Refinishing rocker arm faces

thuban

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It seems that over time, the rocker arms develop a shallow groove in the center of their contact surface, right where the cam lobe break over the top. Anyone refinish these if they are not too bad? If so, do you just stone them. I haven't seen this mentioned.

Thanks,
Thu
 
It seems that over time, the rocker arms develop a shallow groove in the center of their contact surface, right where the cam lobe break over the top. Anyone refinish these if they are not too bad? If so, do you just stone them. I haven't seen this mentioned.

Thanks,
Thu
The rocker faces are chromed plated to reduce surface friction as to the thickness I don't know that. If grooves are really deep,I would look for good replacements,you don't want to mess with the rocker face geometry to cam lobe contact
 
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Mine were worn and a UK member, Paul Sutton, very kindly refaced them for me. Have read threads about refacing the tappets, very technical, getting the correct radius so they aren't too noisy and don't wear again. How's your machining skills? Or buy new ones and get ones with Allen-key style adjustment instead of the original square heads.
 
Mine were worn and a UK member, Paul Sutton, very kindly refaced them for me. Have read threads about refacing the tappets, very technical, getting the correct radius so they aren't too noisy and don't wear again. How's your machining skills? Or buy new ones and get ones with Allen-key style adjustment instead of the original square heads.
I like to fool with porting heads and leave the machining to those who know what they're doing. Me personally I'd look for good ones and use elephant foots.
 
Raymondo, Thanks for getting back with me. Nice to meet ya! I think I can handle the machining. I was just wondering if anyone had a specific way which worked well for them. I have a couple of sets but I'd rather salvage these if possible.

Thu
 
Hi Jack, Do you have a brand of feet that have been working for you or you would recommend? I don't think I want any part of Mike's "XS Performance Rocker Arm Set"
Thanks Thu
 
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Raymondo, Thanks for getting back with me. Nice to meet ya! I think I can handle the machining. I was just wondering if anyone had a specific way which worked well for them. I have a couple of sets but I'd rather salvage these if possible.

Thu, this leads to some of the threads on refacing tappets- http://www.xs650.com/posts/409339/

There's a lot of reading there, interesting stuff but I'm not the owner of a machine shop. Cheers, Raymond
 
Thu, this leads to some of the threads on refacing tappets- http://www.xs650.com/posts/409339/

There's a lot of reading there, interesting stuff but I'm not the owner of a machine shop. Cheers, Raymond

Raymondo, that made my brain hurt! I suppose if engineering and making a better mouse trap is your kinda thing, It's all well and good. I have a powder torch. I can build these up, hard face them or whatever. But I would need to make a jig for the facing. I don't have time for that. I'm losing a crop sitting here! :laugh:
I think just a light stoning and with the kind of riding I do this thing will probably be running after I'm on the wrong side of the dirt.
Thank You, Sir.
Thu
 
Hi Thu! Yeah. Don't do the "elephant foot" adjusters, unless you want your valve stems to last forever, and be easier to adjust. :wink2:
And unless you can feel a definite groove in the rocker arm faces, or they're exceptionally corroded/pitted, I think they'll be okay. I don't recall if you said how many miles are on it, but they oughta last damned near forever. :twocents:
 
Yep, XS650 rockers are very durable, but I've seen a few that were badly worn, probably due to PO's abuse (low oil, oil not changed for a bazillion miles, gas in crankcase, etc.) If the rockers are badly damaged you might want to check the camshaft lobes with a micrometer. NOS rockers were plentiful not too many years ago, but they've gotten pretty scarce. I have some good used specimens in need of a good home. Send a PM if you're interested.
 
I'm gona try and cover all the bases here.
Tebo, Yep the valves need to rotate not scuff back and forth as pointed out in parts of 2M's and goodgollyjosh's discussion. I'm with ya. Miles, no I didn't. They should last a long time, factory.
grizld1, These are spares. They are in a V-cover and head set I'm putting on my bike after a shop repair failed. Very much appreciate your offer.

2m, they are in good shape except for the hair line down the middle. (Wonder how deep the case hardening? is on these?)
Anyway, for those that have heard it all; when I put the head together I didn't have a matched V-cover and head set to put on it. I used what was on it. Head was dusty and dirty but not oil stained. During the cleaning, I discovered that some time in the past, the valve keepers on the left rear intake valve departed the groove in the valve stem. The valve spring retainer rattled around on top of the valve before being swept under the cam lobes and driven thru the valley area under the left hand lobes. A shop? repaired the hole ( which evidently did not effect torque of the head or seal of the head gasket) by first riveting a piece of been can in the hole and epoxying over it.
You can't make this stuff up. Mean time, I found and purchased a 77 head set. If the guides are good, I'll just transfer all the parts in my head over, hand lap the valves and I should be good to go. It was worth a try and I may have broken the epoxy loose when cleaning. Look at all the experience I'm getting!
Thanks
Thu
 
... they are in good shape except for the hair line down the middle. (Wonder how deep the case hardening? is on these?)...

The rockers are forged, quite hard already. Typical case hardening (Not sure if that was done) runs about 0.005" - 0.010" deep. A light resurfacing could be tolerated. I found casehardened tips on the OEM adjuster tips, running about 0.040" deep.

Your judgement call on the hairline wear lines. In the shop, they'd be replaced. Some members here are running with worse rockers. Probably a source of extra clatter.

The floor of the cam tunnel has seen damage from others in here, usually from a lost/wandering adjuster. There's no structural demands down there, and the floor can be safely welded...
 
Here is an example of where a right cylinder exhaust rocker arm and cam lobe function failed. Reason unknown as the engine is a parts source. Likely even just set too tight as the whole rest of the top end is in very good condition.
My point here is that a part out engine
can be found about anywhere. These rocker arms are easily found and very inexpensive.
What I would recommend protecting is your camshaft ! Find a part out engine. If your cam shaft lobes are in good condition why risk resurfacing the rocker arms as a what, test ? A good camshaft is a more expensive and a key part to protect.
I believe this 83 engines life ended right here at the exhaust lobe.
I’ve wondered what that sounded like..
-RT
 

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2M, ever repair weld the floor? Just wondering the route to take. Yep, the structure was/is still solid. I'm taking it out of service but might be interesting to repair.

Machine,
Your post is right on. I'm just going to cannibalize the parts off the damaged head and cover, to this set. Good pix really brings the point across.
Thanks, Guys
Thu
 
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