Chris Bradley builds a T500 racer - Chapter 5

On my next visit to Crooks Suzuki in Barrow another problem became apparent. As I chose to use 18" wheel rims the Allspeed expansion pipes would probably ground out. This had me really worried, I felt like every move I made had some kind of adverse action. Being a novice I was learning by my mistakes.

Crooks to the rescue. Les Trotter who was made famous last year when he entered aT500 in the Manx Classic held on the Isle of Man. Famous because the race which is for machines dated up to 1968 and is dominated by Manx Nortons and B.S.A's etc. and is not for the likes of a Japanese oil burner such as Les Trotters. However, Les, in association with Crooks Suzuki had proof that T500's were racing in 1967 and placed an entry for the race. It shook the Classic racing scene and created an uproar of protests from people involved in the Manx Norton industry. You see the T500 is just too bloody fast for a Manx Norton, (in the right hands) and there would have been a flood of T500's being built and entered for the race. So they banned it, but nice try anyway Les.

Where was I ? Oh yes. Les had decided to try a shorter swinging arm on his machine to improve handling. This would mean using different pipes to accommodate the back wheel. So I bought Les's old pipes and he got some new ones.

Alex Clapson took my - his-? Allspeeds back and every one was happy.

It was about this time I started thinking about a fuel and oil tank. Crooks were also putting something together by way of a Café Racer seat unit. Something that would fit onto a standard frame without modification for those not wishing to take out the hacksaw. I t was a consideration at the time until I spoke to Peter Keyte.

The T500 motor can be run on pre - mix only, by making some modifications to the crankcases. Allowing fuel mix to access the outer main bearings. Because the lubrication system on the T500 is so good already, I decided to keep the oil pump and have a supply tank in the seat.

The oil system pumps oil to the barrels and outer main bearings. Oil from the bearings is then forced by a centrifugal thrower along a hole in the crank pins to feed the big ends. What could be better than that. Yes I decided to keep the oil pump and then I could also use the T500 standard oil tank filler cap too. (sad isn't it ).

I rang Peter Keyte and discussed with him my requirements, I also sent along some photo's of TR.500's I had down loaded off the internet. Courtesy of Murray Barnard.

Pete was well aware of what I needed, and able to offer me some good advice. In addition he had a frame for a T500, left him by Don Leeson, who was also building a T500 racer.... That's bloody handy I thought. Another Coincidence ? Pete also showed me a photo of a genuine TR500 that he had done some work on owned by a chap called Dave Evans which looked great. Pete could build me a seat and also include an oil tank, inside but separate. I got Roger to make me a threaded neck for the oil filler cap and that was that. I waited a couple of months for the bits from Peter and when they arrived. Well I was delighted.

Although the genuine TR500 racers had a huge screw on type filler cap I felt that a standard Monza cap would be more practical and safer. Peter agreed and I think it looks OK.

Once I had some body work the thing started to look like a motorbike.

I set to work on some sheet aluminium and crafted myself a rear mudguard. Because the T500 frame is made from fairly thick pipe I was able to attach the mudguard with M5 round head socket screws, by drilling and tapping the frame.

I also managed to save some more weight off the top frame tubing when I was able to see where the seat would go. It really is a heavy lump, and needs to be trimmed wherever possible. More and more I could see a racing bike in the making.

The real tuning part of building a two stroke racer is what you do to the barrels, and the exhausts. Good advice would be to make changes to port timing in stages until you arrive at something you can manage.

As Murray Barnard had already done a hell of a lot of work studying this subject and has made the information available for us free, I decided to base my motor on something he had tried and tested, plus a little bit. I only hope I can ride the thing.

Spares for T500's are still relatively cheap so it doesn't do any harm to have a few pairs of barrels and experiment a bit with different dimensions.

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