Mailman’s XS2 a full on restoration

[Mailman]

Sounds like your rings have not seated completely and you are getting a lot of blow-by past the rings. I only have 100 miles on mine but not seeing any oil leaks. I used nothing but red grease on the gaskets. I have both breather tubes wide open and the hoses are pretty dry.
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You restricted your tubes. That coupled with blow-by could cause pressure in the crankcase forcing oil past the gaskets.
How have you been breaking the engine in?
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I’ve been riding it as I do all my bikes. I’ve had it out three times now, each time long enough to get it good and hot. I always make sure to do a bunch of running up through the gears at a pretty hard throttle to build cylinder pressure.
Followed by deceleration for lubrication.

 

[GLJ]

Hopefully as you put miles on it the amount of oil coming out the breather tubes go down.
So get out there and ride!

 

[gggGary]

The bike rides and handles really nice , but you can feel it squirm a little if you try to push too much speed going into corners. I believe most of that is due to the retro tire tread pattern of the Dunlop K70’s, also the 34mm forks probably have a little flex to them. The tires are also VERY wiggly when rain grooves are present.

The inestimable John Chaves, fearless leader of the pack at the Ozarks rally, really makes time on https://www.motosport.com/product/?...&pssource=true&rkg_id=0&segment=badger-street
Last year a vulture underestimated just HOW fast a TX650 can be moving, leading to it's immediate demise. JC was not tarred but got pretty well feathered.
He also ran them on his 75.

 

[Mailman]

What size tire do you have on the front? I know 3.25s aren't very good on rain grooves. They tend to track in them. That was the size I had on my 650 Seca and it wiggled all the way. Almost dangerous.

Oops sorry I failed to respond earlier. Yes I’m running a 3.25 size. I had it out today and got on a parkway that had rain grooves, I felt like I was riding the mechanical bull at Gillys!

 

[Mailman]

Chasing an oil leak

So earlier I commented that this engine was just naturally messy. I need to amend that. I was blaming oil vapor coming out of my vent tubes for making the underside of my bike and my back wheel an oily mess. The starter gear case was all oily too, so I made another assumption that my gasket was leaking. Before I took my 75 mile ride yesterday, I had the left cover off and cleaned everything in there, and cleaned the underside of my frame and rear wheel. By the time I got home yesterday and pulled the bike in my garage, there was a small drip coming from under the left side cover. Hmmm......I was thinking about this last night and there are a lot of potential suspects under that cover, nothing to do but dig in.

First glance , I can see the shift shaft guard is covered in oil and oil has been slung around under the side cover.

It was dripping from the starter gear case, the shift shaft guard, the drive sprocket. Ah well hell....I’m just gonna pull everything off and take a good look.

I pulled the chain , sprocket and shifter guard off and found what I was looking for. The back side of the sprocket was wet with oil, the sprocket was slinging oil all over and the chain was carrying it to the rear of the bike and throwing oil all over my rear wheel and spokes.

This is a little puzzling because the sprocket nut was tight and I had put a layer of Hylomar on the back of the sprocket where it tightens against the drive shaft.

I am going to clean everything up and try it again , this time maybe a little Yamabond on the backside of the sprocket?

At least it doesn’t look like I’ll have to replace any seals.

We shall see.
Bob

 

[Jim]

Memories fuzzy today... but I believe that drive shaft sprocket spacer pulls out of the seal pretty easy. I'd pull it and do a little "backyard resurfacing" to it.
Hard to see from the pic, but it looks like there could be a burr or two there. Could even give the inside of the sprocket the same treatment.

 

[Jim]

Yeah... al little fuzzy today.
I believe the inside surface of the spacer does the sealing. I'd check in there for a burr also....

 

[Mailman]

Memories fuzzy today... but I believe that drive shaft sprocket spacer pulls out of the seal pretty easy. I'd pull it and do a little "backyard resurfacing" to it.
Hard to see from the pic, but it looks like there could be a burr or two there. Could even give the inside of the sprocket the same treatment.

Ah well, I’m too fast. It’s already back together with a smear of Yamabond on the inside of the sprocket.

We’ll see how she goes!

 

[5twins]

Yes, both ends of that metal sleeve need to be in good shape, and smooth. The inner edge seals against the inner race of a bearing inside the engine. The outer edge seals against the back of the sprocket. If the inner edge doesn't seal, oil gets in between the sleeve and the countershaft, and runs out along the splines on the countershaft. That's why we make that sprocket nut so tight. You're trying to seal two metal to metal spots (both ends of the sleeve). I'm not sure anyone ever gets this spot to seal 100%. On mine, even with the sealer added to the back of the sprocket and to the front under the lock washer and nut, I still always see several oil streaks emanating from the shaft when I pull my cover. It's not a bad leak, it doesn't drip or anything, but it's obviously not sealed quite 100% either .....

 

[kshansen]

I have a similar problem on my 1982 I need to investigate myself.

Wonder if machining a grove in each end of that seal spacer and using a thin oring would work? Probably not a good idea as the grove would reduce the clamping surface too much!

 

[GLJ]

It's not a bad leak, it doesn't drip or anything, but it's obviously not sealed quite 100% either .....

Could be considered a built in chain oiler.

 

[Mailman]

On mine, even with the sealer added to the back of the sprocket and to the front under the lock washer and nut, I still always see several oil streaks emanating from the shaft

I remembered the sealer on the backside of the sprocket, bit I never thought to add it under the lock washer and nut. It’s not ALL back together yet, I just cleaned everything good, applied the sealer , then tightened the crap outa that nut. It might be worth the effort to spin that nut back off and apply some sealant under there.

 

[GLJ]

I remembered the sealer on the backside of the sprocket, bit I never thought to add it under the lock washer and nut. It’s not ALL back together yet, I just cleaned everything good, applied the sealer , then tightened the crap outa that nut. It might be worth the effort to spin that nut back off and apply some sealant under there.

Just think of the chain life you'll get with a small leak. Kind of like a Scott oiler.

 

[Jim]

If you're gonna take it back apart.... a little sealant on the inside of that spacer wouldn't hurt either. If we think this through.... oil is always gonna get past the threads and nut on the outside. That's why we use acorn nuts and copper washers on the rest of the engine where we need an oil tight seal. The inside of the spacer is where the sealing happens.

 

[Jim]

Re-read my comment above. I edited it after you read it.

 

[GLJ]

I’ve noticed that suddenly my bike feels like it is accelerating a little harder and revving a little more freely

I've quoted you from my thread because my questions pertain to your bike.
How does the engine fell compared to your 77? Reason I ask is I've always been under the impression that the 72s had the best factory cam grind. Last year before the emissions BS. I've never ridden any newer 650s.
Also since it seems to be breaking in has the amount of oil coming out your breather tubes reduced?

 

[Mailman]

I've quoted you from my thread because my questions pertain to your bike.
How does the engine fell compared to your 77? Reason I ask is I've always been under the impression that the 72s had the best factory cam grind. Last year before the emissions BS. I've never ridden any newer 650s.
Also since it seems to be breaking in has the amount of oil coming out your breather tubes reduced?

It’s interesting to compare the two models. Of the two, I feel the ‘77 would probably be my first choice for a trip of any distance, it just feels a little smoother and it has taller gearing and modern tires.
But for just ripping around the neighborhood and shorter day rides, I really like the character of the XS2 motor.
It just feels more aggressive and torquey and the exhaust note it throatier. The vibes also feel different, the ‘77 is smoother while the XS2 pulses in a good way. I already have hearing loss, and I’m going to make it worse because I never want to wear ear plugs when I’m on my XS2, I just love the sound of that bike!

 

[Mailman]

Oh and yes, the oil vapor from the breathing tubes seems to be a non issue. I think I was wrongly blaming the breathing tubes for making an oil mess on the underside of my bike, when it was really coming from the drive shaft/ sprocket interface. Some Yamabond on the backside of that sprocket and a good retightening has seemed to stop that or seriously slowed it down.

 

[Mailman]

Got the bike out this morning for a good hard run. A little over 300 miles on it now, I changed the oil and greased the swing arm. I’ll soon be ready to re torque the head and check all the adjustments again. I’m really happy with the way the bike is running now. I’ve done two changes now, overkill probably but oil is cheap and I want these early run hours to have nice clean oil.

On a side note. I’ve been carefully watching the cam seals because they have caused others so much grief.
They are weeping a very small amount, not a big problem but my electronic ignition circuit board is under one of the covers and I am starting to see a few spots of oil and some misting on the circuit board. You can see how that circuit board is mostly covered by the rotor. So I will have to periodically remove that rotor and carefully clean the circuit board with some Q tips and ? I’m not really sure what would be suitable for that.

 

[Jim]

and carefully clean the circuit board with some Q tips and ?

I've always used this stuff.....