Yamaha TD3 1972

Many years ago in a galaxy far, far away, I had the bright idea that it might be fun to get either an old TD3 or a TZ to play with.  At the time there was no class for the bikes to race in, so I figured this could be a fun cheap way to get a trick street bike. 


I tripped over this thing in AMCN and it was described as a TZ with RD400 motor and wheels.  Of course the forks and swingarm were also RD, the pipes were an abomination and the fairing had a huge hole for the headlight, but we all have to start somewhere. Right? 


So I was thinking RD400 with TZ chassis might be a really sweet street bike but it needed work, so I bought a complete but dusty old RD for parts.  Does this sound familiar to anyone? 


That RD looked much better after a wash and was way too complete to strip for parts, so it was restored, run for a couple of years and then sold.  Then I found a later E model  which was also almost complete and ended up as a project with flush mount filler cap, Swarbrick pipes and RZ500 footpeg hangers. Then the F that joined it was soon back on the road as a custom hot rod.


In the meantime, I was taking all the RD bits off this bike to use on that succession of RD's.  Somehow this was going in the wrong direction.   


Some years later I was scouring the classifieds again and Post Classic racer David Casey, a local Post Classic racer of some note, was selling off some DS7/TD3 Yamaha stuff and I managed to bring home a set of nicely modified forks and a pile of other parts.


And that started the long journey for TD3 parts to turn this into a real TD3. 


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The frame turned out to be in pretty good condition.  TZ frames crack badly at the lower rear mount and this one was no different, so it was dispatched to Bob Martin Engineering for repair and reinforcement.  The radiator mounts were removed at the same time - the same way as almost every other "TD3" racing in Australia. 

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Somewhere along the way, I was paid in kind by a customer who had more parts than cash to spare.  He "gave" me an NOS swingarm which had evidently been lying around at a distributor's warehouse in Malaysia for years.  It was in great shape and in went a new set of needle rollers and we were set.

I managed to talk Rick Merhar of Accu-Products out of the pair of Koni  Dial-A-Ride  shocks with adjustable damping and that pretty much took care of the rear suspension. 

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The front wheel came from a DS7 project I collected along the way.  It's an RD or XS650 hub fitted with a nice flangeless alloy rim and reground RD350 disk, the same as most other TD3s competing in Post Classic racing today.  

On went a fully overhauled RD caliper and new master cylinder and braided stainless steel brake line for Mike's XS in the US and I also bought a couple of different sized new master cylinders to dial in the right balance between power and feel.

It may not be state of the art radial pump or carbon-carbon, but Kris Jepsen won at least one AHRMA F250 championship with this set up, so it can't be that bad.


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At the rear end, I could not locate a big drum TZ/TD wheel, so I took an RD/XS rear drum and lightened it considerably. It was also modified from rod actuation to cable and ventilated in the style of the works Yamaha racers of the time. It's not a genuine TD3, but it looks pretty good.

That was laced into a good XS650 or TX750 WM3 (2.15") alloy rim with a new set of spokes and that took care of the rear wheel.

I bought a bent TZ rear brake lever from Frank Camilleri and repaired it to work with a GT750 Suzuki rear brake cable. A new return spring was sourced from Mead Speed to complete the rear brake set up.

We spooned a set of very low mileage Dunlop TT900 tyres on to save the rims.

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The ex David Casey fork legs turned out to be nicely modified internally, so the sliders were polished and rebuilt with Motul oil and new seals.  I had the top triple clamp ground down and welded to look slightly more like a TZ style triple clamp and slipped on a pair of GBM clip-ons I had kept in storage for a couple of decades - for just such an occasion.


Mike's XS in the US supplied a new Steering damper like those fitted to the early "widowmaker" Kawasaki triples. They are cheaper than fancy alloy bodied dampers and work fine on these light bikes, and look period.  Period!

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The tank was  bit of a mess and took many weeks of cleaning off old paint and Bondo, followed by weeks of panel beating to get it back into shape without any filler.  I'm not sure I'd want to do that again.

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The original fairing with the headlight hole had been repaired and fitted to a TZ250B I sold a few years ago.  It was  replaced it with a neat replica that I had stored away especially for this project.  Little did I realize how long it would take to mate the two. 

The screen was supplied by Racers Edge in Victoria and has also been in storage for a couple of years, waiting patiently to see the light of day.

The fairing mounts were pretty beaten up.  Fortunately they are easy to repair, so that's what I did.

I grabbed a spare front fairing mount and TZ/TD tacho off another project, along with genuine clutch lever and throttle assembly which were lying around the shop waiting to be noticed.


The seat that came with the bike was a pretty average aftermarket version of a TZ750 ducktail style which was too heavy and didn't look right.  It was replaced it with a new upholstered replica from a local racer in the Midwest who had just bought it from Mead Speed in the UK for one of his projects and then had a change of design idea and no longer had a use for it.  His loss, our gain.




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The RD motor that was fitted when it arrived, was sold off with a pile of other RD parts after I moved to the US. That started a hunt for the right parts to build a TD3. I realized I would probably never find a transmission and dry clutch at a reasonable price so planned to use an RD400 transmission with RD crank and modified DS7 barrels.

Then I located a pair of barrels and heads at the right price and salted them away for the day when it would all come gloriously together and rise like a phoenix from the ashes  - right!

Carburetors came from an AMCN classified ad, and were cleaned and re-jetted back to stock TD3 specifications.  I already had spare pistons, gaskets and seals from building race winning motors for Chip Larkby and Kris Jepsen in the US, so this was starting to look feasible.


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Crankcases were the next hurdle. I managed to get a TZ motor out of a kart in Canada which was  great excuse to drive up to see the Niagara falls and pick up a motor. 

I then grabbed a couple of mix and match TZ and RD motors and parts from a guy in Detroit and one of them had also been in a a kart.  It had a set of  cases with grooves for the mains and rubber mounts and was stamped with a TD3 number and overstamped with what looks like a California Kart shop stamp.  

The next hurdle was overcome at the Mid Ohio swap meet a few years ago where I found a complete transmission, clutch and set of primary gears at the right price. Even more amazing were the unobtainable dry clutch covers which he also sold me.  They are so good that they look as if they were never fitted on a bike.  No scratches, no wear marks. Nothing.  They were perfect.

If I were to race this bike, I'd put the outer cover away on the shelf and race with a resin replica from Mead Speed, but that's just me. That new set of covers is too nice to get road rashed.

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I already had a FEMSA ignition which bought  years ago from the UK for this project, so I'll have to test that before this project rolls out the door. 

I had a set of early TZ250 (C model I think) exhausts with integral mufflers that should match the porting very nicely. All they need is a coat of fresh BBQ high temp paint.

The pictures below are two TD3s belonging to American racer Kris Jepsen, multi-time AHRMA champion and prolific race winner. Both bikes were rebuilt in our shop near Chicago. The first (backup bike) is more RD than TD, but does have an alloy tank, TD3 top end and crank and RD400 transmission.  The other is TZ350 based and has a replica fiberglass tank. It has an air cooled TD3 top end and the bottom end and chassis are the same as a TD3.

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As soon as  it's finished I'll be offering it for sale in Australia. It's time to let it go to a good home.  


It has been built as it was designed - as a racer. This is not a super shiny expensive paint job with a motor full of worn out junk. The motor has not been run since it was completed, but it should be possible to mix a fresh batch of race gas, pour it in and fire it up - but don't forget hearing protection. 


For more details email:    teazer "at" pinkpossum 'dot' com