EVO engine. What to watch out for?

Discussion in 'Engine, Fuel and Exhaust' started by JBC2565, Jan 14, 2011.

  1. JBC2565

    JBC2565 Junior Member

    Have a 1998 FLSTC (Heritage Softail Classic) with the EVO engine,
    32K with an S&S upgrade cam and rev-tech 6 sp. (I know need a baker but had it when I got the bike and had no issues for 25K. Thanx Spectro 6 spd platinum)
    Just wondering reliabilaty (sp?) of this engine or things I need to watch out for?
    Did buy the oil filter adapter for "complete" oil change but wondering about anything else I need to know.
    Been running Mobil1 Twin cam 20W-50 since 2000.
    Runs great but as she gets older, want to be pro-active instead of re-active.
  2. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

    Make sure you warm it up until the valve covers are warm to the touch before taking off on it. That will extend the time until you need to change the base gaskets. If the base gaskets start leaking (one or both), fix that right away or you will have a blown head gasket once the jugs start moving.

  3. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

    As TQ said and add that the lower rocker gaskets can leak also and were updated to a single piece thin metal gasket

  4. karlsbike

    karlsbike Active Member

    As the fine gents said.
    I can only add that the EVO bottom end is mostly bullet proof, in particular late EVO's. With proper warm-up that scoot can take some serious abuse, and the '98 cases are good for future upgrades as well.
    Earlier cases - like mine - can crack if bored up for larger cylinders. That's why I opted for new cases when I wanted more power (that resulted in me getting the rest of the parts for a complete engine, but that's how it goes;)

    One more thing; Excessive oil blow-by should be checked (i.e. oil out of the airbox) - this could be a sign of worn rings, or just worn check-ball/spring

    The Evo's don't have heat problems, don't have chains or belts in the timing chest that can do really bad things internally, don't have problems with the crank, or the main bearings, don't have problems with the comp sprocket, etc, etc. Can you tell which one I prefer?
  5. fisherman124

    fisherman124 Active Member

    frind has a 96 three times around the clock , he rides like he stole it ,enjoy
  6. karlsbike

    karlsbike Active Member

    Re-reading your post I see that your scoot has only done 32k miles. My best advise is then:
    Keep riding it for another 32k miles and don't worry about it. Then you can start looking for stuff that may need attention...
  7. Jack Klarich

    Jack Klarich Guest

    As said earlier Evos are good motors just need warm up time and more frequent oil changes than Twin Cams enjoy your ride:D

    NEWHD74FAN Experienced Member Retired Moderators

    As others have said the EVO engine was very durable...it was the "revival" of H-D as a company using the funds from AMF. Many old timers give AMF a bad rap, but the $$$'s they plowed into the EVO development paid big dividends later, saving the H-D company from "extinction" and eventually it's success enabled the H-D family to "buy back" the company and field a whole generation of engine designs that exist today...:D
    Last edited: Jan 14, 2011
  9. marcus22

    marcus22 Junior Member

    Whats the Tappet screen. my dad has a 94 and he probably doesnt know either.
  10. Fossil

    Fossil Active Member

    Get a shop manual for your year and model of evolution and read it. For now go to Bandit.com and follow their directions to register your EVO for their parts book. This will get you into looking at copies of Harley parts books for your year. Go to engine and oil pump and you will find the tappet screen and where it is. It will also show you how it goes back together. It is lockated near your oil pump on the rear of the right case. When ever you pull the spark plugs get a small light to shine in the hole. You will see cross hatching on the cylinder wall. The rings never seat. The cylinders are barrel shaped and when warmed up become a round cylinder. The rings really seal when this happens. There is nothing to break in as every thing is on bearings or bushings and they do not break in.