More HC piston questions?


4 replies to this topic
  • NJDirtdog1

Posted January 02, 2010 - 10:46 PM

#1

OK i was just talking to a friend about going through with the 13:5.1 on my 03 yz450. I told him i figure by doing this it will be better for piston to valve clearance since i am running stage 1 hotcams. He seems to think, that by doing so there will be to much compression and i have a good chance of damaging the valves if i dont get stronger ones such as titanium or such. Mind you this is coming from a car mechanics standpoint, but i figured i would ask the masters. I am looking for that beastly low and mid without a bore so i figured this would be the way to go. But is it nescessary to do the valves and put ones with more guts in?

  • 426 NOOB

Posted January 02, 2010 - 10:59 PM

#2

OK i was just talking to a friend about going through with the 13:5.1 on my 03 yz450. I told him i figure by doing this it will be better for piston to valve clearance since i am running stage 1 hotcams. He seems to think, that by doing so there will be to much compression and i have a good chance of damaging the valves if i dont get stronger ones such as titanium or such. Mind you this is coming from a car mechanics standpoint, but i figured i would ask the masters. I am looking for that beastly low and mid without a bore so i figured this would be the way to go. But is it nescessary to do the valves and put ones with more guts in?


if im not mistaken your 03 already has titanium valves. there are people here that run cams and hi comp pistons and have no problems.

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  • grayracer513

Posted January 03, 2010 - 09:50 AM

#3

OK i was just talking to a friend about going through with the 13:5.1 on my 03 yz450. I told him i figure by doing this it will be better for piston to valve clearance since i am running stage 1 hotcams. He seems to think, that by doing so there will be to much compression and i have a good chance of damaging the valves if i dont get stronger ones such as titanium or such. Mind you this is coming from a car mechanics standpoint, but i figured i would ask the masters. I am looking for that beastly low and mid without a bore so i figured this would be the way to go. But is it nescessary to do the valves and put ones with more guts in?

Most aftermarket high performance pistons will have more valve clearance, but your Stage I cams have no more lift than stock, so that's a non-issue. Your bike also already has titanium valves, and high-compression pistons add no more stress to the valve train, anyway. If it needs valve work, it will be independent of whether or not the piston is changed.

  • Wes Woodin

Posted January 04, 2010 - 06:37 PM

#4

I would add stiffer valve springs or new ones.

  • NJDirtdog1

Posted January 07, 2010 - 01:14 PM

#5

I was going to try and change the springs and seals just to do it because im sure it has never been done before but thank you all for the info!





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