Radiator and Oil Cooler cowling

I hadn't got around to fitting the final part of my fairing. It is a plastic cowling or duct that fits between the radiator and oil cooler, behind the front mudguard. The air is getting cooler now we are firmly into the autumn months. I thought it would be good to try it when the heat is easiest for the cooling system to deal with.

The cowling itself is made from a different type of plastic compared to the fairing itself. It is more rigid and, I hope, heat resistant. It has an aluminium heat shield patch on the rear, corresponding to a fitted position just in front of the exhausts.

It is retained by eight screws that wind into spring clips and two M6 bolts that also secure the top of the oil cooler.

I'd bought some replacement clips from Lings as part of a larger order. I decided to use stainless self-tapping replacements for the original black screws and dabbed Waxoyl on the clips to keep corrosion at bay. The M6 bolts were also replace with stainless alternatives: in this case, button-head screws with stainless penny washers.

One thought I had was that the cowling could improve cooling by forming a dam of cool air when the bike is in motion, rather than the cool air 'escaping' through the gap between the radiator and the cooler. In slow traffic, it would be of limited value or worse, with the exhaust being unable to radiator or convect heat back out to the front of the machine. Then again, when the fan engages, it could benefit from the fact that only cool air could be drawn through the radiator rather than hot air spilling back out from the exhausts.

A short ride tonight didn't really prove anything other than that the cooling system is behaving predictably and the fan came on after idling stationary for a while. Fair enough.

Radiation

I had decided to fit a radiator from a later model Trophy 1200 because they are quite a bit wider and my bike had been running very hot before I took it apart. The 1991 models were all fitted with identical radiators, from the 750 Tridents through the 1200 Trophy. I'm guessing that hot running had been an issue with the early bikes because from some time in 1992, as far as I can tell, the 1200s were fitted with a version that is about 5cm/2" wider.

I got a second hand radiator from a 1999 model. It came complete with fan and stone guard, both formed in plastic rather than steel as in the 1991 versions. My original radiator guard and fan housing were pretty rusty but I have more confidence in the finer mesh of the original guard than the plastic version.

So I bought some gold anodized aluminium mesh from Homebase and cut it to size so that the plastic guard would hold it in place.

I decided to fit braided sleeving to all the hoses. I could pretend there's a functional reason for doing this but it's basically a cosmetic decision. The hoses on these engines are not pretty. I've either achieved a better blend to the look of it with the braiding or just drawn attention to it. You decide. I like it anyway.

I'd checked that the thermostat was working properly before installing the top hose. I bought a jam thermometer to do this, heating a pan of water up with the thermostat immersed. The thermostat is marked '83' and it opened at about that temperature, according to the thermometer. So all's good there.

The radiator is retained by two M8 bolts at the top, which also double up as mountings for the fairing subframe, and four M6 bolts at the bottom (two each for brackets on the lower corners).

I filled the radiator with a 50:50 mix of Bluecol and de-ionised water. That's a stronger mix than is needed in rainy England but the coolant also contains corrosion inhibitors so it seemed like it would offer more protection than a lower ratio might.

I had fitted stainless collars around the ends of the hoses, under jubilee clips. With the system filled I noticed a slight leak from the hose which connects the rear of the cylinder block to the water pump. I removed the collar and then tightened down the clip more than I would normally do. The result was no more leak. I'll have to check all the joints come start-up, along with the oil plumbing I added for the oil temperature and pressure sensors.