CRF100 stopped running
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    commander
    Posts: 40
    Joined: Mon Feb 09, 2015 7:04 am

    CRF100 stopped running

    by commander » Tue Mar 10, 2015 9:06 am

    Went on a ride with the kids after church on Sunday and my oldest daughter's bike stalled and wouldn't restart. It was dark so we were already struggling to get off the mountain, and we were still a LONG way from the truck so we had to leave it on the side of the trail and retrieve it yesterday.

    I'm very meticulous about service and had just been completely through the bike (fluids, filters, cables, brakes, etc...) in preparation for spring, and the bike ran fine for about 6 hours before dying.

    After it died, I checked the following:
    ----Air filter is clean.
    ----I had just cleaned the carb, tank, and installed fresh gas, so I know that it was flawless.....but just in case I also made sure it was getting gas through the carb.
    ----Although the plug looked good, I replaced it anyway.
    ----It's getting spark, although I can't tell if it's a good one.
    ----I kicked it with the plug out and it's at least getting some compression (finger over the spark plug hole test), so the crank or rod isn't broken or seized. I don't have a compression tester but am trying to find a buddy that does.

    When kicking it, sometimes it will backfire like it's trying to run.....and sometimes it will kick back. I'm thinking it might have jumped time or broke the timing chain.

    Any recommendation on where to start my search? I'm decent with a wrench.
    '12 RZR4XP.....heavily mod'd, now driven by the wife
    '06 CRF250X (mine)
    '06 CRF150F (my oldest daughter's)
    '04 CRF100 (my youngest daughter's)
    '07 KLX110 (now in storage, waiting on my son to grow into it)
    '04 CRF50 (my youngest son's)
  • User avatar
    commander
    Posts: 40
    Joined: Mon Feb 09, 2015 7:04 am

    by commander » Mon Aug 03, 2015 10:23 am

    I'm pretty late on updating this, but I found the issue.....and I was correct about it being a timing problem, although it was ignition and not the valvetrain.

    Although you couldn't tell by looking from the outside, the case cover (magneto side) has busted the wall between the sprocket and magneto. That let mud and pebbles get into the flywheel area and a pebble must have wedged between the flywheel and pulse sensor, causing it to break.

    Unfortunately the pulse sensor is part of the entire stator assembly, so I have to buy a new stator, flywheel puller, and case cover with gasket. But it's all good......I had been wanting to add a light to it anyway, so this gives me all the reason I was needing to upgrade to the 110 watt stator from Baja Designs......which is still a lot cheaper than the OEM stator.

    After all is said and done, I'll only have less than $175 in the repair......and that includes adding the light. 8)
    '12 RZR4XP.....heavily mod'd, now driven by the wife
    '06 CRF250X (mine)
    '06 CRF150F (my oldest daughter's)
    '04 CRF100 (my youngest daughter's)
    '07 KLX110 (now in storage, waiting on my son to grow into it)
    '04 CRF50 (my youngest son's)

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