Archive for the ‘M – Engine’ Category

XS650: Rocker Shafts   Leave a comment

Been building myself a couple of XS motors lately. 277° and 360°. Have had the blocks together for some time – gearbox and crank, new bearings and seals etc.

Got round to stripping down an old XS1 head the other day. Just to check her out. Actually not too bad, some leakage around the top of the inlet valves, guides ok, valve stems straight. Cam ok. Rockers starting to wear a little. Decided to replace them and the shafts as I had a new set lying around and I have a new cam.

First you need to remove the 4 press fit sleeves that seal the outer-headstuds. You can simply bash these out but I wanted to remove the rockers and the shafts sit pretty tight (unlike the SR500) so I popped the rockerbox in the oven for a while.

The sleeves knock out easily with an 8mm socket.





Then you can get to the rocker shafts. These are tight.The puller I had rustled up for the SR500 wasnt up for the job but still had the longest 6mm thread I had on hand so I simply packed the outside with a socket and an old gearbox bearing and wound the shafts out.





Total time, less than 5 minutes once heated (if you heat use the oven and not a torch – no point in risking warping the box).

Slapped her back into the oven for a few minutes before inserting the new shafts and rockers. Dont forget to blow out the oil galleries first, and lube.

If wanting to reuse remember to bag and label: left/right, inlet/outlet


Posted May 29, 2016 by xscafe in Motor - Head, Uncategorized

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XS650: Oil Filters   1 comment

Had my hands in a couple of motors last week. An early XS1 that, judging from the bearing seats, has had as hard a life as Keith Richards face. An XS-D that looks pretty clean inside. Both had what look like original filters.


Top: XS-D .. Bottom: XS1 – both showed damage from over-tightening the screws.

Neither gasket had been pre-treated before installation. An SF hammer was required. The gaskets did separate. In half.


Early filter left with full metal jacket. Right: pleated mesh with magnet, right-hand end slightly crushed. Mesh on both sides intact.


Rear: Early filter has no magnets. Mesh is only spot-welded. Later filter has magnets both sides. Mesh is fully cemented. Much more surface area. Mesh is finer.

Early oil flow problems? Filtration issues? Strange the prone corner was never properly reinforced.


Left ends intact.


Fronts. XS1 filter, mesh has started to separate at the spot-welds.

Although I’ve seen much worse both these motors could have benefited from a few more oil changes.

Was pleasantly surprised to see the original XS1 filter here. And that it had survived so much punishment for so long before giving out.

Both engines have obviously been warmed up slowly-the ends are still intact. The mesh separation on the early filter probably derives from crankshaft rotation – from the look of the bearing seats this motor has sung – full throat – louder than Sleazy Joe.
(143.2dB in Hassleholm, Sweden, 2008)

The XS-D filter could make a good emergency reserve. After fitting an end protector. And rechecking each oil change.

Take care of your engines and they will take care of you. These are very much ladies.

Posted February 1, 2016 by xscafe in Motor - Oil, Uncategorized

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XS650: Rocker Shaft Removal   Leave a comment

Have been cleaning up a couple of SR500 heads. Ready for porting, new valves and rocker shaft bushing. Needed to remove the shafts. Rooted around in the odds’n’sods bin.

  • 2 x pieces 6mm threaded rod
  • 1 x long open ended 6mm joiner
  • 2 x 6mm nuts
  • 1 x 6mm dome nut
  • 12 x large 6.5mm washers
  • 1 x piece duct tape

5 minutes. No cutting. A perfectly good 6mm slide hammer.


Screw into the rocker shaft. Off you go.


Same principle for the XS.


XS650: Vibratirry Bowels   Leave a comment

Was cruising through fleabay and found this: …


Pro-1 Racing is now offering ISOTROPIC FINISH services on YAMAHA XS 650 Motorcycle Transmission . Note this is a machine shop service on your transmission. Isotropic Finishing is not a polish process but a super finishing procedure. This process is a two stage chemical process to produce a super finish know as an Isotropic Finish. The first step is a chemical interaction with the metal where a film that is 1 micron thick or 1/100000in. The parts interact with the ceramic media and a vibratirry bowel. The second step is also a chemical reaction that produces the super finish know as the Isotropic Super Finish. This two step process takes about 4-6 hours in each step with a total time of 10-12 hours. Parts are constantly inspected and measured, during both processes. After parts are finished, all parts are Ultra-Sound cleaned and coated with a rust prohibitor.

Parts received are inventoried and digital picture are documented
We would like to have the transmission disassembled if possible,we offer services to remove gears from shafts for an extra charge.
We inspect parts parts and advise if we see issues

We use BV products from Melbourne Australia. I acquired all of the knowledge and procedures during my stay there in 04/ 2015.
The experience was very exciting and I’m looking forward to share all of the beneficial results.


• reduces friction,vibration and noise
• improves Shifting on Vintage bikes and Harley Davidson’s
• Race bike application
• longer life on parts
• reduces lubricant temperatures
• reduces metal to metal pitting
• less inertia= lee friction=reduces fuel consumption
• stress relieves parts

Applications include

• gears and shafts
• camshafts
• crankshafts
• rocker arms
• valve springs
• transmission gears

For more information, please feel free to call;
Short Block Charlie/ Pro One Racing at ### ### ####.



sorry Charlie, your block’s shortness could have something to do with your vibratirry bowel

In essence this is a vibration finishing process. Uses non-abrasive media. On chemically coated machined parts. Creates a non-directional finish. Removes stress risers. Improves surface finish and edges.

Main benefits seem to be stress relief, reduced friction, less heat.

Isotropic Finish is related to the non-directional vibration finish. The chemical treatment serves to speed this process up

BV Products actually do exist. Couldnt find any medical warnings on their site.

Posted December 28, 2015 by xscafe in Motor - Gearbox, Uncategorized

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XS650: Tappet Covers   Leave a comment

Was ratting round in my spares shelves/boxes. Found a 3-bolt tappet cover with slots instead of bolt holes – wtf?

Then found three more

Ah so! Early XS1 covers. No O-ring grooves. Gasket pure.


tappet covers outer

tappet covers, outside … early 3-bolt, slotted, gasket, … 4-bolt decompression cover, XS2, holes, gasket … 3- and 4-bolt cover, holes, gasket … 3- and 4-bolt covers with holes and an o-ring groove cut – 1 set alu, 1 set chromed



tapppet covers inside

tapppet covers inside … here you can see the flat gasket faces and the grooved o-ring covers





Posted October 15, 2015 by xscafe in Motor - Head

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XS650: Cool Poster   Leave a comment

XS650 Poster - green

XS650 Poster – green


The poster version below is available (size approx 2.4:1).

reworked poster … points and advance unit detail … engine stand removed

Posted February 14, 2015 by xscafe in M - Engine

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XS650: Daryl Rephase   Leave a comment

Mr Rephase and the media circus. Interesting article. Motorcycle Trader. June 2014.

Daryl Rephase XS650

Daryl, Professional Motorcycle Tuning, Melbourne, Australia … 270° XS650 Rephase


Daryl Rephase XS650

also read: …. Professional Motorcycle Tuning

Posted June 25, 2014 by xscafe in Motor - Crank

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