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Thread: Kahuku Hare & Hound 2018

  1. #1
    Join Date
    Oct 2009
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    Default Kahuku Hare & Hound 2018

    Race report, months late but figured it'd make a good post.

    Entered in B-Open class for the Kahuku Hare & Hound race back in July. The race was from 10am-4pm (max time), one long loop with a gas checkpoint halfway thru. The North Shore got a bit of rain that week, so there were parts of the woods that were pretty swampy. There was some rain during the race, which made matters worse and many participants claimed it was one of the toughest races up there in years.

    My YZ-250 had just undergone a fresh top end rebuild (from the yz-submarine incident), with only 3 hours on the new piston. I replaced my radiators when I did the rebuild, and instead of buying the $250 a piece Yamaha radiators, I went with a $100 ebay set that many people claimed were great quality, just a harder metal (break instead of bend). I planned on getting some beefy guards anyway, and figured i'd be fine. The radiators came with "free" silicone hoses, which I was weary of due to the fact that silicone hoses are normally about $100 for these bikes. The quality seemed ok, so I put the hoses on against my better judgement (more on this later).

    I actually had a great start to the race and was flowing pretty good about two hours into it. Previous hare scrambles, I'd always hit a physical brick wall (fatigue) at some point, making finishing the race alive the only priority. This race, I was still pushing myself and feeling good when I got to a few gnarly, muddy hill climb sections that were major bottlenecks for the entire pack of riders. I knew my bike was overheating a little, which is not that big of a deal normally. My YZ when it gets too hot will rev surf a bit and overall I could always feel when it needed a little break (usually I needed one just as much). I did that after these tough sections, but shortly after the bike started to overheat again and was displaying some very odd knocking sounds and was down on power. I have a little overflow coolant tank under my seat that allows the coolant that would normally spew out when hot, would just cycle back in. I never once noticed a big cloud of coolant smoke or even smelled burning coolant to think I ran out, and just thought I pushed my bike a bit too far.

    It got the the point where I could only ride for a minute or two before needing to take a long break and I knew something was very bad when I saw my clutch cable melting on my cylinder. The bike became very hard to start and when it was running had very little power. Luckily, a short ride later I recognized where I was, and knew I was coming close to the gas check which brought us back into the main park where the main dirt road/ pits were. My bike was rev surfing like crazy as I pulled up to my gas jug that was marked by a sock in a sea of 100 gas jugs. Some guy even came up and said (Hawaiian pidgeon accent) "Bruh, that don' soun too good". He was right, and after filling up my bike and giving it another long break, I tried to start it just to ride over to the finish to turn in the tickets for the check points that I did complete. I knew my bike was Pau (done).

    I kicked and kicked and kicked, no joy and the bike had no compression. I could literally turn the kick starter with a few fingers, my top end was shot for sure. Walked back to grab my truck and pick up the bike from the gas check, I ended up checking things over before we left and at that point noticed my bike had run dry from coolant entirely. Poured some coolant in to see where it was leaking, and sure enough it was those damn ebay hoses. Three tiny pinhole leaks that must've allowed my coolant to slowly leak out without me noticing. Note to self, and a lesson for all: Ebay radiators for dirt bikes are ok, just don't use the hoses they come with!

    Rebuilt the top end again, and the piston with 3 hours on it looked 10x worse than the wiseco that I had just replaced with 100 hours on it. The piston rings were so worn that they were flush with the walls of the piston. Gotta love Yamaha for using that Nikasil coating on the jug, because it had barely any damage at all except for a little hazing of the walls. I re-honed it very slightly, just to rid of the smooth parts, and the bike was up and running in no time. Finished about mid-pack for B-Open, and am really disappointed because had I just finished the race, I would've been in the top 25 out of 120 racers guaranteed. Anyway, here is a video of the carnage:

    https://www.youtube.com/watch?v=RrOUabGvGkM
    Last edited by ccaarmerciill; 10-17-2018 at 03:56 AM.

  2. #2
    Join Date
    Aug 2008
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    Default

    eventful day!

    But now you have a friend bike for me to kill myself on whenever we get out to Hawaii.

    Making me excited for Mancation in 2 weeks, and also nervous that my brand new top end is going to pop on me while i'm there haha

  3. #3
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    Oct 2009
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    Quote Originally Posted by ITGbuDeev View Post
    eventful day!

    But now you have a friend bike for me to kill myself on whenever we get out to Hawaii.

    Making me excited for Mancation in 2 weeks, and also nervous that my brand new top end is going to pop on me while i'm there haha
    I'm sure your top end will be fine. Just try to avoid full throttle for the first hour or so. Take a few breaks early to heat cycle it a bit.

  4. #4
    Join Date
    May 2009
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    Quote Originally Posted by ccaarmerciill View Post
    I'm sure your top end will be fine. Just try to avoid full throttle for the first hour or so. Take a few breaks early to heat cycle it a bit.
    I usually heat cycle the top end before riding it.
    -Christian LRRS/CCS #856 ECK RacingGMD Computrack Boston | Pine Motorparts/PBE Specialists | Woodcraft | Street & Competition | OnTrack Media

    2011 Pit Bike Race CHAMPION!

  5. #5
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  6. #6
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    Just doing full warmup of the bike, then letting it cool down completely, then repeat a few times. I like to ride it when doing this so I can give some gas under load to ensure the rings wear and seat properly. I just take it easy for the first few hours of riding and take breaks. Have had 0 problems after rebuilds doing this.

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