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Thermostat repair

Posted: Tue Mar 06, 2018 5:01 pm
by paso750
Nigel H. posted the following on FB and gave the permission to copy it in the forum.
Cooling issue update...turns out a broken thermostat, where the pin is held by a plastic bridge was broken. Thermostat sticking, opens a bit . But not a lot, so bike temp at 100c.
Purchased a second hand Aprilia thermostat after reading post from paso site. I looked at how to sort out hose size difference and angle, Aprilia in take is straight, where 907 is a right angle. So decide to take apart collar around thermostat and swap over the right angle piece from 907 thermostat to Aprilia thermostat. Slow process to bend up collar, 907 thermostat pops out and not found for days!!! No matter as I silicone and re attach collar. No leaks after 300km, temp at 85 while riding at 100kmh in 35c heat. I fitted a new Spal 5" fan as well. Temp gets no higher than 95c in traffic on 35c day. I think it a success. Best part is I still use Samco silicone hoses, looks original and no need for reducer hoses etc. I will still carry a spare on up coming 3000km Tasmania trip and hoses etc just in case my fix fails. I buy last and only Aprilia thermostat left in Australia ( yes seriously) and order another so I can make another spare.

Working perfectly I think, though one day in cold rain temp dropped to 60c. I felt thermostat should've kept it at 75c.

Re: Thermostat repair

Posted: Tue Mar 06, 2018 10:38 pm
by Tamburinifan
Thx f sharing, FAQ material.

Re: Thermostat repair

Posted: Wed Mar 07, 2018 10:45 am
by paso750
It is in the FAQs now. I posted here because many wouldn't have seen it.

Re: Thermostat repair

Posted: Thu Mar 08, 2018 1:59 pm
by Finnpaso
VERY GOOD job, Gerhard :thumbup: :thumbup: :thumbup:

Ps. I still WONDER, that You have sooooo.... much time to be in internet with thesekind of things? :mrgreen:

Re: Thermostat repair

Posted: Tue Dec 01, 2020 3:17 am
by icekube1
Just chiming in to say that I replaced my failed thermostat over a year and 3k+ km ago using the method described in the OP. A new ST2 t'stat was the donor.
No silcone used on reassembly, the new O-ring from the donor and some care peening down the clamping ring was all that was necessary. Works a treat and no bodges required.

Re: Thermostat repair

Posted: Fri Dec 04, 2020 10:45 am
by blazing928
Glad my idea is still working...always a risk!
Cheers nigel