Announcement

Collapse
No announcement yet.

a beautiful motorcycle engine

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • a beautiful motorcycle engine

    I've long admired the looks of the Yamaha 650 twin. There were quite a few on the streets of New Zealand cities in the 1970s. It was better than my Honda XL250 in one respect: it used Allen screws on the cases, instead of Phillips like Honda did at the time (I still have the an impact driver in my tool chest, for removing those).

    How good was this engine on the inside?

    Last edited by aostling; 04-20-2016, 11:46 PM.
    Allan Ostling

    Phoenix, Arizona

  • #2
    I replace all the philups screws I remove with SHCS's, sometimes button head cap screws if the area looks better with that style.

    Protip: get the proper JIS screwdriver.. with built in impact :P and those screws come out like butter.
    .. Wouldn't put those butter screws back in however.. :P
    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

    Comment


    • #3
      I had a friend that had one & at a stop light at idle the front wheel would bounce 1/2" off the ground. My wife has a Suzuki Savage 650 Thumper that didn't viberate that much.

      Comment


      • #4
        A number of old time mechanics said that engine is based on the Triumph Speed Twin, which would seem to bear out Flylo's
        comment about the front wheel bouncing.
        Yamaha must have made some improvements...a buddy had one, I had a Bonneville. On his you could see what was in the mirror.

        Comment


        • #5
          I had a 1981 650 Special bought new and it was much better than the old twins like the Triumph and Norton. I had a Norton and there was always a question whether it would start without me being drenched in sweat or leave some kind of puddle wherever you parked. The Yamaha has better carbs, better ignition, electric start and no oil leaks. Some vibration, but not a deal breaker unless you are trying to ride all day. Not a power house or speed bike of the day by any means. I sold mine to a nephew who sold it to a friend who sold it to another friend so reliability was not an issue. Mike

          Comment


          • #6
            This honda? Did some work for a guy on this one. Never did get to hear it run though.

            Andy

            Comment


            • #7
              When I look at the brake rod the words that come to mind are,
              "Oh dear Lord!"

              --Doozer
              DZER

              Comment


              • #8
                The Yamaha wasn't cursed with Lucas "prince of darkness" electronics but didn't have the class of Triumphs IMHO. I had a '69 Bonny & still have the '73 Trident with 189 miles since total restoration I can't ride so needs to go.

                Comment


                • #9
                  Kenny Roberts won the A.M.A. Grand National Championship aboard a ’73 XS650 Yamaha Tracker.

                  Comment


                  • #10
                    It was a parallel twin without secondary balance shafts, built up crank, based loosely round the layout of the older brit stuff but with modern for the time improvments so some vibration and you could knock the crank out of true if you get too extreme, but oil tight and you could take them out to quite amazing capacities. We used to call them the japanese triumph and a lot of ex brit bike riders ended up having one back in the day when they were current.
                    Nowadays I believe they are taking them out to 999cc with bore and stroking, rephasing the crank for less vibes, bigger oil pumps etc etc.
                    There's masses of enthusiast stuff out on the web if you search for it. Its still very much an aquired taste over a modern 4.

                    vpt, I believe thats a super (wet) dream aka cb400n donk. Imho the worlds most boring honda engine. secondary balance shafts, low down torque eliminated in the aim for smoothness, no personality and kitten fart exhaust note and a frame that flexed because they put big holes in it so you could pass the socket to take the head bolts out right through the main spine that I see the custom bike builder responsible has kept! I've had several of them. They were the sort of bikes I bought cheap (we used to call them 30 quid specials which is about 40-50 bucks), formed no attachment to but ran for over winter so if you fell off it didnt matter & the salt didnt wreck your proper bike then threw them in the spares pile when they went expensively wrong (Camshaft tensioner problems usually which meant a strip down to resolve). Absolutely no comparison to the personality of a xs650. Probably by now theyre rare and theres some people restoring them in the same way people restore austin allegro's just because they became rare.

                    Comment


                    • #11
                      I've always loved the aesthetics of the up until the late 70's/80's parallel twin engine better than any other design. Don't what it is, maybe the left/right symmetry or something, but to me it's the most pleasing. The xs650 is a popular vintage racing bike so I'm guessing the engine is a good'un inside, or it wouldn't have as good a following? Dunno, not much of a yammie guy.

                      Comment


                      • #12
                        Originally posted by Mike279 View Post
                        I had a 1981 650 Special bought new and it was much better than the old twins like the Triumph and Norton. I had a Norton and there was always a question whether it would start without me being drenched in sweat or leave some kind of puddle wherever you parked. The Yamaha has better carbs, better ignition, electric start and no oil leaks. Some vibration, but not a deal breaker unless you are trying to ride all day. Not a power house or speed bike of the day by any means. I sold mine to a nephew who sold it to a friend who sold it to another friend so reliability was not an issue. Mike
                        Had the good fortune to know a BSA dealer/mechanic who had raced at the Isle of Mann in his youth. He helped me with the Bonny and when we were done it started first time every time, didn't leak oil and idled on the center stand without dancing around. It was no problem smoking my friend's XS 650...but I think that bike was heavier than the Trump.
                        So, better is subjective.
                        No question about the carbs and Lucas...a great cloud of smoke erupted under the seat when riding...'course I was miles from home. Instead of a nice heavy ground wire there were a number of small gauges paralleled, lose one, lose 'em all.

                        Comment


                        • #13
                          Originally posted by Carm View Post
                          Had the good fortune to know a BSA dealer/mechanic who had raced at the Isle of Mann in his youth. He helped me with the Bonny and when we were done it started first time every time, didn't leak oil and idled on the center stand without dancing around. It was no problem smoking my friend's XS 650...but I think that bike was heavier than the Trump.
                          So, better is subjective.
                          No question about the carbs and Lucas...a great cloud of smoke erupted under the seat when riding...'course I was miles from home. Instead of a nice heavy ground wire there were a number of small gauges paralleled, lose one, lose 'em all.

                          Ditto.

                          Certainly can't speak for everyone's bike but the Nortons I had as well as all the others except for one, were all kick start only.
                          The Nortons never leaked a drop of oil and were always a 1 or 2 kicks at the most starter. The 750 and 850 Norton were bigger of course than the Yamaha but both were much faster than the simple displacement advantage alone would suggest. Handling of the Yamaha also was not in the same league.

                          Having always owned kick start only bikes I've always kept the bikes in tune and perhaps more important, myself in tune with the engine of the bike. One has to listen to what it is telling you or face the merciless wrath of kicking your guts out.
                          My current bike is one I bought at the end of '77 and is one of the last kick start only HDs. It is almost always a one kick, or two at the most starter. If anyone else tries to start it they are left dripping wet from sweat on a bike not running. Technique is more important than brawn. More often than not if I had trouble kick starting a bike it was due to not being in tune to what it wanted.

                          But yeah I have a lot of respect for the Yamaha XS650, it's always been very reliable and one of the most aesthetically pleasing designs from Japan. I was saddened when it was dropped from production.
                          Home, down in the valley behind the Red Angus
                          Bad Decisions Make Good Stories​

                          Location: British Columbia

                          Comment


                          • #14
                            Yeah, I had kind of a personal mechanic for the Norton too. Dunstall parts were the hot ticket back then and I had a lot of them on that bike. I liked it a lot a just couldn't afford to keep her running. After I had to grind the crank and fit a new set of bearing my budget was toast. Still needed to refresh the top end and I could not swing it. Sold it to a College professor that did not know how to ride it. He brought a friend who drove it around the block. He was trying hard to get me to lower the asking price until his friend came back with an ear to ear grin. Mike

                            Comment


                            • #15
                              If you are blessed with a heavy kick start 'cycle and weak leg muscles plus magneto ignition there is a dodge that may make starting easier, or so I have been told.

                              Take a lead from the magneto cut out switch to a terminal on the electric horn then by holding the horn button the interrupted voltage from the horn contacts will be applied across the magneto points causing a 'shower of sparks' whenever the points open. The theory is interesting but I have never tried it.

                              Comment

                              Working...
                              X