Motorcycle project!

I’m also a fan of motorcycling. It’s a fun hobby, not too expensive, and it provides a wonderful change of pace. Frets and worries just seem to blow away in the slipstream. I’ve been a biker for 30 years on and off, but I’m no hardcore rider. I’ve likely covered 40K miles or so during that time. Family comes first, so when my kids were little the bikes stayed put. Now that they’re a little older, I’ve been doing a bit more riding.

Much like my cars, I usually have one reliable expensive bike in my garage. But I can’t resist good deals when I find them…so I’ve probably owned ten or twelve bikes so far. That sounds like a lot, but these are *really* cheap bikes, rarely in running shape, often without titles. Up to this point, I’ve only owned or worked on Japanese bikes. It’s largely because they’re cheap, but also because they have a huge amount of value. Lots of Honda, some Yamaha, a few Kawasaki too. Most were revived under my supervision, and left under their own power. In order of purchase, here’s the ones I recall:

1974 Honda CB750K ~ 1978 Honda CB750K (My brother’s bike) ~ 1984 Honda VF1100S Sabre v65 (flawless condition, rode it for ten years) ~ 1983 Honda VF750S Magna v45 ~ 1984 Honda VF500F Interceptor 500 ~ 1985 Honda VF1100S Sabre v65 & 1984 Honda VF1100S Sabre v65 ~ 1995 Honda VFR750F Interceptor (another ten year ride) ~ 1985 Honda VF1100S Sabre v65 ~ 1987(?) Kawasaki Eliminator 600 & ’85 Ninja 600 parts bike ~ 1985 Yamaha XV535 Virago 535 ~ 1997(?) XV750 Virago ~ 2002 Yamaha XV650 Virago 650 Classic, Midnight Edition ~ 2004 Yamaha FZ6 Fazer (current ride) ~ 1986 VFR750F Interceptor (current project)

There’s only two in the stable now…one to ride, one to build. Summer ’21 was filled with motorcycles, lots of buying & selling. I sold my trusty old ’95 VFR and picked up a more comfortable ’04 FZ6 for everyday riding. Lots of V-Twins too: I flipped an XV535 and an XV650, helped out a buddy with a really nice XV750.


Despite having worked on all those bikes, (as usual) I’m looking for a cheap bike. It’s getting later in the season, the weather has turned, always a good time to pick up a project. Fast & frugal, preferably some sort of a junkyard rescue. I’m sure you might be wondering: “Why?” That’s a good question. Why buy old junk when far better & newer bikes are relatively cheap? Because I’ve gotten to the point that I want to do a “build”. Buying a cheap bike in crappy cosmetic shape means that you really can’t screw it up. if it goes south, it was already junk, no need to worry. Philosophically, it’s a good place to be.

To make a long story short, I picked up a cheap VFR750 project. That brings my total to six bikes in a year (and it was fun)! The only one that’s still not running is the VFR. It needs a frightening amount of work, but I’m not planning on a full restoration.

The VFR might end up as a long-term “build”, something I haven’t done before. For this to work, in my mind, the bike has to be something barely worth saving, definitely not worth a restoration, but fun enough to be worth the effort. So I’m slowly evolving what was once a worthwhile sport bike into a scruffy street fighter. I’ve been learning about suspension tuning, geometry and material work, likely with a focus on metal finishes. With luck, it’ll end up with modern looks, vastly improved handling, decent lighting and lots of updated tech. Ideally, not straying too far from the spirit of the 80s. Think red segmented LCDs and origami folded paper style. Read on for the gory details!

It all started out with this Ninja 500 rescue article over at Revzilla. I popped over to Andy Greaser’s article about the Reliability Rally. Sounds interesting, no? I took a quick look at the rules, and found myself inspired. It’s rare I discover things I can totally agree with in both spirit and purpose, you might feel the same way. Not only did I agree literally with Andy’s well-written words, but I also felt at home figuratively with the community spirit in which those words were written. So I came up with a quick plan. Find a cheap bike, one with “a wheel in the scrapyard”, and scrounge enough parts to make it worthwhile. It’d be my first build too. Up to this point, I’ve only restored or modified bikes. Doing a bike “build” is a far higher level of accomplishment, taking it to the next level if you will.

It took a few weeks, but then I found my ride…a 1986 Honda Interceptor. This is the first year of the gear-drive Interceptor. While it seems like old VFRs have gotten a little scarce recently, these V4 models were built to last and were very popular. I also have a lot of experience with Honda. With luck, I’ll have some useful spare parts at the shop, and other parts shouldn’t be a huge problem (eBay, CL, FB). The chassis was quite modern for the 80s, a fully aluminum spar frame with a matching aluminum box section swingarm. Older bikes tend to have better ergonomics as well, here’s a great comparison tool for your research. When this one popped up on my local CL, I immediately decided it had to be saved. I contacted the seller to set something up. He seemed quite honest and up-front: “It’s basically junk, but if you want to check it out I’ll text you the address. Stop by whenever you have the time and let me know if you’re interested.” This sort of an arrangement might seem like a scam, but for old junk it’s not unusual. He mentioned that it’s at a rental property he owns, but he travels extensively. His tenant can show me where it’s at.

So off I went, to a random address, based on a phone call with a guy I’d never met, based on a Craigslist ad. It all turned out exactly as described. Was the bike a rusty, mouse-gnawed mess? Yep. Are the fairings a mere memory, and astoundingly rare these days? Yep. Is the maintenance schedule booklet not up to date, missing a few stamps? Definitely! In all seriousness, I’m not sure I can bring her back, but it just felt right. She’s got some serious miles (50K), lots of questionable mods, more than a few hacks. Time always tells what can be salvaged, and I’m not out of pocket much more than scrap value. If I fail, there’s no real guilt attached, she’s never going to be a garage queen.

I called the seller back and told him I was interested if he was flexible on price. He replied in the affirmative, and he had himself a deal! We arranged a convenient date for the payment, paperwork & pickup. When I got there, the bike was still loaded on his trailer. We delicately lined our trailers up, back-to-back, and prepped my new project for transfer. I had brought some cardboard boxes to provide a sliding surface, and we used my electric winch to carefully transfer the bike from his trailer deck to my trailer deck. [not really] I just looped a steel cable around the rear wheel & dragged her across. The power winch was key…made it almost TOO easy! This winch is the cheap Harbor Freight model, with the witless remote control. It worked well enough, whenever it received a signal anyhow. I was very willing to take some time with the remote, since we’d have both gotten a good workout with my little 10′ come-a-long. I’ll be hacking in some manual controls just in case…the winch is useless without a functional remote. New batteries did nothing to help out. Anyhow, on to the pictures!

Other fun facts: this 1986 model (VFR750F-G) is a California edition, fitted with a rudimentary evap system. Commonly known as an “RC24”, it’s powered by a 750cc V4 motor. Many mid-80s Interceptors sold here in the ‘States were fitted with a slightly smaller 700cc motor to avoid US tariffs, but this one got the larger engine. Perhaps it was to compensate for the emissions-system power losses? Alternatively, it could have slipped in before the tax increase. There were a lot of ways to get the larger motor. For instance, our common-sense neighbors to the north got the full 3/4 liter, as did the rest of the world, from what I’ve heard. Thanks a lot, Harley.

This generation of VFR was fitted with gear-driven cams to resolve some durability issues with the earlier V4s. They’re a neat little bit of racing technology, and the scissor-type split spur gears keep lash in check. They make a lovely, unique, mechanical sound when underway. It’s hard to describe. You just have to hear a V4 to understand, I guess.

This specific bike is a really early build. The ’86 is the OG VFR. If I’m reading the VIN correctly, it’s the 78th VFR off the line.

Even better, I’ve apparently rediscovered a long-lost bike from another blogger. I was doing an image search, looking for cowling ideas (the ’86 has a unique single-year-only fairing that’s nearly impossible to source) and stumbled upon a very familiar-looking dual-headlight mod. Here’s his retrospective article about this bike…and he’s confirmed it’s the genuine article. How about that, eh?

Here’s the official plan for restoration, as of October ’21:

  • Unload a 540# (200KG) sport bike from a trailer despite three locked-up brakes and flat tires from the trailer without getting maimed. Put the bike back up on its own feet again. (Done, Oct. 8)
  • Give the bike a name. I’m thinking food…wasabi, onigiri, or tayaki. Don’t panic, they’re all tasty Japanese delicacies, much like this bike. I’m also strongly considering calling her “nezumi” (mouse) (ネ ズ ミ) after all the urine I found at the bottom of the air box. Or maybe I’ll call her “Furui bangō nanajuuhachi” (old nunber 78) (古い番号78). I also found a great quote here: “People throw out 人馬一体 (jinba ittai) all the time for Miata, but another 4-character idiom in Japanese is 十人十色 (juunin toiro): ten people, ten colors. Different strokes for different folks.” If you’re not familiar with Mazda’s motto here’s another fun tidbit: “Jinsha Ittai, which, in Chinese characters, means oneness between car and driver.” Send suggestions my way.
  • Remove varnish from fuel tank (link).
  • De-rust tank if it can be saved (link1~link2).
  • Get the motor un-stuck, spinning nicely (Done, Oct. 8), check compression, valvetrain, clutch & gearbox. New blue coolant, Rotella T6 (oil) & plugs.
  • Evaluate electrical system, fuse box (Done, Oct. 8) & upgrade regulator rectifier to Shindengen FET type.
  • Pull, clean & rebuild carbs. (Pending, Oct. 9)
  • Pull, clean & rebuild brakes. (Pending, Oct. 9)
  • Pull, clean & rebuild clutch. (Pending, Oct. 9)
  • Clean what’s left (link), rebuild cooling system while the carbs are cleaning. I think we’ll need a new radiator, this one is rashed.
  • Reinstall carbs, but only if the brakes are working! Fire it UP. Put out resulting fires (if required).
  • Evaluate chassis: forks, rear shock, wheel bearings, chain & seals. (Right rearset replaced, eBay part, Feb. 11)
  • Fork overhaul, new fluid, and consider potential upgrade to thicker cartridge forks or Gold Valve emulators (link).
  • New tires, unless a fork upgrade turns up. (Pending, Feb. 9)
  • Parts list: lock set, center stand (very unlikely), if possible.
  • Find a decent fairing, maybe a cheap cafe racer type to match the dual roundies.
  • Super bike or flat track bars. I love the look of clip-on bars, but they’re hell on my lower back.
  • Sheepskin saddle pad. Seriously. Until you’ve felt the sheer shaggy comfort of a sheepskin, don’t knock it. I know it looks like you’re riding a fluffy dog, but it works. I’m told that the finest benefit of age is wisdom, but self-assurance comes along for the ride. It’s important to thoughtfully consider others’ opinions before disposing of the ones that don’t match your own. Thresh the chaff from the wheat, as they used to say. 😉

I got a few hours on Friday (Oct.8), ticked off a lot of tasks. First, I had to unload the bike. That was pretty easy, a low-profile floor jack and a couple of dollies got it movable. Then I pulled the frame pins and tilted the trailer deck. With a little encouragement, it slid off the deck like an omelet out of a cast iron skillet. Then I unbolted my 2500# electric winch (another CL special), folded up the trailer and put it away.

One of the best things about a V4 is that it isn’t incredibly top-heavy. I was able to easily lift it myself, using the proper technique. Once it was up, I proceeded to carefully remove the frozen brake calipers. It’s a job that requires delicacy (I used a pry-bar and mallets). Although the (mismatched) tires are wasted, I pumped them up to 30psi. Makes the bike oh-so-much easier to roll! The tire valves actually held pressure; but eye protection is advisable & highly recommended.

I’m sure you wanted pics, feast your eyes on the mess:

Now that it’s somewhat mobile, I shifted it into neutral, rolled it over to the toolbox, and began removing parts. Off came the saddle, side panels, misc. trim, fuel tank, and radiator. The coolant was a little low, but at least it was fairly fresh. That’s definitely a good sign. However, the radiator is an obvious mess, significantly bent from an impact on the filler neck. It must have been something substantial too, strong enough to split the pressure cap. I’m not sure it can be saved. I’ll try though, as I believe it’s the original brazed brass part.

I was somewhat worried about the missing airbox lid, but it came off easily enough (be sure to use JIS screwdrivers like these!). The carbs were surprisingly clean, CV sliders were only slightly sticky. Three are perfect, one is pretty sticky. Might be a torn diaphragm or varnished gasoline…hopefully not dried mouse urine. I’m pulling them off for an intensive cleaning & rebuild anyhow.

I pulled the plugs next. Not that great, definitely evidence of rust on the electrodes. I’d assume it’s also in the piston bores.

Now for the moment of truth…time to check under the cylinder head covers. With baited breath I unbolted them and peeled them off. They look excellent! I’ll check valve clearances later, but I was pleased by the gleaming valvetrain.

I knew the motor was stuck on something when I originally checked it out. I was guessing the rings were stuck, or it had a little rust in the upper cylinder bores. If I want to do a quick test on a motor on a completely dead bike like this, get the rear wheel off the ground, then shift into the highest gear. Spin the rear wheel in the usual direction of travel. A healthy engine will require some force at the wheel to overcome compression, but you should be able to spin the motor with relative ease. Don’t try this trick in a low gear, nor with the ignition on. You’ll strain your back and you can potentially kick-start the motor.

This motor would do a quarter turn but remained somewhat stuck. That’s actually a good sign…typically it’s just surface rust inside the cylinders. In all cases like this, my next step is Marvel Mystery Oil. Pull the plugs, pour a few judicious ounces directly into each of the bores, walk away for a few hours. MMO quarts are commonly sold at auto parts stores. It’s a very thin penetrating oil with a viscosity somewhat like reddish water, and it smells strongly like mint. That smell is wintergreen oil – an excellent solvent for organic gunk like dried grease, gasoline varnish or oil sludge. It also has other additives that do a decent job with rust and corrosion. Please give MMO the respect it deserves, wear proper PPE when using it. I cannot imagine what something this minty fresh would be like splashed near my eyes; you can smell wintergreen oil across a backyard. Decent ventilation, barrier gloves and goggles are a must. Wintergreen oil can irritate your airways and is easily absorbed through the skin. Large doses can cause permanent liver damage, especially when mixed with other OTC NSAIDs.

Once I’d given the MMO an hour or two to do its work, I started freeing up the motor. Most motorcycles have a large bolt on the flywheel for manually turning the motor. On these bikes, it’s in the right timing cover, underneath a small threaded aluminum inspection cover. I carefully used a six-point 17mm socket to remove this cover, as they are quite delicate and easily stripped. Beware of too much force. Don’t be tempted to heat it either, they’re sealed with a rubber o-ring. Once the crank bolt was exposed, I slipped the 17mm six-point socket onto my 2′ breaker bar, and gave the motor a little gentle torque (200 feet-lbs or so, LOL). Once it stopped, I’d back it up a little, then give it a little more gentle torque. Eventually, it made a full 360 degrees. That made me happy.

My last chore of the day was to give the bike a little power, and see what worked. I started pulling fuses and other critical connectors, giving them each a generous shot of contact cleaner (CRC makes a decent one but DeoxIT D5 is the best I’ve used). I hooked up a jump pack (something like this), used a screwdriver to twist what’s left of the ignition switch. I was rewarded with gauge backlights, a few status lights, and the turn signal seems to work. No blown fuses, no smoke, no burning smell either. All good omens, the gods must be happy. The low beam even powered up, although erratically.

I remain cautiously optimistic about the bike.

Oct. 9: Today was hydraulic day! Front brakes, rear brakes and clutch all came off for cleaning & inspection. I also dismounted the gauge cluster and headlight unit. I’ve found an ultrasonic cleaner is an excellent choice for rebuilding stuff like this, even though it’s not really that great with degreasing parts. The master cylinders were in passable shape. As expected, the clutch slave cylinder & calipers were more or less frozen. A little penetrating oil and air pressure is useful at times like this. I’ve succeeded with the front brake master cylinder, rear brake master cylinder, the left front brake caliper, and the clutch slave. The clutch master will need replacing, it’s too far gone to economically rebuild. I’m still working on the other two calipers but I’m optimistic that they can still be saved.

As it stands, I’ll likely need to rebuild the front calipers with new seals, bushings, and some slider pins.

Other missing functional parts include the fuse box cover, much of the air cleaner, and a broken pedal stay.

I also managed to remove the carb rack assembly. If you’ve never done a V4 carb rack, you owe yourself the pleasure. It’s like a continuous challenge to fit your hands where the fasteners happen to be. A long reach JIS would have been a big help. The four carb boots each have a pair of clamps retaining them on the carb spigots. A correctly set-up VFR will have all the screw heads pointing out to the left side of the bike. I totally mangled the boots, but they’re expendable, still available from Honda and other online retailers like Partzilla or PartsFish. The ’86 VFR750 doesn’t cross-list with many other bikes, I’m told it should be Honda part 16211-ML7-000.

I’ll also upgrade the bowl gaskets, the air screw o-rings, and whatever else I can get here at V4 Dreams.

Oct. 10: More cleaning, more fixing, more trouble. I keep a list of parts I need as I go, but I won’t be buying anything until I’m sure the bike will run.

I’ve started tearing down the carbs. Lots of sticky green goo, the signature of our local ethanol blend fuels. It’s quite resistant to common cleaners. I could take them apart and ultrasonically clean them; however, the plastic junctions are quite delicate. Furthermore, my preferred ultrasonic solution (a generic knockoff of Formula 409?) isn’t terribly effective either. As an alternative, I’ve heard good things about a simple pine oil cleaner bath. Pine-sol was the go-to choice, but it’s been nerfed; no pine oil since 2014. I’ll be trying out an alternative called Pinalen, commonly available in the motorsports section of Lowes and Family Dollar. “Nice!” is supposed to be a good choice too, but I haven’t found it locally.

Oct. 13: I bought three gallons of Pinalen at Lowes, and a suitable plastic food storage bin at Target. I prepped the carbs by removing the upper covers, needles & CV slides. I also removed the bottom covers, jets, floats/float valves and the idle air adjuster screws. I was quite diligent in keeping rubber o-rings out of the acidic Pinalen bath, even using a bent paper clip to yank the tiny idle air control valve o-rings out. The carbs are sitting in this ad-hoc bath for a day to see what the solvents will do. This is a pungent process, I’d strongly recommend doing it in a detached building or outside. The cleaner almost immediately darkened & fogged up as I poured it through the carb “rack”. I’ll update this tomorrow, hopefully it’ll perform as advertised.

Oct. 15: The Pinalen appears to have done the job. I soaked the remaining carburetor “rack” assembly for 24 hours, then attempted to neutralize the acidic Pinalen solution with an alkaline bath (just hot water & A&H washing soda powder), then finally rinsed it well with cold running tap water. As others have noted, any magnesium parts (the lower plenum in this case) had a noticeable black sheen. I also noted some mild white powdery corrosion on the zinc carb bodies and some emulsion where the varnished fuel had been. It was slightly worrisome, so I sprayed the entire assembly in WD40 and left it overnight. As others had suggested, this appears to stop any corrosion, and that appears to have been successful. My conclusion is that it’s a useful technique. It allows you to soak the complete assembly at once, and is relatively harmless to rubber and plastic parts. Sure, it failed to clean the worst of the varnish, but it’s massively better than it was. I’d suspect a longer soak might have done a superior job, but I didn’t want to risk it on a cheap build like this. I’ll finish it up with some spot cleaning and re-install the plenum once the new boots get ordered.

OTOH, the small parts were not as successful, especially the commonly-plugged “slow” jets. This bike uses Keihin VD carbs with size 38 slow jets (incredibly small, 0.38mm) in all four carbs. They’re famous for plugging up on the V4 bikes; some are worse than others. I loaded up my pin drill with an 0.35mm bit and carefully reamed them out. They’re back in the Pinalen bath as I type this.

In other news, I worked on the hydraulics. The good news is that the front brake master cylinder, clutch slave, and rear master are all cleaned, functional and ready for re-installation. I went through my spare parts and reassembled the adjustable levers with some salvaged parts. Both levers were mangled, but they’re now fully functional (albeit mismatched). I think they’re from an ’85 v65 Sabre of my recent acquaintance. I also borrowed a clutch master cylinder from another random V4 to get the bike rolling again. Might have been a v45 Magna, or perhaps a VF500f? Who knows? If the shoe fits…wear it.

2021 ends with the bike in a more or less rolling state. I’ve ordered some carb overhaul kits. I’m also looking for some decent parts to replace the broken bits. Updates will slow down, but this bike will run on the road again!

Well, now it’s Feb 2022. Groundhog Day. While Phil (of Punxatawny) didn’t find his shadow, I found my suspension upgrade. And it came in one tidy package. Some people call them a Triumph TT600. It appears that this bike had a bit of trouble with the #1 piston. I’d guess it “dropped” a valve. That’s bad. When that happens, the piston & valve fight over the combustion chamber. The valve tends to lose these fights, snapping off at the stem, and finally seeks revenge. It strives to be free. In this case, the valve peened the piston until it broke on through to the other side. Do you recall the video game “Breakout”? Remember when you’d get the ball above the wall? That’s more or less what happened in there. Onto the rescue process:

I know, this was a bit impulsive, but the price was right and it wasn’t too far away. I’m not really sure what will be required to make it all work harmoniously…time will tell.

Pro tip: It’s almost always better to buy a complete parts bike instead of one assembly. There can be a surprising bit of resale and scrap value in the extra parts; it’s likely other parts can be useful regardless. I’m also inspired by seeing how things are put together, it’ll keep me motivated. If you buy one assembly and forget a part, it’ll end up costing both time and money. Just be sure you have available time, space, money, etc..

The nicest thing about this bike is that it has most of the parts that the VFR needs; hopefully I can make them work. It’s a judicious assortment of potential upgrades, no doubt about it. Let’s start at the front: 43mm Kayaba cartridge forks (with adjustable compression & rebound AND aluminum internals), a lightweight 17″ 3-spoke alloy wheel, 330mm Nissin brakes. The rear end is decent too: a remote reservoir Kayaba rear shock with adjustable preload, compression & rebound, mounted on a similar rising rate linkage, with a big, fat 17″ rear wheel on a stout alloy swingarm. With luck, this stuff will swap right over without too much work. I’m also going to take a crack at mounting up the funky radiator/expansion tank, as well as the headlight/front subframe, and the saddle/rear subframe.

Feb. 9, 2022: I spent some time measuring up the front forks. The TT600 has fork spacing of 200mm, an offset of 40mm, and an installed stem height of 215mm (measured from the top surface of the upper clamp to the top surface of the lower clamp). The VFR fork spacing is 182mm(?), also with a 40mm offset, and an installed stem height of 235mm. I think the TT600 axle is 25mm, and the VFR is 24mm. These are just quick measurements, likely inaccurate, please do your own research!

I also took a few measurements of the rear swingarm. I misplaced my larger metric rulers so we’re switching to SAE inches. Please bear with me.

  • VFR swingarm is about 14.25″ total width, perhaps 11″ inner width. Front pivot is about 9.25″ wide. From the front pivot, total arm length is ~23″, min axle length of 21.25″. Rear shock is approx. 11.75″ tall (still installed, thus not an accurate comparison). The VFR exhaust hopefully won’t cause problems, it has approximately 15″ open space between the pipes (silencers). We’re in the ballpark, I think.
  • The TT600 swingarm is about 13.25″ total width, perhaps 10″ inner width. Front pivot is about 9.25″ wide. From the front pivot, total arm length is 23.25″, min axle length of 20.25″. Rear shock is approx. 12.75″ tall. That’s not an ideal measurement…parallax makes for inaccurate measurements, the spring is still heavily preloaded, the shock is still carrying a bit of chassis weight, etc..
  • The VFR front wheel (16×2.5″ mounting a 110/90-16) is 23″ diameter and about 4.25″ wide with 10.5″ rotors.
  • The TT600 front wheel (17×3.5″ mounting a 120/70 R17) is 24″ diameter and about 5″ wide (slightly taller & wider) with ~12″ rotors.
  • VFR rear wheel (18×3.5″ mounting a 130/80-18) is 26″ tall, and about 5″ wide. The chain wheel is offset 4″ from center, and the disc is 3.25″ offset.
  • TT600 rear wheel (17×5.5″ mounting a 180/55 R17) is 24.5″ tall, and about 7″ wide (both shorter AND wider). The chain wheel is offset 4.5″ from center, and the disc is 3.25″ offset.

As for the wheels…front won’t be an issue since I’m planning on swapping the entire Triumph steering assembly (forks/wheels/brakes) as a single unit. The forks *should* be long enough to prevent rake/trail problems or clearance issues. As a happy coincidence, the TT600 has a wheel-driven speedometer gearbox. It does use an electronic pickup, but with a little luck I’ll be able to convert it into a cable-drive unit, or pop the entire Honda ‘box onto the Triumph axle. These gearboxes have a surprising amount of interchangeability.

Let’s move on…to the rather more important topic of suspension geometry!

  • The TT600 forks are somewhat shorter than the VFR. I don’t have hard numbers yet, but the internet tells me TT600 forks might be 43x775mm (I measured 763mm (30 1/16″) unloaded) vs. the VFR’s 39x835mm forks (I measured 831mm (32 7/8″) unloaded). Those measurements should be consistent, taken with the forks fully unloaded, from axle center to the top of the fork tube (i.e. not including the cap thickness). Granted, the taller TT 600 17″ front tire makes up about 12mm of that (1″ diameter/2). Thus, we’ll have to find 48mm (~2″) of length to keep similar dimensions, although the tire will change the final rake & trail dimensions. I’ll likely end up adjusting the rear suspension to compensate, but there are other solutions I’ve found. ‘Gullwing’ top clamps  will “drop the forks”, effectively sliding the Triumph forks further down the stem. Longer 43mm tubes would work too, but anything custom will blow my budget. Cruiser tubes tend to be longer, but they’d have to be compatible with the cartridge internals as well…very unlikely.
  • Preliminary numbers: the VFR has a 27.5 deg rake and 108mm (4.2″) trail. Double-checking those numbers let me verify the calculator I’m using, and my measurements. VFR has a 23″ diameter tire, 27.5 deg stem rake, 1.57″ offset, 32.88″ forks, 0 deg tree rake) comes up with 4.22″. Inserting the complete TT600 front end into the VFR frame only changes two of those numbers: (24″ wheel, 27.5 deg stem rake, 1.57″ offset, 30.52″ forks, 0 deg tree rake) resulting with a 114mm (4.48″) trail. Such a small increase shouldn’t really be a problem, and it saves me the considerable difficulty of sourcing & fitting a different triple clamp. My preliminary conclusion is that it’ll be a little more sluggish at lower speeds, but also somewhat more stable and less nervous on the highway. Not a bad compromise overall, I’ll update numbers as required.

However, that’s only a basic calculator, meant only for front suspension changes. I’m also planning on fitting different diameter tires. The net result of a taller front tire and shorter rear tire will raise the front end, increasing rake and trail slightly. However, the much shorter forks will outweigh the tire differences. They also offer an advanced calculator that’s far better suited to my purposes. Adding in the wheelbase and both wheel sizes allows a far more accurate idea of critical rake, trail & wheelbase numbers. Given that the stock VFR has a wheelbase of (1475mm / 58.1″):

  • Swapping only the TT600 wheels into the VFR stock suspension makes no changes to wheelbase (58.1″), but trail lengthens from 4.22″ to 4.48″. I’d expect rake would get slightly longer, but this tool doesn’t calculate rake.
  • Swapping the TT600 wheels AND the TT600 forks shortens the wheelbase from 58.1″ to 56.9″, steepens the rake from 27.5 deg to 25.08 deg, and shortens the trail from 4.22″ to 3.88″ (100mm).

All-in-all, not too extreme. It’ll sharpen up the handling a bit, and losing a few pounds should make for an entertaining ride. Coincidentally, this will is getting similar to my old RC36 (26deg / 99mm trail), and that was a really sweet handling bike.

So I got a few hours to mess around with the bikes today. An unusually warm February day was quite a bonus. Sunny and 52degF? Is it summer? The Triumph parts were quite similar to the Honda bits. The VFR has a slightly longer stem, but it was actually possible to mock it up. If I had a lathe I could have possibly made it work directly! A stem swap is still the plan, should be fairly straightforward.

I’m planning on drilling the upper bridge to fit taller tubular bars, so the clip-ons are temporary. I was actually shocked at how well it all fit together. The Honda still has conventional ball bearings, the slightly shorter Triumph is a little odd. But we expect that from them, eh? The Triumph has an, um, kinda unique steering bearing setup. This one had an upgraded lower bearing (“Timken” roller type) and a sealed upper ball bearing. Might be a double-row, I’m not sure. In the never-ending search for lightness, Triumph used an aluminum stem, held together with a pair of comically large & thin hex nuts to properly tension the bearings. Sadly, I don’t think it will be usable, but I’m still considering options. Perhaps an upper spacer shaped something like a well nut could make it work.

I also took a look at the rear wheel. I wanted to see if it would work in the VFR swing arm, and it turns out it does! It’s tight, but it fits.

There are a lot of parts in common, happily. The VFR axle is significantly longer, but the same thickness, 20mm IIRC. The rear sprocket is the same pitch (520?), but the TT600 is down quite a few teeth, and the rear brake is significantly smaller. The TT600 wheel & spacer stack was a great fit…I slid it all the way over to the left to line up the chain. The brake carrier was too thick to fit in the remaining space. That needs more work anyhow, as brake carriers are functionally different designs. The TT600 carrier fits into a slot in the swingarm; the VFR has a long torque brace bolted to the carrier and the swingarm.

Overall, I have to say that today was quite fun & productive. Also note the freshly-installed right rearset (footrest), cost me $20 on eBay.

Feb. 16, 2022: The front brake lever had no resistance when I bought it, a quick check verified that the master cylinder piston was firmly compressed in the cylinder bore. I had hoped a little penetrating oil would loosen it up (PB Blaster in this case), but that was not to be. So aside from that cursory attempt, I took it off the bike and left it for later. This, it’s become today’s fun project. A brake master cylinder is a very simple machine. On a motorcycle, they’re usually a quite simple singe-piston design. There’s a return spring with an attached lip seal, then a cast zinc piston with a backup lip seal, then (sometimes) a flat washer and a snap ring to hold it all inside the cylinder bore. Pop a little dust boot over the end to wrap it up. Remove the assembly from the bike, remove the lever assembly, then pull it apart from the rear.

This is one of those jobs where snap ring pliers would be useful, but the ones I own are really cheap. I’d recommend getting a decent set for this job (skinny but with good reach), as none of the clever/cheap removable jaw types will do. I spun the ring with a pick until it was lined up with the extraction cutout, then compressed it with a pair of small precision long-handled pliers. Usually the return spring will be pressing the piston against the snap ring, so it helps to have three hands, but that wasn’t the case this time. This particular piston had a lot of fight left in it, jammed in the bore quite solidly. I exhausted my usual bag of tricks:

  • It didn’t budge with air pressure, and penetrating oil wouldn’t work.
  • I could have used a clamp on the brake pistons to push it back, but this bike has opposed piston calipers.
  • I could have connected a brake hose to another master cylinder and forced it apart with hydraulic pressure, but I didn’t have a working one handy.
  • I ended up (accidentally) breaking it apart and extracting it in pieces. The rear segment of the zinc piston snapped off while I was prying it out (a medium flat bladed screwdriver is quite effective). Once I removed the rear half of the piston, I pounded the front half out with a drift into the front of the cylinder (a dull screwdriver with a round haft will also do). I suspect the seals are worn, not reusable, but time will tell.

All the components went into the ultrasonic cleaner for a little bath. I like to use an aqueous non-flammable all-purpose kitchen cleaner at full strength (like Lysol, Pine-sol, Formula 409, etc.). It is astoundingly effective with hydraulics, easily breaking up the powdered residue of dried-up brake fluid. I ran into a problem, however. The ultrasonic cleaner can damage some coatings, including anodized aluminum. Apparently that’s what Triumph spec’ed from Nissin for their master cylinder. I don’t think it’ll be a problem, but I’m no engineer. This will require some thought.

Feb. 19, 2022: Ordered some new front steering bearings and a 14mm generic Nissin front brake overhaul kit. Once it arrived I popped it into the freshly cleaned brake master, perfect fit! I’m still not sure on the flaking finish, time will tell. As for the steering bearings, they’ll be used when I slide the VFR stem into the Triumph fork clamps. The lower clamp appears to have the same 30mm tapered bore, although it’ll need some modifications to the steering stops. The upper clamp will need to be bored out to approximately 24.7mm (1″). I have a step drill I’ve been waiting to test out, should be fun! Just need a larger 1″ bit and we’ll be prepped for the swap. I’ll be starting off with the clamp-ons, but I might also drill the mounting holes for the handlebar while it’s all apart. Nah, it’s better to wait.

April 4, 2022: I put this project on hold to pursue my recently arrived BMW 535i. I was also involved in a motorcycle low-side that put me out of action for a few weeks. Updates will follow, but at a slower pace. Be sure to check back for updates!

Jan 27, 2023: No time for updates. I’ve had many projects in the meantime! Updates will eventually show up, don’t worry.


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