Faults and Problems

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  1. Flip
    Flip
    Wanted to get a page going on faults.

    I have had a few, all of them so far have been post restoration issues.

    My altenator failed as soon as I got the bike. The stator had a short to earth. CJ750 kindly lent me his spare until some more parts arived.

    My side car was badly out of alingment. It had 70mm of toe in at the front wheel, it should have had 10. It killed the first set of tyres very quickly.

    A rear hub failed, see the photo here. It had been welded up before. Bill kindly couriered me a new hub.

    I broke a clutch cable and a brake lever broke.
  2. Clay
    Clay
    Flip any idea if the alternator can be upgraded? I think I read somewhere the output is only 65 watts and running around with the headlight on will run the battery flap. My headlight is 90/100 watts, the bike has a new battery in it and was flat yesterday after lots of testing and starting so I'm keen to boost the alternator if I can.
  3. Flip
    Flip
    Yea mine came with the same bulb, throw it away and just put in a good quality 55/60 one, your headlight will be heaps brighter and your battery won't go flat. The wiring is not big enough to supply 10 amps to the bulb.

    My stator was buggered when I got my bike, it had a direct short to earth, took me ages to find out why my alternator only made 6 amps and not the 20 it was meant to. I have also heard that the rotors fail in time because the wiring breaks or shorts out internally. I have spares if you need them.
  4. Clay
    Clay
    Ok I replaced the 90/100 with another one from Supercheap. Looks like I should get a 55/60 to fix the battery problem!

    Who have you been getting parts from, I think I should stock up on the common stuff.
  5. Flip
    Flip
    Repco had them
  6. Clay
    Clay
    Turned out my rotor was shorting to ground so no charge. Flip very kindly lent me a rotor which I'll put in shortly. Hopefully this fixes the flat battery problem I've been having

    I did a 120km charity ride on the weekend, bike ran great apart from the massive rear wheel lockup it did on me, I was doing 90 - 100k. Thought I had a seized engine but no it was fine. Anyone else have a brake lockup for no reason?
  7. Flip
    Flip
    I had a set of aluminum alloy shoes resoled and put them in, seems when they get hot the alloy expands more than the steel hub and the brake slowly jams on. I have another set of steel shoes that I will take to saveRbrakes shortly and see if they work better.
  8. Flip
    Flip
    Just another minor CJ750 problem. Seems the starter motor leaks oil on most motors.

    The O ring seal on the starter motor started leaking oil badly. I pulled the starter off, note you have to align two gears in the timing case by rocking the bike forward and back in gear to get the starter out. Cleaned the area with solvent covered the O ring with blue heldite. Put the bike back together and the bike leaked oil worse than before.

    Pulled it apart again, brought a new O ring (what I should have done the first time). Covered the oring with gasket cement. Put it all back together and it has stopped leaking. I found that the old O ring was damaged when I put the bike together. I also fitted a little bit bigger O ring. The twit in the shop said it was a 3.5mm thick but it was a 1/8th".
  9. Flip
    Flip
    Had some wheels respoked by spoke wheel services in Chch. The old guy too one look at a broken spoke and said "Oh these chrome spokes always break, try there you won't have a problem"

    They used motorX spokes. He did a great job, so far so good. We put 3 people on the bike the other day and went into town no probs.

    The old spokes were only lasting 3-4,000 km before they began breaking.
  10. theo
    theo
    Problems with trying to balance carbies. Check first that the main jets are the same size. Mine came with an unmarked one [from a reco kit????!!!!] and one marked .92. I presume that the kit part was made for you to drill out to the appropriate size when replacing as I have another unopened kit with a similar part in it.

    Now to do those other balancing tricks
  11. theo
    theo
    Pull starter button apart occasionally, water gets in and contacts oxidize, but are easily cleaned. Can be improved by changing mounting of the switch from horizontal to the vertical, so that water drains out. Also the standard ignition key switch does not contain any lubricant. Lubricate with propper electrical grease, which will help with waterproofing as it is also not waterproof.
  12. Flip
    Flip
    I drilled the jets on my std carbs out to 1.05mm it runs heaps better and runs a lot colder now. I actually don't think the motor life would have been good with the std jets because the plugs used to be white after a run, they are now a nice tan.
    My side-low-high-park switch was playing up, I just sprayed some electrical cleaner in it an it is now working perfectly.
  13. Flip
    Flip
    Well my old CJ shit itself. I ran the big end on the right cylinder. There was a lot of ground up alloy from what I believe is the bearing carrier and very little steel in the oil. The out of center big end broke the bottom off both pistons as it rotated. It actually failed very quickly over about a 5 mile distance. We were about 200 miles from home going up Burke's pass so getting the bike home was an ordeal. All the parts, new crank, pistons, oil pump only came to $500. I have taken the opportunity to cut all the ports much bigger and fit high speed pistons.
  14. Flip
    Flip
    Got the bike together, and are running it in.

    Fitted some high speed (thin ring) pistons, and so far they seem to have mostly eliminated the oil burning. The port job has worked brillantly, its pulling like a train, seems to have about 20% more torque but haven't run it at speed yet. Had a few issues with the timing key on the front of the crank shaft. Seems that there are two types, a woodruf and a flat 5mm key. I had the new crank shaft machined to take the flat key.

    I am trying out some new head gaskets from Bill seem to be some plastic coated aluminium material. I have about 20 of them. I have kept my expensive solid copper ones just in case these fail.

    Went for a nice ride on it in the weekend in the hills behind Oamaru, hit a bloody big pot hole and its put my back out.
  15. Flip
    Flip
    Putting a 4mm washer under the heads of the spokes stops them from breaking. Works brillantly well.
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