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Post by hopwheels on Nov 2, 2006 14:37:02 GMT -5
Hey gang:
What all is entailed in a top-end rebuild? New valves, springs, rockers, piston kit, timing chain, gaskets and seals? I know there's machine work (valve seat grinding, cylinder honing/boring), but beyond that, is it a job for the experienced only? My '78 has almost 39,000 miles on 'er, and I think it's time. Don't know if the po ever re-did the top end, but I don't think so. There's just a lot of "clackity" sound coming from/around the top end even after she's warmed up. Found a sound file online somewhere of a stock SR500 and mine sounds much less smooth comparatively speaking. Thanks.
PS: And I guess hope for little cam wear, or it's replacment time for that too?
Gary
Hopwheels
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Post by StewRoss on Nov 4, 2006 1:28:23 GMT -5
Hi Gary, Yep pretty well what you said...some things though: Valves can be refaced if they haven't gone too far...avoid a knife edge on the sealing face of the valve...certain recipe for a burnt valve... Cam and rockers probably shouldn't need replacing at that mileage...however they may depending on how the bike's been looked after...only by looking can you assess...always do regular oil changes after you've done this. You might consider replacing the cam bearings...geniune... Valve springs are also something that can be checked...can't recall the spring pressure...replacements are probably cheap (...genuine only...unless you have a performance cam...then the selection is a personal thing)...R&D??? On the whole, not a hard job at all really. SR  |
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Post by hopwheels on Nov 4, 2006 10:26:04 GMT -5
Cool. Thanks Stew. I've got most of those parts on the way, other than new cam bearings. I'm going to try and rebuild a separate top-end and then transplant it onto my motor. Less down time that way.
Gary
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Post by hopwheels on Nov 6, 2006 1:07:54 GMT -5
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Post by StewRoss on Nov 6, 2006 3:21:23 GMT -5
Hi, Looks like it should work...the cutouts are so you can put the valve spring retainer collets in more easily... SR  |
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Post by hopwheels on Nov 8, 2006 10:03:36 GMT -5
Hey Stew:
I found a similar one at an auto parts store and bought it. (Sometimes I don't like eBay for things like this tool, 'cause you can't hold it in your hand and see if it will work). Worked great. Got to get the whole top end over to a media blaster now. I'll have a bunch of questions getting into the rebuild. I don't have any machining equipment, so getting the valves ground/seated and the cylinder honed/bored (I went up a half size on the piston) will require a shop. Not sure where to go nearby for that.
Gary
Hopwheels
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Post by StewRoss on Nov 9, 2006 3:20:40 GMT -5
Hi Gary, Great stuff...be careful about the blasting though. Some people are prone to almost blasting alloy away...the other issue is be really finicky with cleaning of the head etc. after it has been done! Really careful!!! I'd also mask up the mating surface of the head and cam box with aluminium tape if you do them separately... Make sure that you clean every speck of the stuff from the head inside and out. This stuff can make short work of your engine if you leave it in there. SR |
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Post by hopwheels on Nov 10, 2006 11:52:40 GMT -5
Thanks Stew... good warnings! I'm going to try and have the guy I use take great care (he's a true machinist, so maybe he'll get the importance of not altering any critical surfaces). Is there a tried and true method to flush out the parts afterward?
Gary
Hopwheels
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Post by StewRoss on Nov 10, 2006 21:39:05 GMT -5
Hi, None that I know of except be very picky...block off oil galleries etc. to start with and pull out the rag or whatever you use carefully to avoid stuff falling in...the stuff still mages to get to where it shouldn't though... SR |
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Post by fenz on Nov 11, 2006 6:11:36 GMT -5
I have had good success with a sand blaster with glass media instead of sand.You can hit gasket surfaces with out any worries of removing metal.However i agree with Stew block up oil galleries and wash it out and wash it out again.
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Post by hopwheels on Nov 11, 2006 11:31:38 GMT -5
Thanks gents.
Gary
Hopwheels
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Craig
Junior Member
Posts: 66
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Post by Craig on Nov 11, 2006 19:39:54 GMT -5
I hear soda blasting is a good alternative - less harsh then sand and beads, and can be washed away easily with water! Only in Sydney, as far as I know ( www.sodablast.com.au)  Rgdz CL |
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Post by StewRoss on Nov 12, 2006 5:36:13 GMT -5
Hmm, that sounds interesting...I'll check it out. SR |
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Post by miker on Nov 13, 2006 8:42:30 GMT -5
I've seen soda blasting recommended for removing the finish off the cast wheels. Should work pretty good.
miker
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Post by colinjay on Nov 14, 2006 1:21:44 GMT -5
I had the topend of my stock SR "Hydroblasted" when I rebuilt it back in 2000. A very good finish looks like new, it is a lot finer finish than glass bead blasting. I had my work done by Gregg who runs a small auto machining w/shop in Cheltnam? (I think) in melbourne, he specialises in working on Merc's, Porsche's etc and is quite expensive but does good quality work.
Hydoblasting uses glass beads in liquid (water?) I am trying to find someone here in SA that does this type of blasting but it is not common.
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