Tuesday, January 17, 2006
Many cylinders, 2 strokes, One large bang and a bad smell!
Dave ("the back") and I were busy on Saturday - I hope you enjoy the tale!
The plan was to swap the RG500 and the engineless special with the two kettles in my garage. This was being done to allow Dave to service the kettles and get them MOTed so that they can be converted to cash. Seemed like an admirable objective, so I was happy to help. I turned up at Dave's place at about 11:00 to find that Dave was still getting the bikes (RG500 and special) ready to move. The problem was fitting the exhausts to the RG. The thing is a nightmare of ducting. The rear pipes weave their way through the frame and the attachments for the front ones are jammed right behind the radiator. Anyway, in due course the bikes were assembled and put in the back of Dave's van. The high point (as far as I was concerned) was seeing the speedo on the special indicate 30-40 mph as I was pushing it along Dave's gravel alley. Hmm, I wonder if that is accurate?
A little later we arrived at the back of my place. In order to simplify the "Fox, Rabbit, Cabbage" problem which was in danger of developing we emptied my garage of bikes before we unloaded the RG and the special. At one time we had 6 bikes with 12 two-stroke cylinders between them (would have been 15 except the special has no engine) lined up along my garden path. Dave was all for me taking a photo. I couldn't be bothered, but take my word for it, it was quite a sight!
We re-filled my garage with RG, special and two MZs (now known as "TS" or "Black" and "ETZ" or "Orange") and loaded the two kettles into Dave's van again. The Red kettle has no brakes. Believe me loading something as heavy as a GT750, with no brakes, up a 30 degree plank concentrates the mind!
By the time we got back to Dave's it had started to rain. Not "p down", just heavy drizzle but enough to make things less pleasant. Unloading the brake-less kettle Dave slipped but we managed to save the bike and ourselves from obvious injury. Kettles were installed in Dave's shed and we returned to my place for lunch (the now traditional home-made torpedo roll) and a tinker with the Black MZ.
I had got the Black MZ ready as a rolling chassis, complete with engine which I had been completed the night before. The whole thing, with freshly Hammerited frame and cleaned up engine, looks quite nice (ask Dave to confirm). I got Dave to check the clearance between the piston and head in the squish band. He confirmed what I thought - the 2nd head gasket I took out when I removed the head was there for a reason. I now have an engine with too much compression. I decided to put that right later. We fitted the exhaust(the slightest of turns on the exhaust nut and dangling from the rearmost stay) and dropped the (already cleaned internally) petrol tank into place and fitted the hotwire assembly I had built already. I really recommend this by the way. It takes dodgy old wiring or an improvised hotwire out of the equation.
Now came what was supposed to be the high point of the day - the attempt at ceremonial "lighting". My objective was to get a response, any response. That would be good. I attached the (fully charged) 12 volt battery off the off the ETZ (can't do much harm for a few seconds?), balanced it on top of the back wheel, between the frame rails and tried the spark plug. Loads of sparks, "bloody well should be, it's being given twice the voltage". So, on to step two; We poured a gallon of mix into the tank and turned on the fuel tap. Petrol p'ed everywhere.The fuel hose may or may not be split, but it definitely leaks. I gave the starter several hefty prods, using various combinations of choke and throttle. Not a sausage, not a cough.
We examined the spark plug. There might be plenty of petrol on the floor, but none was getting through to the engine. I decided we should "retire hurt" and Dave went home. A mug of tea and some cogitating later I decided to have another go. I had dismantled and cleaned the carb some time earlier, but I suspected the needle valve. Down in the garage I removed the carb and took off the float bowl. It was dry! Aha! I'm on the right track! The problem was that removing the needle valve assembly means removing the float, which requires tapping out a pivot pin. A short while later the carb was cleaned, reassembled and refitted and I was ready for another go.
OK. Deep breath, switch on the ignition, switch on the fuel (to reserve), fuel dribbles down the outside of the carb. I gave it a hefty kick with no choke and a little throttle.Nothing happened. Oh well, have another go and then give up. I gave it a half-hearted prod. Ouch! The bloody thing kicked back (and I was wearing soft soled wellies). I'm not having that! I gave it a full kick. There was a loud bang, followed by a sound like a machine gun. The engine had blown the exhaust out of the cylinder and was running well. Having tried to maim me the damned thing was deafening me, was goingto poison me with carbon monoxide and given the chance would probably try and cremate mewith all the petrol that was swilling around on the floor. I know people say that motorcycles are dangerous, but not usually when stationery! I lurched for the kill switch and ran to open the door.
I stood in the door and took a deep breath of fresh air. The garage stank (I had used plenty of oil assembling the engine) and even though it was now silent, my ears were ringing.I had a good grin. There was no doubt about it, the engine was in good shape. The timing had to be approximately right and nothing could start that well with dodgy crankshaft seals. I decided to share the experience with Dave. Before I did I examined the engine. The battery had jumped of and lodged itself between the back wheel and the frame. While dislodging it I must have shorted something, because the engine gave another loud bang asthe fuel remaining in the cylinder ignited!
I went up to the house and entered Dave's number into the mobile phone. I returned to the garage and refitted the exhaust. I kicked over the engine and pressed the "go" button on the phoneat about the same time. The engine started first kick, so it wasn't a fluke. Once again itblew the exhaust, so I couldn't even hear myself think, never mind whether my call had connected. Dave later described the sound as listening to a cross between a machine gunand an insane fax machine. I don't know what he heard more of; "sound noise" or "electrical noise". Whichever it was, I bet all the protective circuits in both my phone and the telephone system were tested by the incident. I hung-up the call, switched off the engine and decided to pack up for the day.
There can be no doubt at all. It's alive! And dangerous too!
The plan was to swap the RG500 and the engineless special with the two kettles in my garage. This was being done to allow Dave to service the kettles and get them MOTed so that they can be converted to cash. Seemed like an admirable objective, so I was happy to help. I turned up at Dave's place at about 11:00 to find that Dave was still getting the bikes (RG500 and special) ready to move. The problem was fitting the exhausts to the RG. The thing is a nightmare of ducting. The rear pipes weave their way through the frame and the attachments for the front ones are jammed right behind the radiator. Anyway, in due course the bikes were assembled and put in the back of Dave's van. The high point (as far as I was concerned) was seeing the speedo on the special indicate 30-40 mph as I was pushing it along Dave's gravel alley. Hmm, I wonder if that is accurate?
A little later we arrived at the back of my place. In order to simplify the "Fox, Rabbit, Cabbage" problem which was in danger of developing we emptied my garage of bikes before we unloaded the RG and the special. At one time we had 6 bikes with 12 two-stroke cylinders between them (would have been 15 except the special has no engine) lined up along my garden path. Dave was all for me taking a photo. I couldn't be bothered, but take my word for it, it was quite a sight!
We re-filled my garage with RG, special and two MZs (now known as "TS" or "Black" and "ETZ" or "Orange") and loaded the two kettles into Dave's van again. The Red kettle has no brakes. Believe me loading something as heavy as a GT750, with no brakes, up a 30 degree plank concentrates the mind!
By the time we got back to Dave's it had started to rain. Not "p down", just heavy drizzle but enough to make things less pleasant. Unloading the brake-less kettle Dave slipped but we managed to save the bike and ourselves from obvious injury. Kettles were installed in Dave's shed and we returned to my place for lunch (the now traditional home-made torpedo roll) and a tinker with the Black MZ.
I had got the Black MZ ready as a rolling chassis, complete with engine which I had been completed the night before. The whole thing, with freshly Hammerited frame and cleaned up engine, looks quite nice (ask Dave to confirm). I got Dave to check the clearance between the piston and head in the squish band. He confirmed what I thought - the 2nd head gasket I took out when I removed the head was there for a reason. I now have an engine with too much compression. I decided to put that right later. We fitted the exhaust(the slightest of turns on the exhaust nut and dangling from the rearmost stay) and dropped the (already cleaned internally) petrol tank into place and fitted the hotwire assembly I had built already. I really recommend this by the way. It takes dodgy old wiring or an improvised hotwire out of the equation.
Now came what was supposed to be the high point of the day - the attempt at ceremonial "lighting". My objective was to get a response, any response. That would be good. I attached the (fully charged) 12 volt battery off the off the ETZ (can't do much harm for a few seconds?), balanced it on top of the back wheel, between the frame rails and tried the spark plug. Loads of sparks, "bloody well should be, it's being given twice the voltage". So, on to step two; We poured a gallon of mix into the tank and turned on the fuel tap. Petrol p'ed everywhere.The fuel hose may or may not be split, but it definitely leaks. I gave the starter several hefty prods, using various combinations of choke and throttle. Not a sausage, not a cough.
We examined the spark plug. There might be plenty of petrol on the floor, but none was getting through to the engine. I decided we should "retire hurt" and Dave went home. A mug of tea and some cogitating later I decided to have another go. I had dismantled and cleaned the carb some time earlier, but I suspected the needle valve. Down in the garage I removed the carb and took off the float bowl. It was dry! Aha! I'm on the right track! The problem was that removing the needle valve assembly means removing the float, which requires tapping out a pivot pin. A short while later the carb was cleaned, reassembled and refitted and I was ready for another go.
OK. Deep breath, switch on the ignition, switch on the fuel (to reserve), fuel dribbles down the outside of the carb. I gave it a hefty kick with no choke and a little throttle.Nothing happened. Oh well, have another go and then give up. I gave it a half-hearted prod. Ouch! The bloody thing kicked back (and I was wearing soft soled wellies). I'm not having that! I gave it a full kick. There was a loud bang, followed by a sound like a machine gun. The engine had blown the exhaust out of the cylinder and was running well. Having tried to maim me the damned thing was deafening me, was goingto poison me with carbon monoxide and given the chance would probably try and cremate mewith all the petrol that was swilling around on the floor. I know people say that motorcycles are dangerous, but not usually when stationery! I lurched for the kill switch and ran to open the door.
I stood in the door and took a deep breath of fresh air. The garage stank (I had used plenty of oil assembling the engine) and even though it was now silent, my ears were ringing.I had a good grin. There was no doubt about it, the engine was in good shape. The timing had to be approximately right and nothing could start that well with dodgy crankshaft seals. I decided to share the experience with Dave. Before I did I examined the engine. The battery had jumped of and lodged itself between the back wheel and the frame. While dislodging it I must have shorted something, because the engine gave another loud bang asthe fuel remaining in the cylinder ignited!
I went up to the house and entered Dave's number into the mobile phone. I returned to the garage and refitted the exhaust. I kicked over the engine and pressed the "go" button on the phoneat about the same time. The engine started first kick, so it wasn't a fluke. Once again itblew the exhaust, so I couldn't even hear myself think, never mind whether my call had connected. Dave later described the sound as listening to a cross between a machine gunand an insane fax machine. I don't know what he heard more of; "sound noise" or "electrical noise". Whichever it was, I bet all the protective circuits in both my phone and the telephone system were tested by the incident. I hung-up the call, switched off the engine and decided to pack up for the day.
There can be no doubt at all. It's alive! And dangerous too!
# posted by tom_gillies @ 10:10 AM 
