Sunday, 16 September 2018

Everyday TR1 - new TM38 carbs (part 2)

Those who know me personally, know that I am allergic to various things: I am allergic to stock (as I assume it can be improved on, once you know what you actually want), I am allergic to trailer queens and showbikes (as I am absolutely convinced that bikes are built to be ridden) and I am absolutely and totally allergic to any mods that decrease usability with the given scope of a bike. Choke knobs that are not (easily) reachable from a sitting position are exactly such a case.


Drumroll, bring on cable chokes – and while we're at install some new inlet rubbers.


As even my local bicycle shop charges somewhat questionable prices for nipples, I bought some brass roundstock and made my own.


Then it was "just" a matter of determining the correct lengths and solder them on.


Handy trick for soldering cables: Gently clamp them in a vise, adjust to the correct height and then solder them. This way they can't move and you don't burn your fingers. And always tin up the cable as a first step.




As I have the throttle-cable splitter on the right, I've put the choke-cable splitter on the left. Cable routing turned out a lot easier than I initially thought. (Read that as feared.)



That sees the choke-cables installed. I didn't synchronize them in any way, just made sure that the cables where the same length within the accuracy of measuring tools available, mainly because I only use chokes "full throttle" and then shut them off, so slightly differences should be neglible. Syncing the carbs themselves is an entirely different matter.

Sunday, 2 September 2018

Everyday TR1 - new TM38 carbs

And one day everything is working fine and going smooth. And you get bored. And you strife for improvement. Now even though I have a set of perfectly good Mikuni VM38-9s, I have had a set of TM38-85 sitting on the shelf for way too long.

But first start with a problem aka. oil-leak. Admittedly I had already bought some aluminium roundstock to repair the lower valve-cover thread. Turns out, those heads leak substantially less, when tightened up properly.


The stock jetting with #22.5 pilots and #230 mains is "a tad" on the rich side, a more conservative #20, #190 was chosen for a first start.


Interestingly the rear of the carb is tapped for a air-jet, but the port is run open. As the parts out of the VM38s will fit, I might give those a shot (6DP4-needle and 0.5 air-jet instead of the stock 6FJ4).


The slide assembly is relatively straight forward, the paper gasket got greased up so it won't stick to the cover or carb body.


The throttle cable holder is vastly different and looks a bit like an afterthought. Those M3x10 screws will have to be swapped out for allen bolts as I foresee them to seize in the aluminium slide in the long run. With that being said, a bit of copper-slip should prevent that for now.


The 51-6506 2in1 throttle cables (available from various XS650 shops), are a bit too long, so shortening by about 10-15mm is due in the long(-er) run or you end up with lots of slop on the throttle-grip. A bit of decent allen-bolt hardware should make maintenance a lot easier.


In order to be able to oil the cable from the top, a bit of shrinkwrap seals the adjuster against the cable.


The cable is too long by about 10 to 15mm, so at the very least the bit from the junction box to the throttle grip has to be shortened. Once I get to sync'ing the carbs, I'll probably have to shorten those as well.



The benefit of the TM38-86 is their 47mm outer diameter on the engine side, which makes them a straight fit in the stock inlet rubbers.


Fuel line routing is dead simple, but squeezing a filter in there might present some challenges as there's really not that much space.


Bit of hose-clamp-magic as I seem to have run out of good quality neoprene fuel hose and the normal stuff gets mushy within days, with the fuel we have available overhere.



So what's the first verdict: Jetting will take some effort. Overall the length is very similar to the old VM38s due to the longer inlet rubbers. The sync plugs on the stock rubbers are a heaven's sent for getting the carbs dialed in and there's once more a lot to learn. First step will be to shorten the cables to reasonable lengths and then play around with various air-jets as the mid-range is running very lean. Mains are too big, which is weird as it's the same size that works with the VM38s, but maybe this is due to the synchronization not being what it is on the other carbs.

Sunday, 26 August 2018

Just ride.

Currently busy as F... with mostly non-bike-building-related things.




Normal operations will resume soon.

Saturday, 18 August 2018

Phour days to phantastic - a Honda CX500 tale

WARNING LONG POST AHEAD.
Or in other words, what have you been doing all the time.

Now this story deserves a preface. My dad has got two Moto 6.5s, a four-valve XT and a 1200 Suzuki Bandit. After hooking him up with the concept of taking the bike to get to work a certain inadequacy of the bikes available to him became apparent. The Moto 6.5s are collector pieces, so a broken indicator (and they break off very easily) is an absolute nightmare as you can't buy them new and hardly ever even as defect items, the XT is nice but not really suited to go to his office at highway speeds without thrashing the living hell out of it. (It's a stretch of unrestricted Autobahn and the XT will do 120kph on a good day.) And lastly the Bandit is pretty cool with all of the above, but on those few kilometers to work the oil hardly gets to temp and the rear tyre wears down quite a bit on the Autobahn. With that in mind, my dad wanted something was good as a daily, cheap to run, preferrably shaft-drive, approx. around the 50hp mark and blessed with not too many cylinders. Oh and to top that off, it had to be somewhat cool. The times when buying smaller Guzzis meant buy one get one free and the fact that spares should be easy to come by, rather quickly lead us to finding a Honda CX500. Remember a few years back when they were everywhere? Yup, not anymore. 

This is the story of a dead cheap, bought almost blindly ex-Austrian Gendarmerie (when the police in the countryside was still referred to that way), then parked up in a damp shack and then bodged back into life by one of the pre-owners and then hastily changing hands like a contageous disease in Autumn, 1982 Honda CX500 PC01, with about 73,000km on the clock. 

Everyone in even remotely their right mind would have left their hands of it. We didn't. Quite on the contrary, after assessing the situation (and having the bike sit for about six months) a plan was formed to tackle this bike in three stages: The first of which you will see here. 

The first stage was to get this heap back on the road with as much effort as necessary to get it to a point where it is technically sound and will pass inspection, but not much more beyond that point, especially not in terms of cosmetics and all in all for a 1000 Euro budget.

We initially kicked this off by touching up all the rusty spots on the frame with rust-converter, originally my dad had visions of taking the frame off and media blasting it and then properly painting it, but this would have dramatically clashed with both the intended use, timeframe to get her back on the road and also budget. 


Quite a few spares were amassed and trust me, when you look at the photo below there wasn't much that in the end wasn't necessary. 


It's always a brilliant sign, when the brakes work at the seller's and once parked up at home the brake fluid leaks past the pistons. I wasn't expecting much, but this was truly a bit shocking for me. 



I ordered some stainless brake pistons in the UK as I am no big fan of the chromed aftermarket ones, especially as this bike is meant to be used and I don't fancy digging into those next year the same time again. 


The finished calipers still blend in nicely with the somewhat tatty appearance. A pair of steel-braided brake lines and a 14mm brake master complete the brake chapter.


Next up were the forks. Badly pitted, leaking and most likely a bit bent. Par for the course really. 


The water oil-mix that came out of the forks clearly indicated: someone tried to wash the poor thing. Please also note my dad's safety boots. Because work safety all the time.


As noted before: The forks are actually shot, but a bit of oil, new seals and a lot of elbow grease should get them to the point where they are usable for a year or two and by then probably will be replaced with something a bit beefier. (I am thinking about a set of 37mm out of a Bol d'Or and stiffer springs.)


The seal didn't *pop* out but more came out with the least amount of possible resistance. It was well oiled on both side, because it had shrunk so much because of age.


They say you can't polish a turd. I have never been one to believe in that sort of negativity. And to be fair except for two or three pitting marks, which to be fair are bad enough to kill the seals, this turd came out quite shiny.


Onto the elephant in the room, or in other words, the one massive fault on the bike we didn't spot during the initial inspection. Or in other words: Ever wondered what happens, when you jam a M12x1.75 into a M12x1.5 thread?


Luckily the front engine cover was rather cheap. Unfortunately it meant removing the cooler and various bolts holding the engine to the frame to get it to move. 


For those not as versed with the CX500,  the fan sits on a taper on the cam and is an absolute b*tch to remove. So it stayed on. 


If you leave the clutch cable on the cover you can quite simply pop it off by pulling the clutch.


Say what you will about Honda CX'es... but the layout with the gearbox under the engine, in this picture on the left behind the clutch, that's pretty amazing. Big sprocket on the right is the oil-pump and the one on the middle is the front end of the crank, which also gives you an idea on just how much of a short-stroke engine that little V-twin is. 


New cover for something around 45 Euros, making a sensible insert for the oil-drain and fixing that clutch cable perch would have probably cost about the same. I might still do it just for kicks as the old one is a sacrificial part now. 


After greasing up the gasket, it went back together with reasonable ease and only a minimal amount of swear words. 



The rear drum brake liner only needed some filing on the edges and a bit of casual attention with a wire brush. It didn't seem to have beeen used much.


With the bike on some new, well new to this bike, BT45s she's a roller again.


The location for the oil-filler is a bit of a sick joke though. There's probably a special Honda funnel to get the oil into the engine. For now it will be fired up on some of the cheapest mineral 15W40 (without friction modifiers) and the oil will be changed after 50 to 100km to get ride of all the old residue inside the engine. Even though admittedly it look pretty clean.


The last part was to tackle the wiring harness situation. To be honest, it could have been a lot worse, based on what I've seen on some decomissioned BMW K75s, still it was a bit of soldering here and there, a couple of new plugs and everything is working again, except for the instrument lighting. 




So what's still missing: Carbs still need sorting (the repair kit is already here), but it will be done in one go together with new inlet rubbers, which are still somewhere in transit. The old girl needs some NICER indicators (but we're edging on cosmetics here), the front mudguard needs painting or replacement, but more likely just a coat of primer and white to blend in with the rest of the bike. And then most importantly a road-worthyness inspection and a bit of test-riding.

Plus roughly ten-thousand things that crop up, when you bring such an old girl back to life.

Saturday, 11 August 2018

Aprilia Moto 6.5 - fixing the carb of #2

So my dad might have bought another Moto 6.5 late last year, because it was a series two, which had some incredibly Italian upgrades such as: A fuel pump, which means you can actually use more than 2/3s of the fuel tank. Altered jetting so it uses less fuel and a slightly different plus some other minor fixes. Oh and also because it had a little flaw, which made it come in at the right price.

There's no photographic evidence of how we moved the upgraded parts from #1 around, i.e. the Suzuki rear shock and the forks with stiffer springs, but it was quite a job, trust me. We thought we could pull this off in a full day, it turned out it was more like two and a half days...

As you may know, the engine in the Moto 6.5 is not the same as in an Aprilia Pegaso or a BMW F650, as the Moto 6.5 got the real deal 5-valve, twin-cam hot-rod Rotax single, which admittedly goes like stink.

Now the reason this bike was so cheap was because someone (presumably when taking the carb out), had sheared off the cable holder directly at the carb. This part is nla from both Aprilia and BMW, but (and here comes a bit of world knowledge) the same BST40 carb is installed in various KTM LC4 models of the very late 90ies to early 00s. You see the spare-part number below. (Just tell them it's for a 2001 KTM LC4 Adventure 640 and you're golden. Oh and the part is a whopping 5,30€ at the time when this post was written.)


Goes into the threaded hole on the bottom left. That's also where the pre-owner glued in the choke plunger with some superglue. 


With that done it was time for some hooning round the yard and yes, it goes like stink. Honestly, these things are FAST for a single. (Terrible to work on, but fast...) Unfortunately my dad has turned down the request to fit a TM40 flatslide on the other and find out just HOW FAST we can make her go ... 


With this Moto 6.5 now bearing the greasy seal of approval, it's time to get back to the secret project that's going on at GreasyGreg headquarters... because my dad got another new bike.

Friday, 3 August 2018

The new TR1 engine - the first 200 miles (part 29)

Now with the first approx. 300-something kilometres (200 miles) done, it's time to look back a bit, report some of the mishaps and also ultimately evaluate whether all of this was actually worth it. (Hint for the impatient: Hell yeah.)

As can be seen in the picture below, yours truly didn't skimp on oiling up the cylinders properly, which resulted in a massive smoke cloud inside my workshop. It might have been so bad, that this Winters mouse problem might be a lot less substantial than the years before.


The first 30km of run-in were generally rather uneventful, it was a very hot day and due to the increased internal friction and some (admittedly) rather tight clearances the oil quickly got to 120 degrees celsius.


Interestingly enough, for some odd reason, the front cam cover just didn't want to seal properly, even though it was fine on the old motor and not even a new seal would cure it.
 

I also installed the wrong oil-pressure switch (a closer), which meant the warning light would light up instead of go out. The Volkswagen-part-number below will get you a blue 0.35bar opener, which is an acceptable substitute until I can get a switch for the correct range. It starts flickering at around 0.6bar, which is quite a bit lower than you'd want to go in terms of oil-pressure on such a crank.


... and then there was a little rideout with my dad, when spontaneously the rear plug decided to call it quits and I had to get some H*nd*-branded BP7ES plugs. Aside from that I could feel the engine starting to free up at around 100km on the clock and it became apparent that the old girl is actually quite a bit faster.


Because I didn't want to drill holes into the cylinder heads, I originally opted for BT1100 inlet rubbers. This sounds like a clever idea on paper, but it isn't as the retaining lip is a different shape and the carbs aren't held in very well. At this point I also started to tweak the carbs and installed #185 mains, instead of the #175s I had in there before. I also had to tweak the air-screw a bit and increase the idle speed as those welded up heads just flow A LOT more air.


As one forkleg of the originally installed XS1100 forks was a bit bent, a good used stanchion was acquired. This was also the moment to do the long overdue fork-oil-change on the other leg. 


230ml of 15W fork oil was used and in hindsight, next time I might go with a 10W again as it's a bit stiff.


... and a little dab of molykote to decrease the break-away stiction.


The airfilter got a bit of cleaning and re-oiling as well.


And even the oilchange revealed no nasties.


This is BEFORE cleaning the magnetic drain plug.


The only leakage left at this point was the seal around the clutch actuator arm. Fortunately this is a generic industrial item with 14x25x5mm dimensions and a single lip seal and it sets you back a whopping 3 Euros at your local bearing shop.


Removal can be done in situ, you just have to screw the adjuster bolt all the way out, then you can insert a flatbladed screwdriver and just pry it out when the cases are hot. A bit of vaseline or petroleum jelly on the in- and outside of the new seal make installation a lot easier.


So what's the verdict, how does she go? Well, she goes like stink. Initially I worried that the bigger ports and valves would lead to losses down low in the rev-range, but there weren't. Objectively I would actually assume, that there's even the odd extra newton-meter/pound-foot happening, but as the whole engine now revs a more linearly you don't feel it as much. The biggest difference is from 4000 rpm onwards. The old girl now just SHIFTS. With the 750 heads you could feel that she was running out of breath somehwere around or shortly after 6000rpm and the last thousand rpm to the redline were only to be used as a buffer. Now she happily revs to 7500 and would probably even go a bit higher, if I hadn't set my limiter accordingly. I did notice that sucking through the frame is now definitely holding the engine back a bit.

On the whole I am very happy with how the engine turned out and she goes just as I would have hoped, I admit that it will be a couple more weeks until I am able to harvest the full potential of the engine, as I am still dialing in the carbs and with only approx. 300km on the clock there's quite a bit of freeing up going to happen.