YAMAHA XS650

Poor Mark Hay­cock. This is a hound of the bas­ket cases.

Classic Motorcycle Mechanics - - CONTENTS -

Mas­ter Mark delves deeper into the bow­els of the bar­gain XS650 – but what does he find?

We looked last month at a few of the elec­tri­cal faults I found on a Yamaha XS650 I bought a lit­tle while ago, but the prob­lems were not just elec­tri­cal, as we shall see. To re­mind you, if we look at Photo 1 the bike re­ally did not look too bad when I got it home. I think this just goes to show that judg­ing the con­di­tion of a bike from a photo of a gen­eral view can be rather de­cep­tive. Let us take a closer look at some of the me­chan­i­cal and cos­metic is­sues. This is a pretty com­mon one un­for­tu­nately (Photo 1). The head­lamp rim has been scraped be­cause clearly the bike has been down the road on its side at some point. It is not fea­si­ble to re­pair this dam­age as although it could be filled with body sol­der, the rim would need to be rechromed and it would be cheaper to just get a new rim. It is a small point but rims are quite ex­pen­sive for what they are and this dam­age spoils the whole bike, so it was a pity the owner did not high­light this in the ebay de­scrip­tion. The cause of the rim dam­age is con­firmed by the state of the front brake mas­ter cylin­der (Photo 2). This would prob­a­bly have al­lowed mois­ture to en­ter and cause cor­ro­sion within the hy­draulic sys­tem. The re­place­ment bolt is a neat touch, no doubt be­ing nec­es­sary be­cause the Phillips screw head was hope­lessly chewed up, even worse than the other three. Photo 3 shows an­other ex­am­ple of the un­sat­is­fac­tory na­ture of Phillips heads for screws on mo­tor­cy­cles. The screw it­self is too soft and it is very easy to dam­age the head, par­tic­u­larly if it has rusted in place. It should have been re­placed but no doubt as it is chrome-plated it is quite ex­pen­sive. But at least it was there… un­like what we see here

(Photo 4). In­stead of three chrome-plated domed (acorn) nuts we have quite a mix­ture: a rusty domed nut, a plain nut and, well, noth­ing: the nut and its stud are com­pletely miss­ing. I don’t like in­su­lat­ing tape as the ad­he­sive al­ways de­te­ri­o­rates into a sticky mess. It might be okay as a tem­po­rary re­pair but th­ese of­ten end up be­ing per­ma­nent. The pre­vi­ous owner ev­i­dently did not share my view as there were lots of bits of bright blue sticky tape over var­i­ous elec­tri­cal con­nec­tions, but at least they were not vis­i­ble from the out­side. The ta­chome­ter drive is vis­i­ble so he had been care­ful to use black tape in­stead to bodge it up, as it would match the frame colour (Photo 5). Need­less to say the re­pair did not work and there was ba­si­cally noth­ing hold­ing on the drive or the oil within it. The main prob­lem was that there was a bit miss­ing for some rea­son, pre­sum­ably be­cause some­one had put it down and forgotten where. Why not just re­place it then, as it was avail­able as a Yamaha part and not ex­pen­sive? Prob­a­bly be­cause the me­chanic did not have the ben­e­fit of a proper parts list so just gave up. An­other piece of lat­eral think­ing is demon­strated here (Photo 6). A piece of wire is use­ful in an emer­gency tool­kit, but it is meant to be for a ‘get-you-home’ bodge, not a per­ma­nent re­pair. Maybe the pins which were meant to be used could have been found in the same place as the tacho drive part. A cou­ple of nuts and bolts would have been a rather more ac­cept­able bodge. Later I needed to re­move the left hand crank­case cover and was struck by this cu­ri­ous pro­jec­tion on the gas­ket face (Photo 7), which ex­actly matched a cut-out in the cover. I won­der how that mod­i­fi­ca­tion was made? Maybe by some­one not notic­ing that one of the fix­ing bolts was still in place fol­lowed by a light tap with a big ham­mer. The same some­one had at­tempted a re­pair with what looked like epoxy resin, but ev­i­dently this had not been a great suc­cess. The fail­ure of the fix might have been caused by a lack of sur­face prepa­ra­tion be­fore stick­ing. How­ever, even if it had been done prop­erly I still think it is ask­ing a bit much for epoxy to stick hot en­gine parts to­gether: again this might work as a tem­po­rary bodge but not a per­ma­nent re­pair. There is a rea­son­able way to do this and I shall be ex­plor­ing the tech­nique soon. If you do in­tend to leave a bike un­used for over a month or so it is best to drain the car­bu­ret­tors if you can. The rea­son is shown in Photo 8. This is all that was left of a float-bowl full of petrol af­ter about 10 years. Ac­tu­ally, this is not as bad as some cases you come across as there is still a sign of the gunge be­ing a sort of liq­uid so it will be slightly eas­ier to clean out than solid gum. The smell is very hard to wash off so wear gloves for this. Now, the rear sus­pen­sion is a pretty im­por­tant part of a bike as it does af­fect safety and one would like to think that peo­ple would not take chances with th­ese crit­i­cal com­po­nents. So how about Photo 9? There is quite a prom­i­nent crack in this up­per mount­ing so I won­der how it was caused? The clue might be in the flat area to­wards the out­side (left in this pic­ture) which cer­tainly gives the im­pres­sion that it has been belted with a fairly heavy ham­mer. This is strange as I should have thought that the only rea­son to be tempted to do this would be to get it to fit or to get it off: and a blow down­wards would not be much use. Maybe the pre­vi­ous owner had got as fed up with the bike as I had be­come. More to the point, how did it get through the MOT? Will we find out? Stay tuned!

1 1/ Don’t judge a book... The XS looked good in pics, what hap­pened? 2/ Mas­ter cylin­der and mois­ture re­ally do not mix! 3/ Phillips head screws aren’t the best in this ap­pli­ca­tion. There may be trou­ble ahead... 2 3

4 5 4/ The mix­ture of bolts and fas­ten­ings re­ally beg­gars de­scrip­tion on Mark’s XS650! 5/ Pre­vi­ous owner had style: he chose black tape on the vis­i­ble tacho drive! 6/ That ‘get-you-home’ wire bodge is here in­stalled as a per­ma­nent fix. Oh dear, oh dear! 6

7 7/ This was the view Mark saw when he re­moved the left-hand crank­case cover. What on earth? 8/ This is why you should drain the carbs when you leave a bike be for a good while. 9/ Cracks on the mount­ing point for the rear sus­pen­sion is the ic­ing on the crappy cake!

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