Nanno's "mule" a TR1 for everyday


After making some good progress on the engine earlier this week, there was one other thing that has been bugging me ever since I bought this bike. When I bought the bike I suspected that it had been in a crash at least at some point in its life. A few fork swaps and the fact that a rubber mallet was needed to install the upper frame in the lower frame mounts lead me to believe that the frame was buggered as well.

But before I could swan-dive into the frame swap, I decided that I had to tackled the heads first. Not very surprisingly I found a leaking valve cover. The reason it was leaking was due to a combination of really poorly executed thread repair or in other words: The threads were COMPLETELY on the proverbial p*ss.

Some fresh engine paint to make the heads look representable.

Well my crash-free XS1100 fork legs, I've been running the last few years have turned out to be not quite so crash-free, one of them suffering from approx. 4-5mm (1/4") of runout.

Next was trimming some no longer needed parts of the frame. I have a different breather setup than stock so that rear bit of pipe was no longer usefull to me.

The paint job was nothing to write home about, a coat of grey primer and then another one of satin black. I also painted the yokes, because they were looking a bit tatty and ever since I painted the lower one on the Turbo black I wanted to do the same on the mule. (Mind you a hot and humid 30 degree Celsius day is perfect for painting and even I can achieve some half respectable results!)

New steering stem bearings installed and frame and yokes are back in unison.

And that's the new frame installed and among many other things, the rear subframe bolts align correctly and the airfilter base isn't bent anymore... Fun-fact: This frame is so straight (compared to the old one) that to my huge surprise, the forklegs fell back out, whilst I turned round to pick up the allen wrench from the workbench. The old yokes required some serious twisting and turning AND a rubber mallet to get them in and out.

And some damage you find along the way:

I've had charging issues for a long time on this bike, with one of the main reasons being this plug. It's been well fried since... no idea. Cleaned the contacts and filled it with di-electric grease and it should be good until the new engine goes in, which has a good plug.

So you hear me going on, on just how badly bent the frame was, but then again, everybody can say that. See those brake pads? My old forks even required an extra washer to center the wheel in the forks.

Looks just like before (almost)...

... the old girl tracking straight is a nice bonus though. 8)



Oh the usual... I bowl, I drive around...
nice work. did you straighten the legs? The old small diameter forks are surprisingly easy to bend. I watch a buddy straighten one simply by pushing on it with his body weight while it was in some v blocks.


No, I simply bolted on the ones that were in the turbo (for now) and ordered a new stanchion for the forks that were in there.

And yes, I've "corrected" fork legs in the past, but because this one was as bent as it was, it has damaged the chroming quite a bit, so I would have to send them out to get re-chromed. As such a good used one is the cheaper alternative.


... and she lives again.

(This is a video from the very first start earlier today...)


You all know how the story ends (with a working engine), but the steps in between might be interesting to some.

So first I installed the clutch.

and then there was the elephant in the room, aka the stripped threads of the valve adjuster covers. So I made some press-fit plugs...

... and glued on an old valve cover with superglue to act as a guide ... (Btw.: Superglue is indispensable in every half sensible machine shop. Once heated over approx 100 degree Celsius it will disintigrate or if that is not an option, a quick splash of Acetone will soften it up instantly.)

Drilled and tapped and we have a leak-free valve cover again. (As I wasn't as content as I make it sound now, I put this head on the front to have easy access in case it wouldn't work out... ::) )

I went through my stash of cams and gear and picked a nice set that came together with a nice set of hardpad rockers.

Ball bearings are a must

Timed up (I am starting to become a huge fan of painting those adjustment marks

Even though the rockers came with only lightly worn adjusters, I opted for some swivel head adjusters as they protect the valve ends from getting gauged and as such result in much longer valve-adjustment intervalls. (Remember this is one of my daily drivers...)

And finally I stole a good plug off an old XV1100 alternator as the one on there was slightly cracked.

There's a blog-post that goes with all of this:


I admit I'll keep this one a bit brief(-er), as some of the steps are rather well known by now.

Stripping the bike down to the frame was a quick and easy enough job to start with.

Taking the exhaust apart required a bit of gentle newtonian-persuasion or in other words a rubber mallet. There will be more on the Mk.7 exhaust further down this post.

Old engine out.

Seriously say what you will about chain enclosures, but if you 115,000km sprocket and chain looks like this...

This lower stud wasn't only a bit bent, but also the threads were pretty knackered. And once more it was one of those "special" M10x1.25 Japanese standard threads.

On paper the BT1100 inlet rubbers are the perfect tool for the job to fit VM38s or Dellorto 40iess, but the geometry of the retaining lip is different, so they don't sit right and more importantly don't seal very well.

And then there was this little thing: Ever since I built this very first Mk.7 exhaust, it bugged me, that the exhausts weren't level AND I couldn't find the fault. (I admittedly only had rather limited time to check...) It turned out that the downpipe of the left silencer was a bit too long and bottomed out in the joint causing the Y-pipe to shift and thus have both exhausts sit at different heights.

In the end this all turned into a one-and-a-half day marathon, because of all the small niggly bits that needed touching up - like this solenoid cover, when you use heavier gauge wires.

Talking of solenoids... this one shorted out BEAUTIFULLY. From now on, I will check continuity on every solenoid with a meter before installation, because in stock form one side will always have continuity, that's the side that goes to the starter.

Aaaand a bit of the good ol' 20W50 (mineralic) oil for running in. Cheap and cheerful and thick enough to protect the engine during those first km and especially hot weather (currently every day was over 35 degrees Celsius, which is over 100-something F)

... and the corresponding blog post:

That's it, now you're up to scratch. The next post will be about what happened during the very first break-in run and my experiences/verdict on the welded up heads and then (at least from an XV-perspective) I'll pick up work on the Turbo TR1 again...


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.)

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.

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.

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.

(More on the blog - as usual)

Popeye SXM

Also used for MX
Impressive work. What do you think your compression is with the welded heads? I am planning a TR1 cafe race, already have the dona, and looking to wake up the motor a little. Did you get around to shortening the jugs?


Compression is a hair short of 10:1 (figuring in the inaccuracies of my measurements it is somewhere between 9.7:1 to 9.9:1)

Nope I didn't shorten the cylinders, it's not something that will actually increase the power notably, but it will improve squish and therefore efficiency.

If you want to liven it up, also consider a different exhaust and carbs. Those two made a hell of a difference even on an otherwise stock engine.

Popeye SXM

Also used for MX
Compression is a hair short of 10:1 (figuring in the inaccuracies of my measurements it is somewhere between 9.7:1 to 9.9:1)

Nope I didn't shorten the cylinders, it's not something that will actually increase the power notably, but it will improve squish and therefore efficiency.

If you want to liven it up, also consider a different exhaust and carbs. Those two made a hell of a difference even on an otherwise stock engine.
Thanks. I am considering fuel injection possibly with throttle bodies from a Ducati bandit. is advertising performance cams which is also a maybe :D


EFI might be nice, but be aware that running your ignition over MS is not gonna work without a 36-1 wheel driven by the cam. Hot cams... well, they might work, but all the racing guys in Germany (and there's quite a few really fast TR1s), don't have much good to say about the cams aside from the Megacycle ones. Especially as the stock valve springs are too hard and bind rather quickly, which means you have to buy the whole lot, if you want to enjoy your build a little longer.


Gold Coast, Queensland
Re: Nanno's "mule" a TR1 for everyday

Hey mate. Nominated your bike for bike of the month. Hope your cool with that.


Sort of a somewhat final update. (for now and before I bore everyone to death with it) The engine has now covered roughly 1000km. I am pretty happy with what I've built. It really took until about 750 - 800km for the engine to really free up and start to unleash the full potential. I had to upjet next to everything from the old setting as the engine sucks in a lot more air. My VM38-9s are now set to:

Pilots: 17.5
needle: clip one lower than middle (richer)
Mains: 185
Airscrew: 2.5 turns out

Overall the engine revs happily to 7500rpm, yet still is driveable from 2500rpm onwards, even though I admit, that the old motor with 750 heads had more torque between 2500 and 3000. From then onwards they are on par and from 4000 onwards it's not even remotely comparable. Currently I end up being too fast by about 20 to 30kph wherever I go compared to the old engine. Oil-consumption, even during break-in was rather moderate, at around 300ml on 800km, which makes about 400ml on a thousand and I expect that to get better with the miles clocking up.

So my final verdict, are the welded up heads worth it: Well, yes and no. Yes they are definitely a nice way to make some extra power, but at the cost of shifting the power band up by 500-600rpm. Some more extensive porting might bring that figure down another 100 rpm or so, but that would require some very extensive work including building up the ports etc., which is way beyond scope for a nice lively daily ride. All in all considering the effort involved in making them, I don't think a production run is really viable, give the fact that overall response is non-existant in this forum. So if you're interested: I have one spare set, which I will sell and that's probably it for 2018.


... as if I were ever happy and content, with what I build.

TM38-85, first preliminary jetting tests, show rather promising results with #20 pilots and #180 mains.


As you might have noticed, I am pretty fond of the TM38s, but the original choke location is annoying as hell. Luckily there's cable chokes.

Let's start off with a bit of "where's Waldo?" - no really there's a choke knob in this picture.

Rising to the occasion I also swapped out the inlet rubbers as the old ones were... old and from my parts bin, i.e. they were already old before they made it there. So there you go: inlet rubbers, 2in1 junction box, a few bowden-cable-ends and two new cable-chokes (M10-thread - thank me later, when you find out, why this info is important 8) )

The nipples are 6mm for the lever on the bars and 4mm for the chokes.

A few tips 'n' tricks, if you plan to replicate this: Rather make the cables a tad longer or you might encounter an over-rich condition when turning the bars. The other trick: always tin up the ends of the cables as well. I usually etch them with "soldering water" (sulphuric acid) and then tin them up the first 5mm (1/4"). Now GENTLY clamp the cables in a vise and adjust so the cable end sits slightly below the end of the nipple. This way the tin will be sucked in into the nipple and you have to do next to no cleanup afterwards.

... and with a tad too much tin, it'll look like this:

That's what it looks like now under the tank. I use an old ratchet strap to hold both junction boxes to my TCI, so they can't rub and stay nicely put.

If you did a half decent job with the cable lengths there should be no need to sync the choke cables, as they only know "full-throttle" anyway.



The welded up heads are giving me some grief, so I decided to overhaul the XV700 heads and convert to them on Thursday and subsequently find out what the h*ck is wrong with those heads as it's eating plugs whenever you give it a decent handful. :-\



As you saw, I later then used XV1100 parts, if it's your first XV-engine build (or you don't have a fully equipped engine shop and have to pay for certain mods), go with older Virago stuff.

That being said, I have a second set of welded up heads and if you want, you can have them. Thing is, it'll be a while until I find the time to dig into them. I will very soon start a new engine for a certain someone on here and that will have to be done before digging into anything else. Also my dad wants me to dig into some of his bikes and get them up to a comparable standard as my old junk.

With that being said, let's get back to some more info on what happened (for those of you, who follow the blog, nothing new, sorry).

Those welded up heads are all about learning for me and of course, make heaps of power. As you can see in the pictures below, I've got some mad heat issues in the head and at the same time it acts as if it were running really rich. If you look closer at the piston, you will see by looking at the shape of the carbon deposits, that the swirl I wanted to create worked beautifully. (Tear-shaped residue on the piston.) It got a bit hotter than I like, but the clean sides on the pistons indicate that the combustion is centered nicely in the middle and there are no hotspots on the sides, which was my biggest worry with such a huge combustion chamber.

So the "mule" will now be set up like a good everyday engine should: very torque-oriented. But first a bit of damage on the XV700 heads had to be cured. One of the fins had broken off, when I had the heads shipped over from the US. Old grime and dirt was so deep into the pores of the ally casting, that it was an absolute nightmare to weld.

Bit of the old flapwheel action made it look representable enough for the underside of a cylinderhead. :r:

... and some more prep-work like running a die over all the studs and a tap through all the threads.

And (of course) new valve stem seals and lapping in the valves.

From here onwards it was a pretty quick route down from this:

to this:

Unfortunately, good Gen1 cams with little wear on them don't exactly grow on trees or in other words, I only had exactly one set left and so I had to move them over from one set of heads to the other.

New heads on.

Just because you've done dozens of these things, doesn't mean you're not allowed to take a note on the inside of your engine cover. (Also it came out as a nice arty-farty-shot with the lights 'n' all :bg: )

And then ultimately introducing you to the three-legged-throttle-cable-spider (cables being oiled with super-thin sawing machine oil) and even if you don't believe me: It makes one hell of a difference.

The new TM38-86 carbs finally being set up and ready for action.

... and installed:

One of the funniest things about the new engine that I only noticed yesteraday was, that for the first time in about 6 years, I now have an alternator, which works on all three phases. Now how's that funny? Well simple, I was so used to the charging system being insufficient, that I totally got used to riding around without lights or only on LED pilot lights, that when I did some measurements yesterday, I was a bit shocked to find out, that the bike now actually charges below 2000rpm just fine. (Not the worst of surprises to be honest - especially as my sidecar currently isn't charging at all...)



This is two posts in one:

The last bit of fine-tuning comes in the shape of having to get a different needle. Specifically one that is a bit richer than the one that is currently in, especially in the first 1/4 of the needle operation.

After quite a bit of research, I found the data for the following table containing the recommended needles for a Mikuni TM38:

As a result I ordered a set of 6FJ40ies, as the bike is running an oversized pilot jet at the moment. (Causes it to run really rich, when hot and give me sub-par gas-mileage.) Which I hope to cure with the richer needle. That being said, I also (sort of) created my magnum opus on how to jet carbs, determine the right needle and various other lesser issues. If that's the sort of thing you're into (and lots of reading), then please go ahead and have a look. Generally, if you guys want to have more info on how I go about tuning carbs poured into articles, let me know and I'll give it a shot - I've got some ideas on best practices, fault finding and others. Mainly because I've been chasing a few on the TR1 and my XS-Triple sidecar (which is also running on flatslides and gives me plenty of headache).


Just a quickie: This is the picture to go with the post above:

As you can see, thee 6FJ40 is a lot slimmer. It looks rather dry overhere, if I can get rid of the inlaws quickly enough, I might give the old girl a quick shakedown and see if this goes in the right direction.

Full blog-post here:
Top Bottom