Monday 21 December 2020

The XV sidecar - building the rest of the engine (pt.4)

Last time we left off with me hoping that the courier service wouldn't let me down. Well, it was more than a week, so probably some things happened. Even without immediately having all the parts at my disposal there was a lot more that could still be done. 

First was to assemble the rotor and mark out the correct position on the teeth (you basically do this blind).

Then clean out the oil-pickup on my oil-pump (Gears were fine, yet still...) and install it


As the 750 clutch was missing some parts, it was about time to overhaul that one as well. Springs were overly compressed and the clutch disks completely worn.



As the center bolt on v-star cylinders is longer (M6x100mm to be precise), I had to get a set of those

The other thing was to clean the pistons, as unlike last time on Bumblebee, these were in very good condition, except for the oil-scrapers, which had failed prematurely. A bit of spray-on gasket remover softens the baked on carbon and makes it easier to clean.


But these are just the cosmetics, not pointless, but mostly cosmetics. The important part are the ring-grooves. In order to clean them, you need an old set of rings, of which you clip off a piece or two and then scrape the grooves until they are free of carbon buildup.

Before scraping, after just a light brush with a SOFT brass brush.

And after an hour of thorough cleaning. As a result now the rings move freely in their grooves again.

With the pistons good to go, it was time to focus my attention on the heads. In general the ports on these heads need a mild touchup and not much more, at least not for road use.

I am fully aware, that polishing valves is more or less pointless... but they look too good AND it slows down carbon buildup on them. 



In order to reduce the seat pressure, I mix and match harder and softer valve springs in the hope of getting a bit more life out of the rockers. 




I know these are somewhat debated amongst SR/XT-users, but I love swivelhead valve adjusters as the grant much longer life to the valve stems due to the greater contact patch. Downsides? Heavier and at some point the ball will wear down resulting in the adjuster screw touching the valve and thus resulting in the adjuster breaking. (Ask me how I know...)


 

6205-Z single sided, metal-shielded ball bearing instead of the stock ally journal. 

 

Plenty of assembly lube on the cam.

All assembled. The blue line on the bolt means, it's loctited in. If you can't build an engine in a single go, you have to have some signs for yourself which of the jobs have been tackled and which haven't. (Another one would be my habit of painting the alignment dots on the cam-gear with white paint, so I know the corresponding cylinder has been timed up.)

Tapping the spark-plug thread, because there's not a lot like screwing a spark-plug in a freshly cut and oiled thread.

The camchain adjusters needed some attention too. In stock form the v-star adjusters are too short to work in an older Gen1 engine case with the correct tensioner blades. 





The new buttons have a 16mm head diameter, which is 7mm tall (compared to the stock 2mm) and the bit that goes into the tensioner is 8.6 in diameter and you can basically make it as long as you like, but I went with 6mm. Material was slightly better grade mild-steel (St.52), because that's what I had on hand and it machines lovely.


As I plan to run VM38 carbs on the sidecar and the VM38-200 inlet rubbers don't have any provision for vacuum ports I installed them right in the cylinder heads. The tubing used is 6mm ally tube with 1mm wall-thickness.





And one last tip: if you ever want to use your oil-filler cap again, you will have to trim the bottom most cooling fin of the front cylinder. 


And there you have it: a XV and XVS1100 hybrid.

Not going as far as to say it's ready to be bolted in, but it's quite a bit closer now.

No comments:

Post a Comment