XS650 Top End Buildup

Jim, you state at the very beginning that the bottom end was disassembled. Was it something in the bottom end that necessitated this re-build? So, were the cylinders okay? And the cylinders just needed a hone and new rings, and you re-used your old pistons?
 
Jim, you state at the very beginning that the bottom end was disassembled. Was it something in the bottom end that necessitated this re-build? So, were the cylinders okay? And the cylinders just needed a hone and new rings, and you re-used your old pistons?
Reason(s) for taking it all the way down... first, it leaked oil out faster than I could pour it back in...:rolleyes: Main reason is I'm doing a full restoration on the bike. That thread is here. Yes, cylinders and pistons were OK. Just a hone and new rings.
 
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This is just for additional information. Regarding the guide bar nuts, stock versus replacements from Mikes XS.
There have been some concerns raised regarding possible differences in dimension , resulting in the front cam chain guide being mounted further rearward in the cam chain tunnel.
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Here is the OEM on the left vs Mikes on the right.
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Mikes measured out at 12.4mm vs. 11.5mm for OEM
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The OEM and Mikes were then both installed into the cylinder with new copper washers and the amount that protrudes into the tunnel was measured. The OEM measured at 2mm beyond flush vs 3mm for the Mikes unit.
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So the replacement from Mikes extends into the tunnel 1mm further. I cannot say if this has a negative impact.
I’m just posting this here at Jim’s request.
 
But neither solves the bad chrome issue. Use them if you want but I consider them a total waste of money, money better spent on other more needful things (steering head bearings, new brake line, good rear shocks, elephant foot valve adjuster screws, HD clutch springs, fork brace, the list goes on and on).
 
$4.35..........If rebuilding a Basket case and these parts were missing it is a small cost. There can be reasons for needing to buy these parts......or go to Evilbay and pay some one who thinks any XS650 part is their retirement fund
 
$4.35..........If rebuilding a Basket case and these parts were missing it is a small cost. There can be reasons for needing to buy these parts......or go to Evilbay and pay some one who thinks any XS650 part is their retirement fund

Hello! I have a basket case... lol. can you suggest fair retailers for parts as needed in a cyl./top end rebuild? Thank you.
 
Hello! I have a basket case... lol. can you suggest fair retailers for parts as needed in a cyl./top end rebuild? Thank you.
Best thing to do is start a build thread and ask for advice there.... so all your info will be in one place.
 
Before you torque the head down, you need to install the two covers where the points and advance mechanism go. The flanges on these are what centers the cam and cam bearings in the head. If you torque the head first, these covers probably won't seat properly and your cam and bearings won't be properly centered. EDIT 2/3/19. For the most accurate cam centering, install the housings without the gaskets and o-rings and tighten. Once you're satisfied they're seated, take 'em back off and install them with the gaskets and o-rings. END EDIT.

To replace the camshaft end seals, press them out and back in with a hyd. press if you have one and a socket just slightly smaller than the seal.

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If you don't have access to a press, use your vise the same way using the socket and a piece of wood...

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As you can see in the next pic, the Tour Max seal kit I used isn't quiet the same as the OEM seals. They're a little thinner.

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New is on the left, OEM on the right. Where the OEM was flush on both sides when installed, the new one will be slightly recessed on the outside (red arrow). Just make sure the inside of the seal is flush with the inside flange after pressing in (red arrow in next pic.).

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Install the gasket and O-ring.....

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.....a drop of blue loctite on the 6 screws (3 per side), and torque the covers into place. Don't forget to add the cone shaped starloc washers to the screws. Not really sure why Yamaha saw fit to use a gasket and O-ring on these...

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If you had the rocker arm shafts out, don't forget to reinstall the plugs first. Now you can go ahead and torque the head as described previously.

The oil tube is next. The union/adapter has a crush washer that needs annealing or replacing.

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You'll need a 22mm crows foot to properly torque this (a 7/8" SAE will also work). Don't forget to put the crows foot 90deg. to the torque wrench so the torque value doesn't change.

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There's two copper crush washers for each banjo bolt.... one between the bolt head and the oil tube and another between the oil tube and the rocker box. Treat them as previously explained.

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The cam chain tensioner is next. I back the tensioner all the way out and then thread it back in a turn or two.

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A light coat of sealant on both sides of the gasket.

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And install the tensioner assembly.

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Once the tensioner is installed, I adjust it in until the pin is recessed about 1/16" to 1/8" (green arrow). Note: This is just for the initial run. After I'm satisfied everything is good on the run, I'll readjust it per the book. Make sure the copper crush washer (red arrow) is either new or annealed and tighten the lock nut down while holding the adjuster. Install a new o-ring in the acorn cap (red arrow) and install it.

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The next step (for me anyway) is to install the engine. Once installed I'll spin it over 'till I get good oil flow showing inside the valve covers. Once I'm happy with that I'll go ahead and adjust the valves and install the valve covers... then the carbs... exhaust.... well, you get the idea. Hope you guys found this helpful.
Jim I have indeed found this very helpful. However I need a little more advice. Can you suggest the best way to install the rocker arm shafts. Before I proceed to screw this part of the re-assembly I thought that I would seek out some advice.
 
Jim this is all very helpfull and I am ready to do the final assembly. However I need some advice on the best way to install the rocker arm shafts. Before I screw it up I thought that I had better seek out someexpert advice!
 
Jim this is all very helpfull and I am ready to do the final assembly. However I need some advice on the best way to install the rocker arm shafts. Before I screw it up I thought that I had better seek out someexpert advice!
I just tap 'em in with a brass drift. Make sure there's no burrs on the shafts or in the bores, liberally lube the bores and shafts and slowly tap 'em in.
As soon as they clear the first bore, set the rocker in place and keep tapping. Nothing special to it really.
 
Thanks. Hope it helps you.
Hi Jim, I was interested to see Robin’s post about the oil baffle going in the head before the top end build-up. Naturally I checked mine and it isn’t there! Of course and a picture taken on the head right after dis-assembly shows no indication that one was there. Clearly somebody was into this engine at some point before Robin bought it. Just to be sure I looked through all of the parts taken off the bike during tear down and nothing is there. I visited mylocalYamaha dealer today to try and buy one and not surprisingly they couldn’t even produce a picture of the head! Any hints as to where I can secure one of these baffles
 
The head off of my XS2 did not have that baffle when I pulled it off, and I’m quite certain I was the first one in there since the factory built it. I reassembled it with out it.
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