Cooling
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I had originally intended to use a car rad and there were a couple of choices. The VW Golf mkIII rad is the same size as the Polo one used by Westfield for their becs (430mm x 322mm) and therefore a good candidate. I spoke to Serck about this rad and found out that there was a version with ports on the nearside, which would permit shorter and neater plumbing runs from the engine. The Serck number for this rad is 2719914. Jeremy Phillips recommended another good candidate in the 86-92 Golf Gti 16V rad, Serck number 2719030. This radiator is a little smaller at 430mm x 305mm but again more than up to the job.
I did some head scratching over exactly how to plumb all this lot together. Neither rad had a pressurised cap on it, so I would need an external expansion tank with one on. More importantly I had four outlets and one inlet from the engine to fit into two ports on the rad. Not impossible to combine these various flows, but I was wondering how you could be sure that the right flows were maintained. This is important because the R1 has a water cooled oil cooler matrix and you really need to be sure that this is working. In the end I decided that it would be easier and probably more reliable to simply use a radiator from an R1 and plumb it up exactly as Yamaha intended.
I ordered a brand new R1 radiator, complete with expansion tank and fan from PDM Racing who I had spoken to previously about engines. By chance they had a brand new bike in that they were stripping that week and the whole lot came a couple of days later for £100. When you work out what it would cost for a car rad, fan and expansion tank this was also a cheaper route and the radiator is all alloy and about 400mm x 300mm, so obviously up to the job.
Obviously the radiator was never intended to fit onto the front of a Striker, so it was necessary to make up some mounts. It would have been quite easy to make up a small frame for the rad to sit in as it has three mounting lugs that are very easy to bolt onto. However I decided that I wanted to kill three birds with one stone here: mounting the rad; blanking off around the rad so that the airflow was directed through it and not around it and also provide mounts for the nosecone. In the end I made up a fairly elaborate panel, with a duct through it that did all three of these out of some 18G ally, which was very light and much stronger and more rigid than other rad mounts I have seen.
The plumbing on the R1 engine is fairly complex with five outlets: two ¾” from head into stat; one 3/8” from oil cooler; one ¼” from stat plus the main 1” outlet and one ¼” from the back inlet plus the one 1” inlet at the back. In order to avoid having a tangled mess of pipes I decided to make aluminium pipes up to reconnect each port to its respective one of the radiator. The first job was to relocate the thermostat as this was literally sticking out of the side of the car in its standard location. I tried various things with this but it seemed impossible to keep it in something like its original position due to the extremely tight fit of my engine to the bonnet. Anyway as I needed to get the main outlet from the stat over to the offside where the main inlet port on the rad is it seemed sensible to use the stat to redirect the flow over to the other side of the car. I made a bracket for the stat that mounted it in front of the engine and turned around 90 degrees so that the outlet was pointing to the right. It was then possible to one the rear existing ¾” steel outlet pipe untouched and cut the front one down to a short straight bit with the original end (with the bead on) welded back on to make it a bit longer, so I could actually get a hose clip on it. I then used three 90 degree elbows and some short bits of ¾” bore aluminium tube to reconnect the stat to the head. All the aluminium pipes were bent to fit in their respective position, with the two pipes that ran from the back of the engine from the main inlet to the nearside of the radiator being the most complex. I used 1” OD pipe for the main runs, ½” OD pipe for the 3/8” bore run from oil cooler to rad and 3/8” OD pipe for the ¼” runs from stat the the inlet round the back of the engine. All pipes were secured to the chassis with rubber lined p-clips and where possible to one-another with a pair of p-clips riveted together, back-to-back.
I used a combination of Samco silicone elbows and 50mm lengths of straight hose to join all the pipework back to the engine or rad. I even replaced the short straight run of original plumbing between pump outlet and water jacket and oil cooler with a Samco straight reducer and short length of 3/8” so there are no weak links in the system.
In the end I was very pleased with the plumbing. It is all very tidy and the runs of pipe are all direct and free flowing with aluminium pipe used everywhere with silicone hose or elbows used only for joining rather than as a length carrying water. Where aluminium pipe was used I did the old trick of putting a short 3mm pop-rivet through each end to provide a small ‘bead’ onto which a hose-clip can grip and prevent the hoses pushing off under pressure. With the smaller bore pipes, 3/8”, ½” the corresponding silicone hose, ¼”, 3/8” was stretched quite a bit and was very tight so I am not too concerned about this coming off under pressure. I used proper Jubilee clips throughout with rolled edges to prevent them cutting into the silicone hose and solid bands (rather than the type where the worm gear runs in slots through the band) as recommended by Samco.
With the radiator mounted as high up as possible on the front of the car it is still about 2-3 inches below the level of the thermostat (the highest point of the plumbing). This means that air in the system will naturally settle in the thermostat housing rather than in the radiator, where they would be expelled into the expansion tank. This could cause problems if there was sufficient air in the system to stop the thermostat getting hot and opening, i.e. if it were sitting in air, not water. But, the ¼” outlet in the stat housing is ideally placed to bleed air out of the system manually. In the end I jacked up the front of the car as high as possible, to get the rad at a similar height to the stat, and filled the system with plain water with 2% Red Line Water Wetter through the radiator cap. This got the system virtually full and the final bit of air was then bled out through the ¼” outlet on the stat by filling the system through the disconnected bit of hose that was on it. I do tend to think that any air in the system will tend to be pushed into the radiator anyway where it will expand out of the system as it would in the bike so I am not too worried about getting an airlock, especially as there seems to be virtually no air in the system anyway.
I did get the original expansion tank, but managed to inadvertantly make a hole in it cutting off one of the mounting lugs. However I soon found a suitable replacement in the form of a Jaz one quart recovery tank which also had convenient mounting point for going near the rad outlet in the nosecone and used ¼" fittings.
I decided to use Red Line Water Wetter because I have heard lots of good things about it and with a water-cooled oil cooler matrix I am probably more reliant upon efficient cooling than most.
With the plumbing finished and the coolant filled it was now time to think about getting the electrics on and starting it!