For Wombat Cota 172

[David Lahey]

Wombat what's that about Kiwi VMX rules and changing eligibility dates?
JC I thought that it was only the 123 that had the small wheels.
I'll post a nice picture of a little Monty from the Hunter Valley

[cappra]

The Cota 172 engine is nothing more than an over bored 123.  The 123 had a
54mm bore, and the 172 was 60.93mm bore size.  Both had 54mm strokes.
Oddly, the 172 was actually a 157cc displacement.  Don't think there is enough
material to be taken out to 64mm.  Another strange thing is that the 123 used
a 25mm carb and the 172 used a 20mm carb.  I remember that Bultaco did something
like that, using a smaller carb on the 325 than the 250, perhaps for lowend response.

[JC]

Yes, but I seem to recall reading that the bike's development started as a full 175 & was downsized from there. Also seem to recall that there's a fair bit of 'meat' in there for boring out, but I could be wrong.

Dave, how good were they in competition? (There's a chap up here w one for sale fairly cheaply, so I'm considering it, sort of)

[David Lahey]

I think how well they go depends on how big you are. Not because of the motor performance, which is quite good, but because they are a bit smaller than other trials bikes in length. The TY175 suffers a bit from this too, but the Cota 172 feels a little bit smaller again.
Have a read of the TY175 vs Cota 172 comparo in T&T magazine. I think it was by Ken McIntyre. I think there might have been a comparo in ADB too but can't remember too much about it.
I'm 5'10" and found my mate's 172 a bit cramped (in 1976) but he was a bit shorter and it suited him fine. The main place I noticed it was in the fore-aft distance between the handgrips and the footpegs.
There was a bloke (Chris Lyons) who rode one in SE Qld trials at quite a high level back then and he didn't seem to have any issues doing well on his.

[cappra]

I agree.  If your over 180 lbs (at the max) you should not be riding a Cota 123 or 172.
They were very light and nimble for a lightweight rider! 

[Wombat]

Wombat what's that about Kiwi VMX rules and changing eligibility dates?

It's just a comment about the Kiwi flexibility with their VMX rules and regulations in general.
And now I'm stuck trying to think of a good example...

You may have noticed many of our threads can go for page after page lamenting the Aussie over-regulation and hair splitting opinions on the eligibility of certain models.
Complaints of MA riding roughshod over the interests of the Members... accusations of a small 'power group' controlling our sport and not always for the best etc, etc.
DJ & Bill often mention the 'turn up and ride' attitude to the Kiwi VMX in general.
Probably how ours was intended before committees got involved.
Nothing dodgy though! I'm sure they have enough rules in place to keep things tidy.

From the outside looking in it appears (to me) to be a bunch of enthusiasts agreeing to ride/ race without getting 'buried in red tape'.
So, when you said "we wanted to allow people to ride..." I saw that as common sense flexibility - for the good of the sport... how it should be.

[David Lahey]

Thanks Wombat
Yes I reckon we fit the NZ model in twinshock here. The only bike I know of that has been stopped at machinery because of it not being within the spirit of the rules was a special that was built in the late 1990s. The frame was a (geometry and appearance) copy of the then current GasGas frame (twin spar perimeter frame). It did have two shockies and drum brakes and an air-cooled (DT250D) motor and was a credit to the bloke who made it, but didn't even resemble anything that had been made in the twinshock era.
Frames (and anything else) here in OZ can be modified in any way the owner fancies and still be eligible. Common changes people make on 1970s bikes are to change the steering geometry on bikes that had slow steering, to lower the footpegs on bikes that had them quite high, and to move shockie mounts to increase rear wheel travel a bit. Bikes from the 1980s are rarely modified as they are pretty good in those areas already. The footpeg mods are mostly driven by the current rules that allow stopping without penalty.