'79F Rebuild thread

[Forden]

Many thanks to those who have helped me out so far--I thought I'd document my progress with the bike and keep questions in one place rather than make a pile of new threads. Questions are in bold. I've embarked on a partial rebuild and am deciding how far to go.

Current state: I got the cams safely out without breaking the chain (see "Cam Chain Binding?" thread) and decided to pull the head to (at least) replace the stem seals and lap the valves.

Here she is when she came home, 42K miles, garage kept and one owner but hasn't been run in a couple years:

IMG_2501 by Forden Photography, on Flickr

Here she is now:

67271116574__93A42EF6-5ED9-4B44-B4FB-59F0F1CBFDA8 by Forden Photography, on Flickr

The head before I pulled the valves:

IMG_0022 by Forden Photography, on Flickr

The head with valves out and some (not all) cleaning done:

IMG_0024 by Forden Photography, on Flickr

Question: looking for tips on full cleaning of the combustion surfaces and ports--manual says wire brush, and I did that conservatively, but I don't want to mar the surfaces or valve seats. Plus the ports are a wonky shape for getting something in there (esp. exhaust ports, intakes are pretty clean of course).

A couple cylinder shots--some vertical marking but maybe a hone will be enough? Haven't decided whether to pull the jugs now or not, but probably will to measure everything at least. I don't really wanna go back in later if it needs rings now.

67271105710__E81372E8-8FE0-43B9-AF95-300B7A9346DA by Forden Photography, on Flickr
67271015267__B29E2C59-F43F-408E-9350-65D4374D55AE by Forden Photography, on Flickr

Rear cam chain slipper shows some loss of material in the back, chain sides look fine: is this in definite need of replacement, and should I be worried about chunks of this black material (not sure what it is) floating around the crankcase?

IMG_0019 by Forden Photography, on Flickr

Tire: Ordered tires from Amer Moto Tire, Shinko 712r's, 100/90/19 front, 130/90/17 rear. I searched the forum and found consensus that that size would fit the rear, but looking at it I'm a little wary that it won't clear the drive side... Reassurances welcome on that.

Thanks for looking--grateful for this forum community.
Mike

[bikerphil]

Mike...yes the Shinko 130/90 will fit the rear with no issues, that is the size you want. Many of us use the 110/90 on the front if you don't mind a little water getting past the fender. It really fills up the fender. 100/90 will also work if you prefer the narrower look.

Can't help much with the engine rebuild, I usually just change the engine.

Your bike looks nice.

[cajun31]

Many thanks to those who have helped me out so far--I thought I'd document my progress with the bike and keep questions in one place rather than make a pile of new threads. Questions are in bold. I've embarked on a partial rebuild and am deciding how far to go.

Current state: I got the cams safely out without breaking the chain (see "Cam Chain Binding?" thread) and decided to pull the head to (at least) replace the stem seals and lap the valves.

Here she is when she came home, 42K miles, garage kept and one owner but hasn't been run in a couple years:

IMG_2501 by Forden Photography, on Flickr

Here she is now:

67271116574__93A42EF6-5ED9-4B44-B4FB-59F0F1CBFDA8 by Forden Photography, on Flickr

The head before I pulled the valves:

IMG_0022 by Forden Photography, on Flickr

The head with valves out and some (not all) cleaning done:

IMG_0024 by Forden Photography, on Flickr

Question: looking for tips on full cleaning of the combustion surfaces and ports--manual says wire brush, and I did that conservatively, but I don't want to mar the surfaces or valve seats. Plus the ports are a wonky shape for getting something in there (esp. exhaust ports, intakes are pretty clean of course).

A couple cylinder shots--some vertical marking but maybe a hone will be enough? Haven't decided whether to pull the jugs now or not, but probably will to measure everything at least. I don't really wanna go back in later if it needs rings now.

67271105710__E81372E8-8FE0-43B9-AF95-300B7A9346DA by Forden Photography, on Flickr
67271015267__B29E2C59-F43F-408E-9350-65D4374D55AE by Forden Photography, on Flickr

Rear cam chain slipper shows some loss of material in the back, chain sides look fine: is this in definite need of replacement, and should I be worried about chunks of this black material (not sure what it is) floating around the crankcase?

IMG_0019 by Forden Photography, on Flickr

Tire: Ordered tires from Amer Moto Tire, Shinko 712r's, 100/90/19 front, 130/90/17 rear. I searched the forum and found consensus that that size would fit the rear, but looking at it I'm a little wary that it won't clear the drive side... Reassurances welcome on that.

Thanks for looking--grateful for this forum community.
Mike

well you have it that far so in case you are interested Search Results for “yamaha xs1100” | Page 2 | CRUZINIMAGE.NET

the cam chain guide is in bad shape and yes something might be down in the pan. drop the pan and you may find it unless it has already come out in previous oil / filter changes. here is an ebay link to some used parts for comparison purposes. Yamaha 1100 XS SPECIAL XS1100 Used Engine Cam Chain Guides 1981 YB93 | eBay Yamaha XS1100 Cam Chain Guide/Slider Tensioner | eBay

as for cleaning further, do you have access to someone who could soda blast? no real danger of removing anything but the gunk.

did you get a chance to check the compression before tear down? that first site i listed is very reasonably priced and although i have not used them they have received good reviews from a few on facebook who have. price beats weisco..

[DiverRay]

These engines will go over 100K miles with no problems when taken care of. Your engine looks pretty clean, and I would replace the cam chain and followers, install the ACCT from a newer bike, just clean the cyl. walls with oil and a scotch bright, and re-assemble with new valve seals and gaskets. But then, that's me, and I'm getting too old to want to rebuild many more engines!

[Forden]

did you get a chance to check the compression before tear down? that first site i listed is very reasonably priced and although i have not used them they have received good reviews from a few on facebook who have. price beats weisco..

Thanks. I did check compression when I picked it up--numbers were artificially high (as I put a little mystery oil in each cylinder as it had not been turned in a while) but consistent across all four. I was planning to test again after doing clearances, then I had to pull the cams after the chain slipped, so decided to just pull the head. no's 1&2 showed a good bit of oil in the exhaust ports, so I figured I better do the seals at least and maybe rings too. I'll measure clearances/wear limits before I decide on the rings, thanks for the cruzinimage link. I gather I'll need to pull the jugs to replace the cam chain guides anyway.

I looked into wiseco, it appears they are only supposed to be used with wiseco pistons?

[oldyam80sg]

How did the coils work out? I have Metzler tires on my bike, but they have not been changed in years. Still nice with no dry rot.

[Forden]

Haven't gotten to coils/electricals yet. Thanks OldYam for sending though. Finally got the jugs off last night--that was fun. Took a couple hours of scraping corrosion with a dental pick from between two of the post bolts and the hole in the cylinder (found on the forum this was not unique to me... same two posts/holes others had problems with, second ones in on the exhaust side...). Pistons are out and rings removed. Now lots of cleaning (and scraping gaskets, ugh) and measuring to do before reassembly. Man there was a LOT of gunk between the cylinder and the crankcase.

What is the expected lifespan of a cam chain on these bikes? It looks fine, no doubt has stretched of course, but tensioner should compensate? Thanks to Eric 2WheelFun for the self-adjusting tensioner.

Thanks everyone. More as I go...

[Forden]

Finally ready to install the jugs--pistons soda blasted, new rings, cylinders honed.
Question: the Athena gasket kit came with small o-rings for the cylinder/head studs, but the parts fiche doesn't show them, and sadly I don't remember whether I removed any during disassembly. Do I need them? Not talking the big ones that go around the bottom of the cylinders. It does look like the top of the crankcase is machined for them.
Thanks all.
Cheers
Mike

[hjohnriley]

Hey Mike!
It looks like we are both working on the exact same bike, except mine has the dark blue paint. Geraldine, as I call her, has a little over 3,000 iles on her and sat for the last 30 years, until I got her on July 25th of this year.

My biggest issue was spark. There is TONS of help on this forum to test continuity with a multimeter and it helped me greatly to finally pinpoint the problem...if you encounter this issue...make sure all connectors are clean and all grounds are soild.

After carb rebuild I was able to fire her up and she absolutely purred like a kitten. I am redoing brakes, will service drive and then I will need to order tires (thanks for the info on that, very helpful) before I take her for a ride.

Good luck on your bike, nice to know someone is working through many of the same things at the same time!
John

[Forden]

Hey Mike!
It looks like we are both working on the exact same bike, except mine has the dark blue paint. Geraldine, as I call her, has a little over 3,000 iles on her and sat for the last 30 years, until I got her on July 25th of this year.

My biggest issue was spark. There is TONS of help on this forum to test continuity with a multimeter and it helped me greatly to finally pinpoint the problem...if you encounter this issue...make sure all connectors are clean and all grounds are soild.

After carb rebuild I was able to fire her up and she absolutely purred like a kitten. I am redoing brakes, will service drive and then I will need to order tires (thanks for the info on that, very helpful) before I take her for a ride.

Good luck on your bike, nice to know someone is working through many of the same things at the same time!
John

Good looks, John, your journey to first fire has certainly been shorter than mine! To be expected, as mine has 39K more miles on the clock. I'll update the thread with all I've done soon, but am close to bolting carbs and exhaust back on to see what transpires. Just waiting for a parts order. Meantime rebuilding brakes and about to pull the forks to rebuild those. I'm procrastinating on the electrics, in all honesty, because I've gotten better with them but still dread chasing ghosts... It did have spark when I bought it, so hopefully that won't be an issue.
Cheers,
Mike