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camman

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About camman

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  • Location
    Iowa
  1. camman

    Hotcams

    Stage 1 cams
  2. camman

    KTM 250 / 300 crank SNAPPED!

    OMG people the flywheel weight is the problem! All that extra inertia suddenly slowing down on a motocross track fatigued the shaft. Probably broke right across the keyway too!
  3. The material is 8620 that has been case hardened. Not saying it can't be done but it is very difficult to drill out the case and then tap a new thread. The case depth is 1mm so you would have to drill with at least 2mm bigger drill the tap. Good luck
  4. camman

    Cylinder Works Big Bore 434cc Fitment Issues?

    Old issue. The spigot radius was too large and interfered with the case. Long ago solved.
  5. camman

    Primary gear pin doesn't fit in HotRods crank?

    Hot Rods is aware of this they will send you a replacement. Or you can simply file down the pin and save yourself the hassle. It's retained by the gear so you won't have a problem by just turning down the pin diameter a .001.
  6. camman

    CRF450R FULL REBUILD KIT HELP!

    Hot Rods connecting rods are manufactured in the USA and heat treated at an aerospace certified heat treat facility. Materials and heat treat are certified by sectioned and micro hardness testing. The crank webs are made in Taiwan at one of the most well known OEM crank suppliers in the world. Hot Rods outsells the OEM aftermarket 2 to 1. You are very unlikely to have any issue with their cranks.
  7. camman

    Unicam cam material

    Honda uses JIS SCM420 whereas HotCams uses SAE8620. They are nearly identical materials with the 8620 containing more nickel. They have essentially identical mechanical properties.
  8. camman

    CW big bore issues

    This might be obvious but do you have the piston turned around? Arrow pointing at exhaust?
  9. camman

    '14 engine grenaded - Anyone Else?

    It all boils down to how hard you ride. Trail riding a motocross bike and you will easily make 60-80 hours on a crank. Full throttle racing on a motocross track with big up hills and sand and you are pushing your luck at 25 hours. When I hear about these 300 hour cranks the owner is either full of BS or one hell of a slow rider!
  10. Competition makes the breed stronger, consumers should be happy that Yamaha jumped in the off road game (like them or not) We will all benefit. Arguing over which bike is better is sophomoric at best. People should be thankful that we have choices.
  11. Well I have been pure orange for the last 12 years until I bought my FX. I have never looked back. The FX is undoubtably the best off road bike for me! There has always been something funny handling about a KTM that just never made me 100% confident. I like KTM and probably always will but for now Yamaha is getting my business. They earned it!
  12. camman

    270 Kit

    I have a CW kit on my FX. Just rode it today in the snow. I like it. I was concerned that the bike wouldn't lug down as low as the stock cylinder but it was fine. No stalling and it definately lifts the front end up much easier with the throttle. I'm very happy with it. Oh we did do a remap as stock isn't the greatest.
  13. I am assuming by pulse duration you mean the returning compression wave that rams intake charge back into the cylinder. If so the duration of this event is mainly controlled by the blow down duration (ex open to top of transfer open) - no one wants positive pressure when the transfers open so by the time the piston reaches the top of the transfer port nearly all of the pressure is gone. The exhaust gas temperature influences the time for the returning compression wave but this has little influence on the duration of the wave. The length of the convergent cone will strongly influence the length of the compression pulse and its magnitude. A short steep angle convergent cone creates a steep and short duration returning compression wave, a long and shallow cone creates a long pulse with low magnitude. There are also expansion and compression waves still bouncing around inside the pipe from previous cycles these "residual" waves also affect the duration and magnitude of the "ram charge" pulse. Ultimately, one has to simulate these waves in an unsteady gas dynamic program to even begin to track all the wave interactions.
  14. camman

    Vertex

    There is a reason why Vertex uses those pain in the ass clips! The extra tangs on the non OEM clip add mass and will actually contribute to the clip falling out when the piston is at high rpm. It's a rare circumstance but it has happened enough to require an improved design. If there has ever been a 5 cent part that can cause more damage its a wrist pin clip!
  15. camman

    Big Bore Failure

    Since both exhaust valve heads broke obviously the exhaust cam was not timed properly. Don't beat yourself up too much anyone that works on their own bike is going to make a mistake someday. That is how you get smarter.
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