Yamaha TZ250A 1973

I like a challenge and I'm always on the lookout for a good "project".  I had previously obtained one through a complicated swap for a pair of Honda CB92 race bikes back in Australia, but that one was sold when I moved to the US. I have also built, modified and tuned several Yamaha race bikes for others, so I know what makes them tick.

Before vintage racing took off, I had managed to collect a few TZ parts waiting for the right project to use them on.  One day I was chasing after a motor with some TZ parts on it and when I chatted to the seller, he said he had something I might be interested in.  

It turned out to be an "almost complete" bike that "used to run" and it was almost next door, in Detroit. The bike was in a pile of boxes and most of the big parts appeared to be there. It was missing a few bits - like the front end and the right barrels, but it was a great start.  It even had a set of crankcases with matching numbers. 

It is always interesting to speculate as to what the story might have been.  Did a previous owner take the swingarm off to lend it to a friend, or did he sell it in a time of need?  We will never know. 

The plan, if that's too grandiose a term, was to rebuild it back as a race bike to the same standard as when it came from the factory. I'm no fan of over-restored show bikes.  

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The frame turned out to be in good condition.  TZ frames crack badly at the lower rear mount and a prior owner had added some rather heavy bracing which had to be ground back to a more reasonable size.  It is a genuine TZ frame and in great condition. I cleaned it up, check it over and painted it just the way Yamaha did back in the day. 

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I sourced a Vesco swingarm but wanted this bike to be stock.  When Kris Jepsen's TD3 was in the shop we swapped swingarms. He got the Vesco that he wanted for the TD3 he was racing at the time, and I got a stock Yamaha one that I wanted. A classic win-win. 

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The front wheel came from a well known on-line auction site and wasn't cheap, but it was complete. All the linkages were in good condition and it had the original skinny aluminum rim. it even had an old cracked Dunlop KR76 triangular tire on it. Perfect!

The wheel was stripped, cleaned, inspected polished and reassembled. It now has an AVON race tire in a suitable size for that rim.

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The original rear wheel was in great condition and  came with the correct, original aluminum rim.  The brake operating lever looks to me like a replacement as it is machined differently to all the others I've seen.  It is aluminum and the spline patter is correct and it's the right shape and size, so maybe it's just a later replacement part.

I had an NOS left side rear brake foot lever still in the wrapper, so I decided to build it as an old school European/British lever arrangement.  Fortunately the shift lever can be fitted either side, so it would be easy to change it to left shift/right brake.

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Rick Merhar at Accu-Products, who supplied most of my vintage Yamaha parts, managed to dig out a pair of original forks from his private collection. These forks not only have that unique gull wing style top triple clamp, but they are dual diameter - 35mm at the top and 34mm where the sliders run.  

They were stripped and polished and look rather nice.  Fortunately, I had NOS levers already put aside for this project and new tacho damper rubbers too. I had a pair of genuine TZ clip on bars put away already, so this was starting to come together. 

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The tank had been modified at some point in its life and the sump was way too short. So the bottom of the sump was carefully removed. The tank was cleaned up and replacement sump was fabricated and welded by a great welder who recently passed away. Without Pete's skills my projects would still be piles of bits on the floor. R.I.P. Pete. 

With the new sump in place, the original base was welded back in place and there's no way to tell it was ever done.

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The fairing and seat were cleaned up, repaired and repainted.  The seat cover came from the UK, which now has several good TZ parts suppliers.  By the way, the belly pan is fiberglass painted to look like the aluminum ones fitted in some countries. the fairing is the same shape as those used by Jarno Saarinen, Kenny Roberts and Kel Carruthers at Daytona in '73. In fact I was tempted to make it a tribute to one or other of those riders, but there are so many bumble bee bikes, I decided against it. 

The rear fender is genuine TZ250A but the front fender is not. I have no idea what it was supposed to fit, but it was new, available and almost a perfect fit.

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 The motor came with the wrong barrels, but fortunately, I had a set of NOS barrels that I bought in Australia years ago.  I don't trust old chrome plating, so the plating was stripped and they were plated with a fresh coat of Nickel Silicon Carbide by the good people at Millennium technologies in Wisconsin.  The head was the correct ribbed type A head in great condition, and I had a pair of brass carburetor clamps and phenolic resin carburetor spacers. 

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Crankcases are genuine TZ type, and the numbers match the frame number, as it should.  I have a suspicion that they may be replacements (they are in such good condition), but there's no way to be sure. 

Primary gears are correct 4 peg type and the 6 speed race transmission was in great shape.  All that needed were new shims and circlips. All the seals and gaskets were replaced, and a good crank was slipped into place. 

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When the ignition was run on our test bench it didn't fire up until almost 1,000 RPMs, a sure sign of a damaged slow speed coil. The coil was rebuilt to Yamaha specs, reassembled and now fires on the bench with a flick of the wrist. 

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The exhaust had been modified over the years to silence the noise and it took a lot of time and effort to restore them to stock and to manufacture new parts for the mounts.  Thanks must go to Lynn Garland at Vintage Specialties who sent me pictures and sample pieces and dimensions.

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Now it's finished and gathering dust in the garage, it's time to let it go to a good home.  This is the most desirable and collectable of all the TZ twins and sure is the best looking.  It's a 1973 TZ250A.


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. 


SOLD August 2009