I am new here but i find this forum very interesting so i thought i would post a question here.
So here we go i rebuilt the head on my 400 ex as i was putting the top end together i realized the compression pin that rests under the end of the can was missing. my question is how or will this mess up my motor runnig.. A couple machanics have said it wouldn't make a diffrence but im not so sure . any ideas or feedback would be greatly appriciated .. ty in advance..

 

If you have a stock cam it wont start with out it.

 

Yeah thank you for your reply this is what i thought to. As i have been serching the net and stumbled across a vidoe explaining this issue and have also found a couple fixes . in the video it says you can buy a hot cam and it completly disables it. As i am a machanic i decided to disasimble the cam to remove it
It was relitivaly easy to press the cam off the timing gear ears and everything slid right off. Now it looks exacly like the hot cam that is the recomended way of getting around this issue. The only difrence is a pin sticking out of the can shaft it's self about a 1/8th inch and a oilport hole. The pin isn't hitting anything as i manually spin it. I believe if i tap a plug in the oilport that is exposed to alow oil to run right on past it it should work correctaly. Thank you again for responding to this post i will get it finished putting together tomarow and if it runs without any problems i will update this post..