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Discussion in 'The Garage' started by Raymondo, Jun 13, 2019.

  1. Superjet

    Superjet XS650 Junkie Top Contributor XS650.com Supporter

    Seems to me what I have read about the white dot on the Boyer it is there to get the bike initially running. Timing is to be set based on timing light and plate adjusted accordingly. Maybe this helps.

    MaxPete, Raymondo and Jim like this.
  2. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    Thank you, Superjet, the link gives a very clear step-by-step guide to installing Boyer Bransden ignition. As you say, the white spot is there to give initial guidance for setting the rotor and timing plate. The timing plate is initially set with the screws halfway along the mounting slots, to allow for future adjustment.

    When all done, you run the engine and check with a strobe that the mark on the crankshaft rotor moves from 'F' at idle to full advanced - appears to be called full lead by our US friends? - as the engine is revved. I don't know at what revs it reaches full advance, probably 3,500-4,000?

    But, assuming that this initial setting is about right and has not been adjusted, the magnet/white mark would still be visible through the viewing hole. So I am wondering why the ignition on my bike seems to be so retarded. My guess is that this is due to the cam chain tensioner having been adjusted a long way in, which would retard the cam and both valve and spark timing.

    The only problem with that argument is that the spark timing does not seem to be as far retarded as the valve timing. Possibly, as the tensioner has been adjusted in stages, at some point a PO has used a strobe to correct the spark? Which is now out again due to further tensioner tightening. But we are in the land of speculation. And speculation is the godparent of many a foul up.

    Meanwhile, coming slowly to the conclusion that I need to change the cam chain. And the counsel of Wise Men is to do that before even starting the engine. Though, I did run her for 5-10 minutes without a bang or a nasty death rattle . . .

    Just how big a job is the cam chain? Too naive to think it's just (!) whack the engine out, lift the cam box cover, change the chain, reassemble and lob the engine back in?

    Back in the day - 1983, in fact - starting with a faulty but running SR500, took the engine out, dismantled it, split the cases, replaced a gearbox component, reassembled the bike and had it running before my wife (girlfriend in those days) got home from work. She was initially incredulous. Please excuse a senior citizen's reminiscences.
    madmax-im, MaxPete and Jim like this.
  3. Jim

    Jim I have a plan. It's something to deviate from. Top Contributor XS650.com Supporter

    I'd do as 2M previously suggested.... first verify the TDC and timing mark are correct and the piston is indeed at top center. Once you're certain of that, see how far out the cam is. If it is 24deg as it appears, you're dangerously close to a valve hitting a piston. These are interference engines.

    If it's out that much.... don't run it again and count yourself lucky you got away with it once. I suspect what you're looking at is a combination of a stretched chain and a badly worn front chain guide. That means pull the engine and redo the top end.
  4. 5twins

    5twins XS650 Guru Top Contributor

    With the chain really stretched, it's also possible it jumped a tooth on the sprocket if the adjuster was loosened way up and the motor turned over. So, you could be looking at a combination of the worn chain and it jumping a tooth.

    How many miles are on the bike? By 20K miles, the cam chain can be pretty stretched out, not because it's a weak part but mostly because it wasn't looked after and maintained properly. Mine on my '78 was about toast at that mileage, but the adjuster looked no where near screwed in as far as yours is. I'm going to mention again - that type D tensioner with no lock nut could have contributed to the worn chain. If previous owners adjusted it frequently, every time they put the cap nut back on they may have inadvertently been making their adjustment tighter.
  5. Jim

    Jim I have a plan. It's something to deviate from. Top Contributor XS650.com Supporter

    Good point. one tooth on the cam is good for 10° (36 teeth). One tooth on the crank sprocket would put you 20° off (18 teeth). A stretch equal to one link would put you off 5° (half the stretch on the front side and the other half aft).
    One tooth jump at the crank and a stretch equivalent to one link would put you at 25° off.... close to your 24°
    Raymondo, madmax-im and MaxPete like this.
  6. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    Well, in line with the general consensus, looks like I'll be spending today in the garage. At least it's raining.

    Will try and ascertain whether the TDC mark on the alternator corresponds to actual 'piston right up there'. The plug holes are at a low angle but will see what I can find out by using a torch, peering in, poking with a pencil, etcetera.

    Will not spend too much time on this exercise because have come to accept that I need to change the cam chain. And probably the front guide as well. Don't really want to pull the barrels off and disturb the pistons but moving into that in for a penny, in for a pound territory. Assess what I find as I go and do the necessary.

    So, I'll start preparing to take the engine out. And drawing up a shopping list. Very helpful guidance on other threads about what I'm likely to need.

    As an analogue person living in what has become a digital world, I don't really do social media - no Facebook or any of that nonsense - so a bit backward when it comes to on-line etiquette. Today, just noticed the Like button which I suppose should have been using, so today went through this thread and scattered a few Likes around. BTW, what are Trophy points? How many do I need to win a Triumph twin?

    Really, I'm a rider not a tinkerer and certainly not a mechanic. Still not sure why I bought this XS but it was my intention to ride not rebuild/restore. Oh well, life is a journey not a destination and the thing about a journey is you never know what might happen along the way. Always better to embrace the unexpected than sit down and complain.

    Reflective moment over, off to garage.
    Mailman, Moabite, Jim and 1 other person like this.
  7. MaxPete

    MaxPete Life with Lucille...I suggest, she decides. Top Contributor XS650.com Supporter

    A top end rebuild on these engines is not really a tough task and as you’ve noted Raymond, there are several excellent guides to help you along.

    Jim likes this.
  8. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    Thank you all for the incentive - I'm going in.

    In answer to 5twins question, the bike has just shy of 27,000 miles recorded. Of course, I don't know if that is correct as I have nix past history. But from general condition, probably right.

    Adopted TooMany and Jim's suggestion and investigated the TDC mark - the good news is that the pistons are indeed at their highest on the mark. But I expected that, anything else would have been a worry. Another worry.

    A start has been made removing, uhm, ancilleries?


    Although setting out very reluctantly on this journey, I have to say the the bike is a pleasure to work on. Most fasteners are in perfect nick and hardly any have been too tight. So, very easy to dismantle, in huge contrast the some bikes I have pulled apart.

    I could mention a certain Triumph 650 twin - if there was a fastener which hadn't been butchered, I never found it. Some like the crankshaft pinion retainer nut appeared to have been assaulted with a sharpened screwdriver to get them off and to get them back on again. And as for the QD (!) hub - it took the best part of a day to get the back wheel out. Not fun.

    But on this XS, even the exhaust system came off easily. No balance pipe or any of that nonsense. Which leaves the engine almost ready for the Big Lift:


    There is an air of mystery about the bike. A lot of work has been done recently. Well, she sat in a showroom in Devon for a long time - first caught my eye some time last year. But recently in miles. For example, new chain and sprockets. When I pulled the chain off today, it was very greasy but this seems to be the grease they are supplied with. No dirty chain lube. Here's the gearbox sprocket area, usually one of the dirtiest areas on a bike:


    Almost clean. Confirms the bike has hardly turned a wheel since new chain and sprockets. And as I noted earlier, there are lots of nice touches. Allen screws on the cases, brand spanking new stainless chain adjusters. When I took the l/h engine cover off, well, I know a new gasket when I see one.

    But it's got problems lurking. Cam chain stretched and/or jumped the sprocket? Some trepidation what I might find.

    Think I might call this bike Nessie.

    That's a Scottish joke - who knows what might lurk beneath the beautiful and serene surface?
    Mailman, MaxPete, Jim and 1 other person like this.
  9. Machine

    Machine Race the wind Top Contributor

    no worries. Looks like you found an XS in very nice condition. Perhaps somebody just managed to improperly set the cam chain on the wrong link and never finished their XS project.
    Interesting about the cleanliness under the left engine cover .
    Raymondo and Jim like this.
  10. 5twins

    5twins XS650 Guru Top Contributor

    You're experiencing first hand just how much work is involved just getting to the point where you can tear into the top end (engine removal). So, it's best you inspect and fix anything that needs it while in there. Typically, you replace the cam chain, front cam chain guide, and the valve guide seals. A few leaky valves may be found and need to be lapped back in. Inspect the pistons, rings, and cylinder bores. Usually, at least new rings are required as the ends gaps are too large and out of spec. Worst case is worn cylinders requiring an over bore and new oversize pistons & rings.

    Don't feel bad or that you got unlucky. These are good bikes but pretty much every one of them needs their top end looked into now. It's an age thing. The front cam chain guides are failing quite regularly because of it.
    Paul Sutton, Mailman, MaxPete and 2 others like this.
  11. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Just cogitating here.

    I wonder if your scenario is similar to Fossi's.


    He had inadvertently moved the crank while the tensioner was out.

    Your 24° camshaft retardation could be a combination of:
    - Being 2 teeth out of alignment (20° there)
    - 8° of cam retardation, at the crank (the remaining 4° at the cam)

    The engine *will* run with 8° retarded cam.

    Fossi's bandaid fix is in post #7...
    Paul Sutton, MaxPete and Raymondo like this.
  12. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    Machine, one possibility is that somebody spent a lot of money then became fed up and sold their newly-finished project. However more likely they encountered or foresaw problems like the ones I'm dealing with and sold the bike.

    5twins, all good advice WRT what I need to look at and possibly fix. WRT feeling bad or unlucky? As I said above, life is a journey and you have to embrace whatever happens - am I becoming more philosophical as I get older? I bought the bike to ride. But it's not like I need the bike to go to work tomorrow and when jobs in the garage go well there's a feeling of satisfaction. You bond with the bike. And the bike ends up better & hopefully more reliable than it was. No I don't feel bad.

    TwoMany - could be a similar scenario. I don't believe I have turned the motor and made the cam chain jump. But, in answer to Machine, I postulated PO sold because they encountered or foresaw problems. So it's possible PO turned the motor over with tensioner out, put the cam timing out and decided to sell for that reason.

    I quite like the 'bandaid fix' but I feel I'm far enough along the dismantling road to carry on and take a look what's in their.

    Or to carry on the Loch Ness theme - what's down there.
    Paul Sutton, Mailman, Jim and 3 others like this.
  13. Machine

    Machine Race the wind Top Contributor

    Yes, perhaps taking a chance on buying a non running project is also hoping for some luck.
    Done it. It worked out fine. Hope yours does as well !
    Jim likes this.
  14. MaxPete

    MaxPete Life with Lucille...I suggest, she decides. Top Contributor XS650.com Supporter

    Well Raymond - looks like you've got yourself a ballgame!

    Stick at it - when you get this old gal running again, the innate goodness of a Yamaha XS650 will come through and you'll hardly be able to get your helmet off for the huge goofy grin you get by riding it.

    BTW - on buggered fasteners...I can understand how an old fastener can become stuck and need to be bashed-up to remove but I have never understood why someone would then put that very same fastener back on the bike/car etc. It just seems to be such false economy.


    Raymondo, Paul Sutton and Jim like this.
  15. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    Thank you all for your continued interest in my XS.

    To answer Pete first, the Triumph TR6 seemed to have been regarded by PO as an old bike rather than a classic to be cared for. I bought the bike as a runner, a bike to ride not a project.

    A little bit untidy but all there. But when I got the bike home and took a closer look? Every expense had been spared - one shocker was the mismatched con rods. Evidently there had been a blow-up, and the engine had been rebuilt with a r/h crankcase from a different year and just one con rod had been replaced. Strewth! And you just wouldn't believe the electrics . . .

    I saved that bike. It took hundreds of hours and I spent more than the original cost of the bike on parts and engineering services. The current owner is very happy with her but the experience put me off old British bikes and I decided next time I'd buy a bike I could jump on and ride. Not a project. Astute readers might notice a theme here.

    Machine, I didn't buy this bike as a non-runner. It was supposed to be a real head-turner, a subtle custom on a Triumph Thunderbird theme and I bike I could just jump on and go. A great little runner with a lovely exhaust note.

    I spotted the ad last year:


    Just a sample from the photos on the seller's site.

    Asking price was £3,995. I kept being attracted back to the bike. It was still there. This year, price fell to £3,495.

    Don't particularly like the mock-Triumph thing, but it looked like a well put-together, clean, interesting Japanese 70s classic. Like a worm inside my brain, I kept going back and looking at the website. In May, price fell to £3,000. I phoned the seller and we had a chat.

    The events of the following two weeks will do for another day - don't want this posting to get too long.

    Besides, I've got a bike waiting in the garage.
    Last edited: Jul 11, 2019
  16. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    Quick update. This was the scene in the garage at 10am:



    Used wooden plank under the engine and couple of jacks to take the weight, then pulled the final engine bolt out.

    Of course, not going to do anything silly like try and lift the engine meself.

    Tentatively tested the 'feel' and lifted it a wee bit more with the jacks. Repeated till without much warning reached that oh-my-god-im-gonna-drop-it-or-make-one-huge-effort-and-get-it-on-the-bench moment.

    All's well that end's well . . .
  17. MaxPete

    MaxPete Life with Lucille...I suggest, she decides. Top Contributor XS650.com Supporter

    Yup - the XS650 lump is really f@cking heavy - but a strong lad (or a determined old guy) can juuuuusssttttt lift it onto the bench - once.

    ….and then go sit down to recover with a BEvERage.

    The point is - a smaller four-stroke engine (think XS/CB/GS/KZ400) or a two stroke/ring-ding engine would likely be a fair bit lighter and a large 70's multi like a CB/XS/GS/KZ750-1000 or a Honda Gold Wing etc. would be utterly impossible for one person to lift - and certainly not safely - but as is the case with many other aspects of these bikes, the XS650 is right in the middle and in many respect, just right IMO.

    Last edited: Jul 11, 2019
  18. Mailman

    Mailman Hardly a Guru Top Contributor

    Somehow it always seems to work out that way doesn’t it? When I bought my ‘77 it was supposed to be a turn key, get on it and ride bike. It took me over a year to get it where it needed to be. As chronicled here,


    When I pulled my motor, lifting it just about killed me, and I had help ! So before putting the motor back in, I added some bracing straps in my attic and hung a support ring and bought a chain hoist. Beautiful! I could’ve installed that motor while drinking a cup of coffee!

    DAD985F4-13A9-4140-AA02-D01F41F06964.jpeg 7E2E12E7-3955-424C-B46B-D09F86245602.jpeg B485911E-7F8E-47F9-8CCC-2B6E7CEF3763.jpeg
    madmax-im, TwoManyXS1Bs and MaxPete like this.
  19. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    Two pictures which summarise progress this afternoon:



    One unexpected problemo - before removing l/h point housing, need to remove BB rotor. There's a 13mm nut on the r/h end of the long rotor shaft. But holding the crank and turning the nut just causes the rotor and its magnets to turn. Decided against bodging. Quick email to BB. Their recommendation? Hold the magnets with mole grips and the nut will turn fairly easily. But be careful, the magnets can shatter like glass. Ahem, I'd call that a bodge.

    The other slight hitch was the last valve cover I took off - the four-stud one at l/h exhaust. With nuts removed, the others were freed off with a light tap from a rubber mallet then wiggled off fairly easily. But that last one held out for ages. Even when it was well clear of the seating, it still wouldn't let go till it was completely free of the studs. I suspect the studs aren't parallel - maybe one has a slight bend.

    The O-rings on the valve covers are pretty much garbage.

    Otherwise, mostly good. The cam faces and rockers that bear on them are pretty good. The adjuster screws aka tappets have suffered - the faces that bear on the valve stems have broken through the hardened surfaces, so they will be replaced. And were they loose? Felt the tappets on the compression cylinder - your hoping for just a wee 'tap'. These were like the seesaw in a kiddies play park. Must have been loosened off for some reason?

    The combination rubber/steel washers for the head bolts have suffered. I'm sure I read on here that people replace with brass washers?

    Tomorrow, get to grips with the cam chain. Haynes manual says remove six bolts and take the entire tensioner housing off, but surely that's not necessary?

    Enough. Think I might go and have that beverage Pete mentioned.
    TwoManyXS1Bs, MaxPete and Brassneck like this.
  20. Raymondo

    Raymondo XS650 owner, fettler, setting out on a journey

    I like the pulley system, and love the careful frame prep - plenty tape etc to protect everything. But you possibly need to work on toning the smug expression back just a little.

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