Hi all!
Im plan to rebuild the engine and need to know;
-Do I need replace all ball bearing with all new one or just reused them? If I need all new and where I looking for to buy a new set ?
Thank you!
305 engine ball bearing
Hi Dream,
That depends of the state of the ball bearing. If you showed the bearings some respect with tearing the engine down, there is a chance that you don't have to replace all bearings. Clean the bearings with petrol and dry them with pressed air. Inspect the bearing, it's play and the sound it makes when turned around quickly and then decide the re-use it or not. I'm afraid that you need experience for listening to and feeling the bearing behavior when turned around quickly. To get a feeling buy a new C3 (a C3 bearing has larger internal radial clearances, normally used in applications where bearing temperatures can rise quickly ie. engines) bearing in a size comparable with the engine bearings and clean it with petrol and dry it. Feel it, touch it and listen to it while turning it around and compare with your bearing removed from the engine. If the bearing is relative cheap, I would replace it, but some bearings are really hard to get, and thus expensive (special bearings, for example the crank bearings). All together the price of the all bearings could go over 200 USD, so be very careful with the bearings you find in your engine cases and treat them nicely. No, I'm not aware of special bearing kits for this type of engine's, at least I never seen one. Jensen assembly of Japanese motorcycles requires great peace of mind (Pirsig)
I thought I was going to be replacing bearings upon dissasembly. It' just as Jenson said. Use care when tearing down and more than likely they'll not need replacement. My cam bearings felt like they had sand in them before cleaning. Washed em in Mineral spirits and blew dry and they were smooth as can be. Inspect them as u would a wheel bearing. Look for nicks, scoring and pits. If they dont look good , and dont fell good, they're not good. I think you'll find them individually aftermarket, but i bet they are pricey for good replacements.
Brent 64' CB77
65' CB160
Hi Tuan,
All bearings in the engine are special bearings, the part numbers contain a model number, except the bearings for the camshafts. These bearings are regular 6004-C3 bearings, and sold everywhere. The differemnce between regular bearings and special bearings are grooves for circlips, holes for positioning or lubrication, and sometimes the diameters (for example crank bearings). Bearings you should renew if possible are : counter shaft bearing : roller 5X6.25 (p/n 91102 253 000) If the right crank bearing is damaged (check for wear on the crank surface) try to obtain one of these (depending on engine number) : 91002 259 010 or 91002 259 020. If there is a lot of slack in the primary drive train, try to get both bearings (main bearing with p/n 91003 259 000 and the left crank bearing with p/n 91001 259 010 or 81001 259 020 depending on the engine number. If the chain (to the rear wheel) was to tight in it's life, there is a good change that you have to replace the bearing 91004 259 000. Sometimes these bearings pop-up on ebay, and if you are planning to ride your dream a lot, don't hesitate to buy these bearings when these pop-up, even if you re-used the ones in your engine now. Jensen assembly of Japanese motorcycles requires great peace of mind (Pirsig)
Thanks Steve,
On the same exel sheet of bearings I also composed a replacement list for the oil seals in the 305 engine, here they are : shift shaft / kick starter p/n : 91202250000 size (ID-OD-TH) : 14-25-7 p/n eriks : 10005836 / 10008718 material : NBR drive shaft p/n : 91203259000 size (ID-OD-TH) : 30-62-8 p/n eriks : 10006003 material : NBR point shaft p/n : 91204259000 size (ID-OD-TH) : 16-28-7 p/n eriks : 10005857 material : NBR crank shaft seal p/n : 91201259000 size (ID-OD-TH) : 32-65-7.5 p/n eriks : not for sale (only 10 mm thick) material : shift drum p/n : 91201200000 (91201283000) size (ID-OD-TH) : 12-25-4.5 p/n eriks : not for sale (only 5 mm thick) material : clutch adjuster p/n : 91205200000 size (ID-OD-TH) : 22-26-29.8 p/n eriks : not for sale material : clutch rod p/n : 91205259000 size (ID-OD-TH) : 8-21-6 p/n eriks : 1005190 material : NBR starter sprocket p/n : 91208259000 size (ID-OD-TH) : 20-30-5 p/n eriks : 1006423 material : NBR www.eriks.com Jensen
Last edited by jensen on Thu Dec 10, 2009 2:46 am, edited 3 times in total.
assembly of Japanese motorcycles requires great peace of mind (Pirsig)
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