Problem after gasket job on EVO

Discussion in 'Engine, Fuel and Exhaust' started by Freddy2081, Jun 10, 2013.

  1. Freddy2081

    Freddy2081 Member

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    Hello Everybody!!
    This weekend was take your bike apart weekend...
    With my brother in law took my 1988 heritage apart, got a set of new gaskets, piston rings and did the job.
    Everything was done according to manual, torque values etc.
    Long story short, we put the engine together, put the tank on, carburetor was there, fire it up and only the rear cylinder works.
    giving it a little gas makes the front cylinder work as well, but there was a lot of back firing and at idle the front cylinder wouldn't work.
    Did a compression test on both cylinders and result was around 130psi for both.
    Spark plugs spark.

    Engine is stock, bike has 5700 miles (yes five thousands) is a 1988 80ci. Carb is Mikuni HSR 42, Exhaust is hard krome or something like that.. Bike was running fine before the job, just had very bad leakage from the rocker covers and front head.
    Where should I look?? Brother thinks we might have inverted the pushrods, I doubt it, but would some like this happen with inverted pushrods??
     
  2. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    First thing i would suspect given the information you have provided is that there is an intake leak at the inlet manifold to front cylinder head gasket giving a weak mixture to the front cylinder

    Brian
     
  3. Jack Klarich

    Jack Klarich Expert Member

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  4. Fastlinnie

    Fastlinnie Member

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    Sounds like a intake leak. I would check that first.
     
  5. Freddy2081

    Freddy2081 Member

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    Didn't even think about it.
    Let me add to it.
    As I said the carb is a MIKUNI HSR 42, now, my bike had the butterfly carb and the flanges were rubber. I got the mikuni manifold for the carrb, but when I received it I figured that you needed to use the stock flanges (metal ones) which I didn't have.
    Dealer only had 1 flange in stock, so I figured while waiting for the other one I would put back on the rubber ones just to check, but at this point I wouldn't waste gaskets on something that needed to come off anyway, so just used the crappy 25 years old gasket that was sstuck on there....

    Will do an intake leak check, or I'll just wait for the right part to arrive and finish the job right....
     
  6. Fastlinnie

    Fastlinnie Member

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    Yes I don't they will seal right .
     
    Last edited: Jun 10, 2013
  7. Jack Klarich

    Jack Klarich Expert Member

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    If you have the stock compliance fittings, throw them as far as you can and upgrade to the new style flanges and you will be a lot happier
     
  8. Freddy2081

    Freddy2081 Member

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    LOL
    As a matter of fact I can't use the new mikuni manifold because of those stupid rubber things. Waiting for the part to arrive, the dealer only had 1 of the new style flanges, then I promise I will throw them as far as I can...
     
  9. Breeze3at

    Breeze3at Well-Known Member

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    Stock pushrods have 4 different paint splashes on them, and must be put in the correct postin. Rear ex.= purple (2nd longest) Rear int. = blue (shortest) Front int. = yellow (2nd shortest) Front ex. = green (longest).
     
  10. Freddy2081

    Freddy2081 Member

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    Yes and I was able to slightly see the color of the pushrods although they are 25 years old.. But for some reason he thought we got it right....
    [​IMG]