This page details my 2005 mechanical project, yes its a 1979 Yamaha XS650SF Heritage Special, its likely to be a longish project as the original idea was to look around for a motor and transmission to use in a chopper frame that I was intending to build from scratch. This idea came about after watching many episodes of American Chopper, OCC and good old Jesse James, well I figured some of the stuff I was watching was very crudely put together and maybe I could do up a chopper of my own, following of course my usual concept of economically building my own version of such a machine. During my search I happened upon this fine machine, the price was right so I purchased her and have now stripped it bare and have re-built the carb's and pet cock's already, next is to be the engine and frame. Of course the electrics (wiring) will need to be completely re-worked as the poor old beast was left un covered for years in our Canadian winters..... ;-( I have built a Compression and Leak-Down tester and will check the mill before stripping it down.

(Sold to a fellow from the Sunshine Coast area just north of Vancouver Canada.)

The old girl as I got her, sad and forlorn looking having been left completely unprotected from the elements.

I removed the disk rotors, skimmed them up on a large four jaw chucked lathe and drilled them to increase cooling, acually I like the pattern ;-) it looks better than a plain disk. After looking around on several Yamaha owner bulletin boards I realised that many folks had done this and reported falsely I believe that drilling disks is difficult and risky. This is not the case at all, some folks reported the disks are so hard they cannot be drilled unless one has a handfull of drills and the smoke is so heavy you need to be in the open to do it! This is of course totally untrue, both my disks were drilled with 2mm pilot holes, 4.5mm starter holes and 7mm final size holes, using one bit for each ! There was no smoke or dulled drills, Just be sure to set your drill press to a slow speed for the larger drill and hold the disks carefully using a modest amount of coolant, no smoke or judder should be evident otherwise you are simply drilling too fast. You do not need to "clamp" the disks either, just take your time and go slowly ! It took approximately 2.5 hours to complete drilling both disks including countersinking and finish sanding the surfaces. More pictures and text as time permits.......


OK, its time for an update, as of July 2005 I have the frame and all tins glass bead blasted now and all are sporting a new Mercury Blue powder coat. Here are a few pictures to illustrate how the bike is turning out so far.

Newly Powder coated frame

Swing Arm, thus far without the new brass bushings purchased from Frank Jahnke in Europe.

Tank looking good outside but the newly Kreemed inards were very sad to see, more on that later !

Bat Box as it came off the beast

And now after paint and refurbishing of all the electrics.
I have also undertaken to do the modification from the old style internal oil filter to an under engine mounted cartridge type and here are a few shots of the machining steps. For some reason the Clear Hard anodizing turned out to be a grey color but hey, what the heck its on the bottom of the engine anyhow.

Partially machined bottom view.

Completed but Un Anodized.

Here shown with brass coupling and plug in place. The coupling is machined from a standard purchasable 3/4" 16NF pipe thread coupler cut to length and the centre turned (or drilled) out to facilitate better oil flow. The finished section is secured into place using two nuts tightened against each other and removed later, the unit is cemented in place in the plate using JB Weld or some similar hard setting 2 part material that is not sensitive to heat or liquids.

As it will look on the bike.

Here is the diagram as I downloaded it from the web as drawn by Fred Dyen but with a couple of small but necessary corrections and additions. Fred's PDF can be seen at:
http://home.gci.net/~dyen/pdf/Yamaha_XS650_Oil_Filter_Adapter.pdf
The original article by Dave Bath in Australia can be seen at:
http://www.xs650.org.au/tech4.html
Firstly the thread size of the coupling pipe should be the same as that of the commercially available filter (3/4"-16NF) shown at upper right of drawing.
Secondly I modified the depth of the counterbore where the plug bung is to be inserted to more readily accept the tapered tap that I had on hand to a depth of 1.5" using a .61" drill, the correct tap designation of 3/8"-18NPT as shown at lower right of the diagram.
Thirdly I recalculated the correct position of one of the oil journal (through holes) to be .860" from the top or longest flat edge as shown at the lower left of the drawing.
Fourth I calculated and added the centreline mounting hole dimension to be 1.477" from the top edge of the same drawing as above.
Fifth are the details of the brass coupling pipe that attaches the screw-on filter cartridge, I used the same thread as the cartridge for simplicity, this thread is 3/4"-16NF and is shown in the upper left of the page. It should be noted that the brass plug only serves to fill the end of the long hole leading to the filter and is a standard purchasable pipe plug with a thread size of 3/8"-18NPT.
And lastly the filter cartridge details I show are simply one of locally available device and other types may be available to you. Mine is a WIX filter # 7035 Napa Gold purchased from Napa Auto Parts.

**** NOTE **** After attempting to instal the new filter on the engine prior to inserting it back into the frame a serious error was found in Fred's PDF diagram, the center mounting hole at the brass plug end should be 6mm closer to the edge of the plate. It could be reworked easily but I opted to delay the instal till a later date when I have time to modify / rework it neatly by first plugging the incorrectly positioned hole and re-drilling. So if your copying the filter mod please be sure to use your old oil filter plate as a guide for measurements rather than relying on the PDF on the web.



The damaged bearing surface can clearly be seen here, this is what causes the infamous "Centre Indent" feeling of the XS650 when the wheel is removed. No its not meant to feel that way :-)

Here you can see the newly installed tapered needle bearings purchased from MikesXS.
The lower bearing is easily installed by first removing the old cup, This was carefully cut off using a Dremel cut-off wheel, as the bottom tree section had already been painted and one didn't want to risk damaging it with levers etc. Then the bottom stem was placed in the freezer over night and the bearing itself was warmed up for a few hours, the hot bearing then simply slipped onto the cold stem with no brute force necessary.
The Bearing cups were inserted into the head tube on the frame one at a time using the same freezing technique and a length of 1/2" threaded rod with two nuts and a pair of purpose machined disks, actually a couple of heavy gauge large diameter washers would have sufficed. Both outer shells slipped into position with no fuss or force required.
Only one nasty blunder to report so far, I de rusted the tank and treated it very successfully with Kreem before powder coating ....Bad mistake !! The Kreem bubbled with the heat of baking after the powder coat process and went a very dirty shade of brown kind of like Aero chocolate to look at. I will of course have to remove the coating and redo it. More on that later !


It is now October 1st and I have fought a fierce and lengthy battle with the tank, the Kreem after baking was a real bastard to get out. The manufacturers stated that Acetone or MEK would remove it....indeed it will easily remove fresh un-baked Kreem after soaking but if its been hardened, forget it. The tank sat for a month and it softened and some came out but I ended up putting the whole tank into an industrial tumbler along with some triangular stones, well to cut a long story short the darned bung came out and flooded the outside paint job with Acetone, peeling my nice powder coat off. This time around I will take no chances and Kreem first then paint the outside myself with no heating. More news as I progress with that saga.
OK now for some more pictures, here are a few of my progress to date as of October 1st 05.
Left side
The clutch lever screw holes were totally worn oval so I machined all three sections out and inserted some hastily turned brass inserts.
The handlebar switches were terribly corroded inside so all were stripped, cleaned and repainted. View prior to re-working.
For those confused like myself after reading some folks reports on how to open the forks, here is a view of the illusive Fork Nut.
My homemade long wrench approaching the nut.
A view of my modest workspace in-between the garden shed and the rear fence of our property :-(


It is now October 22nd and the engine is in the frame again, wow what a fight, had to rig up an engine lift with three 4*4's and a chain hoist loaned from a friend. They are tricky to get in that tiny space when never having done it before. Now I know what to look out for next time should be quicker and easier. Right now I have aching muscles I didn't even know I had :-) Here's a few more pics to illustrate progress to date.
Nice clean engine on home made engine stand.
Another shot of the front
From the back
My newly designed and manufactured staninless steel rear indicator lamp brackets, made because the grab bar had been lost by the previous owner.
Fresh coating of underseal on rear fender. A further coating was applied to cover all wiring before assembly on bike.
The original oil filter had a hole blown in it so it was repaired and a stainless steel deflector was installed to keep the oil from damaging it again, there is a hole in the engine between the crank halves that must have a high pressure stream directed right at the filter in its most vulnerable spot right where the brass screen is flat (not pleated). So a simple right angled bracket deflects the oil to the sides.
The Newly inserted Stainless Oil Deflector bolted under one of the filter mounting bolts.
Left side of the bike with newly installed engine.
The right side after much struggling to get the engine inserted (first time for everything :-)



Hello again, its now March of 2006 and the beast is finished. There were a few tense times since last year especially with the gas tank saga. To explain, the heat damaged coating never came out to my satisfaction (left a slimey mess) so I purchased a used tank off Ebay, it had some light rust inside and a few dents so I opted to derust it first due to the nasty chemicals needed, rather than waste more money on a full Kreem kit as I still had the coating left over from my previous screw up, I used a mixture of 15% Phosphoric acid, 2% Butyl Alcohol, 80% water. This brew quickly and efficiently removed all the rust, I washed out the tank and coated it with Kreem as per the instructions, I have to add here that this material is bullet proof if the process is followed correctly and I would'nt hesitate to recommend it to anyone. After the coating cured I aired out the tank and sent it out for paint at a local body shop, they put on a few coats and after block sanding covered them with a few more coats of clear. I did not try to match the blue of the powder coat but rather opted for silver.

The only other slight problem was with the seat cover purchased from a commercial outfit in California as a direct replacement for make, model and year. Well to cut a long story short the cover was 1/2" to short around the edges and was crudely made to fasten onto the seat pan via a pull chord.........yeah right ! It looked horrible, and simply didn't fit properly. My daily work involves toiling with assemblies requiring great precision, good manual dexterity and extremely fine tollerances (microns)..... After many hours struggling with the cover which was too small to fit the stitching begun tearing through the cheap material used in manufacture.....to say I was pissed would be an understatement as this was an expensive cover and should have been better made. At this point I had ony one option, to remove the crude pull chord and use rivets. I decided as the material was thin and weak to go with screws as they are easier to tension without pulling through the fabric. Rather than using plain screws I inserted countersunk washers under the screw heads to facilitate a better overall process. Yes, it looks a tad hokey but, hey it was better than scrapping an expensive piece of crap cover. Maybe later I will replace it if the sight of it bugs me enough.

Enough babbling its time for some pics of the finished machine so here you go:
This is how the used Ebay tank looks now.
The Gauge cluster.
Left Front view.
A look at the right side.
After re-assembly and a few nervous moments some fresh gas was dumped into the tank, the kick start was pressed into service to get the oil circulating to all the innards, the choke switched on and the ignition key clicked to the run position and the starter button pressed, and on the third try she roared to life, sputtered a few times as I set the tick-over speed on the carbs. I was very impressed to find that lads who had suggested not messing with the greasy grimey gopher guts of that old engine were right, she sounds good, so far no major problems have arisen, after a couple of hours of checking all the systems I took her out for a spin....what a rush ! The distinctive sound of that parallel twin is exhilarating to say the least, and the characteristic vibration through the handlebars is wonderous to re-discover as I coasted gently down the farm roads near where we live. Memories of my youth immediately cascaded back to this almost 60 year old brain....fun ? Oh yes, It was well worth the effort to do up a classic old machine like this.

I hope you have enjoyed the story of how this old rust bucket has been reborn and please feel free to ask, if I can be of assistance with the knowledge I have gained during this wonderous journey one will be happy to do so.

Since the bike has been riden quite a bit the centre stand seemed to be really tough to use so upon further investigation it was seen to be cracked (guess I never noticed the crack when cleaning for powder coating :-( . Anyway some pieces of steel were hurriedly shaped and welded into place to again provide a sturdy support for the old girl. Here are a couple of pics to clarify a bit the methodology of the repair.
View of the crack found.
Parts manufactured ready to weld.
Parts ready to weld onto old stand.
Completed and painted.

Page Last Modified: 22 July 2006.
Click Here