1. 2 Stroke Husqvarna Motorcycles Made In Italy - About 1989 to 2014
    WR = 2st Enduro & CR = 2st Cross

250-500cc Wr300 2010, Coil Resistance Values?

Discussion in '2 Stroke' started by Scott T, Jun 5, 2021.

  1. Scott T Husqvarna

    Husqvarna Motorcycle:
    Wr300,
    Other Motorcycles:
    None
    Hi all.
    I'm new here, glad to have found such a great forum!
    I got myself a 2010 WR300 recently to start competing in enduros and hare and hounds events.

    I am in need of some assistance with a high rpm misfire that my bike has suddenly developed.
    The bike starts and runs perfectly, but will misfire on a large throttle opening at high rpm, on a previously strong running motor.

    Typically I discovered this on a test run as I was making final preparations before heading off to an enduro the following day.

    I've been through the usual suspects, reeds are good, exhaust isn't choked up, silencer and packing is good, good fuel flow, checked the gaskets, power valve operation and can't find anything wrong, tried different spark plugs and plug cap, the stator looked clean and dry and the wiring connections are clean.

    I have tested the ignition coil and it is measuring around 17k ohms primary and 1ohm through the plug cap side, I'm not sure if that's within spec?
    My next step would be to test the stator pickup coil but,
    I don't have the expected values and haven't been able to find them online.
    The manual makes no mention of the resistance values, and the Husqvarna parts guy I've spoken to can't find the information either.

    I was hoping one of you fine people would be able to help me out.
    I really don't want to go down the route of throwing parts at it blindly until it runs properly again.

    Cheers Scott
  2. rockdancer Husqvarna
    Pro Class

    Location:
    Sunshine Coast, Australia
    Husqvarna Motorcycle:
    2013 WR125, 2019 FE350
    Try searching through old threads. I know there are posts on the 125 ( I posted some) not sure about 300
    Sounds like stator or coil .
    Is the intake boot ok ? Whats the plug look like?
  3. Dirtdame Administrator

    Location:
    Rock Springs Wy
    Husqvarna Motorcycle:
    11 WR300,13 WR125,18 FE501
    Other Motorcycles:
    17 Beta Xtrainer
    I have found that it usually seems to be the CDI that goes out on the WR300, although this happens more often on the later models that have the Ducati ignition on them, where the coil and CDI are an integrated unit. The stator and generator parts are rarely the suspect. My 300 has been reliable over the years, but my 125 took a dump in the same way, back in 2018, in the middle of nowhere. The power just flattened out and then misfiring occurred....then the bike quit running. After about 15 minutes, it fired up, but would die at higher RPMs, so I had to finish my ride at very low RPMs to get back to the staging area. For me, it was an easy conclusion that it was the CDI that was going out, because the same thing happened back in the mid 80s to my Honda XR200 R, so it was the first thing that came to mind when the problem presented itself. I got a new CDI, slapped it on and haven't had any problems since then. Due to the bike's age, I'm not sure that the CDIs, either the earlier ones or the later ones are still available from the manufacturer though.
    rockdancer likes this.
  4. Sonnie Mee Husqvarna
    A Class

    Location:
    England
    Husqvarna Motorcycle:
    Team Motorex Husqvarna CR125
    Sounds like CDI trouble to me there probably not available anymore though still worth trying to find one I think it is the same part no and cdi from 1999 - 2010 on the WR/CR 250 and 300 best thing would be sto see if you can find someone with a 99-2010 wr 250 or 300 that would let you try it on your bike to see if the issue is resolved then you will know whether to look for one or not
    rockdancer likes this.
  5. Scott T Husqvarna

    Husqvarna Motorcycle:
    Wr300,
    Other Motorcycles:
    None
    Thanks for your help folks.
    To update, I tested the stator primary coil and it showed 127 ohms.
    After speaking with a company over here that rewinds stators, they reckoned that might be a bit high so I had them rewind it.
    Unfortunately this hasn't cured the issue, if anything it's worse, so I am waiting on a new CDI.
    I haven't tested to see what resistance the rewound coil is showing yet, it could be the original was good and I may have to have it rewound to the original 127ohm resistance...... Guessing I'll know when I get my hands on a CDI.

    Rockdancer the intake rubber has under 5 hours on it, along with an extra gasket I fitted to cure the horrendous design of the moulding number on the reed block sealing face, mine wasn't actually leaking there beforehand but it's no wonder that they do, after discovering that.
    As for the plug it's not showing signs of being overly lean or rich.
    I suppose I could plug chop it whilst it's misbehaving, but I'm pretty sure that would be inconclusive, if it was ignition related, as the fuel would be unburned and probably show as too rich anyway.
    Might be worth doing, as it may show a really bad lean condition, but at the moment I'm fairly certain it's not an air leak.
    rockdancer likes this.
  6. Scott T Husqvarna

    Husqvarna Motorcycle:
    Wr300,
    Other Motorcycles:
    None
    Dirtdame and Sonnie Mee, you were spot on, a replacement CDI has cured it.
    They are no longer available from Husqvarna, but Horsepower Ignition in Belgium supplied a replacement for the stock ignition system.
    All good again.
    Cheers folks.
    Sonnie Mee and Dirtdame like this.
  7. Sonnie Mee Husqvarna
    A Class

    Location:
    England
    Husqvarna Motorcycle:
    Team Motorex Husqvarna CR125
    Glad the issue is resolved for ya