Yamaha XS650 650cc twin


  Me and my twin (4/04)

The Yamaha 650cc SOHC vertical twin was produced from around 1969 to 1983.  It vibrates and doesn't have blinding speed, but is brutally reliable and a genuine hoot to ride. The original 4-stroke motor design is rooted in the Toyota 2000 GT engine which was designed by Yamaha.  Comparisons to the classic British vertical twins, Triumph, BSA, Norton, et al, are not without merit.  Early models were notoriously poor handlers, but had excellent engines.  Around 1975, Percy Tait, renowned Triumph motorcycle engineer and racer, tweaked the Yamaha 650 frame for his own racing team greatly improving the handling characteristics.  Yamaha implemented his frame modifications and made a good engine even better.

Ironically, today the Yamaha XS650 is one of the most popular bikes in the UK and Europe, examples in good condition fetch well over $2,000US.  The engine features 3 caged roller bearings on the crankshaft, 4 on the single overhead cam,  and needle bearings on the rocker arms.  An electric starter and front disc brake were added in the 1972 XS2 and an electronic ignition system in the 1980 G model.  Through out the 650s production life improvements were implemented and the last several models are excellent bikes.  

Since its introduction I have owned four Yamaha 650s.  I bought my first one new in 1972, it was an XS2, and I rode it until 1977.  In 1982, I traded some stereo equipment for a wrecked 1978 XS650SE.  All the damage was to the front forks.  I had it back on the road in a day and sold it in 1985.  I donated my parts bike, a 1980 XS650G model (3G0-002552), to a friend who needed the engine.  My current 650s are a 1981 XS650H "Special II" (4N9-001289), which is on the street and running great, and a basket case 1972 XS2 (S650-130176) that is being restored.

Prototype XS650 ca. 1914  

   XS650H (10/04) 

My H model Special II was rescued in the spring of 1995.  It had been abandoned, due to a broken clutch cable, in an open barn in rural Maryland since 1987.  The barn served as a pigeon roost and the birds made their nests directly over the bike.  After several years the owner covered the bike with a plastic tarp.  The bike remained for several more years and the bird's droppings did wonders to the finish.  The owner had attempted to fix the clutch cable and removed the left side crankcase cover to gain access to the clutch mechanism.  Unfortunately, he became frustrated and left the bike in this state for 8 years. 

As soon as I got it home I washed the entire bike twice to remove the pigeon's coating of droppings, broken eggs and feathers.  Once it was freed from it's fecal cocoon I cleaned the carbs, changed all the fluids, installed a new battery, plugs, clutch cable and left side case cover.  

The bike only had 6000 miles on it, started immediately and ran very well.  I had to immediately replace many of the fasteners, much of the chrome parts and the front fork tubes.  The NOS Yamaha sissy bar and Willie and Max bags were added that same year. For Daytona Beach Bike Week 1998 I rebuilt the engine, had it bead blasted and polished, installed K&N pods and handlebars, an NOS exhaust system, O-ring chain with new sprockets, and replaced more fasteners. 

During 1999, I added the second front disc, repainted the tank and sidecovers, recovered the seat, replaced the tank emblems, and more fasteners. 

For Y2K, I installed a fork brace, stainless steel fasteners and mounted superbike handle bars.

For 2003, I installed tapered steering bearings, rechromed and re-laced the front wheel, installed a mag/drum brake rear wheel.

In 2004, I added braided stainless steel brake lines, an all-metal master cylinder from a later model and slotted disc rotors donated by a XS11, and a bikini fairing.

My next update will be a high performance 2-2 exhaust.

 

   

 

   

 

These pictures show some of the updates I have made to the bike. 

The slotted rotors were warped and require machining, so I put the stock ones back on. 

The front rim was re-chromed and relaced over the winter 2003/4 and the rear wheel is from an 1981 SH. 

The bikini fairing is from Omar's Dirt Track Racing.

Rat Bike    Rat bike

      This is an early photo of my '81 H after a good washing, but before I really cleaned it up.

Clean engine   Clean engine

The engine top end after bead blasting and before the barrels were painted black

Randy, his TX650A and me  

I had the privilege of meeting former Society Prez Randy Steinmeyer in November 2001

   My 1981 "Special II" (10/99) 

   member #4278