Sunday 25 August 2019

The XS Triple Sidecar - tachometer drive seal

My XS Triple Sidecar has got two major areas, where it leaks oil like it's getting paid extra to do so:
  1. the cylinder base gasket, which is a design flaw as there's no bolts holding the cylinder to the cases, which especially around the camchain leads to the affore mentioned leaks.
  2. On the tachometer drive. 
After a bit of research, it's one of those I-should-have-done-it-when-swapping-the-engine-in-jobs. Luckily someone at Yamaha must have forgotten drawing up the tach-drive and made it a completely removable unit, only held in by an M6 bolt and a C-clip.


Heating up the aluminium outer case, freed up the threaded inner section. Not sure if this is always so well stuck or whether it was due to the all-year-round-nature of my sidecar. 


As now the whole lot is properly heated, the seal almost removes itself without my help, i.e. it was so hardened and shrunk that it nearly fell out.


The seal is a 7x13x4 seal, which is (luckily) still available new as it used in various other bikes, part no. #93104-07036 and it's not even very expensive.


As the M6 bolt installed was most likely the wrong one anyway and it was rather mangled, a longer stainless bolt with a lot of copper-slip will do the honours of holding the tach-drive in place in the future.


While I was in there, I noticed a little stress-crack in one of the joints of the new headers and patched it up as well, while the exhaust was still hot.


And that's the sidecar back on the road and in service again.


On the same afternoon I got into a bit of a down-pour and guess what, after almost two years of riding around, I couldn't smell hot oil being burned off on the headers, but only steam from the water  that splashed up on the engine.

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