1974 BMW R90/6

Discussion in 'General Motorbike Discussion' started by mark77, May 15, 2019.

  1. mark77


    May 15, 2019
    Likes Received:
    Hello everyone,

    I bought this bike in the early 90's. It was cheap because it wouldn't start. I'm terribly dumb so I took it to the local BMW dealership to get it going. They called me after a couple of weeks and told me to come and get it. They couldnt get it going either. (!). I bought a workshop manual and started to learn how it worked. It can't be that hard, half a volkswagen. If it has air, fuel and spark, it HAS to start, no? Read up on setting the ignition timing. Adjusted the points by removing the rubber grommet on the engine fly-wheel side. Still wouldn't fire.

    So I went back a step and figured, "If I rotate the engine manually and jam a stick in the sparkplug hole, that will show top dead centre" Set the points again and away she went. The timing marks stamped into the fly-wheel bore no correspondence to the truth. So I just put some paint on the fly-wheel where I thought the spark should fire and left it like that for years.

    Much later, a BMW air-head whisperer told me what the story was. Apparently, someone had removed the gearbox at some point and replaced the fly-wheel in the wrong position. (Later models had a key-way to prevent this, apparently)

    He said that the dealership probably used a strobe-gun to set the points and when that didnt work, they just gave up.

    Anyway, she's done 399,000 kilometres since then and I've never had a problem. (apart from the fact that the brakes are shit-house, it handles terribly and has less performance than my 250cc Honda) But, I love it and hope to keep it until I'm too old to ride. (Which probably won't be long lol)

    P.S. she now has electronic sparks.

    Thank you!
    mark77, May 15, 2019
    AlexBrown11 likes this.
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.