<div class="FTQUOTE"><begin quote>Originally posted by: ctateusa1

right it will change it but not enough to necessitate any change at all with the chain.



cam timing will always be set at the same spot (as long as you set it up right)</end quote></div>

The only time I could see a real change would be with dual cams, because it would be harder to get them in time. but since you shave the head equal all the way across it shouldnt matter much at all.

 

<div class="FTQUOTE"><begin quote>right it will change it but not enough to necessitate any change at all with the chain. </end quote></div>
On one of our race engines it changed the cam 8 degrees. I don't know what you consider "enough to necessitate and change" but 8 degrees is a lot!!! But then again we took .125 off the head to make that much of a change. Try to put a head back on a block that has been shaved and see if cam lines up on the factory marks. Believe me it won't.

<div class="FTQUOTE"><begin quote>cam timing will always be set at the same spot (as long as you set it up right) </end quote></div>
Again, this is not correct. Chain or belt tensioners will do nothing to correct the degree problem. The tensioner will only tighten one side; the non tension side.

The way to look at it is like this. A chain or belt has a certian pitch. If you change the distance between the head and block that distance will be shorter but the pitch will be the same distance. The distance on the slack side will be taken up on by the tensionsers. The tension side will be shorter but the chain or belt pitch will be the same which rotates the cam many degrees out of factory spec.

The above is very hard to visulize and even harder to write so a person can see what is going on. It took me a long time to see what was happening.

ctateusa1 the best way to do this is take an old engine and play. That was the only way I could see what was up.

 

I have to say that i agree 100% with turbo doctor.

 

Yhea but on the 4strokes it would be tough to take that much off of a head and not have problems with the piston contacting the valves.

And he did not say anything about shaving the block as well.

I know that the tensioners will not correct valve timing.

I can see that taking that much off would change the valve timing considerably.

 

I've always shaved my head myself, sometimes I ask the wife to check if I missed any hair...oh nvm.

 

yep... thats all i got to say. i'd not waste my time shaving the head. i'd just do the common up grades exhaust, jets, filter, clutch ect.. as far as your exhaust question you would be better off just getting the after market than taking out the spark arrester. taking it out of the stalk muffler really doesn't do crap (little gain in power) but make it loud and annoying. and when you blow your motor or put after market parts on the inside then consider messing with your head. but over all the amount of gain of amount of work/problems that can come up after the fact isn't worth it.