(Engine) Is there a prefered or ~best~ year or years?

[Jeeter]

For the "Cheney Competition Hardtail Father-Son Tribute" project bike. The engine needs to be able to deal with ~roughly~ 60-odd HP, street use, pump gas. While not a race bike, I want to be equipped with the best engine factory run in the XS650 lineup. Experience has taught me that the latest engine version (of any given design) is not always the most desireable.

That having been said, what is the most prefered year-run of the XS650 (specifically the engine)? The most aftermarket support, the "best" castings, the best head design, the best clutch, the best trans, and so on. Often times mixing-matching years of components is best (let's say the 75 clutch with the 74 transmission and 77 heads ... just throwing rocks in the air here to make a point).

Longevity is important, I'm hoping to have this bike until I draw my final breath (hopefully 25+ more years). So it's got to be the engine era that lends itself well to rebuilding and repairs, as well as the other requirements.

So there it is. Thanks for the help, I'm not looking to be handheld, I just need some conversation and discussion on this notion to get me started on my quest for the engine core. I'm hoping to order that Cheney Sonic Weld frame tomorrow or the next day. I'm still goofing with some health issues so some of the time I'd hoped to devote to this project has had to be somewhat diverted, otherwise I'd have ordered that frame a couple of weeks ago!

 

[5twins]

Here's what I like - '74 or newer "447" motor and '80 or newer clutch. I know the ignition went from points to electronic in '80 but I don't really consider that because most everyone throws a Pamco on these anyway.

 

[TwoManyXS1Bs]

Yes, `73 and older have unique rod/crank/cam/camchain setup, difficult to get parts.
You don't want those.
Send them to me...

 

[gggGary]

Yes, `73 and older have unique rod/crank/cam/camchain setup, difficult to get parts.
You don't want those.
Send them to me...

Or me.....

The good news is that post 73 you can't go far wrong.
There is a tranny gear change 76ish?
For the long haul with hard use I'm fairly convinced a welded crank is a must do.

 

[Vincenthdfan]

Yes, `73 and older have unique rod/crank/cam/camchain setup, difficult to get parts.
You don't want those.
Send them to me...

Me first!

 

[Jeeter]

Yes, `73 and older have unique rod/crank/cam/camchain setup, difficult to get parts.
You don't want those.
Send them to me...

You guys remind me of this dude that tried to talk me out of the all-tube preamp in my 1962 Hammond A102 (those tube preamps are worth about $600 working or not). Of course in his estimation I needed the all new solid state preamp in my classic Hammond, y'know, ya really don't want any of that old junky tube crap in the organ, now do ya!



I mean being the good samaritan that he is, he even offered to take the "old junky tube preamp" off my hands so I wouldn't have to be troubled by it any longer, for free! He even offered to pay the shipping, I mean, what a guy!



I just don't understand why he got so upset when I told him to go screw someone else over! Haahaa!

Ok, kidding here, right? I'm not implying that any of you are crooked or trying to manipulate me out of more desireable parts. I'm just making fun of how you guys have made it sound.

"You don't want those rare parts in that box that are worth a few Terabucks, you want these crappy modern replacement parts that I just happen to have right here handy, and I'd be willing to help out a fellow biker and take a loss in a trade for those old valuable parts. These are not the droids you are looking for...."

Heheh ...

Ok, so seriously here ... If I got it right, I want to avoid the pre-74 engines unless I'm wanting to stick with something like an all-numbers-correct restoration (or something along those lines that respects the original engines in pre-74 bikes). Do I have that right?

So something like a 74+ with a welded crank (I may end up doing some sort of rephasing weirdness anyhow, so I would guess that welding the crank would be a part of that process, que no?). If I've done my math properly increasing displacement to roughly 750cc or so may be a must for the power figures I'm looking at (uh .. right?), that said is Nikasil suggested or is that mondo overkill? My point is that the cylinder bank is another part that that is sortof aftermarket in a sense so the model year of the barrel set is sortof moot, right?

Ignition and other periphrials (carbs, et al) will all be aftermarket (Mikuni round slides, someone's ignition , Barnett or ?? clutch system, and I'll also look into transmission undercutting at which point a total trans uprate may be incorporated).

Is the 1980 clutch basket somehow superior to the previous years? Since just about all of the clutch's plates/springs/steels will be aftermarket just about all there is left is the basket and bearing(s). Is there a nice clutch mod available (perhaps something like added plates .. aka "thicker stack"). Or is that stock configuration stout enough to deal with a bit of spirited riding? I would guess that aftermarket plates/steels/springs are a must whether or not any other clutch tricks are done?

What of the head? Is there a prefered year of head casting that lends itself well to machining uprates or other mods (porting, oiling mods, and so on)?

Are aftermarket rods required for heavy street use (the occassional wheelies, clutched power slides, and basic juvenile dirt-bike-type riding on the street when the mood strikes me or the 5 Hour Energy kicks in).

I'm so friggin excited about this bike. Let the healing begin.

OH! One other thing. What kind of highway fuel mileage can I expect from a 60-odd HP XS650 when ridden nice and responsibly on the freeway? The next town to our east is Gila Bend Az, it is roughly a 90 mile trip. Parker Az is roughly 100 miles north. I'd like to begin thinking about what type of fuel tank I will use. Obviously needing about 100+ miles of range.

Thanks folks!

 

[TwoManyXS1Bs]

Well, I guess my cover is blown. Yes, that pre-74 stuff is for us old farts. Relics that require a special hand, and a love for unique torture...

I'd recommend that full Heiden 750 kit, complete no-brainer bolt-on, larger cooling fins (important for Arizona). It fits the later '74-on 447 engines.

 

[gggGary]

Yeah the early stuff is mainly for the restoration crowd. In all honesty I have pretty much all I need in early parts. Even an early rod 750 kit. Which is kind of a good news bad news deal. I think if it ever goes on an engine I may have to spring for carrillo rods so it holds together. Better for me might be to get a set of late pistons to fit the bores and use a late crank.
The best years info is pretty much found in various posts here if you look but early 70 production cams (to #??) are supposed to be the hotrodders choice but generally the "big rod" early internals are not the hot tip.

 

[Jeeter]

I am looking at a 1981 engine with a reported 8k+ miles on it. Is there any reason I would not want this engine (being a 1981 I mean)? Seller says it runs and has "decent" compression. I suppose I'm not too worried about that if I intend on some sort of big bore setup later (just thinking out loud here).

So, what say you? A (claimed) running 1981 for about $230+/- shipped.

 

[TwoManyXS1Bs]

Wow, some shippers charge that much just for shipping to a commercial dock!
That's because the engine weighs over 150 lbs. It should be crated, on a pallet, that's a bit of work. Unless it's being trailered from the next county, something doesn't sound right.

Or, you super lucked-out...

 

[member3480]

OK all kidding aside and not pulling your chain what you are asking for may take a while to find. Any XS650 motor is fine and run well. Me I send all the old stuff to TWOMAMY because he likes to tinker with them and he built a bigger garage so I am trying to fill it. If you want a motor that has a little more stay with 1980 to 1983 last years built. Yes there are some good parts in there upgraded from the older ones BUT!!
You are looking at this the wrong way. Go out buy myself a 8,000 mile motor and I am good WRONG... You are dealing with a 30 yr old motor could have 1100 miles on it and if it was not taken care of put away right you still got a boat anchor.
I have had motors come into my shop and guy says it only has 3,000 miles on it but it runs rough. Open it up and has bad piston or bad valves or water damage from sitting.
So here it is..... NO WHAT YOU ARE BUYING and a motor that is $250. needs to be rebuilt TRUST ME . I build and sell motors for a lot of bikes and I get you guys maybe 4 times a month coming in with a motor that bought it for $150 $250 even $350 and tell me I want to stick maybe $150.00 into it to freshen it up HAHA. For a joke I take a can of brake clean spray it on the motor and say ALL DONE you are freshened up that will be $150.00.
Do yourself a favor do some more homework and know what you are going to buy and how to test it. You may LUCK out and find that $250.00 GOOD motor. But my experience BIKERS TEND TO TELL WHITE LIES ......

 

[5twins]

The '80 and newer clutch has a spring-loaded damper plate at the bottom of the clutch plate stack. This "cushions the blow" every time you engage the clutch. This is important because the 650 doesn't have a rubber mounted rear sprocket, it's solidly bolted to the wheel. To absorb drive line snatch and shocks, the 650 uses 6 little coil springs mounted on the back of the clutch hub. Over time (and more so if abused), these springs can start breaking.

What some consider a drawback is in order to fit that dampened plate, one friction plate was removed. On a stock 650, that really doesn't hurt anything but on a highly modded engine, maybe it would.

If you're like many of us, your 650 will become an ongoing project. As you learn more and more about them, you will try various mods until you find what works best.

 

[weekendrider]

5twins now you will have some looking for a spring on the plates.
They will remove the retention wire, find 3 metal slip plates and deem it broke
cause you say it is spring loaded.
Expect a thread titled MY CLUTCH IS MISSING PARTS.
An yeah the capitals were on purpose, for illustration. I know you hear well enough I don't have to shout.

 

[5twins]

Yes, I suppose I could have worded that differently, even though Yamaha does call that part a spring .....

It is actually a large Belleville style washer.

 

[Jeeter]

OK all kidding aside and not pulling your chain what you are asking for may take a while to find. Any XS650 motor is fine and run well. Me I send all the old stuff to TWOMAMY because he likes to tinker with them and he built a bigger garage so I am trying to fill it. If you want a motor that has a little more stay with 1980 to 1983 last years built. Yes there are some good parts in there upgraded from the older ones BUT!!
You are looking at this the wrong way. Go out buy myself a 8,000 mile motor and I am good WRONG... You are dealing with a 30 yr old motor could have 1100 miles on it and if it was not taken care of put away right you still got a boat anchor.
I have had motors come into my shop and guy says it only has 3,000 miles on it but it runs rough. Open it up and has bad piston or bad valves or water damage from sitting.
So here it is..... NO WHAT YOU ARE BUYING and a motor that is $250. needs to be rebuilt TRUST ME . I build and sell motors for a lot of bikes and I get you guys maybe 4 times a month coming in with a motor that bought it for $150 $250 even $350 and tell me I want to stick maybe $150.00 into it to freshen it up HAHA. For a joke I take a can of brake clean spray it on the motor and say ALL DONE you are freshened up that will be $150.00.
Do yourself a favor do some more homework and know what you are going to buy and how to test it. You may LUCK out and find that $250.00 GOOD motor. But my experience BIKERS TEND TO TELL WHITE LIES ......

Good advice for those that are not aware of those things.

Just to make sure I'm properly understood, I am WELL AWARE that any 30 year old engine is going to need rebuilding, bottom-up. However one must start somewhere, am I correct?

I never once assumed that I was going to buy a perfectly good running engine with no age rot and unabused. This isn't my first rodeo, however it IS my first XS650. Which is why I asked if there was any reason why I wouldn't want to start with the 81 engine, I'm not familiar with the breed of cat.

But thanks again for the advice. It always pays to be a bit cautious when buying used anything.

 

[Jeeter]

The '80 and newer clutch has a spring-loaded damper plate at the bottom of the clutch plate stack. This "cushions the blow" every time you engage the clutch. This is important because the 650 doesn't have a rubber mounted rear sprocket, it's solidly bolted to the wheel. To absorb drive line snatch and shocks, the 650 uses 6 little coil springs mounted on the back of the clutch hub. Over time (and more so if abused), these springs can start breaking.

What some consider a drawback is in order to fit that dampened plate, one friction plate was removed. On a stock 650, that really doesn't hurt anything but on a highly modded engine, maybe it would.

If you're like many of us, your 650 will become an ongoing project. As you learn more and more about them, you will try various mods until you find what works best.

This will be something like the 8th or 10th (er?? doesn't really matter after a while ... ) bike I've built. They are NEVER "done". Not ever.

Good information on the clutch damper. I am familiar with the design you speak of (nearly every single car with a stick has that exact same clutch damping setup, very commonly used idea it seems). Is the clutch basket a component that may be interchanged between model years? Meaning that if a person wanted to use a damped clutch (or non-damped, whichever) may either type be retrofitted to the basic 447? Just checking the options

Since the bike will be a rigid framed street tracker, every little drivetrain "glitch" is felt by the transmission and engine. Every throttled-back decelleration and each "blip" of the throttle is transfered so much more directly to the engine's components with rigid frames that I would imagine any amount of power delivery damping would be a good thing. So thanks for the info on the clutch basket/dampers. I'll have to add that to my considerations as the engine becomes more in focus for this project.

The opportunity for the 1981 engine in question just sortof came-about. It prompted the questions about whether or not it makes a good foundation. If so, I may take the opportunity to snag that engine now while the opportunity exists. However I most likely won't even turn a wrench on the engine for a bit, as it stands I'm working on the roller first.

 

[Jeeter]

Yes, I suppose I could have worded that differently, even though Yamaha does call that part a spring .....

It is actually a large Belleville style washer.

So ok, wait. If that is a thrust washer then I'm having trouble figuring out how it dampens rotational jitters and "slams" (like the coil springs on a car-type clutch plate do). If that is actually a Belleville then isn't it's purpose to provide a constant pressue on the clutch pack to prevent some type of chattering?

At least that's the way it looks like Yamaha applied that "spring", from the exploded view there.

 

[Jeeter]

Wow, some shippers charge that much just for shipping to a commercial dock!
That's because the engine weighs over 150 lbs. It should be crated, on a pallet, that's a bit of work. Unless it's being trailered from the next county, something doesn't sound right.

Or, you super lucked-out...

Uh .. whut?

It seems like you think I meant that the engine would cost $230 for just the shipping. The phrase "$230 shipped" that I usedf means that is the total cost of the engine, shipping and all.

 

[TwoManyXS1Bs]

Uh .. whut?

It seems like you think I meant that the engine would cost $230 for just the shipping. The phrase "$230 shipped" that I usedf means that is the total cost of the engine, shipping and all.

No, no, I understood you. $230 shipped is, for me, a bargain! Living in the wilderness does that. I'd take it, but consider it as the first in a line of collections from which to cobble together a unique build.

That later transmission may have smoother sliding dogs/cogs. It also accepts the overdrive 5th, if you get it to fit the shaft.

Here's a can of worms. Running hardtail lets you run less drivechain slack, compared to swingarm. That reduced slack can reduce driveline snatch, if you keep it attended.

 

[5twins]

The baskets will interchange. I put the newer dampened one on my '78. My understanding is the little bit of "spring" pressure makes the plates engage smoother when letting the clutch out, instead of letting the pressure plate and clutch springs just slam them together. My original '78 clutch (not dampened) would always let out with a little bit of a "clunk" when taking off in 1st gear. This newer set-up engages nice and smooth.