Exactweld TZ250

[cheb]

Something I'd not heard of before:





https://riders.drivemag.com/features/ex ... -all-odds/

[Nobby]

My BiL rides their Bike in the European classic open class. It is a thing of engineering beauty. Ill hunt out some photos.

[Nobby]

7A0C6AF4-ECA2-44CA-B85E-7982D3367AB4.jpeg (73.07 KiB) Viewed 1443 times

Look at it carefully , the more you look the more you’ll find.
This was the Bike a few years back. It has a new front end now.

[Nobby]

F0AEA68A-C98C-42EA-9230-3EF938BCC60E.jpeg (339.66 KiB) Viewed 1438 times

[Whysub]

I remember one being raced in various 250cc club championships in 1994/1995. It was a scruffy, run of the mill looking bike, but it transformed into something really interesting once the bodywork was off.

[cheb]

7A0C6AF4-ECA2-44CA-B85E-7982D3367AB4.jpeg

Look at it carefully , the more you look the more you’ll find.
This was the Bike a few years back. It has a new front end now.

That is very pretty.

[Nobby]

7A0C6AF4-ECA2-44CA-B85E-7982D3367AB4.jpeg

Look at it carefully , the more you look the more you’ll find.
This was the Bike a few years back. It has a new front end now.

That is very pretty.

It's their own engine. A twin tandem disc with 4 carbs. Rear end bolts to the crankcase and front on the cylinder head.

Have you spotted the rear brake system ?

[cheb]

Using a pipe as the stay rod to save weight?

[Nobby]

Using a pipe as the stay rod to save weight?

yes , and the master cylinder as the lever as well.

[cheb]

Yes, now I squint at it a bit harder.

[demographic]

Cathcart always did write the best stuff for PB years ago and that article being one of his just confirms it.

[The Spin Doctor]

I remember seeing that out on the circuits...

[Nobby]

24741A51-2E68-4BE3-B3B2-CE2C9306CC93.jpeg (20.39 KiB) Viewed 1327 times

I had always thought it was a rotax engine, I didn't realize it was their own engine too

Another dodgy photo taken from the Internet

[Nobby]

Can someone tell me the advantages of a tandem twin over a more conventional parallel twin?
You can use disc valves on a parallel twin and surely there must be losses gearing the 2 cranks together.
They seemed popular for a while in the 80s but ultimately V-Twins seemed to work better

Me, thinking on the top of my head and don't know shite.....would assume that a single/ parallel transfers are not restricted by the confines of having to squeeze cylinders together. Is a guess. I shall get that question off to the Boys that designed it.

[porter_jamie]

Package, and you can have a disk valve on both sides

[cheb]

It'd be narrower, and with with small capacity water cooled cylinders there'd be no extra cooling problem nor would the motor be too long.

The crankshafts would turn in opposite directions too, that might be an advantage.

That's my guesses anyway.