Stock Bike...204's....030 gasket?

Discussion in 'Engine, Fuel and Exhaust' started by 6shootr, Mar 23, 2012.

  1. 6shootr

    6shootr Member

    Looking at adding Cometic .030 gaskets on my stock TC88. I'm installing SE 204's and using the stock pushrods. I'm not planning on having my heads reworked at this time.

    Does anyone see a problem with this? What will my compression be with this setup?

    I know I'm just a few $ and bolts away from a big bore but funds aren't there right now. Besides, that will give me something to do next year!
  2. Jack Klarich

    Jack Klarich Expert Member


    You should measure the deck height of the new set up.

    Put the new pistons and cylinders on with the old base o-rings.
    Bring the piston to top dead center.
    Put a straight edge over the cylinder directly over the wrist pin.
    Then measure the gap with a feeler gauge.

    Ideally the gap measured here plus the thickness of the head gasket should equal between .030 and .035. You will be changing at least .015 from stock gaskets
  3. traveller

    traveller Member

    I used a cosmetic .030 head gaskets on my tc88 after i milled the heads .050 and i ended up with 9.80 to 1 compression and really like the gains it made.

    BUBBIE Well-Known Member

    Using that SE204 will give you a big difference and the .030 instead of the stock .045 will make a little difference to help your LOW end torque.. Good set up the way you are using it..

    Take a look at this Calculator IT WILL come up as the 95" motor so Pay attention to the little numbers as it Might Not be your numbers in the calculator.. The .030 gasket comes up also Standard,,,,,, You need to change IT to .045 gasket to compare to see the Difference... AND use the stock 88 engine size,,,,, Then put in your SE204 cam into the picture using the right year/model type

    The gasket does give more SQUISH and a little more compression.

    Big Boyz Head Porting - Twin Cam Compression and Displacement Calculator

    Continuing on Some thought for you.......

    If you have not figured this out yet. You loose some static compression when using the SE204 cam and staying 88" for now,,, but gain back about 7 lbs when you use the .030 gasket instead of the .045 stock size...

    Now, Later, when going 95" you DO gain a Good amount of compression and that = POWER...

    So the SE204 is a good cam for you Now and Later Now,it will show considerable Power increases,,, THEN going with just stock 95" pistons... You will be right at the Sweet spot for compression 180lbs.(sea-level)
    IT Will run good on pump high octane fuel also. (easy to find 91)

    Then some head work as a Big bonus.

    Careful here though,,,,IF you use Higher Compression Pistons when you go 95", YOU Will gain Too Much compression and a Problem'd bike will result... Hard starting and kick-backs and the need for PR valves in the heads and Higher octane fuel than you can get out of a pump.

    You can use the calculator to insure you don't go over 180 lbs of static compression(best running and starting Not higher)

    I have run my older TC'm at 183 lbs (best)195 (max)...

    Another build, 208+ (too much) and Kick backs common.
    Then having to give back power of too high compression by retarding the timing so the kickbacks were gone..

    I guess that is what is meant by Give and Take

    Just More Food For Thought.


    BUBBIE Well-Known Member