Drilling holes in engine case mount?

Discussion in 'General Questions' started by Neufcruz, Feb 14, 2016.

  1. Neufcruz

    Neufcruz Member

    image.jpg image.jpg if I remove studs, fill holes to make stronger, do you see any issues with drilling to holes ( as shown) to run some bolts through to mount universal mount (as shown?)
    This seams to be the easiest without getting some custom place to cnc me a piece. Should work if that engine case/mount is strong enough. Sorry pics are sideways.
    Thoughts please!

  2. crassius

    crassius Well-Known Member

    should be no problem - on some with totally hosed mounts, I'll even go back a bit more & toward center a bit to mount a piece of angle iron to make a mount
  3. Neufcruz

    Neufcruz Member

    Great and thanks. Once I get this mounted then I can fab an exhaust piece and start mounting electrical etc...
    Getting close
  4. HeadSmess

    HeadSmess Well-Known Member

    ditto that. that whole lug sticking out of the case is solid... well, it doesnt connect to inside the crankcase in anyway... drill away :)
  5. Neufcruz

    Neufcruz Member

  6. sbest

    sbest Active Member

    I don't think you would even have to fill the stud holes.
    A rule of thumb is to have the same depth as the diameter.
    So for a 6mm stud, you should have at least 6mm of depth.
    You have much more than this there.

  7. Neufcruz

    Neufcruz Member

    Thanks guys but I overthought this and solved my initial space issue and getting carb level by simply smashing the filter down some. 2 weeks of headaches and bashing my head against the wall solved in 30 secs. :)
  8. sbest

    sbest Active Member

    Ha! Been there buddy. That is where it is good to have a friend in on the project with you.

    2 heads are 4 times better than 1.

  9. Neufcruz

    Neufcruz Member

    Yeah, totally over analyzed it. Finally getting some time this week to work on it so hopefully can get the windowed piston in and officially mount the engine. Then wait for the next hurdle:)
  10. sbest

    sbest Active Member

    Don't make the window too big.
    The Yamaha Blaster comes stock with a windowed piston and I learned NOT to make the holes any larger.
    (that is not what caused this stock piston failure. It was rpm and too much clearance)
    They are barely strong enough as is. No room for modification.
    We (my son and I) pull the cylinder frequently and check the pistons for cracks.
    He hates doing it because we often find them. Not looking does not make the cracks go away!

    (right piston is a forged cold seize also called a 4 corner seize)

  11. Neufcruz

    Neufcruz Member

    Mine has 1 window about that size. Just put it in? Do I put a silicone sealant between the jug and engine case? It did not have any when I took apart. Gasket was clean and in perfect condition. Also, should I run a bead around the head and jug? What type do you recommend?
  12. sbest

    sbest Active Member

    Just a gasket, preferably a new one but if you don't use sealer with good judgement you can often re-use the old one.
    The piston to head clearance is close on these engines so if you leave out a gasket parts can touch.

  13. Neufcruz

    Neufcruz Member

    What sealant do you recommend for base gasket,head gasket , intake and exhaust gaskets? Gonna take apart and put back in metal gasket that came with.
    Thanks for the help. Waiting on the offset intake and 8mm ball bearing for the springer chain tensioner. Once I get all this done then I can start with the electronics.
  14. sbest

    sbest Active Member

    No sealer, that is what the gasket does. I have had my head and jug on and off a dozen times as I tried different mods to chamber and ports, mostly on the same head, base and manifold gaskets.
    I did have to replace the headgasket as it compressed after 3-4 uses.

    If you do put sealer on them, I typically only put it on one side just to hold it in place for assembly, and often that is just contact cement.

    If you plan to assemble it once and never take it apart again you can seal it all up but you will curse it if you have to disassemble. One of the best sealers for motorcycle use is ThreeBond sealer:
    Yamaha sells a similar product, Yamabond 4:
    These are tenacious sealers that are hard to clean up but proven sealers even in applications without gaskets.
    If I was satisfied with an engine configuration and was going to ride it across the country, these are what I'd use.
    They can be used in all applications, head, base and both manifolds but consider is a final seal.
    You will destroy the gaskets taking it apart and the jug will be difficult to remove.

    Another type of sealer often used in race engines or things that need frequent disassembly is a filler/release agent, like Graphite spray, aluminum paint or even a silicon spray. I have used all of them. The graphite works best but is dirty, the aluminum paint needs to dry, and the silicon is a release agent only.

    Best advice from 40 years of motorcycle, automotive and industrial experience; just use the gaskets and have spares.

  15. Neufcruz

    Neufcruz Member

    Will do and thanks again Steve!