After all these years the bike that I thought was an XS1 is an XS1B... Help ID Please

The biggest mystery is the engine stamp. No one knows, it looks like 8650 however is may have been an S650 stamp, the photo, to me looks like 8650...

Sending a rod through early cases wasn't all that rare, Yamaha prolly had sets of "unstamped" early cases in the parts inventory.
Factory replacement cases early in it's life would be my guess too.
 
Thanks, Jim,

So what did Yamaha do about the thrown rods? Just replace the engine with the same systemic issue? Or did they beef the rod up? I seem to recall there are two types of rods for these engines... I have old VWs and have tossed a rod and that is not a pretty sight... So the motor is a newer ish one... Doesn't seem all that bad, especially if it has a better rod setup. Does anyone know how to check the engine for one set up or the other. I have ridden this bike all over and the engine pulls and starts easy. Anyhow thanks to all for your contributions
 
Frame # is XS1B. Engine no is odd. 8650 looks to much like S650 with the S looking like an 8 and this could have come from the factory like this. In a case of a replacement set of cases they would be stamped S650 with the Vin no is missing. Did hear about engine cases getting replaced and came fro the Factory with no Vin #'s stamped on them. You could stamp your frame no on the engine if you do but do some research on pics and make sure the stamp looks like factory.

Dose the motor have a 3 bolt tappet/rocker cover covering the left side tappet/. It has to be a 3 bolt cover and no starter motor, (motor hole), on the engine case for it to be period correct. These early motors did have a reputation for stretching the little ends on the rods and breaking. This could result in a rod going through the crank case. Hence the replacement case on yours if this ever happened. not trying to scare you it is a possibility on why the engine case doesn't have a vin #

XS1B's did come out in Candy green so it could be colour correct. Tank single green stripe is XS1. XS1B had double stripes
XS1 and 1B side by side, Candy Green and Candy Orange
View attachment 197392

XS1B candy green
View attachment 197393View attachment 197394

Now you mention the bike Has KPH speedo and a Vietnam vet imported the bike into the US. As much information about this and from where will help. What year it was imported as well if you can well.

There are a couple of guys on here who know these early XS's real well. TXXS is one so a PM to him if he doesn't answer on here may help you with more info.

As for the value. Defiantly worth good money. XS1's are the top of the lst but good XS1B's are the next best thing

650Skull has proved wise once again - I cleaned up the case stamp and look - S650 - so the question is... is this a good or bad thing?

 
A good thing. Although the cases don't have a vin no on them, they are factory original and have left the option to stamp the frame vin on there so the bike is original as far as the numbers are concerned. The circle with the A, looks like it is Yamaha's way of showing it is a replacement case. This doesn't detract from originality as it would probably have the original crank.

A horror story about an XS1 and what can happen to the cases.
Copy of page3 1.jpg
Copy of page4 a.jpg

kev's xs-1 5.jpg
kev's xs-1 4.jpg
 
Note the part where he mentions that he put 90,000 some miles on that motor!
Yes high miles or run hard early motors are going to need the small ends checked at top time, roughly each 30-40,000 miles...
Even late model motors need small end checks they do tend to wear over time.
 
To answer your question about th rods. Early XS1's had a roller bearing in the little end then they changed to the copper coating mid way through the XS1 production.

Info on the rods and their changes in this link near the top post #1
https://www.xs650.com/threads/xs650...workshop-manuals-and-other-information.30569/

That bike had done 90,000 mules, Had a 750 kit and the guy had it for 35 years, (that article is from the Aussie 650 club news letter and is a few years old), so I'm sure as a young guy with, a 750 kitted bike, she had a few power take offs and who knows what else or how many time the red line was passed

Maybe your bike had a similar experience, the small ends had a history of stretching.
 
Another mystery.
Just noticed that the head is 1972 or later.
Maybe it was replaced at the same time as the lower case.

I asked that in post #3 and answered in post #6 that it had 3 bolt tappet covers, (no pics at that time)............that loses its originality. ..........Now i would double check that there is no provision for an electric start on the bottom of the cases.
 
Cases??? Sounds like I should dump this in a lake... Where do I check for this starter mount? When did this head change to the one 4 bolt? I'm getting that headache again. Parting out sounds better now. I'm posting pics to figure this bike out and you have been a great help to let me know what you see.
 
No starter. Upper case has the two gussets behind the left cylinder. Makes them XS-1 or -1B.
Yes, 4 bolts tappet cover on left exhaust. XS-2 or newer.


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Where do I check for this starter mount?
It's on the bottom of the engine to the rear. If it isn't obvious, it isn't there. You'd see four bosses for mount bolts and the hole for the nose of the starter motor.

When did this head change to the one 4 bolt?
The left exhaust tappet cover got four bolts in 1972. That's the same year as the electric starter motor. The '70 & '71 models are the only ones that have three bolt tappet covers in all four positions.
 
Cases??? Sounds like I should dump this in a lake... Where do I check for this starter mount? When did this head change to the one 4 bolt? I'm getting that headache again. Parting out sounds better now. I'm posting pics to figure this bike out and you have been a great help to let me know what you see.

The bracing, (jim points out), at the bottom rear of the barrels on the casing shows it is an XS1/1B case. This, (plus the Vin #),should indicate that there is no provision for a starter motor. I mentioned the starter as a precaution and to eliminate a possibility. Those 2 braces should eliminate the possibility of a starter motor case........just look.

Don't get disheartened about the head not being an XS1/1B. Although it does mean the bike isn't original it doesn't make the bike a part out, useless, no value bike worth more as parts.

The good condition of the bike, makes it is still worth quite a lot of money as is............if the head was a concern then in time an early XS1/1B head could be found and installed. The Tappets/rockers and cam would swap straight over into an XS1/1B head.

it a process and you have all of us helping to identify what is what, and at the end of the day when everything is sorted out, that information is worth peace of mind and if you did want to sell it then the next buyer is going to get an honest buy that is valuable, not necessarily in money terms, but the buyer will be able to make an informed decision and be comfortable knowing what he/she buys is, what it really is with confidence and in that situation a genuine collector will haggle less on a reasonable price asked

Not many can say that, and when they come on here thinking the PO has been honest and tell us about the bike, they get a shock when we burst their bubble.

You have a great bike with a great back story that gives it intrigue and a life, (if you want to put it that way), with its own scars. keep it and don't let what your finding out diminish what you have
 
Thanks, Guys
I don't if you can tell but I've ridden this bike, a lot, and have tons of great memories riding so even it is a bit of a Franken bike The Green Machine is a cool ride no matter what. I just posted pics and parts lists of all the stuff that is coming with the bike... With the engine being a bit off some of the parts won't work but will be provided non the less. Take a look at my media. The plan was to tool around on this bike during retirement however plans change. Hopefully someone else can pick up the baton.
 
What a treasure trove...........Seriously there is literally a Thousand $'s in parts. That headlight bucket with the ring would fetch $500 over here and they are as rear as hens teeth.
 
What a treasure trove...........Seriously there is literally a Thousand $'s in parts. That headlight bucket with the ring would fetch $500 over here and they are as rear as hens teeth.

I don't exactly know it as a fact but I would expect the gearbox parts would be sold out at Yamaha and most other places
They don't get cheaper with years
So the value of the parts stash maybe should be reevaluated .
But I don't think the bike should be parted. As other tells.
 
If you like you can do that

I'll clean it up and take a video, It's cool that I can go out to the bike and kick it over with one or two kicks cold. I learned a long time ago to commit to the kick start process or that bad dog will jump up and bite your leg like a mountain lion.

A cold start ..with sound up high around the valves at Cylinder heads left and right side. and exhaust fumes with a little blipping on the throttle
Can look for smoke.
I think we will be able to have a fairly good idea about the engine status ...the clock 70000 can be much but if it has been rebuilt and .Taken care off
Serviced / Warm up / how much Revving can make a difference.
 
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