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You may say not another article on a water cooled well, yes it is and probably the only LC Lambretta you've seen on a run. Here's how I've done it!
It all started back in 1982 when a local old boy, helped by Mel Brown (whose article was in Jet Set last year) built a 225cc cutdown, a quick botch job was made and he attempted the Easter run to Scarborough, after a seizure (hardly run in) and umpteen stops and fill-ups it just made the 160 mile trip. That was the last I saw of it before it was sold, but hopefully you'll see it later this year.
After that I saw Mel Brown's cutdown at the Doncaster Hunters Sooter Club. Mel seemed reluctant to speak of his ideas but after some lengthy conversation he spoke quite freely. So after seeing briefly two cutdowns, I began to form my own ideas for a complete scoot. In the spring of 1983 I converted my fully-built 1970 Grand Prix 200 to the Liquid cooled LC1 225.
Like all my predecessors I first started with the barrel - a basic Italian cast iron barrel, tuned before hand and then set about with a hammer, leaving only the top and bottom fin and the one above the inlet. The 16-gauge jacket was molded around and after two weeks in the welding shop at work, with careful preheating, brazing and silver soldering, plenty of luck and time, the barrel took shape after the 4 sleeves were placed in position and soldered - one inlet and one outlet pipe (both being 1/2" diameter). A nut was brazed on the barrel to take the temperature gauge sender. It was then pressurised to 50 psi in a bucket of water and no leaks appeared, so it was all bead blasted, sprayed matt black, then rebored to 70mm.
Next came the radiator- I chose a bus heater radiator as it was easily available. The inlet and outlet pipes changed direction and a pressure cap was fitted. An ugly cowling was made around it to stop silly boys prodding and piercing the fragile element. I agree it was unsightly, but as it was an experiment it could be easily changed.
I chose to use a capilliary type temperature gauge and a manual on/off switch. These were both mounted on a neat bracket behind the leggys and in front of the spare wheel.
The water pump I used was a British Leyland Mini's electric fuel pump and this was mounted under the leg shields and piped into the cool side. I found all these goodies by searching the local discount motor shops and there seems to be a wide variety, so it's up
to you. (I didn't find many people interested here and they seemed reluctant to sell anything, so unless an interested chap served me, I kept quiet).
Thinking the fluid in the barrel, pipes and rad weld be sufficient, I set off experimenting. I chose to use 26 volt batteries, wired to 12 volt, to get the pump working. This failed straightaway as my system wouldn't charge them. But when charged the pump worked until it built up pressure in the system and then cut out, as electric fuel pumps do this so as not to flood the vehicle's carburettor. So, without having a change of pump, I made an air bleed in the pressure clip.
At this point I decided to buy a 12 volt Motoplat, ideal for an LC. After a phone call to Dave Webster, who was very helpful and suggested a visit to his shop to speak to Norrie Kerr, and a visit to Ray Kemp (because of a bad rumour that he had built one for future production), I was off again and for 2 weeks running to work and back, the system worked well.
Hardly run in, I set off to Weston-super-Mare in July to prove it ...Ha! After only a few miles at high speed I seized - nothing to do with the water cooled - but the blanking plug in the two holed head fell apart. A quick strip and rebuild and off again. The sun came out and the temperature rose - I worried with a temperature of 95 deg.C. that something drastic might happen, so I went all the way at 50mph.
On the 250 mile trip you have plenty to think about - when I got covered in green slimy anti-freeze, I had plans for an overflow bottle, which up to now hadn't been needed. After a few top ups, and a temperature gauge packing in, I managed the trip, but not to return as the Motoplat coil packed in.
Once home, a new coil from Webbo's, an overflow bottle and a tank under the leg shields to hold more water (aid cooling) and I was off again - a trip to Cadwell race meeting and the Scarborough run, without any trouble.
At this point a new LC2 came about - a newly tuned barrel with slight mods to the inlet pipes, this time having two inlets of 5/16" diameter and one 1/2" outlet. Off again on another run to the Isle of Wight, this time I had boiling problems going, but after readjustments there, I set back with the whole system working correctly at speeds well over 70mph, only to have a leak appear when the U-bend came loose. After some help from Newcastle Setting Sons SC and an old bloke who gave me some water, I made it home.
After attempting to reseal the hole, the barrel cracked, so that was scrapped and I was back to the LC 1 . The big end disintegrated half way to Southport but the cooling still worked and kept it up for the Skegness and Rhyl runs, not even needing a top-up during this time.
By this time I found the cooling worked great when the weather was cool, but when hot, the temperature in the barrel got close to boiling, so further trials were needed. I ran the bike 20 miles a day to and from work over the winter and after 2 more gauges had broken and 3 pumps had failed due to the weather, I decided to scrap these ideas and hunted for different, more reliable types. I even ran it for 2 months in the bad cold (with anti-freeze) without the gauge and pump working without a seize or any mechanical problems.
After around 4,000 miles from the start of the system, I stripped the engine, only to find the piston to be cracked, so a better quality piston was needed.
The start of more ideas followed. A new LC3 230 barrel appeared, chromed on the outside and tuned to pull a high ratio box for motorway driving. An electric temperature gauge was used and a nut was brazed to the barrel to take the sender unit. I chose to incorporate a thermostat, choosing one from a car's electric fan - these are readily available in motor shops and have different temperature ranges. The one I started with cut in at 92 deg.C and off at 80 deg.C. I tried one that cut in at a lower temperature but found the first one best. A fully waterproof water pump was used from a caravan. This pump, 12 volt, pumps a gallon a minute and was fitted in the Vespa toolbox.
With this switch fitted it meant that the pump was automatic and all I had to do was check the pump worked. To do this I fitted a ligh which came on when the pump switched on. This light was fixed next to the temperature gauge which was embedded into a modified Vespa toolbox. I also used a voltmeter as a safety check to know when the ignition was on.
I decided again to stick to a standard finned cylinder head sprayed matt black with heat dispersant paint. From my experience up to now I don't think liquid cooling a head would be worth it as I've had no problems of pinking, overheating or holed pistons and very little carbon build up was noted on head changes.
Anyway, this modification would only mean more problems.
I ran the coolant through the frame, having a 1/2" inlet pipe brazed to the top of the front of the frame. At the rear, the large hole at the top was blanked off and a 1/2" outlet pipe was brazed near it. The two drain holes in the tube were brazed up.
The flow of liquid from the barrel came out of one 1/2" outlet through a rubber pipe to a copper pipe which took the hot liquid up to the radiator (this year a small oil cooled radiator). A rubber pipe was joined to the copper pipe and went through the leg shields into the Vespa box and came out on the offside of the leg shields, into the top inlet of the radiator, the cooler liquid came out of the bottom and through the leg shields into the Vespa box where the pump was fitted into the system. From the outlet of the pump a rubber pipe joined the inlet of the frame, through the frame to the back and out of the outlet to the barrel through a Y piece which went to the 2 5/16" inlets to the barrel. I fitted a drain plug to the lowest part of the frame and an air bleed to the back above the outlet of the frame, and an overflow bottle was hidden in the Vespa box. Just looking at the bike the pipework seems simple, but in the Vespa box it's a bit more complicated and there's not much room for tools.
Finally, a modified flywheel cowling was made and on the scooter runs I found no problem with this system. It's first run was Yarmouth and it made it no problem. It was entered in the custom show and it was here that a lot of interest was shown, so with prompting this article was written. Coming home it was thrashed, only to get a split water hose. Forgetting my spare bits, I had to botch it and thanks to Steve Wilsden for running me around -finding spares for a liquid cooled on a Bank Holiday is terrible - so don't be afraid to knock on people's doors!
Once home a change of pump was needed as the pumping element seized. Next came Newark and it made it there and back, no problem. Problems came along on a trip to Rayspeed when the pump burnt out and caused all sorts of problems.
So, I left it and picked it up coming home. Having disconnected the pump to stop blowing fuses, I thrashed it home, beating a Honda 250 Super Dream 20 miles to home. With no pump the temperature stayed at 100 deg.C., proving that in the event of a failed pump you can still get home.
A new pump was made out of the two knacked ones, not finding a perfect pump yet, could one be used from the well known and proved Jap bikes? Maybe, but I haven't the time or money, so I'll still toy about with electric ones.
Here I'll leave it with more ideas in the pipeline. Thanks to everyone invlolved over the last 18 months and I hope to see you on the runs. Any information and criticisms are welcome.
Mark Broadhurst