This is a very together, stock and complete bike. I've only owned it for 3 years, so not much has gone wrong. Everything works as advertised like it did right off the factory floor 31 years ago....
But... I ended up installing a specifically made for XS11 thick aluminum billet fork brace shortly after I got it and that REALLY improved handling... particularly around the twisties/tight curves. Before that, it tended to wallow and drift, and didn't respond well to my attempts to tame it round curves (with or without proper line set up, aggressive leaning or throttle steering). In fact, this is often reported negative on stock XS11s. So I highly recommend a fork brace (at least).
I have a mid range stumble/hesitation between 1500 to 3500 RPM. Otherwise it idles perfectly smooth at 1K an comes on like a Shinkan-sen ('bullet train') during hard acceleration and RPMs above 3500. Suspect carbs need to be sorted out (even though previous owner said he had done that). They're either dirty or some circuit/jet is clogged. Makes it run ROUGH and anemic during mid RPM range. Annoying!
Finally -- maybe related to above mid range sag --my XS11 gets really bad mileage (about 25MPG?) even when not driven aggressively. They were known for less than great tank ranges/MPG numbers, but this is a bit too much. My 69 Kawasaki Mach III two stroke triple does better than 25MPG!! (but only barely... :-) ) Anyway, I'm SURE this is all part of carb issue. I don't think it's ignition or timing related cause otherwise it idles and accelerates too well.
Make no mistake, the XS11 is a well-designed, well-built rugged and reliable quality machine... even by today's standards. Fit and finish attest to that as well.
When the XS11 debuted in 1978, it immediately became the reigning superbike king (for that year or so at least) from 'the land of the UJMs'. Fastest accelerating (quarter under 12 seconds stock) and highest top speed production bike your quickly shrinking dollars could buy (remember the high inflation back then??). :-) It knocked Kawasaki's KZ1000 off the superbike throne for good.
The XS11 is 'historically significant' because it was Yamaha's first 4 cylinder four stroke bike and 'real' response to the escalating super bike wars of the Jimmy Carter years.. And it was a big bore bike... 1100ccs... rivaling Honda's equally big GL1100. Yamaha's previous 3 cylinder lineup (XS750s and XS850s) sold well and serviced quasi unique niches -- i.e., 'standards' for casual touring and 'specials' for cruising. But none of Yamaha's venerable (and SMOOTH) shaft drive triples pretended to be or were designed to take on the big superbike market head on. Only the 78 XS750E model came remotely close... and even the much perfected faster/sportier 'E' couldn't compete with Kawasaki's bigger bore 4 cylinder liter superbikes, etc.
So...when the XS11 (as in 'Excess Eleven' :-) ) was introduced in 1978 and joined the XS750 triple line-up, it simply blew the triples away... along with the rest of the competition. To appreciate the XS11's impact when it debuted, one can compare it to the later V-Max's stunning impact and media hype when it first came out in the mid 80s. It was THAT big of a deal in 78... at least on the performance side (i.e., after all, the XS11 was well styled but not exactly a profound styling exercise or sensation).
While the shaft driven XS11 may not have the following that the CB750, CBX, Z1/Z1000, GSX1000s or other superbikes of that era may have, the list must be growing as the XS11 seems to withstand the test of time better than other 'neo classics'. XS11s are one of the strongest running late 70s/early 80s 2-valve muscle machines to come out. They were smooth, comfortable, QUICK, FAST, POWERFUL and reliable. You can lug them around town relaxed, or turn up the heat and shred pavement (ala 70s style) or accelerate till holding on for dear life (i.e,. fighting not to slide off it's smooth, flat slab seat). Make no mistake... this is NOT an XS750 triple with an extra cylinder tacked on!! IT was a ground up new design targeted to be the biggest, baddest and meanest bike on the road. And so it was... back then. Of course, it did share some parts and components with it's smaller triple brothers -- much like BMW later did between the K75 triples and K100 four banger 'flying brick' stable mates.
My XS11 -- sporting a "Macho Maroon" stock paint job and tasteful/tidy Yamaha XS 'standard' styling -- is pretty much ALL stock, clean, fresh and original, with relatively low miles for its age. No rust anywhere (except for bottom of muffler tips). Yes... the paint scheme really IS called "Macho Maroon" which is a very appropriate color name for these brutes. For this IS (or was at least) truly a macho bike. These 4 cylinder XS11 lumps were so strong and bullet proof that Yamaha used them for Maxims and FJ1000/1100s for quite a few years after. And don't let the shaftdrive fool you. XS11s really are brutish machines powered by sheer muscle DOHC aircooled 'tuned' (as in 'fork tuned?' :-) ) marvelous 'excess' engines. And though I haven't (and never will) done it on my XS11, I've seen them pull high wheelies from stop light pop launches. Ouch!! That poor tranny, middle gear, shaft and rear end... But what POWER! Especially for a 550 lb + bike built 30 years ago. Imagine what XS11s would of done with a chain drive instead.
Yet XS11s were (and still are) so comfortable, reliable and durable/powerful that owners back then outfitted them with Vetters fairings and the like for some serious long distance touring. Some have said that XS11s were as comfortable for touring as Honda Leadwings... Mine, however, is remains a stock 'naked' all rounder. No aftermarket fairing to spoil this king of the streets' trim. Cause it's in the street light spontaneous drags, this bike truly impresses... when everybody can see up close and personal what this bike really was capable of doing -- back then. Yeah I know, it's nothing compared to today's hyper bikes...
But it's still exhilarating... even at "slower" sub 100MPH speeds. Then again, just about any 70s something bike was/is 'exhilarating' over 80MPH... :-)
So what specifically do I like about my XS11? It's got more than enough power, speed and torque for day-to-day contemporary riding -- whether commuting, day riding or touring. I more than keep up with newer stuff (ridden 'conservatively'). Clutch action is light but positive/linear. Tranny is straight from "Yokohama Silk Hotel". Engine is amazingly responsive and lively -- except for specific mid range problem I cite in first section (CV carbs and 70s EPA restrictions may be leaning it out a bit) It handles VERY competently and confidently -- now that I added fork brace. Shaft drive makes for quiet trouble/MX free operating, though it can 'misbehave' a times with some notchiness or 'drive snatch' (at lower speeds). And while the XS11 is not a light bike, it sure does handle like it is -- even at lower speeds. Wide upright handle bars, frame geometry and seating/footpeg ergonomics certainly feel more than comfortable and natural. And, of course, it has the triple disc brake set-up to shut things down quickly and relatively effortlessly without drama. I also like the seat and -- particularly -- the relatively short 31-inch seat height. The gadgetry stuff is dated... but functional and easy to view/monitor (including the headlight bulb failure warning light?).
Back when men were men, and bikes were all engine and proudly unadorned with plastic or fairings, this was a real mean no compromise "macho man's machine" and great 'all rounder'. One bike -- specifically -- an XS11 could do it all... instead of today's specific purpose bikes. Commute, tour, slup around, street drag, do errand or dispatch work, or shrink miles on the open highway. Just don't ask it to scratch out canyon roads and curvies. At least not at speed.
In closing, riders are encouraged to go to the XS750-D2 section and my reflective 'monologue' (or diatribe) on the XS750E. There, I make the admittedly weird 'out there' comparison of neat, 'every hair in place' nicely dressed and pretty to look at Japanese standard 'office ladies' to the 'pretty, tidy, dependable and serious no frills' XS750. Not so for the XS11. No way! This was (and is) more like a beefy, all muscled up Japanese male gymnast attacking the parallel bars or vault in exciting head-on determined fashion! Or a rugby defense man.... It's all muscle, brawn and strength. An over-engineered and over-manufactured bike (of it's day)...that was built to last... and perform reliably day in and day out. If you find a good clean XS11 (or for that matter XS750) to meet your need/desire for a good low dollar traditional 'all rounder' reliable and dependable neo classic ride from Nippon, do give it serious consideration. I seriously doubt they're still making them this way... :-)
(BTW... if you think I love and respect this milestone bike, you should that XS11 expert/lover's book "XS Eleven Heaven". He really loves them... :-) )