jmics19067
LIFETIME SPONSOR
- Jan 22, 2002
- 2,097
- 0
1st a praise about your book,probably the best performance to dollar value I have seen.The knowledge is in depth and yet easy to read for a shade tree guy like myself. I have built 2 94 yz/wr 250 engines for myself out of this book and am very pleased with what I have learned and the performance I have made.
The basics of the engines are 1 for bottom end power and one for top end.
the cylinder for the bottom end I filled in the rear transfer ports to get rid of the hook,filed the power valve sub exhaust port channels,and lowered the cylinder with base gasket thickness to achieve a .040 squish with the stock head. detonation is not a problem since I use good fuel but my question is, will doing the head mods achieve any benefit in helping softening things up a bit with losing too much power?
Also , the top end engine , the sub exhaust ports raised,the exhaust spigot rounded, and the powervalve matched and blended into the exhaust port when in the open position. Assembled with stock gaskets with a squish of .055+ stock head. It is time for a complete rebuild so I am finally going to get the head mods for atleast this engine.While trying to find a way to tinker with something new I found/figured out that earlier connecting rods are 5mm longer so I am thinking of making a long rod engine.With a 3/16" spacer plate and assorted gaskets I can achieve "stock" intake port timing should I aim for this or should I raise them with a different plate/thickness. I do not want to drastically lose the bottom end I have. Will the long rod setup automatically call for more radical porting to work proper? Also will filling in the rear transfers to remove the hook add any benefit to this engine?
Thank you for any insight you could shed for me.
The basics of the engines are 1 for bottom end power and one for top end.
the cylinder for the bottom end I filled in the rear transfer ports to get rid of the hook,filed the power valve sub exhaust port channels,and lowered the cylinder with base gasket thickness to achieve a .040 squish with the stock head. detonation is not a problem since I use good fuel but my question is, will doing the head mods achieve any benefit in helping softening things up a bit with losing too much power?
Also , the top end engine , the sub exhaust ports raised,the exhaust spigot rounded, and the powervalve matched and blended into the exhaust port when in the open position. Assembled with stock gaskets with a squish of .055+ stock head. It is time for a complete rebuild so I am finally going to get the head mods for atleast this engine.While trying to find a way to tinker with something new I found/figured out that earlier connecting rods are 5mm longer so I am thinking of making a long rod engine.With a 3/16" spacer plate and assorted gaskets I can achieve "stock" intake port timing should I aim for this or should I raise them with a different plate/thickness. I do not want to drastically lose the bottom end I have. Will the long rod setup automatically call for more radical porting to work proper? Also will filling in the rear transfers to remove the hook add any benefit to this engine?
Thank you for any insight you could shed for me.
