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  • froty

    From Simon Wilson@siwilson@nodamnspamn.hotmail.com to uk.rec.motorcycles on Fri Jan 9 20:32:41 2026
    From Newsgroup: uk.rec.motorcycles

    On my 790 ktm. Only a couple of miles, it's got a bit more go than an
    Enfield Himalayan.

    Had it in the garage to do a valve check, flipping heck it's fiddly. I
    wrote about it a bit more in FB - but, tl;dr I was very lucky not to
    destroy the engine.

    I'd put the rocker cover back on and then in the evening watched a video
    about how to be extra careful not to drop any shims inside the head. It
    has an unusual ewhere you can slide a rocker arm out of the way (in my
    case indavertently). If you do this and rotate the engine, the cam picks
    up the shim and drops it into the head. I decided to take the cover off
    again and check, and, indeed the exhaust shim had fallen off. Luckily
    was able to retrieve and re-fit it without any extra disassembly.
    --
    /Simon
    --- Synchronet 3.21a-Linux NewsLink 1.2
  • From Peter Fisher@nospam@nosspam.net to uk.rec.motorcycles on Sat Jan 10 07:25:16 2026
    From Newsgroup: uk.rec.motorcycles

    On 09/01/2026 20:32, Simon Wilson wrote:
    On my 790 ktm. Only a couple of miles, it's got a bit more go than an Enfield Himalayan.

    Had it in the garage to do a valve check, flipping heck it's fiddly. I
    wrote about it a bit more in FB - but, tl;dr I was very lucky not to
    destroy the engine.

    I'd put the rocker cover back on and then in the evening watched a video about how to be extra careful not to drop any shims inside the head. It
    has an unusual ewhere you can slide a rocker arm out of the way (in my
    case indavertently). If you do this and rotate the engine, the cam picks
    up the shim and drops it into the head. I decided to take the cover off again and check, and, indeed the exhaust shim had fallen off. Luckily
    was able to retrieve and re-fit it without any extra disassembly.


    Nightmare scenario narrowly avoided.

    I managed to check the clearances on the 350SXF once, but was grateful
    they were all within tolerance.

    On the YZ450F (5 valve) I had to shim one valve (I misremember which)
    and somehow got the exhaust cam sprocket one tooth out. Luckily it just wouldn't start after kicking it over a few times and simply getting the
    chain and sprockets back correctly had it starting first kick, at least
    when cold. Hot starting on YZ450Fs is an other story.

    I was midly surprised that I was able to fit a new cam belt on the MX5
    without drama. It's still extant AFAIK, though I see it is currently on
    SORN having only done 1000 miles and passed one MoT in November 2023
    since I sold it. Probably terminal tin worm.
    --
    Moto Morini 2C/375
    Gilera 175 Sport, Husqvarna 401 Svartpilen
    Honda CB250RS (Not Waynetta!)
    "Do not adjust your mind, there is a fault in the reality"
    --- Synchronet 3.21a-Linux NewsLink 1.2