RT3 modified in 1977

[David Lahey]

I found this photo today and thought some Yamaha owners might be interested in it.
The bike is a modified RT3 and the photo was taken in 1977.
The frame had 2" long spacers fitted in the downtubes to lower the engine (US Dirt Bike mod).
The swingarm is homemade using seamless hydraulic pipe and from memory is 3" longer than the Yamaha swingarm.
The top shockie mounts have been relocated.
The tank has been widened by adding the sides from another tank the same shape to both sides (a la T&T mod)
It has a home made chamber with integral muffler which is not visible.
The forks are RM250A.
The RT3 wheels were retained.
The flywheel has added mass (a la US Dirt Bike mod)
It was geared for comfortable road cruising and would do about 90MPH with ease on bitumen on knobbbies.
It was quite nice to ride.

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[mx250]

You seem to know the bike well Feetup, did you do the mods?

[David Lahey]

Yes I helped with lowering the engine but the brains behind the mods and owner of the bike was brother-in-law George McKenzie at age 17. We were both first year apprentice Fitter and Turners and did the frame mods at George's work one weekend where there was a decent lathe to make the spacers. George's Dad did some of the hacksaw work on the swingarm at the home workshop. George did the rest and the welding, as always.
I think the RM250A forks came from George's MX sponsor, John Walmsley. They had been removed from an RM250A when the A was given B model forks.

[vandy010]

nice work for a 17yr old.

my RT1 still runs the stock frame and straight away when i came to my first corner, the bike felt top heavy. would love to drop the motor in the frame to lower it's centre of gravity a little. if anyones building an RT/DT1 for pre 70 i'd recommend looking into the frame mod as it sure would be a help.

[mx250]

Nice work Feetup - 17yo or not.

Does the bike still exist? It would be nice to see bikes like this survive. They deserve to survive. They represent a period when bikes weren't just brought from the dealer, fueled and raced. Bikes like this show the heart and sole, ingenuity and passion of their owner builder.   

[David Lahey]

Yes the bike does exist but was recently pulled apart to lend the frame to someone for VMX racing - not sure if in pre70 or pre75 - maybe some Brisbane VMX people can help me out here.
For a while the bike had a huge red plastic tank which changed the look a bit but was great for long trail rides. The steel fuel tank is still finished in grey undercoat as in the old photo.
I may have some more old photos of it. Not sure. I'll have to have a look. I'll also take some current photos when I'm down in Brisbane next.