Installing Cooling System Components

The cooling system components on Project 41, an '87 VFR700 F2, were completely removed and disassembled for the bike's resurrection. The individual pieces were cleaned, "de-corroded," and polished or repainted as necessary. Fresh seals, a new OEM thermostat and silicone hoses with new clamps from AS3 were sourced and even a new GPI aftermarket radiator. Time to put it all back together. These steps will generally apply to all the V4s.
(click on an image to enlarge)

(Below) I begin in the cylinder valley by assembling the two fittings and their chrome connecting tube. These components were in tough shape and separating the chrome tube was an effort. After a lot of prep, the parts were ready for assembly with their new, lubricated seals. 

(Below) Next I move to the lower chrome pipe and short water pump hose. The pipe looked terrible upon removal but proved to be mostly surface corrosion which cleaned up with 0000 steel wool and chrome polish. After sliding the lower hose and upper o-ring seal onto the pipe, I insert the upper portion and slide the lower hose onto the water pump housing, lining up the support bolt hole. Then I install the support bolt so everything is correctly positioned before tightening the two lower hose clamps. 

(Below) The water pump cover is next. The new o-ring seal won't want to stay in place during installation, so I coat it with a film of grease to hold it. I'll refer to my cheat sheet to match the bolt lengths to their positions — note how to measure bolt thread length. Tighten the bolts in an alternating pattern, and it's good practice to renew the drain bolt's crush washer.

(Below) Turning my attention to the right side of the engine, I'll first bolt the small coolant nipple onto the engine block with its fresh o-ring. Next I assemble the new thermostat and housing, and screw in the temperature sensor with a few turns of pipe tape (I don't think the sealing tape is necessary, but it makes me feel better). Plug in the sensor's wire connector before installing onto the engine — if you forget this connector, just use a long needle nose pliers to reach it once the housing is installed. Next I install the coolant hoses with their clamps loosely in place and this assembly is ready to go onto the engine.

(Below) The rear hose is slipped onto its nipple, but not tightened, and the thermostat housing is then bolted into place — don't forget the o-ring between the housing and the engine block. Note that there's a long and a short bolt; here the longer is being installed. Lastly, the rear hose clamps are tightened.

The next step is to install the radiator, and I'll enjoy easy access with the forks temporarily off the bike. For this project we've chosen a GPI aftermarket radiator (see Shop Blog post from Aug. '24), but the installation is the same for an OEM radiator.

(Below) Before beginning, I'll polish the chrome oil cooler lines while the radiator is out of the way. Some of the Gen-2 bikes are supplied with black lines, but these chrome lines were covered in dirt and surface rust. About ten minutes with chrome polish and crumpled aluminum foil has them looking new. A soft brass brush helps to clean the difficult-to-reach areas. In the final photo, note the pre-installed Hindle exhaust pipe adapters and springs.

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(Below) The radiator is first slipped onto a stud located on the upper right side of the frame (note the fan wires exiting outboard of the rubber grommet), then the special left-side bracket is slipped into place in the rubber radiator grommet and bolted loosely into the frame. Then work the oil cooler hose into the wire bracket.

(Below) The two lower mounts are next. Often, the grommets won't line up with the frame brackets, as is the case here. I simply loosen the brackets' mounting bolts which allows me to align the radiator bolts and brackets. Tighten the three radiator bolts and, lastly, the lower bracket bolts to the frame. 

(Below) The two large radiator hoses are fitted next, and finally the overflow coolant bottle and its two hoses. I cleaned the bottle earlier, off the bike, using water-based degreaser, very hot water and a baby bottle brush. Rinse well and install. The radiator-to-bottle line has been replaced with a silicone hose which will stretch over the GPI radiator's larger radiator nipple. It's secured at four points (red arrows) and forward alongside the carburetors. The drain line is routed downward alongside the fuel tank drain line, exiting near the right footpeg. Don't forget to plug in the fan electrical connector.

All that's left is to fill with antifreeze, confident in your efficient and leak-free cooling system.