Is this Cam Center Journal too far gone to save?

I am refreshing an 87 XR600R and the top end appears to have been oil starved by the PO. He was riding on a freeway for a couple hours, it started getting louder, he shut it off and trucked it home.

 

 

I pulled the motor apart and there are some parts to replace.  one of the ones that is messed up is the head right at the cam center journal. I have read that you can sand this down with 600 then 1000 grit sandpaper and use them like this. 

 

or do I need to get another head, or send this out to be machined out for bearing shells?

 

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Probably varying opinions,,Mine is clean it up with a fine rounded file and give it a bit of a sand and use it. I just don't think the center journal is that critical,,take a bit to flex the Cam in the center..Can you get shells put in it???..I've yet to see anyone have it done here. As I've said a number of times , a guy down here used to do it on the old XL/XR,,70s models but I haven't heard of anyone doing it on the 600s..How do they sort out the oiling to that point etc is what I wonder??,,though I can't say I've noticed any oil holes or anything in the standard setup that sorts that out..Maybe I didn't see them, have forgotten, or haven't studied the Cam/Head closely enough.

Edited by Horri

I found a link last night to a shop that apparently will machine them out for shells.    I was actually looking at my Yamaha Big Bear valve covers last night and thinking of something.  The Yamahas have this little "Shelf" in the valve cover  right over the valves.   I couldn't figure out what they are for but with a little research, I found they are designed to catch and hold oil,  the oil then drips right on the rocker arm where it hits the cam.

 

pretty ingenious if you ask me.....  I was looking at my cover and I think I could build up a little shelf there pretty easily and have it constantly dump oil right on the cam lobes. 

 

the yamaha is interesting, if you run the engine and then very very carefully pull the caps off,  especially if you can tip the bike sideways to keep the shelf level it'll be full of oil.  that's gotta help having oil constantly dripping right on the cam lobe to rocker arm point.

 

 

A couple of posts on advrider seemed to indicate this shop can remachine your journals and put a shell in there.

 

I would assume that since the journal itself has no oil hole, the oil would come via the camshaft and be OK in shells.  But I am clueless, the fact nobody's doing it would imply you can't or shouldn't be done. or at least that's what it usually implies.....
http://www.enginedynamics.com/index.html

Engine Dynamics or XR`s Only can weld and re-machine the center bearing..

 

B

I work as a machinist in a job shop. It would'nt be that hard to weld it up and remachine it in-line with the others. A person would need to find out what alloy would be best for it. I may be talked into it, or trading with my good head.

Edited by jjktmrider

can anyone give me any hints what jjktmrider likes so I can bribe him into figuring out how I can fix this?  OK jjktmrider, what's the weakness? Cookies?  what is it?! :)   I am going to call some shops and see how much it would cost to do but I'm not even sure what to ask them.

 

what do you mean trade your good head? Do you have a functional one you are looking to sell or trade?  I have two things to resolve before reassembly: the cam journal issue/ head replacement, and Piston/rings issue.  not sure if I should get a cast piston like Pro-x or forged like Wiseco. I am reading through tons of threads debating the merits of each, I am wavering back and forth....

Mmmmm Cooooooooooooooooooooooooooooooooookkkkkkkkiiiiiieeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeesssssssssssssssssss !!!!!!

 

 

Oh, anyways, I did mean I have a good '87 XL head that I would concider trading and I'd then fix yours when I got time to. I'd have to make a spade type tool, or copymill an machine the journal out on the cnc. Not real hard to do but I doubt it would end up perfect without some little pit holes, almost impossible to get all the oil out of the aluminum without some serious cleaners and acid which may do more harm to other parts of the head. Since that journal isn't extremely important I don't think a few small pit holes would hurt a thing, might actually help hold oil. But it would be best to swap both head and rocker cover together, I don't think they are meant to be totally interchangeable.

 

I would go with a forged Wiseco, not much saving by getting the cast and way better quality. That same '87 XL motor I have has a newer 101mm Wiseco piston and I have new rings for it. Hmmmmmmm

Edited by jjktmrider

I've got the same thing goin on in my bike. I'm sending it to xr's only. they weld and machine it for $120 and they do it all the time. I'm having my whole top end done there tho.

Cycle wizard from advrider gets very good reviews to, I'm sending mine to him to get worked over, New valves, valve job, regrind journal, weld and regrind cam.

Cycle wizard from advrider gets very good reviews to, I'm sending mine to him to get worked over, New valves, valve job, regrind journal, weld and regrind cam.

He did my XL600 head.  Decked, SS valves, new seals, new bronze guides,  bead blasted, and I even had him hog out the intake ports to 30mm to match the size of the 83 XL600 ports.  Good work, no complaints.

 

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Did he redo your cam too? I am not sure if I should send him my cooked cam too fix and sell my replacement cam, our send him the replacement oem cam I bought and keep the cooked one for it's core

I was able to save these. Be careful though. Patients and a good eye are key. I trimmed off the messed up part with a dremmel tool. Take off as little as possible you need that surface. And then I used lapping compound between the cams and journals while rotating the cams by and simultaneously tightening the caps half a turn at a time. Just be carefull cause you need like .006" tolerance (impossible to get by hand really) If you want to do this rout mesage me and ill help you out. My head is a little noisy since I put it back together but its been 10-15 hours ago and no problems so far?? Btw these pics are after the dremmel job

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whats that dent at the upper part of the combustion chamber above the sparkplug hole/valves 

 

The '83 XL's had a kicker activated auto decompression valve there. Honda just used the same casting for all the 600's, just never machined the valve hole out.

This is my '83 head when I took it apart, the little valve is seated in there. The top looks just like a miniature intake/exhaust valve.

You can tell which valves were leaking badly on that head plus that it had bad rings and a shot cam lobe(upper right valve).

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Edited by jjktmrider

The '83 XL's had a kicker activated auto decompression valve there. Honda just used the same casting for all the 600's, just never machined the valve hole out.

would give a $hitty burn? i thought combustion chamber shape was rather important for both power and clean burn...?

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