1977 XS650

Racerxnico

XS650 Enthusiast
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Location
Seattle
I have agreed to help a friend with his motorcycle. He inherited it a few years ago from his father when he passed away. Apparently his dad bout it new from the showroom and it has been garage kept its entire life. My friend isn't really a motorcycle guy and he has come to a place where he realizes it is time to part with it and has asked me to help address a few things and help him sell it.

At first glance it looks great, starts on the first kick from cold, and runs strong. ...but I had a little time for closer inspection today and I have a list of things I'm going to tackle and a few questions (in bold).

1. There is a lot of oil on the front of the motor. Is there a common spot that they leak from here? I feel like it would be pretty weird for it to be a head gasket on an air cooled motor and it looks like it might be just below the line of the head gasket. Possibly something with the oil delivery pipe? I figure I'll clean it up and see if I can figure out where it's coming from, but hoping someone with experience can save me some legwork or point me in the right direction.

2. Charging. The battery is charging right at 13.5v when at idle, but when I rev it out it goes up to 15.5v. I've always targeted 14.5 as a top end and I'm worried 15.5v is too high. Wondering if this is common and if only fix is a new regulator/ rectifier or if there are other ways to address?

3. Tires. Front tire won't hold air so at min, I need a new tube. I hate to put new tires on a bike I'm going to sell, but seems a shame not to if I have it off to do the tube anyway. Any suggestions on less expensive rubber? Going to see if maybe Shinko makes a tire that works.

4. Front forks leaking so I'm going to replace seals.

5. Elec starter. While it starts with one kick. Elec start doesn't work. I think I'm going to try and pull it and rebuild it. Looks like I might have to solder new brushes on if it needs them, but hoping I can just clean it.

6. Mufflers have some rust bubbles, but I'm leaving that for whoever new owner ends up being.

7. right side of gas tank has some dents and damage. I'm not too optimistic, but going to see if 100PSI and a suction sup will pop them out. Does anyone have any cool tricks they have used or know of that I can research?

Thanks in advance for any wisdom, advise, and/or encouragement.

jason in Seattle
 

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1. There is a lot of oil on the front of the motor. Is there a common spot that they leak from here? I feel like it would be pretty weird for it to be a head gasket on an air cooled motor and it looks like it might be just below the line of the head gasket. Possibly something with the oil delivery pipe? I figure I'll clean it up and see if I can figure out where it's coming from, but hoping someone with experience can save me some legwork or point me in the right direction.

That's usually the head gasket. Yamaha knew about it early on.... even put out a service bulletin to retorque the head at first service. I'm guessin' most bikes never had it done. Look in Tech menu for the top end rebuild thread. There's a torque sequence and numbers for torqueing the head. Clean it up and sometimes it takes 100 miles or so before the weeping finally stops.
 
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2. Charging. The battery is charging right at 13.5v when at idle, but when I rev it out it goes up to 15.5v. I've always targeted 14.5 as a top end and I'm worried 15.5v is too high. Wondering if this is common and if only fix is a new regulator/ rectifier or if there are other ways to address?
'77 had a mechanical regulator that's adjustable. Procedures in the shop manual.
 
5. Elec starter. While it starts with one kick. Elec start doesn't work. I think I'm going to try and pull it and rebuild it. Looks like I might have to solder new brushes on if it needs them, but hoping I can just clean it.
These starters are about bulletproof. I'd look elsewhere first.... starter button itself is a common culprit. Not so common... but the solenoid's been known to fail also. Wiring.... Grounds.
 
Excellent! Thanks for input. FYI, I don't think I can contain 100PSI in the tank. I just meant run the compressor up to that and see what I can do. I don't have great ideas yet on how to seal it to pressurize. Just some initial thoughts.

Cheers.

jason in Seattle
 
XS tanks are thick and tougher to pop dents out than say a modern Harley tank.
You stated twice that it starts on first kick, that’s a good sign of how well tuned the engine is 👍
You’re going to sell the XS ? Slip a tube in it so it test rides and let the next owner decide on tire choice.
You got a runner 77 in Seattle, Let an knowledgeable XS fan find you. It’s worth a few thou there
 
Sounds like a cool project.
Do not attempt ANY pressure in the gas tank, it'll "unfold". Trust me i KNOW. I kept a bloated Honda tank hanging in the shop for years to remind me. .
Even a piddly 3 PSI over roughly 2 square feet of gas tank tunnel surface is 2 x 144 x 3 or over 800 pounds of pressure trying to pop the tunnel out, that'll do it.
 
That's usually the head gasket. Yamaha knew about it early on.... even put out a service bulletin to retorque the head at first service. I'm guessin' most bikes never had it done. Look in Tech menu for the top end rebuild thread. There's a torque sequence and numbers for torqueing the head. Clean it up and sometimes it takes 100 miles or so before the weeping finally stops.
Agree with Jim here. Retorque of the heads is never a bad idea. You can't see them in your photo of the oil tube, but just behind the tube and just below the head are two bolts that secure the cam chain tensioner. If these loosen up they will make a mess on the front of the engine.
 
XS tanks are thick and tougher to pop dents out than say a modern Harley tank.
You stated twice that it starts on first kick, that’s a good sign of how well tuned the engine is 👍
You’re going to sell the XS ? Slip a tube in it so it test rides and let the next owner decide on tire choice.
You got a runner 77 in Seattle, Let an knowledgeable XS fan find you. It’s worth a few thou there
Nice bike by the way. Should be an easy sell. Good luck.
 
Thanks for feed back all. Especially stopping me from making a mistake with pressurizing the gas tank. That is one of the reasons I like to bounce ideas/ plans off the wall of forums before I jump in.

I'll still try the suction cups on the tank dents. Even if they don't work, it seems like it should be harmless to try.

Will retorque the head and pop off the oil feed tube and check those tensioner bolts.

I'll also try to adjust the regulator. If I do need to replace, it looks like that VR115 approach is the way to go.

I'm hoping to have it out to a couple of moto themed coffee shops and bike nights by the end of the month.

I'll keep you all informed of the progress and let you know if I have any questions.

Thanks again
 
Thanks for feed back all. Especially stopping me from making a mistake with pressurizing the gas tank. That is one of the reasons I like to bounce ideas/ plans off the wall of forums before I jump in.

I'll still try the suction cups on the tank dents. Even if they don't work, it seems like it should be harmless to try.

Will retorque the head and pop off the oil feed tube and check those tensioner bolts.

I'll also try to adjust the regulator. If I do need to replace, it looks like that VR115 approach is the way to go.

I'm hoping to have it out to a couple of moto themed coffee shops and bike nights by the end of the month.

I'll keep you all informed of the progress and let you know if I have any questions.

Thanks again
There's a Classified section here. Suggest you start there. Target marketing. You're looking for a collector who's specifically looking for what you have. These bikes are getting harder to find. I mean, here we are, on a forum JUST for one specific model of a 40+ year old Japanese bike.

Took me months to find our new project bike once the "I want her back!" bug hit me, and we're old farts who didn't care a lot about budget. Found less than half a dozen, most with $900 +/- in shipping and not in great shape. Didn't want to buy something sigh unseen. Closest we could get to my '82 XS 650 Special was an '83 Heritage. The one I found within trailering distance (app 100 miles) isn't bad, cosmetically, but she hasn't been started this century far as I can tell. We've been working on her about two months and we're just now getting to the "put the gas tank back on" stage. Yours at least starts, and she doesn't look like a rust bucket (Some of the ones I found really weren't worth trying to restore). Plus, the mechanical work you're doing will be a Godsend for the new owner. And she comes with a great story! And don't worry too much about the gas tank. You can find most anything, parts wise, on EBay. If that's all I'd needed I'd a been a really happy camper. Errr, biker.
 
Here's the regulator setting instructions .....

Reg Adjust.JPG


Way back, before I changed to the VR115 (great mod), my original regulator was only putting out mid 13's max. I found both gaps were off and reset them. That brought the charging output back up to mid to low 14's max. I didn't even need to touch the actual adjusting screw.
 
had a little time to get out to the garage this evening so I took apart the front caliper. I need to take apart the master cylinder as it is binding and not returning. I got to a point where I was going to disconnect the brake light switch. I moved the metal band out of the way and pulled back the boot, but I'm not finding an obvious way to remove the switch from the brake bracket. I was out of time for the evening anyway so I came in to see if I could find it in the manual (no dice). Looking for enlightenment if anyone can provide it.
 

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Got it. I had tried to push a small screw driver in that hole, but nothing seemed more likely to move and I didn't want to force it until I knew it was correct. I'll go give it another push and a little more wiggle and see if I can get it to let go.

Thanks
 
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