My dead XS650

[Big_Ed]

Yep, it's dead. Ran great for several months - see attached. I had ridden one of these back in my days in California and had seen them for sale in the motorcycle shop in Richmond, but never had a chance to buy one. My son-in-law called one day last year and said "Hey, you want this old bike?" And there it was. I gave his grandfather $200 for the bike; getting the title was problematic but we finally got it and I went to work on the bike. Now, it is a nice vintage 1975 XS650 Yamaha Motorcycle lovingly restored after a 30-year stint in the barn. New items that I put on include: tires and rims, tubes, spokes, brakes (front disc pads and rear drum brake pads), front wheel bearings, brake lines, kickstand, handlebar controls for both sides and grips, plugs, plug wires, condenser, coils (2), ignition points, headlight, horn, Hagon rear shock absorbers, air filters, battery, battery cables, latches for side covers and taillight. I rebuilt most everything to spec including: front forks, master cylinder, brake switch, front brake caliper, petcocks, fuel tank and carburetors.
Original paint, tool kit, original seat (no tears or holes), original air boxes, original chrome on pipes and handlebars –these were in very good condition and I mainly sanded, polished and/or painted, and added a small windscreen. It was a real Thumper to ride - shook like hell and sounded great. Then one afternoon this summer I was cruising up a hill and the motor imploded.

Yep, I rebuilt damn near everything on the bike EXCEPT the engine, although I did clean out many, many mud-dauber nests from the engine fins and other small openings. After I drained the oil and pulled the oil pan off, pieces of the timing chain fell out and a strand of the remaining chain was hanging down. The engine won't turn either so I know something is truly jammed up in there. So now I am trying to figure out if I want to sell it (and for what price?) or haul it my local M/C shop and let them have at it for a few weeks. Hmmmm. Ideas anyone?

 

[Jim]

After I drained the oil and pulled the oil pan off, pieces of the timing chain fell out and a strand of the remaining chain was hanging down. The engine won't turn either so...

Well that sucks. If those are parts of the timing chain in the sump, there's no end of what could be toasted.
These are " interference engines." What that means is the valves open more than the piston allows for. Without the cam timing the valves, they'll hit the top of the piston. That can give you bent valves, cracked pistons.... all the way down to bent connecting rods and a tweaked crank.

 

[WideAWAKE]

Pull it apart and rebuilt it.

Not rocket surgery…

Everything you could possibly want/need to know is here.

Post photos, ask questions.

Nice bike with a blown motor? $300-500?

Paying someone to do it $2500? Plus parts?

 

[gggGary]

You had that looking REALLY good! and a 77 is top O the line.

For shits n giggles tear it down, see what happened. That'll get you comfortable with these simple mills.
Then find another engine; running, or just "tired" needing a top end. Will be a lot simpler and buckets cheaper than rescuing one that has fragged.
I would think one could be found in Virginia for $100, 150.

 

[Melnic]

A shop will charge you out the nose to work on an old bike.
Hope you can get it working the way you want.

 

[Jan_P]

I am with Gary There
Perhaps possible to find a replacement motor
As Jim says there can be a lot problems a risk both cylinder bores are destroyed and the bottom bearings taken a hit
A shop job then becomes economically bad

Borescope perhaps looking in

 

[Raymond]

Replacement engine. Any year of XS650 will do. You will need helping hands or a pulley system to lift out and in but nothing more daunting that the work you've already done. Not dead, just needs a heart transplant and it's far too nice a bike to give up on.

Plus, you can strip down the old engine and see what you can do with it, in the fullness of time as the expression goes.

 

[motormike]

If you like the numbers to match.... fine a nice runner same era..... pop the top end... split the cases .. swap crank.... or find a engine.... go thru it..... I've done the crank swap.... believe me.. if I can swap a crank, it's not difficult.... I did it from the bottom... leave tranny in neutral... no need to touch it.... clean surfaces .... I placed the crank seal on the crank... add Yama-bond.... follow book to torque .....

 

[5twins]

I'm just wondering why this happened. First time I've heard of a cam chain destructing like this.

 

[Jim]

I'm just wondering why this happened. First time I've heard of a cam chain destructing like this.

Same here. Most interference engines have a pretty robust valvetrain. Never head of it happening to an XS.

 

[jpdevol]

Ditto. Rare for a cam chain to break on an XS; need to examine on disassembly. Perhaps it wasn't riveted properly

 

[Melnic]

Replacement that someone did not do the master link correctly?

 

[Raymond]

Replacement that someone did not do the master link correctly?

That's what comes to mind.

If the problem was the cam chain tensioner breaking up - please correct me if I'm wrong - the engine would be rattly but the chain would not break. If something else broke and locked the engine, a lot of things would be damaged but I still don't see that the chain would snap.

When you get the chain out, I'm think you'll find it's the master link that has snapped. Not too sure of the forensics to work out why, but yes likeliest is someone did not do the master link correctly.

 

[motormike]

I had a Cb350 Honda and a Xs1b cam chain snap.

 

[bosco659]

A shop will charge you out the nose to work on an old bike.
Hope you can get it working the way you want.

Just a comment that bike dealers around here, selling new bikes, will turn you away if you want them to work on your “vintage” bike. I know our local Yamaha dealer will not work on my XS. I’m not sure what the cut off year is for denying service. That said, when one looks to buy an older bike they should have some ability to work on it themselves or have friends who can help.

 

[WideAWAKE]

Just a comment that bike dealers around here, selling new bikes, will turn you away if you want them to work on your “vintage” bike. I know our local Yamaha dealer will not work on my XS. I’m not sure what the cut off year is for denying service. That said, when one looks to buy an older bike they should have some ability to work on it themselves or have friends who can help.

I worked at a vintage motorbike/scooter restoration shop when I was just out of high school. At the time there was a huge influx of “restorations” coming for SE Asia. You could spot on from a mile away. We would not work on them, they were so badly built, trying to change a brake cable would somehow lead to having to rebuild a motor haha just a massive can of worms. I don’t know of any shops in my area that aren’t vintage specific that will touch an older bike either. Mainly cause they have been flogged, put away wet, the owners are cheap and parts can take weeks to get. Even a lot of vintage specific shop will only work on a few different bikes they specialize in. Best bet is get your hands dirty and find others who’s are dirtier than yours in hopes they may show you something you don’t know.

 

[Big_Ed]

Gentlemen - all good advice, thanks. I had not considered buying another engine or parts bike for the engine, but that makes sense now. I figure I've put nearly $3200 into the $200 bike already just in new parts and tools alone, I was loathe to just give it up or give it away. Christmas is coming and the bike is happily (?) snoozing in the garage for now. I live on the east coast (Fredericksburg, VA) and if anyone knows/has a spare engine or parts bike they'd like to be rid of, give me a call. 540-760-4180 (Can I put a phone number in here?)
Thanks again and Merry Christmas to all you riders out there - stay safe, keep the wheels on the pavement.
Ed Herbert

 

[toglhot]

Pull the engine out, take it apart tand have a look, if you decide it's above your skill set, to repair and put it back together, then take it to a mechanic. But realistically, they are a very simple engine to work on.

At the very least I think the pistons and valves will be toast, so perhaps a replacement engine would be a good bet.

 

[40north]

It's a tragedy after all the stuff ya did. My sympathies. For myself, the idea that a shop would satisfy the need is very dubious...maybe Jay Leno has such a shop (!) . Again for myself, I'd look for a running parts bike and also do a careful forensic tear down with an eye to saving the OE... agree about chain link etc. BTW I have had gear driven cam on interference engine fail - the big gear failed, snapped the end off the cam, and shattered 2 pistons and the block... 300 cid Ford truck...go figure. All while operating at very low power level... Stuff happens. Best of Luck with the beauty amigo!

 

[Melnic]

Just a comment that bike dealers around here, selling new bikes, will turn you away if you want them to work on your “vintage” bike. I know our local Yamaha dealer will not work on my XS. I’m not sure what the cut off year is for denying service. That said, when one looks to buy an older bike they should have some ability to work on it themselves or have friends who can help.

I'm at 30+hrs plus on my bike, There is a local shop that does work on old bikes and posted on the door is $200/hr for bikes older than 1999.
If that mechanic knew the bike and only spent 10 hours, that's $2K + parts. I'm about $500 into the bike now.
No regrets from me as I've done this before and know the costs. For me, its a hobby. Its the value of the acomplishment for me.

ditto on old bikes, you have to be thinking you will do the work.