VINTAGE OSFS60 TECH HELP PLEASE

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VINTAGE OSFS60 TECH HELP PLEASE

Postby boz » Wed Mar 26, 2014 2:19 pm

Need some help with a vintage OSFS60 open rocker engine which I am trying to dismantle. It's an early one with the solid bar rockers. I know spares for these are hard to get so don't want to break anything. Does anyone know how to remove the rear circular cap, the bit that says OSFS60 on it ? It looks like I should put a small screwdriver in one of the little cutouts but like I said dont want to damage anything but I need to get to the valve cams. Also, I need to remove the rear bearing but there looks to be a screw holding a gear on which goes through the bearing onto a circular plate. Is this a dummy screw as the slot is silly thin and if it is a dummy how do I get the bearing out, will the bearing complete with back plate and gear come out as one ? Thanks.
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Re: VINTAGE OSFS60 TECH HELP PLEASE

Postby chiefss » Wed Apr 02, 2014 10:51 pm

Did you ever get help with your OS60? I have several of them and know how to disassemble and reassemble them. The one you have is the original. They made 4 versions.
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Re: VINTAGE OSFS60 TECH HELP PLEASE

Postby chiefss » Wed Apr 02, 2014 10:55 pm

The little rear cover just pops off. There is a rubber o-ring that keeps it on the engine. The screw under there on the camshaft is REVERSE or LEFT hand thread. Be careful with it. A lot of the parrs from the 75, 80 and 90 will fit in the cam area. There are 5 bearings in the engine. Four are common and one ain't.
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Re: VINTAGE OSFS60 TECH HELP PLEASE

Postby boz » Thu Apr 03, 2014 5:15 am

Can you explain how I remove the front bearing please ? As I said in the OP, there is a screw, or what looks like a screw with a real thin slot in the center of a plate behind the front bearing. Do I remove this ? I know I have to heat the casing before I can remove the bearing but I can't see how to remove the plate behind the bearing to free it up. What I did not say in the original post is that I made the bad mistake of boiling the whole dismantled engine in water and washing up liquid to remove the gunk which has now gone in to every part of the engine. The whole engine is completely gunked up so is now sitting in oil until I can dismantle the whole thing completely, so I really could use some help here. It's a valuable engine which I'm determined to fix up. Thanks.
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Re: VINTAGE OSFS60 TECH HELP PLEASE

Postby chiefss » Sat Apr 05, 2014 10:01 pm

If you mean the screw under the little round cover on the back of the engine that screw has a LEFT HAND thread. It is screwed directly into the camshaft. What you need to do is remove the whole rear end of the engine to get at the camshaft and cits bearings. This engine has 5 ball bearings in it.You said the front bearing are you referring to the crankshaft bearing or the cam bearing? There is one bearing in the middle of all this and it is mounted on the camshaft driver.

I have several books on these but I can't find the OS book. I'm still looking.
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Re: VINTAGE OSFS60 TECH HELP PLEASE

Postby boz » Sun Apr 06, 2014 4:28 am

The bearing I'm having trouble with is the front one. It looks like I have to remove a screw which goes through a circular piece (not sure what it's called) behind the bearing. The screw has a very thin slot, so thin that to me it looks like a dummy screw. Why they would want to do that beats me. Anyway, I don't want to try and force things until I know for sure. Perhaps if you could just go through how you would remove the front bearing on this engine it would help. Obviously the bearing when the casing is heated comes out the front but if this circular piece I mentioned is attached to the back of it then it's not going to come out the front. I've sorted the back of the engine, cams and all that it's the front that I'm stuck on.
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Re: VINTAGE OSFS60 TECH HELP PLEASE

Postby chiefss » Sun Apr 06, 2014 2:30 pm

Once more, there are 5 bearings in this engine. two on the crankshaft which are the front bearings two on the can shaft which are the rear bearing and one in the middle. The middle bearing is held in place by a screw with a allen head. Take that off and and there is a bearing on that part with a slot in it. That is what frives the camshaft. There is a gear on the back of it. I'm still looking for the book on this engine. The back of the camshaft has a screw with a very thin slot and it is a left handed screw.
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Re: VINTAGE OSFS60 TECH HELP PLEASE

Postby chiefss » Sun Apr 06, 2014 3:09 pm

Well, I found all my books on four cycle engines and not one of them has any pictures of a disassembled OS engine that old in it. I really don't want to take one of mine apart but will if you can't figure yours out. It is really quite simple. Take off the carb, remove the front and rear housings (the front has the crankshaft and the rear has the cam shaft). Look into the crankcase and you will see the cam driver with the allen head screw and the slot that the crankshaft fits into. There is a bearing on that driver. The rear housing has the camshaft and it's bearings. The screw in the center of the camshdt is left handed so don't breal it turning it in the wrong direction. To get the bearings out heat the parts in your over to about 250-300 degrees and then tap the part on a oiece of wood. They should pop right out.
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Re: VINTAGE OSFS60 TECH HELP PLEASE

Postby chiefss » Sun Apr 06, 2014 3:20 pm

I found a book. Send me your email address and I'll send you some pictures.
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Re: VINTAGE OSFS60 TECH HELP PLEASE

Postby boz » Tue Apr 08, 2014 12:02 pm

Chiefss, many thanks for all your help, pictures received. The bearing I'm not sure about which is giving me a head ache is the main bearing in the center part of the engine, I guess it's the main bearing. Does it come out towards the front or rear ? If it comes out towards the front then I will have to remove the circular plate on the back of the bearing, the part with the cog/gear on it. How do I remove this, does the screw in the center undo and if it does is it a reverse thread ? I'm asking because the screw has a very thin slot and I don't want to ruin it. I'm sorry I don't know the correct name for these parts, it would be a help if I did but the disk on the back of this bearing has a notch in it where the crank pin engages. I just need to know how to remove this to get it off the bearing. Thanks again for taking the time to help.
boz
 
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Re: VINTAGE OSFS60 TECH HELP PLEASE

Postby chiefss » Thu Apr 10, 2014 10:26 am

The only left hand thread screw is the one you can see with the little round cover on the back removed. Every other screw is a normal right hand thread.
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