Restoring & Modifying 1971 OIF TR120

[NM Bonny]

Just power washed this guy after it I picked it up from my late brothers shea couple of years ago It sat there for about 25 years. In my garage waiting for some warmer weather to continue the restoration. Labor of lover for my big brother.

And the saga begins! Wow, a 750...

One thing I'm really jealous of is that you can replace your rear chain ring with any size you wish, to enable highway cruising. I think earlier in this thread Speedrattle mentioned an outfit that will make one to your specs. I think that I've bookmarked the website if you don't find it. Unfortunately, my nifty-looking rear conical hub presents fabrication challenges that make subtracting a tooth or two very difficult. But not yours!

Are you aiming at a box-stock restoration, or some sort of bespoke custom like mine? Well, not like mine, but I mean a one-off vision of your own...?

Either way, I found KMJones to generally be cheaper for the same parts as elsewhere with OIF stuff. You just want to order in batches to keep shipping low, but even then he's frequently less expensive.

Again, unless you're doing a box-stock restoration, the Dunstall replicas I fitted are excellent--and the 'expanding' Acousta Fil' packing from the UK really works. I didn't think there was much improvement over the scanty, flimsy stuff that came in them, but after the first ride of ~15 mile to the gas station, they really mellowed out, as you can hear (kind of) in the video in post # 615. GoPro video from the saddle this weekend...

I'd encourage you--unless money is no object--to check out the YouTube videos of DIY motorcycle tank painting. It's not difficult, and the only money sink is a respirator, primarily for the catalyzed gas-proof clear coat--though advisable for the primer and color coats, too. But you can save a LOT of money doing this yourself, and produce a professional-looking result--and it's straightforward to make a sawhorse jig to paint these tanks, due to the central through-pipe used to affix it to the frame's backbone.

 

[NM Bonny]

Went out to make up a clip to secure the front brake rotor lock under the seat, and realized I can just put some foam on the battery for now, and gently squish it under the seat to keep it from rattling. However, when I get a chance, I'll make up a clip that uses the lock's mechanism to secure it aft in the recess over the fender...

Re-routed the clutch cable, and that indeed lowered the lever effort. Feels good. Now, to polish the OEM lever to match the one on the El Cheapo master--whose general shape is reasonably close.

Re-routed the speedo cable, and do not think I'll be buying a custom one now. These photos show the routing, which both allows a reasonably gentle radius up front and tucks the cable up away from the front fender--which at full suspension travel was evidently rubbing on the cable's casing. Looks good enough for me...

Now that the rest of the bike is copasetic, those unfinished side covers really stand out. I will see if the teensy bit of leftover color is still viable, and if so get these polished and painted up in coming weeks. I've settled on a design--to use the scant amount I've got--that will be two narrow strips above and below a white rectangle, which will receive one of the Bonneville scripts. But the top blue stripe will protrude forward from the white rectangle, while the bottom one will extend aft.

Need to decide whether the block or cursive script is best. I'm leaning toward the block script, as it feels more '70s...

 

[Rudie]

foam on the battery

Foam or rubber sheet over all the electrics under the seat is a good idea, the siting of all those uninsulated electrical terminals so close to a steel seat pan was yet another OIF detail design fail ... Friend of mine has a sheet of rubber ziptied to the frame tubes at one end, when he wants access to the electrics he just rolls the sheet from the other end up to the zipties.

Know the early OIF vibrated their coils enough the bottoms hit the rear fender; original Lucas coils were oil filled for cooling, hole in the casing, no oil; later OIF (73-on?), the mounting held the coils at an angle so the bottoms were further away from the fender.

Re-routed the speedo cable

Standard routing ziptied to the frame tube under the engine and then one of the tubes in front of the engine does not work? If the cable routed that way is too short, possibly because the speedo. was mounted on the right as standard? If yes, possibly no need for a custom cable - T160 cable is longer because its speedo was also mounted on the right but the gearbox is on the left hand side of the rear wheel.

 

[NM Bonny]

Foam or rubber sheet over all the electrics under the seat is a good idea, the siting of all those uninsulated electrical terminals so close to a steel seat pan was yet another OIF detail design fail ... Friend of mine has a sheet of rubber ziptied to the frame tubes at one end, when he wants access to the electrics he just rolls the sheet from the other end up to the zipties.

Know the early OIF vibrated their coils enough the bottoms hit the rear fender; original Lucas coils were oil filled for cooling, hole in the casing, no oil; later OIF (73-on?), the mounting held the coils at an angle so the bottoms were further away from the fender.


Standard routing ziptied to the frame tube under the engine and then one of the tubes in front of the engine does not work? If the cable routed that way is too short, possibly because the speedo. was mounted on the right as standard? If yes, possibly no need for a custom cable - T160 cable is longer because its speedo was also mounted on the right but the gearbox is on the left hand side of the rear wheel.

Thanks for the info on under-seat electronics. I am going to get out the sewing machine and make a tool roll out of leftover cotton duck, so will think about stitching up a little 'cushion' for double duty: to hold down the rotor lock and cover the electronics. (I have a piece of closed cell foam under the Boyer Bransden box.)

Yes, I noticed that the coils were really close to the fender--so I just lifted them up a touch to spare my shiny new paint. I was thinking about adding an extra O-ring to keep them up a skosh, but will consider a later model tray. Thanks!

Right - I switched the speedo routing to accommodate the forward-mounted gauges in the bespoke dash I made up (tach is not an issue). Okay, I may order a T160 cable and see if the additional length is sufficient to put it back under the engine. Thanks, again!

Update: I see from Steadfast's website that the '71 cable is 66" and the T140 and later is 71"... (and it's a lot cheaper?!). Five inches is a considerable difference, so I just ordered one. Good idea!

 

[Lordmac]

Went out to make up a clip to secure the front brake rotor lock under the seat, and realized I can just put some foam on the battery for now, and gently squish it under the seat to keep it from rattling. However, when I get a chance, I'll make up a clip that uses the lock's mechanism to secure it aft in the recess over the fender...

Re-routed the clutch cable, and that indeed lowered the lever effort. Feels good. Now, to polish the OEM lever to match the one on the El Cheapo master--whose general shape is reasonably close.

Re-routed the speedo cable, and do not think I'll be buying a custom one now. These photos show the routing, which both allows a reasonably gentle radius up front and tucks the cable up away from the front fender--which at full suspension travel was evidently rubbing on the cable's casing. Looks good enough for me...

Now that the rest of the bike is copasetic, those unfinished side covers really stand out. I will see if the teensy bit of leftover color is still viable, and if so get these polished and painted up in coming weeks. I've settled on a design--to use the scant amount I've got--that will be two narrow strips above and below a white rectangle, which will receive one of the Bonneville scripts. But the top blue stripe will protrude forward from the white rectangle, while the bottom one will extend aft.

Need to decide whether the block or cursive script is best. I'm leaning toward the block script, as it feels more '70s...

I really like the color you used on the tank and fenders. I agree that the speedometer cable needs to get hid under the engine. If the seventy-one incher is too short, can you swap the gauges positions? All-in-all, I think you have done a splendid job on yer baby.

 

[NM Bonny]

I really like the color you used on the tank and fenders. I agree that the speedometer cable needs to get hid under the engine. If the seventy-one incher is too short, can you swap the gauges positions? All-in-all, I think you have done a splendid job on yer baby.

Thanks very much!

The paint is 'mist blue metallic' from GM's 1966 lineup. So, the Chevelle SS and Pontiac GTO, et al., got this shade. No formula available anymore, so an old friend who runs The Colorworks in nearby Los Lunas custom mixed it for me--very fine metallic and a hint of pearl in there.

I'd always liked the color but never had the right bike for it, until now...

I've got the primer, white, and 2X catalyzed clear coming for the side covers, so assuming the leftover MBM that Chuck gave me is still liquid, I will post again whenever I've completed the paint scheme. If not, he recorded his custom formula just in case, so I could ask him to mix up another pint if necessary...

I suspect the 71" cable will do the trick. If not, yes, I could swap the gauges around but that means R&Ring the dash I made up and recutting the openings for the cable and fittings--which are asymmetrical. Fingers crossed!

 

[NM Bonny]

Tuning: I could not get the timing light to fire (wondering if these teensy motorcycle batteries aren't sufficient to fire the strobe?), so timed the bike by ear. Then adjusted the air mixture and idle speed screws until I got her idling smoothly at 1,000 rpms. Still need to do Speedrattle's thorough-going mixture testing, but the bike really goes.

Fuel economy: I rode into Albuquerque (via 55 mph HWY 313 along the Rio Grande) and tooled around the city before getting back just as it got dark. Put 55 miles on the clock, and it took 1.115 gallons to fill it back up at the station near my place. So, that's 49 mpg for about 60/40 highway/city, with plenty of 'spirited' acceleration runs--but that also includes tuning the carbs and setting the timing. Is ~50 mpg typical for these machines?

Fairing: The fairing works really well. Your hands are in the airstream, and there are no lowers, so the Beemer will still be my winter commuter. But the protection is surprisingly good: the air flow starts just below my chin--same as the R100RT--with a bubble of still air from that point down to right at the knees.

There was a fairly stiff, gusty wind ripping across 313 out of the southeast (down from the mountain), and although my helmet was tossed about a bit--as it would have been on a naked bike--the fairing seemed to enhance the straight-line stability: this very light bike really didn't react too much to the gusts. Regardless, it's definitely more comfortable above 60 mph behind this classic Ducati-styled fairing--and that long, flat seat allows you to shift around. Really comfortable.

The DIY rear-sets work well. My feet are not too high and rearward like a modern 'pocket rocket,' but now are directly below my center of gravity, so ideal for rising from the saddle for washboards and speed bumps without having to pull on the bars. Finally, the extension I welded onto the shifter did the trick: no more looking down to see if my boot is on the peg.

Tomorrow I'm riding into town again for an appointment, so will try to charge up the GoPro and get a clip zipping down the canyon. That Unit 650 exhaust note is sexy!

 

[Lordmac]

that means R&Ring the dash I made up and recutting the openings for the cable and fittings--which are asymmetrical.

That'll teach ya to customize!

Side note: I recently bought (on Ebay) a really nice, practically unused Smiths (SSM 4003-02) speedometer with a mere four hundred and sixty-two miles on it with the rubber housing AND the chrome mounting bracket. EDDIE, ARE YOU KIDDING! Now I have four to choose from . . . I like having lots of extra gauges . . . see gauge below:

 

[Lordmac]

Fuel economy: I rode into Albuquerque (via 55 mph HWY 313 along the Rio Grande) and tooled around the city before getting back just as it got dark. Put 55 miles on the clock, and it took 1.115 gallons to fill it back up at the station near my place. So, that's 49 mpg for about 60/40 highway/city, with plenty of 'spirited' acceleration runs--but that also includes tuning the carbs and setting the timing. Is ~50 mpg typical for these machines?

After I installed the new Amal Premier carbs on my Bonnie, I get right at sixty miles to the gallon hwy at around seventy miles per hour. I use Octane Supreme (Tetra-Ethyl Lead additive) and ninety-five octane, non-alcohol premium fuel to achieve around one hundred octane and she goes reeel strong on that mixture. I ride mostly at four thousand feet altitudes and thus have high altitude jets in them so it runs leaner than normal jetting. It also idles like a champ.

 

[Rudie]

coils
lifted them up a touch
thinking about adding an extra O-ring to keep them up a skosh

... trouble is, also moves the coil terminals even closer to the seat pan ... Friend with the rubber sheet over his 71 electrics also put an extra O ring between each coil and the standard O ring, his rubber sheet has prevented contact between raised coils terminals and the seat pan for many years.

speedo
'71 cable is 66" and the T140 and later is 71"

Five inches is a considerable difference

... as the actress said to the bishop ...

 

[NM Bonny]

That'll teach ya to customize!

Side note: I recently bought (on Ebay) a really nice, practically unused Smiths (SSM 4003-02) speedometer with a mere four hundred and sixty-two miles on it with the rubber housing AND the chrome mounting bracket. EDDIE, ARE YOU KIDDING! Now I have four to choose from . . . I like having lots of extra gauges . . . see gauge below:

Very nice to have an extra! P.S. I have rubber cups I no longer need, so yours for the cost of postage if worth it to you...

 

[NM Bonny]

... trouble is, also moves the coil terminals even closer to the seat pan ... Friend with the rubber sheet over his 71 electrics also put an extra O ring between each coil and the standard O ring, his rubber sheet has prevented contact between raised coils terminals and the seat pan for many years.





... as the actress said to the bishop ...

I need to do the 'silly putty' test to determine remaining clearance. The insulating sheet is a good idea

 

[NM Bonny]

So, I trimmed the rear lower corners off the fairing, as they were pretty pointy per Omega's take on the Ducati '70s fairing. I actually think the radius more closely matches the lines of this OIF bike, so I'm happy with the aesthetics--as well as not having my knee caps immediately behind those pointy ends!

Here is a video (first of two parts--still working on 2nd), so folks who haven't ridden a vintage Meriden bike can see how it feels and sounds to be astride a Unit 650. I will eventually make my way up to HWY 14 behind the Sandias, which is nice and twisty and less well-traveled, for a more extended and more spirited jaunt...

The mic is behind my back, so the mufflers don't bark quite this loud from inside your helmet.

BTW the tach seems fairly accurate, but the speedo needs calibration and is wildly optimistic right now... reading about 18~20 mph high.

1971 Bonneville T120R custom cafe racer POV

1971 Bonneville T120R custom cafe racer POV - Part 2