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DocSjulle

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About DocSjulle

  • Birthday 12/10/1975

Profile Information

  • Gender
    Male
  • Location
    Denmark

Previous Fields

  • My Bike(s)
    1973 Dnepr MT9, 1980 Dnepr MT10-36
  • My Story
    Always been a petrol head and got my first bike last year. Now a year after I have one running bike, one bobber project, and now the old Russin lump of iron.

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  1. The bike is running great now and I have just changed oils after the first 50km of riding. After my first small test ride the engine broke down because one of the pushrods had become too loose, and gone past the adjustment screw in the rocker. This happened because I had not noticed the pushrod didn't fit the rocker adjustment screw, causing it to sit on the edge of the pocket in the screw, and not fully into the pocket. Then when it was pounded to fit by engine, it became too loose. The exhaust valve was also sticking so that might have added to the problem. But after fixing those issue the engine is working perfectly, and there has not been any problems since, other than the usual adjustment of valves.
  2. I didn't want to go to crazy on the pistons, as I was afraid to lower compression. The ports have been smoothed out too, but not polished.
  3. I was even recommeded to go for 0,15mm on the intake and 0,20mm on the exhaust valves. This was with the standard Dnepr quality valvetrain, and was recommended by a very qualified motorcycle mechanic who has been working on these bikes for 30 years. I got the engine started last week and drove up and down the road a few times. I think it will be running real good when the carbs get adjusted properly. The engine got up to 150-160 degrees Celsius jug temperature without any issues, so I think a slow and gradual running in will prevent any parts seizing up.
  4. The sharp edges on the piston crowns where smoothed to prevent hot spots.
  5. So having both the MT9 and the MT10-36 non running, I decided it was time to rebuild the spare engine and gearbox. Everything was cleaned and taken apart, and both engine and gearbox looked in good shape, needing only new bearings, seals, and of course a total rebuild of the cylinder and head. I bought HQ parts to hopefully make it better and more reliable. FAG bearings, quality seals, Almot pistons, HQ valves and guides from Moto-Boxer. I spent a lot of time cleaning the engine case, crank and rods for casting seams and general rough surfaces. The rods were also balanced, and the new main bearings trimmed to fit perfectly. The heads were mildly ported before installing new guides and getting the 3 angle valve seat job done. The gearbox went together quickly, but the engine was assembled today because I had to wait a long time for the machine shop to bore the cylinders and cut the valve seats.
  6. The bike has been registered some time ago, and I have added right signal lights so it can be used solo too. When I got home I wanted to start it up and drive it back in the garage, but then the gearbox cracked open. It was an old repair which failed again.
  7. Thx for the heads up. The HQ parts from Moto-Boxer have been made to Dnepr specifications but in a much better material, so I hope they will be fine. The CJ valves will be used with the standard cheap valve guides and have a bit more play in them. I think I'll put the heads with valves in the oven and heat them to 150 degrees Celsius to see if they become too tight.
  8. As I have 2-3 engines I need to overhaul I decided to get the HQ valves and guides from Moto Boxer to see the quality. They are a really nice quality, and the valves fit the guides excellent. I knocked the old guides out after cleaning the heads. Heated the heads to 160-180 degrees Celsius in a small oven in the garage, and put the guides in a cup of ice cubes. This made the guides drop right into the holes, only one guide had to be knocked in as I was too slow and it heated up the guide causing it to expand. Now the head just need to go to the machinist to have the valve seats recut.
  9. The stem fits the new Dnepr valve guides perfectly. I think it measures 7.98mm, but I can only measure it with a caliper as I don't own a micrometer. I also checked an old post where someone used Manley valves in 3.575inch length. That is 90.8mm, so the CJ valves + caps are only 0.5mm shorter, and maybe new caps are a bit thicker. Nevertheless I think it's more than precise enough for this job.
  10. I couldn't find the answer anywhere, and ordered one valve to check out the measurements and quality. And the quality looks to be much much better than the original Dnepr valve. The length of the CJ valve is 3mm shorter, but I have been suggested to use the original Dnepr valve without the valve cap to improve on the valve-rocker geometry, and the valve cap takes up 1,5mm, so that makes the CJ + cap = 90,3mm, where the Dnepr - cap = 91,8mm I will have to check the geometry with the head in place and while turning the camshaft, but I think it can be made to work. Here is a picture of the Dnepr valve and collets together with the CJ parts.
  11. I'm rebuilding a Dnepr MT9 OHV engine, and wondered if I could use the exhaust valve from the CJ750 OHV, as it looks like a better quality part, and the collets are a much nicer design. Both intake and exhaust MT9 valves have a 37mm head, 8mm stem and 92mm length. See the CJ750 valve here: http://www.ural-zentrale.de/product_info.php/info/p1386_Exhaust-valve-Chang-Jiang-OHV.html
  12. That's too cool, no need for a boat there. Respect !
  13. The MT9 I bought will take too long to fix up, and having got the sidecar fever, I found a much more complete MT10-36 to get quicker on the road. This also needs some TLC and as both heads are broken, I have had to borrow from the MT9. But after fixing the electrics, adding two more indicator lights to the bike, putting K68s on it, and cleaning and adjusting the brakes, it actually runs now. Next step is to adjust the carbs at bit more, and punching the serial number in the hack, and then hopefully getting some plates on it.
  14. Ivar did you ever get these carburators fitted ?
  15. I actually cleaned and lapped both valves, then switched the wedges from intake to exhaust. It gave enough clearance for the cap to sit on the valve. The engine is much much smoother running now, and the idle was much higher than before. After running it good and hot I let it cool and adjusted the valves again. Then was able to adjust the carburator much easier than before. And the engine revved easier and felt more powerful. But I think I will overhaul the complete engine in the winter as there was a scratch in the cylinder too, and the left side it properly not in any better shape.
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