Bridgestone Motorcycle Parts Discussion Board
Bridgestone Tech Talk => 50, 60, 90 & 100 Talk => Topic started by: Dan44 on August 12, 2015, 10:23:54 AM
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A couple of weeks ago I drained and refilled the oil in the transmission. I left it up on it's stands and everything looked good. I took it out yesterday and noticed that when the bike leans on the kick stand transmission oil runs down the kick stand and pools under the bike, but it doesn't leak when it's on the main stands. Does anyone have any insight for this? I also seem to only be getting 40 mph. Thank you
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Hey Dan44, there are two oil seals on the left side of the engine that hold back transmission oil. One on the gear shift shaft and one on the drive sprocket shaft. Either or both may have failed or dry rotted over the last 40-50 years. It could be a bad gasket or there could be a hole in the crankcase near the sprocket. You should clean and dry the engine and figure out where the leak starts. Hope this helps, Steve
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Ok I'll take a closer look, Thank you for taking the time to answer my question
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So I cleaned her off and followed the leak to the drive sprocket shaft :( I'm not seeing anything in the manuals for replacing this seal without disassembling the entire engine. Is there a little easier way to get to this? I have attached a photo, the screw driver points the the seal that is leaking.
Also looking in the parts manual I think 09090-107 is this oil seal, is that the only part I'll need to replace?
Thank you
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I have never tried and don't know if it's possible. You may be able to remove the oil seal collar p/n 2483-5000 then the oil seal p/n 09090-107 and replace it without disassembling the engine.(?) Any other members have any thoughts on this procedure? Remember, I haven't tried this. Steve
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Dan,
I'm not familiar with this particular engine but based on looking at the parts manual, you have nothing to lose by giving it a shot, Seal 21x35x7 could be available from any good supplier. Also have a look at the collar, if it's deeply grooved replace that as well and maybe the seal 12x22x7 on the gear shaft, just to be sure.
Just a thought, was the sprocket nut tight, the collar seems to rely on being clamped against the inside bearing and the sprocket to stop oil creeping between it and the shaft.
Good luck and let us know how you go on for future reference.
Brian.
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Actually when I took the cover off I found that the nut that is supposed to hold the sprocket on was missing. Maybe I should try getting a nut on there and see if it still leaks?
Thanks guys!
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For future info, most seals like that can be removed using sheet metal screw(s). Use a very sharp punch (hardened nail, ice pick, etc.) to punch a hole through the face of the seal (this will be metal), screw in a sheet metal screw, then use a pry bar or slide hammer puller on the screw to pull the seal. Don't drill the hole for the screw as you don't want drill chips in the bearing behind it. Don't screw the screw in very deep either as you don't want to damage the bearing. This doesn't always work cleanly, but in general seals can be pried out one way or the other without disassembling the engine. Heat around the seal also helps.
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Ok that's what my buddy here at work was telling me this morning too. Then after the old one is out I should be able to oil up the new one and tap it in with a slightly smaller diameter socket and mallet right?
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Yep, just tap her in, taking care to keep the seal aligned with the bore, so it goes in straight. Be sure to lube the OD of the seal ( I use wheel bearing grease, but oil should work as well).
...bert
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I found a nut that fits the drive shaft (M16-1.50) refilled the transmission and drove it around for a while then let it sit idling, the leak seems to have stopped. Thanks for your help guys.
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Cool! Enjoy the ride!
...bert
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Hey Dan44, there's a 17mm splined lock washer p/n 09047-103 under the nut. That may be why it fell off in the first place. Did you check out the parts manual? Have fun, Steve
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Yes sir, the lock washer was still there oddly enough