Aaaaw chucks - or when your lathe's spindle tries to take a u-turn (Matra MDR2A)

Lathes are wonderful machines. They literally are the queens of the machine-shop: Of staggering beauty and sometimes with a temper so vile, hell might freeze over. This, is a story of the latter. (Unfortunately!)

When I bought my old Matra MDR2A, almost ten years ago, I put it into service and that was (pretty much) it. I did some maintenance over the years, but nothing overly dramatic to be honest. Unfortunately recently when I did that clutch pressure plate, I had a little crash. On the upside this finally loosened the chuck just that little bit, so I could get it off the spindle nose. What I found was some old damage and the reason, why I couldn't get it off as it was glued on.

In the course of the process even the three M8 screws holding the chuck to the backplate got a bit bent.

I did, what every good machinist would do: I screwed the backplate back on, but the damage was done: I couldn't find the position again. 

Overall runout between highest and lowest registered as 0.70mm and a half of that on the diameter of the backplate.

Get out the old machinist's blue...

and then start turning her back down until it runs true and *JUST* no more blue is left. 

So that's the backplate all cleaned up again. You can also see a scribed mark on the outer circumference, this is where originally there used to be a punchmark for aligning the chuck to the backplate.

Now the runout registers at around 0.03mm on the outside of the backplate and also on the workpiece directly in the chuck and that's realistically speaking as good as she'll ever get again, after all this is a 1946 to 1948 Matra lathe, so she's well in her seventies.

While I had the chuck off, I also took the backplate off and cleaned out the decade-old grease and replaced it with some fresh moly grease and now she's still a bit sloppy, but waaaay smoother. 

Also found some o-rings to prevent the bar of my chuck key from falling out. (Stuff I do, while thinking about how to assess the damage correctly.)

And here's the reason, why I can exactly say, when my lathe was built - because it was already overhauled once in the 1950ies or 1960ies, during her service with the German Bundeswehr.

So what does the future have in stock? Most likely a new spindle or at least a spindle sleeve to step her up one or two sizes to a M39x4 spindle nose instead of the original M33x3.5. As the nose at the root of the threads is only approx. one (!!!) mm in wall thickness.

Alternatively, I shall admit that, if the right lathe comes along, I might be tempted to part with the old girl. But don't worry, at the moment I am not even entirely sure what the "right lathe" could be.

XT600 engine rebuild - completing the shortblock (Part 2)

It took a while to finally get said oil-pump gasket, which stopped me from assembling the shortblock. Aside from the fact that the gearbox insisted to stay in the wrong side of the cases, when taking the engine apart, it all went pretty smoothly.

Transferred the whole gearbox to the correct side of the cases and wiped the mating surfaces down with a bit of brake-clean and a clean rag.

It really only takes a 1mm wide bead of RTV-sealant (I am using Dirko-HT - also known as the red plague overhere!)

And that's it. This is how it has been sitting in my dad's boiler room for about a week to dry.

As it was so cold, that even the oil got a bit stiff, I'll have to do the manual inspection of all gearbox shafts turning freely this weekend, because whereever the oil accumulated, it was as if I was spinning a shaft in grease...

The XS Triple Sidecar - living with the Triple at -12 degrees

Now as some of you noticed, not much has happened on the blog in the last two weeks. Simple reason: I've been on vacation in Cambodia. So, when I came back it was a slightly nippy 50 degrees Celsius less overhere in merry ol' Europe than in said Asian country. Of course this was the ideal moment to test the actual winter-proofing of the XS Triple Sidecar.

 Step 1, winter-proof the rider. Balaclava, warm jacket, textil trousers with a zip-on top and suspenders, plus some warm three-finger gloves outta do it.

The bike had been parked in the same spot for two weeks and was properly cold. And what happened: Nothing. Well, next to nothing, she simply fired up and with the carbs originally being off a two-stroke snowmobile, the chokes are running really, really rich, which helped tremendously in this case. 

As you can see on the right, it truly was twelve degrees below zero that morning...

















Unfortunately all the bad-weather motorcycling on the sidecar has showed a little flaw in the final drive, as clearly it filled up with water to a degree and once it had heated up a bit, it started to boil over. So a final drive oil-change is due rather soon. And I'll definitely have to come up with a better breather arrangement.

One of the other things was that the throttle cables could do with a bit of oiling and I think I should start investigating towards some proper K&N filters with a 63mm inlet diameter as the cheap ones are pretty rusty by now.

XT600 engine rebuild - cleanup of the new cases (Part 1)

So I am helping out with rebuilding an XT600 engine after the slightly dramatic self-destruction you saw recently. As a matter of fact, as I inherited the Dre-XT-Stück myself a bit of re-familiarization with the XT600 engine won't exactly do me harm, mainly because I want the Dre-XT-Stück to ultimately grow into a 600.

If there's one golden rule to adhere, when someone gives you an engine in parts. Never believe anything until you've proven it yourself. In this particular case it meant cleaning everything even down to the oilpump strainer mesh and I found: Not much. Bit of dust from this engine sitting in a shop for at least a year or two. 

Guess what? Some people have all the look and find an XT600 gearbox with no discernible wear on it for 100 Euros. 

As the engine came with a load of seals and o-rings in original Yamaha bags AND there was a lot of oil around the gearbox selector seal, this one was quickly swapped.

Cases testfitted with the gearbox in. All seems to be there AND working. Unfortunately I couldn't permanently button it up as the gasket between the oilpump strainer and the engine case was missing and I didn't want to use RTV there.

So once the missing gasket has arrived the cases will be RTV'ed and bolted together and then it's really just a matter of throwing some more parts on it and see what sticks and what doesn't.

Project SR500 "intermission"

There is a Greek proverb: "If you want to make the gods smile, make an ambitious plan." Well, this little project was meant to go along the same lines. Just quickly throw together the left-over SR500 bits into a bike and then get rid of it. (As nobody was interested in buying the individual parts!)

So here goes, German 2J4 with from 1980 (so pre-AU), with my spare-parts donor engine re-assembled into an actual engine again.

I started off with a frame I was given ages ago, when I picked up my SR500 sidecar.

Nice surprise, there's even usable air-filter inside the airbox.

One of the missing bits were the forks. My original spare SR500 forks went into the XS400 ratracer two or three years ago. So new bearings and a copious amount of grease...

 ... et voilá: frontend!

Not sure why there was no swingarm in the frame, but same story as with the headstock: Lots of fresh grease and a bit of work later and it's actually done.

I think these are the original XS750 shocks, I wonder how well they will perform. 

Rear-wheel fitted, all looking very good so far.

One of the bigger question marks was the engine. I was pretty sure I had everything except the ignition, but the only way to find out was to go through a lot of boxes and find out the hard way.

First cleaned the original cylinder head of my SR500 hack, which I knew had a good cam, rockers and valves in it.

Then gave the cylinder a quick hone, just to give those rings something to "bite" into.

Unfortunately, I was in fact missing a base gasket, but I did have two head gaskets, go figure... So it was time to make my own. An annoyingly time consuming task to be honest.

Yes it's a used piston, but the clearance is still pretty alright and the rings had nice tension.

All timed up.

Bit of moly grease to protect the cam and rockers during initial startup.

It's bizarre, even though it's not a huge step forward in the grand scheme of things, once I have put the engine in a bike, it feels a lot more done than it actually is. 

So, yes this SR500 is for sale. Is it complete? No. But I am convinced you will hardly ever get a better insight on what you're actually buying. It would make a perfect base for something a bit more individual, not so much as a restauration piece. Personally, I think I'd love to turn this into a vicious little minimalistic bar hopper. I also have some sporty bits, like a flatslide carb, hot-cam, big-bore cylinder, that I could throw in as part of the deal... just in case you're interested.

XT600 carnage

Carnage that's quite a word isn't it. Even more so, if the term is applied to an XT600 engine. This engine belongs to a friend and we basically dissected it to hopefully salvage the gearbox.

[Spoiler alert: that didn't work.]

The engine on its own didn't look too bad and even the starter was still spinning, when you pressed the button...

 Uh oh... that's the woodruff key cleanly sheared off.

Head did have some oil in it. Camshaft bearing surfaces are definitely shot.

But on the contrary those rockers are well usable again.

Now we're getting close. Rings stuck, piston skirt massively scratched. (No picture, but the cylinder is definitely salvageable with an overbore.)

Now we're definitely getting closer: Look at the lock-washer on the crank gear, that's bent over.

And this must be the infamous Yamaha Crankcase Ventilation System (YCVS)!

Obviously the counterbalancer and the crank became a bit intimate. No reports whether kissing happened with or without tongue, but definitely without mutual consent.

The bit poking up: That's the cast material around the bearing of the balancer shaft.

So,  is this ... the Summer edition?

All that is left in the end...

... and yes it was meant to look a bit like a splatter movie.

Next update will be on "project intermission" - curious? Nah, me neither. 😜