Andre3000 55 Report post Posted January 8, 2012 Having trouble spliting motorcycle crankcase, obviously hasn't been apart since new in 1977. I'm hoping some guru's on here will be able to share any tips or tricks they have used to get them apart. Also can anyone recommend some off the shelf penetrating fluid? the wd40 just isn't cutting it. Quote Share this post Link to post Share on other sites
antil33t 90 Report post Posted January 8, 2012 I hear wurth penetrating lubricant stuff is better than wd40/crc ect. Maybe freeze spray? Quote Share this post Link to post Share on other sites
thorburn 120 Report post Posted January 8, 2012 If it's a 4 stroke id put some heat on it where the dowels are Quote Share this post Link to post Share on other sites
hybrid 1039 Report post Posted January 9, 2012 http://www.crc.co.nz/Automotive-Lubricants...7ae9c3-6547.htm Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted January 9, 2012 It's more likely to be the crank main bearings, and gearbox bearings holding it all together. There is a proceedure to split these. Do you have a manual Andrew. When I worked at Whites Yamaha 40 years ago we had a very comprehensive set of tools to do these. Especialy on the 2 strokes. Dont use screwdrivers or metal wedges to do this. Looking at your project thread I would say it's probably terminal with what you have already done to this motor and perhaps not worth repairing. Quote Share this post Link to post Share on other sites
Andre3000 55 Report post Posted January 9, 2012 Will grab some of that crc penetrate, thanks josh. Crank and gear shafts spin freely after cylinders were forcibly removed. Yes i have the service manual. Pistons were at middle of travel when i put in press so i seriously doubt there is any "terminal" damage done by me. I thought splitting cases with wedges was a complete no no, especially if there is no gasket. I will update thread with progress this afternoon. Frame is looking puuurty.... Quote Share this post Link to post Share on other sites
*Glenn* 854 Report post Posted January 9, 2012 Will grab some of that crc penetrate, thanks josh. Crank and gear shafts spin freely after cylinders were forcibly removed. It won't be the shafts that are holding it together. It will probably be the bearings stuck in the casings, and obviously these bearings are pessed onto the shafts. How does the manual suggest opening it up ?? Quote Share this post Link to post Share on other sites
Dave@nz 11 Report post Posted January 9, 2012 (edited) Hi, The usual method of separation of the crank case half's is once the fly wheel is removed from the crankshaft then remove the stator windings. A puller is secured into the threads that the stator screwed in to and pushes on the end of the crankshaft, an automotive crank shaft front pulley remover would do for this used with a selection of long bolts. Tighten the bolt on the end of the puller to apply sufficient to load but not enough to strip out the stator securing threads in the crank case, then if it hasn't moved heat up the area in the side of the crank case around the main crank bearing. It will move with heat and pressure best with more heat than pressure, an electrical heat gun is very good for this job. It is usually the slight interference fit of the crank bearings and the crank case combined with a small amount of corrosion between the bearing and case that will hold them tight. At assembly it might be necessary to heat the cases to install the main bearings. Dave. Edited January 9, 2012 by 87M3@NZ Quote Share this post Link to post Share on other sites
Andre3000 55 Report post Posted January 9, 2012 It won't be the shafts that are holding it together. It will probably be the bearings stuck in the casings, and obviously these bearings are pessed onto the shafts. How does the manual suggest opening it up ?? the penetrating fluid did the trick, bearings popped out easy as, no corrosion inside the block at all. Manual just says to tap around the block with soft faced hammer and to remove all the bolts..... Quote Share this post Link to post Share on other sites
Andre3000 55 Report post Posted January 9, 2012 Hi, The usual method of separation of the crank case half's is once the fly wheel is removed from the crankshaft then remove the stator windings. A puller is secured into the threads that the stator screwed in to and pushes on the end of the crankshaft, an automotive crank shaft front pulley remover would do for this used with a selection of long bolts. Tighten the bolt on the end of the puller to apply sufficient to load but not enough to strip out the stator securing threads in the crank case, then if it hasn't moved heat up the area in the side of the crank case around the main crank bearing. It will move with heat and pressure best with more heat than pressure, an electrical heat gun is very good for this job. It is usually the slight interference fit of the crank bearings and the crank case combined with a small amount of corrosion between the bearing and case that will hold them tight. At assembly it might be necessary to heat the cases to install the main bearings. Dave. Thanks for this in depth description, passed that on to my brother who has a very stubborn duke block. Quote Share this post Link to post Share on other sites
