COUNTING CARBS

I was very interested in Rowena's comments in the January subscriber newsletter regarding the performance differential between single and twin carburettor units. I agree. Although perhaps the twin carb unit may have a slight advantage on acceleration initially, the performance difference when underway is so insignificant it would be hard to tell them apart. The TR7RV certainly has a faster top speed. My friend David has a Triumph T140E and I have a repatriated TR7RVwhich I obtained from Nigeria in several tea chests.

This TR7RVwas formally purchased as an order direct from Triumph in 1979 to supplyT140s and TR7s to the army . They were in army colours and fitted with a single seat. I won my bike in an auction; it was then returned to the UK as cargo . Once it was transferred to my home I was quite sure this would be quite a challenge. The machine was completely stripped of all electrical fittings and the wiring loom. The obvious items like mudguards and stays were easy to identify but, having never seen the machine in its complete condition, the whole job was like a big jigsaw puzzle.

I found the clocks and instrument binnacle and all the handlebar components in one tea chest. I was curious about its mileage - but the clock revealed just 1723km recorded. What had happened?

I stripped the engine, primary side first, to find out if the gearbox had caused the engine to stop turning. It was clear from the state of the clutch and primary chain that the TR7 had done a lot more distance than the speedo stated. The rollers on the primary chain had sections with smashed links and the actual clutch basket had chipped teeth. However, the engine sprocket was as new.

Stripping the rest of the engine, the cause of the catastrophic failure became clear; a blocked oilway serving the big end. I opened up the sludge traps and found machine swarf and some debris had blocked the oil supply. The swarf may have been left in at the time of manufacture, which accounts for the very low mileage.

The left - hand cylinder had overheated so one new conrod and a pair of pistons were fitted . The whole engine was carefully rebuilt; the late Les Harris helped a lot with information, guidance and new parts.

Some time later, David with the T140 and I were travelling back from north Cornwall and I was doing around 60mph. David started to overtake and beckoned me on. Not wanting to disappoint , I dropped down to third gear and opened up the TR7.I soon caught him and selected fourth gear as I passed,and continued on in fifth gear to around 110mph. The speedo showed 115mph but satnav indicated 110. When we stopped for coffee, David asked if I'd been at full speed as he couldn't keep up with me. His 750 was flatout but still could not match my speed.

MyTR7RV is also a lot less trouble to keep at optimum tune. It starts and runs sweetly and is completely oil-tight. I am a Triumph man through and through. I also have a T1SOV- but that's another story - and a BMW R1OORSW.hatever frame of mind I'm in, one of these bikes certainly fits my mood . Stuart Adcock, member 5738

Thanks for that first-hand information, Stuart. It certainly confirms my suspicions on this subject. I searched for a photo of a Nigerian army TR7, but failed. So instead here 's a couple of images of the ones used by the Royal Signals Motorcycle display team. Rowena

Rowena asks for a photo of a three -carb Bantam. I can't manage that but, back in the late 1960s in Croydon, I did see a BSA twin with two enormous SUcarbs sticking out from under the tank. When I asked how they helped the performance I was told they were only for show. The original carb was hiding in between them! Peter J Greig, member 9313