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About jr89xr600

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  1. jr89xr600

    Decrompression lever missing??

    This bike has an automatic decompressor mechanism on the cam shaft unless someone removed it. When the cam turns slowly a lobe on the shaft slightly decompresses an exhaust valve which is why you can turn the engine over. Once it starts the shaft turns faster and the centrifugal force retracts the decompressor. Don't worry too much about 'kick back' as there is a safety feature, another part of the same mechanism opens the exhaust valve when the cam shaft turns the wrong way. It can only kick back a little, and the best way to avoid this is to kick it with conviction the first time, sounds like you do that anyway. You can probably find a second hand lever and cable, as these are little used and the bikes wear out first. I have a couple spare but as thats here in Africa no use to you. Its worth fitting one and very simple to do, as the guy above says they come in very handy when you drop the bike (not that you ever will ;-) and need to clear a flooded carb. Good luck.
  2. I guess its an XR600 I use the same method suggested above, a tie wrap (at least I think thats a what a 'zip tie' is to us poms). I also use small piece of steel tube (i use the body of an old fountain pen) hooked over the straight bit of the spring as this helps to get it tensioned. Then slip a heavy duty tie wrap over the sping. Tug the tie wrap some more till the straight bit of the spring is parallel to the stright bit of the tensioner. If its in front of you you will see what I mean! You can then slip the tensioner into place, and cut the tie wrap and pull it out. After you try a couple of times and you will get the idea and it becomes quite easy. A good idea to think about where you will cut the tie wrap, and which way around you put it on. The idea is you leave yourself one continuous pice of plastic rather than cutting it into two and hoping the bit hold together as you pull it out. Again try and you will see what I mean.
  3. jr89xr600

    crank shaft oil feed? low oil pressure

    yep the screen did have bits of brass in it when I first stripped the engine, but I cleaned everything when I rebuilt the engine and now its spotless. As is all the inside of the engine. I spotted you are in Belgium, from all the way out here (africa) that seems like nextdoor to holland ;-) Tomorrow morning I will press out the crank pin, looking for the dimensions online now. Thanks again for your interest
  4. jr89xr600

    crank shaft oil feed? low oil pressure

    Thanks SDBSKI. and XRMANU, all good suggestions. Unfortunately I already checked all these possibilities. Seals and oil lines all good, and I primed the pump. Before starting I checked at the banjo bolt where the oil line enters the head and oil does arrive, but once the engine is hot this feed contains lots of bubbles and fumes. Tearing out the crank is a major step so I tried everything else I could think of first. But if anyone else with good ideas please tell me. I keep thinking it's something small I forgot to check. I just measured the con rod side clearance (between the con rod and washer) and it was well outside standard. It measured 0.75mm and standard is 0.05 to 0.50mm. I guess this might contribute to the loss of oil pressure However this alone is not enough to explain the problem as the service limit is 0.8mm. It does suggest that the guys who assembeled it were none to careful. I will press it back to the minimum setting. I tried to contact the workshop that did it but get no reply. As you may have spotted I am in Africa (great off road riding here if your bike works, but a long walk to the nearest garage when it doean't;-) I wanted this job done well so I sent the crank to a workshop Holland (wish I hadn't now) maybe SDBSKI would like to pay them a visit they are just next door (Joke!) Still trying to think of something but if I don't get a culprit soon I will press apart the crank to check the crank pin. I will start a new thread to look for the correct dimension for the hole in the crank pin.
  5. Hi folks I have done a big rebuild on my Xr6 and since then had problems with it overheating. There seems to be too little oil reaching the head, (lots of bubbles and fumes not much oil) and I have burnt out a set rockers. I have checked all oilways and seals thoughly, everthing is clear and clean. Tried new oil pump and yes I did remember the little dowls and o rings behind and the in front the oil pump, no better. Any ideas I tried everything I can think of? One suspect, I checked the crank shaft and it seems that is has almost no back pressure. I can imagine that the hot oil might choose to go this way rather than up hill to the head. Sound plausible? Should there be some resistance? Is there something in the crankshaft that restricts the oil flow or is it just the size of the oil hole in the carnk pin. I had a new crank pin and con fitted is it possible that the workshop could have fitted the wrong pin. I can tear down the crank, but its a big job. Can anyone tell me how big the hole in the crank pin should be so I can check it once it's out. Any help much appreciated I am at the end of my teather.