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86 XL600R Rebuild - camshaft experiment?

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I brought home this gem recently, an 86 XL600R. Story goes that the previous owner had an autoshop rebuild the engine, including new weisco 11:1 piston, valves, etc. During the mechanic's test ride he heard a loud bang and stopped the bike - turns out the bang was the cam shaft flange breaking when one of the bolts holding the timing gear fell out. 

Only damage I can see is the cam gear (bent and warped in every possible dimension), cam flange (broken), and some damage to the plastic part of the cam chain tensioner. Somehow the valves and guides seem OK (i.e. they don't leak gas when closed and the head is upside down). 

A semi-local shop said he might be able to fix the broken flange on the camshaft. I trust the guy, if it's fixable he can do it, but would fixing/welding the flange be too risky?

I could replace the cam too, but I'm having a hard time finding a reasonable stock camshaft. Anyone have an extra 83-87 XL600R camshaft? 

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1 hour ago, Pete Morley said:

I'm sure you already know the Honda manual specifically says "use thread locker" on those bolts...

Yes, I will be checking everything that was done to this bike before putting it all back together.

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While you have the motor out, paint it.  I still think a red engine looks ridiculous. :cool:

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Edited by exdirtbiker
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It would be tough to know whether/how the welding affected the cam but really what's to lose?  TIG weld 70S-2 or 6 and keep the temps in check.  I'd fix it and check it for runout (or check it for runout then fix it).  As long as it checks out good I'd run it.  

Now, all that said I don't see how there could be that much damage and the runout still be good.  That's a lot of pressure and it's amazing there wasn't more carnage. 

If you get it fixed take lots of pictures and keep us posted. 

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you had me running out to the shop to see if the flange was pressed on or if it's one piece. Hard to tell, there is an index boss where the flange meets the shaft, but I'm not sure if it's two pieces or not. If it is I can machine a new flange and press it on... anyone know for sure?

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Unfortunately yours is one piece.  I'd say a new flange could be built and pressed on though.  The damage doesn't look nearly as bad from this angle though.  I'd fix that for sure.

Edited by Hollerhead

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3 minutes ago, MagnetMan said:

you had me running out to the shop to see if the flange was pressed on or if it's one piece. Hard to tell, there is an index boss where the flange meets the shaft, but I'm not sure if it's two pieces or not. If it is I can machine a new flange and press it on... anyone know for sure?

IMG_20170921_214953547.jpg

If you can machine a new flange , you can machine off the old one.

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2 hours ago, Pete Morley said:

While you have the motor out, paint it.  I still think a red engine looks ridiculous. :cool:

DSC01719.jpg

An XL with an engine that's not RED?! Sacrilege! :)

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That cam listed above for $129 looked good to me.

How are you going to press on a new flange, and -guarantee- that it wont "walk" over time? or worse, spin a little?

Sounds like a ton of work to save $130.

++++++++

Engine paint: I like to stir that pot once in a while.

It's clearly a personal preference, but I -really- hate the red engines.   I also never dated a redhead.  And I have Mick Jagger singing "Paint it Black" stuck in my head :p

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3 hours ago, Pete Morley said:

That cam listed above for $129 looked good to me.

How are you going to press on a new flange, and -guarantee- that it wont "walk" over time? or worse, spin a little?

Sounds like a ton of work to save $130.

++++++++

Engine paint: I like to stir that pot once in a while.

It's clearly a personal preference, but I -really- hate the red engines.   I also never dated a redhead.  And I have Mick Jagger singing "Paint it Black" stuck in my head :p

Keeping the flange perfectly aligned and in place would probably require it be welded on once pressed or indexed in some way. I can machine a new flange, but fixturing and machining the old cam shaft correctly wouldn't be easy. I'm looking at a new camshaft now.

 

I'm not sure how I feel about the red engine yet. Part of me likes it because it's different. But the previous owner painted not just the engine but everything around and attached to it red: bolts, hoses, wires, oil lines, everything is red. It's a little much.

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Quote

Part of me likes it because it's different

You could paint engine silver... Silver is different. With black pipes.

this is VHT SP127 "universal aluminum" on my GS1000G.  ( the head and cyl - not the side covers, they are raw / polished )

 

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Edited by exdirtbiker
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