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Thread: "Hot" Street engine

  1. #31
    Member
    Join Date
    Aug 2017
    Location
    North Queensland Australia
    Posts
    80
    I've been trawling this forum again and again trying to decipher all the good work you guys have taken the effort to carefully document.
    It's really frustrating what photobucket did to so many threads around the world.
    I found this one

    http://www.sr500forum.com/forum/view...10452&start=90


    on the old forum but so much is lost without the photos you posted with it Hoffman.
    I know it would be a huge task to re-upload the pics in their original positions
    but is there anywhere I can view a collection of your pics you have taken over the years of the engine work you have done?

    Cheers again
    Rabbit.

  2. #32
    Quote Originally Posted by Rabbit8dude View Post
    I've been trawling this forum again and again trying to decipher all the good work you guys have taken the effort to carefully document.
    It's really frustrating what photobucket did to so many threads around the world.
    I found this one

    http://www.sr500forum.com/forum/view...10452&start=90


    on the old forum but so much is lost without the photos you posted with it Hoffman.
    I know it would be a huge task to re-upload the pics in their original positions
    but is there anywhere I can view a collection of your pics you have taken over the years of the engine work you have done?

    Cheers again
    Rabbit.
    I'll just post everything in a new post when I get some time! Been super busy with work / weekend activities. Everything was on Photobucket, but I still have everything. I'll get it back up...

  3. #33
    Parts are off at the machinist.

    I had to order new to me / used stock style rocker arms. They're out being measured now, then we can plug and play with some camshafts I've borrowed and get them back to their respective owner!

    Hi Hoffman, is there any chance you can repost the cam geometry data you posted earlier in this thread.
    Sure thing.

  4. #34
    Bottom end:

    Cylinder being bored with a torque plate:


    This was a new to me cylinder after FedEx lost my old one. It had a new LA Sleeve pressed into it before boring / honing.



    Bottom end parts. Carrillo H-Beam rod, custom Racetec piston, liner with LA Sleeve, o-ringed, and set up with through bolts.

    Old Wiseco piston:


    Chamber mold:


    Custom Racetec piston. I basically sent them the Wiseco, the mold, all dimensions including ring drop depth, etc. and told them to make me something better than the Wiseco.

  5. #35
    Through bolt. What you do is drill through to the bottom of the cylinder case at each stud, drill into the bottom of each stud and thread it. Then you can thread in a stainless bolt after the stud is installed to clamp it down all the way to the bottom.


    Stainless o-ring. To be used with an annealed copper gasket:


    Johnson J2 roller:


    Measured lift profile. I'm working on getting the stock one measured up and an older Megacycle. Like everything, it's a slow process :/

  6. #36
    Cylinder head:

    Intake valve: 1.90 (48.25 or +1.25mm over stock), 7mm valve stem, custom valve guide, custom titanium retainer, Ferrea brand
    Exhaust valve: 1.45" (37mm or -2mm from stock), 7mm valve stem, custom valve guide, custom titanium retainer, Ferrea brand.

    This profile was chosen after experimenting with 5 different backcut and tulip shapes


    Intake port. 1.5" (38mm) opening. Could be opened up more, but I don't want this engine to peak too high. Short side radius is about as wide as you can make it without busting through the casting. Port is very stable on the flowbench.


    Exhaust port:


    Entire assembly on the flowbench:


    Combustion chamber:


    All head work done by Nick Smtihberg. Retainers from R/D and guides from EdCo.

  7. #37
    Flowbench numbers:

    Intake:

    Intake port / manifold with radius plate on left / with carburetor bolted on to the right:


    Exhaust port. 0.700" lift flow number is .600 with a pipe off the end of the port:


    Compared to a previously ported 'junk' head that was for experimenting on, but wasn't needed:


    Nick's signature:

  8. #38
    Valvetrain geometry:


    Note, I have every bit of faith in the accuracy of these measurements (the arc radius is for the J2 roller rockers) for my cylinder head. Keep in mind the exhaust valve has been sunk and the valves are not stock sized. Only use the pivot point locations for the stock rockers. I'm having some measured up now to develop a blueprint for the stock rocker arms. Also, if you use this to develop a cam profile, you're doing so at your own risk.

  9. #39
    Member
    Join Date
    Aug 2017
    Location
    North Queensland Australia
    Posts
    80
    Wow, this is really good information you're posting and will take a bit to digest.
    I take it the cylinderhead moulding was scanned to work out the piston dome shape to work out the compression ratio?
    Is this still an open chamber head ie. no squish?
    Was the chamber machined or is it done by hand? It looks like it's a very accurate shape.

    Very impressive.

    BTW reading your posts has swayed my ideology a bit on exhaust design.

    What bike is this going into again?

  10. #40
    Quote Originally Posted by Rabbit8dude View Post
    Wow, this is really good information you're posting and will take a bit to digest.
    I take it the cylinderhead moulding was scanned to work out the piston dome shape to work out the compression ratio?
    Is this still an open chamber head ie. no squish?
    Was the chamber machined or is it done by hand? It looks like it's a very accurate shape.

    Very impressive.

    BTW reading your posts has swayed my ideology a bit on exhaust design.

    What bike is this going into again?

    Correct. The mold was used to scan and develop the dome shape. We knew the finished cc's of the combustion chamber, plus all the other pertitent information. It'll be right around 10.5:1

    And correct, no squish. The chamber was machined by hand (as was everything on this head). Most CNC heads are really just copies of hand ported masters.

    Here is the bike:


    Here
    Last edited by Hoffman900; 11-13-2017 at 06:56 PM.

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