Getting Ready to Re-assemble My Top End - LOTS of Questions

[poorman9]

Here's the story - I bought this '81 XS650H as a pile of parts, it's got 9k on it, and was dissembled and left in a guys garage for several months. He took apart the top end because it was leaking oil, beyond that I know nothing about how the motor ran.

I've since:

• Bought the Clymer manual
• Ordered a full set of gaskets from Mike's
• Got a new set of rings (read about that here)
• Had my cylinders miced and honed by a professional
• Replaced the master link in the cam chain
• Removed the sump filter
• Washed out the bottom-end with kerosene
• Bead blasted my cylinders, head and head cover
• Carefully cleaned dust and glass from blasting
• Removed any old bits of gasket from mating surfaces
• Cleaned and de-greased everything I could find
  
  What's missing from this list?

Normally I'd just jump in, but this is something that I'd only like to do once. So I've got some questions --

1. What kind, if any, sealant should I use and what gaskets should I put it on?

2. When I had the pistons removed, I marked them 1 and 2, but I wiped off the marks on the cylinders so I have no idea which piston went in which cylinders. What should I do? 50-50 shot right ?

3. Copper washers - gasket set didn't come with any new ones, I know these are important, I've got three old ones sitting on my parts table, should I have more?

4. Should I grease my Camshaft Bearing? I've got Moly grease that I used on my steering bearings.

5. My gasket set came with valve stem seals, should I replace the old ones now? I don't know if this needs to be done, or how much of a pain it is.

6. My crankwheels have developed some light surface rust, check out the picture below, should I do anything about it?


Also, any tips similar to: "Don't forget to stagger the ring gaps," or anything else you've once messed up would be great!

 

[member3480]

If i was you i would replace what you can.Replacing valve seals is not hard just need tool to compress springs to get keeper out. Did you take both wrist pin clips out .Good way to tell which piston goes where .Leave inside clip in. You can use your favorite gasket lube but don't get crazy. Make a check list and do one part at a time. I use hose clamps around rings so you can slid piston in easy and as i build i oil everything with WD 40 or just use motor oil so everything has some lube on it.HAVE FUN

 

[nj1639]

Watch your torque specs.
Center the cam and make sure the cam bearings are set in all the way, wouldn't worry about greaseing them as they get plenty of oil. I use 2 stroke oil on reassembly of any parts associated with combustion.
And very important- watch your torque specs.

 

[pa23driver]

how's your front cam chain guide looking (the thing opposite of your cam chain tensioner arm)? those things are natorious for breaking apart.

you could use some sort of light grease on the cam shaft bearings (i used assembly lube) to keep them lubricated on initial start up.

if you got the head off i would definitely replace the valve stem seals

 

[grizld1]

That rust on the flywheels and primary gear doesn't look good. Your cam chain is already split, so if I were you I'd pop the lower case half, pull the crank, and inspect the main bearings. It doesn't take much exposure to moisture to eat them up, and if you see any pitting at all, they're lunch.

 

[5twins]

A quick count gives me 7 copper washers. There is one under the fitting at the base of the cylinders that the oil pipe connects to and 2 on each banjo bolt at the other end of the pipe. There are 2 small ones on the M6 bolts that hold the front cam chain guide in.

I would replace the cam chain if the motor has 20K or more on it. I would replace the front guide no matter what the mileage. If your gasket set is the new type, the cylinder base gasket is chemically treated with sealer and can go on dry. Head gaskets can go on dry but I like to add some thin rings and lines of sealer for insurance like so .....

Replace the original rubber/metal washers under the 4 outside acorn nuts with brass or copper ones. Use 30-35 ft/lbs of torque on the 8 large acorn nuts.

 

[retiredgentleman]

Here's a good link to read:
http://xs650temp.proboards.com/index.cgi?board=EngineModified&action=display&thread=327

You should lap the valves, and yes replace valve seals.

Have you read the Yamaha Service Manual at sites such as www.biker.net?

No need for a ring compressor; install the pistons from the bottom of the cylinders. The cylinder bottoms have a chamfer. Just use a popsicle stick to push the rings into the cylinders.............its very easy to do.

ThreeBond 1104 is an excellent gasket sealer.

 

[poorman9]

how's your front cam chain guide looking (the thing opposite of your cam chain tensioner arm)? those things are natorious for breaking apart.

Your right, on closer inspection the small outer lip on one side is starting the crack off. I'll be getting a new one from Mike's.

A quick count gives me 7 copper washers.

Thanks for counting I'll be ordering "Top end Copper Sealing Washer Kit" from Mike's
1pc. ( @ Oil feed tube base at crankcase),
4 pc.( @ Oil feed tube - Top of head at bolts)
2pc. 90430-11033 (@Rear of cam chain guide support nuts to cylinder front)
2 pc.# 90430-06014 @(Cam chain guide fastening bolts at front of cylinder)

Here's a good link to read:
http://xs650temp.proboards.com/index.cgi?board=EngineModified&action=display&thread=327

You should lap the valves, and yes replace valve seals.

Have you read the Yamaha Service Manual at sites such as www.biker.net?

No need for a ring compressor; install the pistons from the bottom of the cylinders. The cylinder bottoms have a chamfer. Just use a popsicle stick to push the rings into the cylinders.............its very easy to do.

ThreeBond 1104 is an excellent gasket sealer.

I'll definitively replace the valve seals. I can rent a valve spring compressor from my local auto zone for free.

Ordering a tube of Yamabond

And thanks for the links, those owner's manuals have pretty detailed exploded view's.

If i was you i would replace what you can.Replacing valve seals is not hard just need tool to compress springs to get keeper out. Did you take both wrist pin clips out .Good way to tell which piston goes where .Leave inside clip in. You can use your favorite gasket lube but don't get crazy. Make a check list and do one part at a time. I use hose clamps around rings so you can slid piston in easy and as i build i oil everything with WD 40 or just use motor oil so everything has some lube on it.HAVE FUN

You're right, I left the clips in on the insides of both pistons, so I got that figured out.

I do have some blue gasket sealant that I probably stole from my dad's tool box a couple years ago, but apparently I should spend the money on Yamabond or Threebond

Watch your torque specs.
Center the cam and make sure the cam bearings are set in all the way, wouldn't worry about greaseing them as they get plenty of oil. I use 2 stroke oil on reassembly of any parts associated with combustion.
And very important- watch your torque specs.

Got it, center the cam and watch the bearings.

And torque specs, I was told to be very careful with those, bought a torque wrench from good old Harbor Freight.

That rust on the flywheels and primary gear doesn't look good. Your cam chain is already split, so if I were you I'd pop the lower case half, pull the crank, and inspect the main bearings. It doesn't take much exposure to moisture to eat them up, and if you see any pitting at all, they're lunch.

I actaully sprayed some WD40 on the flywheels this morning, rubbed it around a bit and it cleaned off the rust, i probably formed after I cleaned everything with kerosene last week, up here in Oregon everything starts to rust instantly.

Thanks everybody!

 

[5twins]

If you haven't disturbed those chrome nuts on the front of the cylinders, you probably don't need to replace their copper washers. I never take those off and haven't had any problems with leaks. While there are leak-prone areas on this motor, that's generally not considered one of them.

 

[XSLeo]

On most of the gaskets that haven't been mentioned yet I wouldnot use any sealer. A sealer will glue the gasket and parts together and make it very hard to clean off if you need to take apart.
Ones like the camchain tensioner, oil sump plate, right side cover. A thin coat of grease or oil works well and lets them come apart. Often you can reuse them.
If you have the cases apart the Three Bond is the thing to use. Use the Three Bond on the headcover. Any place that fits metal to metal, no gasket.
Just went back and looked at the pics. I don't think thats an 81 engine.
The alternator stator doesn't have the TCI pickup. The cam looks to have the advancer installed. There is the points backing plate beside the cylinders.
You will need to remove the advancer and rod from the cam to properly install the cam and the housings at the ends of the cam.
Having the points isn't a real problem. If the bikes wiring is set up for points it's fine. If not just a bit of rewiring and they will work ok.
But thats all later lets get your engine together.
I agree with Grizld1 on the crank, the rust on the flywheels means there may be rust on the bearings. Even a small amount of rust will eat those bearings up fast.
A torque wrench is one of the few things I'll not buy from Harbor Freight again. The one I have from them the calibration was way off. Might want to get it checked against a wrench of known calibration.
Leo