Wednesday, 13 June 2018

The XS Triple Sidecar - fixing the sidecar up for roadworthyness inspection

Normally fixing up a winter-sidecar means frantic hacking away on various rusted bits and bobs, but as I had already done most of that, this time it was about swapping out some rusty bolts, chamfering the brake pads, swapping the front tyre for a slightly less bald one.

One of those things was the lower clutch adjuster. It had fallen out on one of the very first test rides and was replaced with a spare M8 bolt I had with me...

It's a good idea to oil a clutch cable BEFORE it goes stiff, and a bit of old engine oil is perfect for the job.

I always chamfer my brake pads as it prevents them from squealing. Especially these cheap ones are very prone to that. 

The speed cable may be rusty on the outside, but oiling it up in Autumn paid its dividends.

The bald front tyre was replaced with a super fine Pirelli Gordon specimen from the late 80ies. It's harder than a rock, has plenty of tread left and no hairline cracks. (Watch this space in two months, when it will look like I've dug it out of a swamp or the like, as they perish very quickly once re-exposed to UV-light.)

I was totally prepared to replace the rear tyre as well, but that super flat Block C has still got some life left in it. 

The last thing to tackle was to weld up the muffler inserts, as I had only tacked them in, when I took them out earlier in a vain effort to find some of the missing horsepower. (It was some well clogged pod-filters!)

As the old girl sometimes struggled a bit with starting I deduced, that (just as on my first XS-triple) a lack of grounding to the right handlebar switch resulted in bad starting at times.

Another thing that I had spent a lot of time contemplating on, was how to solve the lack of a lock to hold the seat in place. I've come up with beautifully elaborate solutions with milled, turned and welded parts of finest stainless or 6000-series aluminium alloys. But in the end a simple R-clip and a hole will do the job almost as fine and the amount of time invested was, as I have to admit somewhat more reasonable.

The sidecar passed the inspection with flying colors, which also means, as soon as the mule is sorted out, I can tackle the mods I have planned for the sidecar, which are: different exhaust setup (angled up a bit so I can swap the rear wheel, without removing the exhaust) and a slightly altered rear-subframe.

Wednesday, 6 June 2018

The new TR1 engine - a fixture for shortening cyllinders (part 22)

Before we get into the matter at hand, let me show you a result. Some people asked me, what kind of finish could be achieved with such a big and heavy flycutter on such a small and puny mill. A pretty shiny one, if I may say so.

What was needed next was a means to hold the cylinder in the lathe. (More on that later!) This was finally the time to REALLY chase the accuracy of my lathe. I ended up with two plugs that would almost seal the bore and would only go off with a slight. *plopp*

Looks good doesn't it and it over the lathe's bed. Well, not so fast... as it doesn't clear the outriggers of my support.

So what you will see in the next installments, is on the one hand establishing the missing base data regarding the squish-height, which in turn defines the amount of material to be removed from the cylinder foot and on the other hand tooling up even further to get my rotary table working with the chuck I have for it.

Friday, 1 June 2018

The new TR1 engine - welding up and machining heads back down (part 21)

Now you can't make an omelette without breaking a few eggs (a lot actually). With the fixture done, the next step was to put it to good use. But first a base-value for the cylinder head volume had to be established and yes, a TR1 head has actually got a chamber volume of 54cc.

To maintain repeatability, I marked out the lines I wanted to meet on a headgasket.

Welding the heads up with MIG and a spool of AlMg5 is messy, but works beautifully. It has to be noted, that you get so much heat into the heads that pre-heating had little effect on the final outcome as I found out on some test pieces.

One of the locating dowels was one hell of a stubborn b*st*rd, but it had no chance against a TIG used in anger and a bolt. (Some hammers and rods were part of the equation as well...)

Pre-heating the head on an old hot-plate.

The first head was milled to size before flycutting, but it turned out, that it was easier to first skim the head and then mill the wedge to size, as this helped a lot with accurately aligning the head gasket with the cylinder head.

No photoshop trickery here: With a nicely balanced flycutter, a large flightpath and high rpm a nice finish was really simple to achieve.

CC'ed the new chamber and et voila: 47 to 48cc. Which means, now I will end up with the same 10.5:1 compression ratio as with 750 heads. 

At the time of this posting another set of cylinder heads will have been fabricated as these had a little more material removed than I would have wanted as the heads themselves were a bit warped. This unfortunately also means, that the piston to valve clearance is reduced, which is not a big issue with stock cams and stock squish-height. Two other issues that will be addressed very soon in the course of this build.

Friday, 25 May 2018

Everyday TR1 - starter swaps and other woes

Now my everyday TR1 "mule", is a good old girl. Generally she only lets me down when there's really no way of keeping it up anymore. And it was well about time again.

The most obvious issue was the starter, originally I thought the battery (well deserved after five years), was a bit weak in the knee, but...

Now the beautiful beads you see in there are most likely grease I applied last year to grease the shaft in the bushing. Unfortunately it smeared all over the rotor and shorted everything out. 

After a bit of cleanup, I thought I was in the clear again. But unfortunately the brushes are already bottoming out and are quite badly.

So after the old starter had come out, there was even more graphite shmoo everywhere...

Now for some odd reason, I started taking new starters apart and so far I have always found something... Pictured below is the pin that is supposed the hold the outer planetary gear ring in place.

Luckily the planetary gear were alright, so the starter swap was doable without draining the oil.

And then... not much the old girl was limping on just the rear cylinder. New spark plugs didn't cure it and after a bit of thinking (and much cursing) the coils were swapped and guess what: at least the front coil was plagued for quite a while, as all of a sudden the misfires that started during Summer last season had vanished.

While I was at it, I applied a new tune to my Ignitech ignition and also apply a tune to the turbo's box, just to make sure it actually works. 

Tricky trick: as the rev-limiter hits really hard, I programmed the advance curve so it goes down from max. RPM to zero advance, which leads to the bike softly stopping to rev any further.

So this is a kind of short break from building the new engine, but as I have written before, this is my DAILY and as such it has to work...

Tuesday, 22 May 2018

The new TR1 engine - tooling up, making a head fixture for skimming and milling (part 20)

Making the fixture to affix and also align correctly on my milling machine was one of those projects which I totally underestimated. The key problem is, that the cylinderheads on Yamaha XVs are case as one piece and don't have a valve cover in the common sense, which means I had to come up with a fixture to be able to fly-cut after welding them up.

Open the stage for four 60mm tall, 30mm diameter pieces of aluminium roundstock. 

Of course they had to undergo some surgery to be usable. Interestingly enough all came out within 0.10mm of each other in length, after just some eyeball measuring with a caliper. Before they are actually put to use, they will faced off once more.

All the posts had to be center-drilled and tapped M6 on both ends.

Have you ever wondered how you can hold a piece, when you can't use a bolt and nut to hold it down ?

Basically what I am doing here is applying the idea of an ER-collet in the opposite direction. So I sliced the stud and used the countersounk bolt as a spreader.

And as you can see, as the studs are turned 0.10mm undersize, about a quarter turn is sufficient for them not to go back into the hole.

Now this is all nice and dandy, but... this is not how I want to fix this to the milling table. So a baseplate was due.

Of course a mandatory "lifting" test was due and even without extraordinarly tightening the 4 spreader bolts it was an easy-peasy affair to lift the head up from the bench. Next up is some more trimming of the baseplate and then make some alignment pins, so taking the fixture of the mill and putting it back on is a quick affair that doesn't require the usage of DTIs or the like.