oh400ex 629 Posted December 12, 2020 Here is a photo update for y'all. Frame has been painted with primer to prevent corrosion but will be worked with more later. Splitting the cases and removing the flywheel went well. Only follow the method described below if you are discarding the crankshaft and replacing with a new one. I held the engine up by the flywheel a few inches above a soft surface (in case of drop) and hit the crank with a large ball hammer. Tapping on the fly lightly helped to loosen a bit and it eventually wiggled out. With the rest of the bolts under the flywheel removed I again hit the end of the crankshaft to begin forcing the cases apart. Keeping the gap even as you split is VERY important. The majority of your force in splitting is on the crank but the transmission side needs some persuasion as well. My favorite method for this is using a soft wooden block and there are always a few points on the cases where it can handle a bit of light impact. Never on a sealing/gasket surface! The force of your hands pulling with light taps to shake things loose is enough most times and is a great starting point. Sometimes you may need to close the gap on the crank side slightly to encourage the transmission side to let go. It should come off straight ideally and if you see it getting < shaped stop and work the closed side. Never pry it apart... you will ruin the sealing surface or worse. Once cases are split the crank can be again hit with the ball hammer to remove from that side. With the part of the transmission that would normally hold the drive sprocket facing up take the top case off leaving the transmission (and likely crank) behind. The transmission can be disassembled easily and kept as one piece. I will be disassembling this unit to check closely for wear but it usually is not needed. Much easier to keep the transmission gears as one unit. Shift drum and forks will need to come out first and can be put back in easily. Bearing were removed with heat from propane torch, impact sockets and the ball hammer. Heat the case and try not to heat the bearing. On this engine, one fell out and one just needed a very light tap. Lots of new OEM parts have arrived so it's time to get busy! Thank you for looking! 2 Share this post Link to post Share on other sites
oh400ex 629 Posted January 15, 2021 Bottom end is mostly done. Replaced all bearings with OEM replacements using freeze/heat and press if needed. No problems with the crank installation or case marrying. I froze the crank and heated the inside bearing race for a drop-in install on the clutch-side case. Using the crank puller/installer and light taps of my palm on the transmission side brought the cases together easily. Everything was coated liberally in assembly grease and I poured oil on/in bearings, gears etc. Seals were pushed in with heavy thumb pressure and driven in the rest of the way with light taps on deep-well impact sockets. Here are a couple pictures of the cases before they went back together. Thanks for looking! 2 Share this post Link to post Share on other sites
Wheeler 2,524 Posted January 16, 2021 looks great! it's exciting getting a motor together! Share this post Link to post Share on other sites