Cota 172 Restoration

Need help finding information or parts for that old machine in your shed? Someone in here will know!

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Phil 850
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Re: Cota 172 Restoration

Postby Phil 850 » Sun Mar 19, 2017 9:26 am

Installed my headset yesterday.
Image
I lost some of the original bearing balls so had to buy more. The originals were 4.8mm (3/16") which I thought was odd for a European bike. The balls didn't fit the race very well so I bought new 5mm ones and they fitted the race perfectly so that's what I have used.
It all seemed to have fitted OK. :D



Rod
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Re: Cota 172 Restoration

Postby Rod » Sun Mar 19, 2017 8:15 pm

Phil, your resto is looking very nice, but seriously why are you wasting time sourcing ball bearings when you could upgrade to new tapered bearings and races. In Motion have them and I'm sure available elsewhere.

https://www.inmotiontrials.com/product/ ... ings-pair/



Phil 850
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Re: Cota 172 Restoration

Postby Phil 850 » Mon Mar 20, 2017 8:32 pm

Rod, didn't know they were available.
It was an easy enough job fitting the original style.

The next problem I have is that I have discovered thar both fork legs are bent back slightly.
I was thinking of putting them in my pipe bender with reinforcing where the dollies are to spread the load and tweak them back to straight.
Anyone have any better methods ?



David Lahey
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Re: Cota 172 Restoration

Postby David Lahey » Mon Mar 20, 2017 9:10 pm

make three half-circle pushing tools about 30mm long from solid metal that match the OD of the tube and push out the bends with a hydraulic press
If you try and do it with flat pushing tools you will make the tubing go out-of-round


relax, nothing is under control

tat ty
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Re: Cota 172 Restoration

Postby tat ty » Tue Mar 21, 2017 5:38 am

Phil.

I recently had the frame, forks and triple clamp on my adventure bike straightened by Laurie Alderton (Alderton Motorcycle Repairs) at Smithfield in Sydney. Amazingly inexpensive especially considering how bent everything was.

Alastair



Phil 850
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Re: Cota 172 Restoration

Postby Phil 850 » Fri Jun 23, 2017 7:38 pm

Does anyone know what colour Montesa red is.
If I can just buy a few spray cans for the tank would make life easy.



tat ty
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Re: Cota 172 Restoration

Postby tat ty » Fri Jun 23, 2017 10:20 pm

Phil.

Perhaps try VW Mars Red in a spray can from BCS paints in Revesby. Inexpensive punt.

Alastair



Phil 850
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Re: Cota 172 Restoration

Postby Phil 850 » Sat Jun 24, 2017 8:29 pm

Thanks Alastair

I also have a problem with the fuel tank itself.
When I sanded it down for painting, in an area on the side of the tank it looks like something leaches out of the surface of the tank. It's like it is a little bit porous.
If I wipe it over with acetone it disappears but slowly comes back.
The tank is empty and has had the filler cap off it for many months so I would have expected any residual fuel would have evaporated by now.

Any ideas what to do before I paint it as I'm sure it will prevent the paint from adhering/curing properly.



David Lahey
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Re: Cota 172 Restoration

Postby David Lahey » Sun Jun 25, 2017 4:40 pm

That is probably oil from premix trapped in a tiny crack or hole in the fibreglass. Oil is very slow to evaporate. You need to fully degrease the tank, making sure the solvent you use is safe with fibreglass and can clean the oil out of the crack/hole.
Acetone can damage the resin in fibreglass quite quickly so for your predicament, something like turps would be a safer bet for degreasing (the turps goes inside the tank). After degreasing with turps you will need to remove the turps residue. Warm clean dishwashing liquid/water does a good job with this. Then the dishwashing liquid residue will need to be removed from the crack with clean water.
After being fully degreased, the crack will need to be sealed off from the inside of the tank. This can be done with polyester or epoxy resin. Epoxy resin is more resistant to the ingredients in modern petrol. There are also propriety tank sealers. Be careful what you use. Some are a type of rubber which in time will fail and cause the owner major dramas.
After the sealing is cured you can paint the tank, confident that petrol won't leak out the crack and wreck your new paint job, at least until you put a new crack in the tank.


relax, nothing is under control

Phil 850
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Re: Cota 172 Restoration

Postby Phil 850 » Wed Aug 09, 2017 8:17 pm

After a better look, I discovered that the porosity is sealing out on the section behind the tank and beside where the exhaust is. I think by the look of the fibreglass is has been charred and painted over.
I ground it back almost through to the other side and reglassed it and sanded back.
Looks to have come up OK and there's no more seepage coming through :D




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