XS650 engine

Well I finally got the XS engine out of the frame. My god it's heavy, the
B&D workmate is straining to support the lump. Everything came apart easily.
The two borked cam bearings fell to pieces but one inner race was cold
welded on, it Dremell'd off though )

Pistons, bores and rings all look good however the 5mm play in the cam
bearings has had an impact. Left inlet valve looks a little hammered on top,
the right slightly less so but still visible. They are not mushroomed
though. Exhausts are fine. Does the Group think they would be ok or should
they be replaced? I could post some pics.

All the valves will come out anyway to be lapped and for the new stem oil
seals.

The screw tappet that bears on the left inlet valve is in poor shape and
deffo needs replaced, the right looks fine but for such a small part it will
get changed anyway.

Here is the blind sider though. The front camchain tensioner blade rubber
was detached from the alloy carrier and had slipped down. The carrier had
seen a little contact from the chain at the top 10mm. Is this a known fault?
it's a weird one and if they are scarce I guess it will need to be bonded
back into place.

 

New tensioner blades are freely available for a few quid.

It's an odd one, though. My guess would be simple old age - the rubber
surface tends to harden, and I wouldn't be surprised if it started
coming away from the metal.

I've been ruminating on whether to replace the blades in the 400 Four
for this very reason. The engine's sweet, but I know that on these old
Hondas the rubber surface can start breaking up, and then it jams in the
oilways with inevitable results.

 

Aye there are little bits of the side missing, it could explain the cam
bearings. 2 separate bearings side by side worn down. 2 bearings on the
other end of the cam perfect. I replaced them all of course. Compressed air
down the oilways methinks.

I'm wondering now whether to do a light deglaze on the bores and throw in
new rings while I have it stripped so far.

 

Are good replacement valves expensive?

Still, it's not a BMW...

http://uk.pg.photos.yahoo.com/ph/ukrmplatypus/detail?.dir=1990&.dnm=3164.jpg&.src=ph

 

I doubt if it caused the cam bearings, though. For one thing, there's a
helluva lot of oil swilling around there and when I replaced the oil
seal, it was because oil was absolutely pissing out.

My guess is that a previous owner had the oil seal pop and just ran it
for too long with a serious oil leak.

Amazing, really, because the engine sounded absolutely perfect.

(There again, so did the RD400....)
..

I wouldn't even bother deglazing the bores, but new rings might be an
idea.

 

Shall find out on Tuesday. If they are cheap with a short lead time then
of course.

 

Not, and trust me on this, with an XS650.

 

I hesistate to imagine what a Vincent lump would do to a B&D workmate.

 

Well considering the complete bike weighed 476lb with 3/4 of a
gallon of fuel (Road Test), I doubt that the engine is that
heavy.

Ken Young

 

It farking is. The whole bike is.

 

Well I think the jury is in on the bearings and front cam blade.
Overtight camchain tensioner. Took the bits down to Geoff Kernahan who
has a lot of experience with XS's. It's getting 2 new inlet valves, the
guides were perfect.

 

Must have happened a long time ago, then, because that was something I
checked early, when servicing it. Set the thing to TDC on the r/h pot,
and set the tensioner so the inner plunger is flush with the outer
housing. Piece of piss.

 

Yes hard to get wrong. Did Timo ever own this bike?

 

No he didn't. He rode it around the block tho'