Author Topic: BS90 Locked Up  (Read 2988 times)

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BS90 Locked Up
« on: November 23, 2008, 03:49:21 PM »
I have inherited my 83 y/o Father's BS90 which he purchased new in 1970? at JC Penney's in Kokomo IN.
The engine locked up in 1971, and the bike has been in his garage since then. I now have the bike in Highland IL., near Saint Louis. Anyone have any sources for a shop to take on the engine project?

Offline hmmmnz

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  • kiwi in scotland
Re: BS90 Locked Up
« Reply #1 on: December 02, 2008, 03:46:24 AM »
sorry wrong country for me to comment on who would fix it up for ya, but the single cylinder bridgestones are so so simple,

do it your self,
the hardest part is going to find the bits, so get a set of digital verniers, and let the fun begin

good luck :D
mini buffalo (chibi copy) 68' mkII 200


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Re: BS90 Locked Up
« Reply #2 on: December 02, 2008, 11:44:13 AM »
The challenge with a locked up engine can sometimes be getting that cylinder out of the bore.  What suggestions do folks have on this?

Dave K

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Re: BS90 Locked Up
« Reply #3 on: December 03, 2008, 07:51:11 PM »
First see if the piston is up and covering the ports. If it is, you can take a spark plug, break the porcelain out of it and thread it for a grease zerk. Of course I hope you have tried to use pentrating oils first to attempt to get some slipperiness to it. Any how, just use the grease zerk as a hydraulic pump. No sense trying to do it in one day, after all the bike has been like this since '71. But every couple of days give the grease gun another pump or two. Once you are down to the ports, then you "may" be able to remove the cylinder studs. This will permit the cylinder to lift off of the block. If that happens, you can now place some bolts with nuts around the base of the cylinder and the block and expand them like a jack. Work slowly all the way around. Use at least 4 bolts and nuts so you don't distort anything. Us some brass stock or even some good clean thin steel stock between the cylinder and also the block, between the bolt head and also the nut, so you don't get these mating surfaces all scratched up. DO NOT TRY TO PRY THIS APART. You will only damage the parts worse and probably also break some fins. Is this a Sport engine with aluminum cylinder or the cast iron cylinder?



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