the spring from the head without welding the hole shut, I have heard that it will not start using the stock cam. I do know that you will be fine using an aftermarket cam.

[mrcribbs]

From what I understand the "hole" in the head is just an oil passage.

I cannot think of any reason why it wouldn't start with a stock cam with the decompression items removed.

[storms400ex]

i removed mine like 3 yrs ago and mine runs great!!!!

[NacsMXer]

Originally posted by mrcribbs
From what I understand the "hole" in the head is just an oil passage.

I cannot think of any reason why it wouldn't start with a stock cam with the decompression items removed.

It should start, just make sure to remove the plunger and spring from the head. I removed the decomp mechanism from my Honda HRC cam and it runs great.

After removing it, I took the cam to a local welder and had the oil passage holes TIG welded shut. I also had him put a tack on each of the locator pins to make sure they wouldn't fall out over time and heat cycles. The oil passages are where the decomp used to sit, so if you don't weld them shut the oil will follow the path of least resistance and leak out of the holes before it gets to the rest of the oiling holes on the lobes of the cam.

http://img545.imageshack.us/img545/9154/dsc0670o.jpg (http://imageshack.us/photo/my-images/545/dsc0670o.jpg/)

http://img842.imageshack.us/img842/2720/dsc0671l.jpg (http://imageshack.us/photo/my-images/842/dsc0671l.jpg/)

[mrcribbs]

Excellent info! Thanks!