ET: Engine (Twin) Inconsistent starting
- Thread starter Peter Salter
- Start date
Also , Most of us that have used them , Use 6, Not 7 ?. Cheers Bill.
There are also dodgy N9ys with iffy printing on the porcelain which should be avoided, Cheers, Stu.
Two months ago I had EXACTLY the same problem with my C Rapide with magneto ignition, Amal 276 carbs, same jets, pilot jets one and a half turns open, spark plug rear B7ES and front B6ES. The engine will only start with the air slides open!!!! As fuel we use here in Holland 100% ethanol-free Shell VPower RON 98 or BP Ultimate RON 98.
Last spring, the engine started to have more and more trouble starting. Especially on the road when the engine was warm. Started with blowing through the jet and the carbs with the compressor which did not help. The carbs also leaked a lot after the floatation. Then I checked the ignition and adjusted it to exactly 35 degrees. But the starting problem was NOT solved. Last year I bought a new camring which I had to correct to exactly 50 degrees with a Dremel (there was a deviation). Then Peter Volkers lent me one of his new magnetos and mounted it on my bike. But the starting problem was NOT solved, so I mounted my own magneto again. Then I disassembled the carbs and took them to a Dutch Section colleague who owns an ULTRASONIC CLEANER. The loose carb houses and LOOSE JET BLOCS bubbled in the cleaner for half an hour. Reassembled the carbs, adjusted the pilot jet one and a half turns, used the backside of a 1/4" drill that I use as a calibre to adjust both throttle slides (a trick that I also recently read about on this forum), and synchronised the throttle slides.
The Rapide started at the first kick, and also the carbs didn't leak anymore. Sometimes the engine doesn't start at once, but that's my own fault (didn't pedal hard enough), then I let both carbs run over for a while and I start with the throttle fully open whereby the engine always starts immediately (of course close the throttle immediately).
Problem was the jet blocs which were almost certainly dirty.
I also painted the carbs (that was also the subject of this forum) with MOTIP Wheelspray nr 4010 which still looks perfect after 3 months, exactly the right colour, cost of the paint, 10 Euros.
Last spring, the engine started to have more and more trouble starting. Especially on the road when the engine was warm. Started with blowing through the jet and the carbs with the compressor which did not help. The carbs also leaked a lot after the floatation. Then I checked the ignition and adjusted it to exactly 35 degrees. But the starting problem was NOT solved. Last year I bought a new camring which I had to correct to exactly 50 degrees with a Dremel (there was a deviation). Then Peter Volkers lent me one of his new magnetos and mounted it on my bike. But the starting problem was NOT solved, so I mounted my own magneto again. Then I disassembled the carbs and took them to a Dutch Section colleague who owns an ULTRASONIC CLEANER. The loose carb houses and LOOSE JET BLOCS bubbled in the cleaner for half an hour. Reassembled the carbs, adjusted the pilot jet one and a half turns, used the backside of a 1/4" drill that I use as a calibre to adjust both throttle slides (a trick that I also recently read about on this forum), and synchronised the throttle slides.
The Rapide started at the first kick, and also the carbs didn't leak anymore. Sometimes the engine doesn't start at once, but that's my own fault (didn't pedal hard enough), then I let both carbs run over for a while and I start with the throttle fully open whereby the engine always starts immediately (of course close the throttle immediately).
Problem was the jet blocs which were almost certainly dirty.
I also painted the carbs (that was also the subject of this forum) with MOTIP Wheelspray nr 4010 which still looks perfect after 3 months, exactly the right colour, cost of the paint, 10 Euros.
Or 6.35mm (if such a drill exists) lol
Yes 6.35 mm drills exist in Holland. After reassembling my carbs after cleaning them (see story above) I first adjusted the carbs on feeling and hearing (at least what is left of that hearing after 50 years of riding only very noisy English and Italian bikes), like I did for the last 50 years. According to the books, the slides should be 1/16 inch open on the engine side, which is a bit difficult to check. As said before, the Rapide started again on the first kick, drove a bit, the engine was doing fine, then I remembered that tip on the forum to check the slide height on the intake side and adjust it using the back of a drill. A 6.1 mm drill fit in the rear carb space and 6.3 mm in the front. Next, using a 6.25 mm drill bit, I adjusted both trottle stops to the same height after which the engine ran perfectly. I live in the vicinity of the big city Rotterdam where the traffic is often enormous, the engine keeps running perfectly for the many traffic lights that always jump red right in front of you, and when the light turns green the Rapide does justice to its name and despite the very long first gear is usually the first to go.
Oh yes, my original 276 carbs are now over 70 years old, I have no idea how many miles the engine has done with them in total. More than 40,000 miles ago, when I did a total overhaul of the engine, I replaced the needles and main jets and I bent the trottle valves, meanwhile the trottle valves are a bit worn on the engine side, new ones are expensive, but the engine still runs fine on them. What I often notice, especially here in Holland with about 200 Vincents of which only 5% is driven more than 100 miles a year, is that these are often equipped with nice modern and expensive Mikuni or Amal Mk 1 1/2 carbs, or other Amal carbs. As soon as the engine hiccups a little or starts a little harder, the old carbs are replaced instead of being cleaned. On most roads here in Holland it is mega busy, almost 18 million people on a piece of land as big as a postage stamp, we don't have any mountains, on the many and often very winding river dykes it is still fine riding (if the many elderly people stay at home with their Ebikes) and then riding my Rapide with small 1 1/16 inch carbs is great. On the highways we are allowed to go up to 100 km/h, but when we can, we pull the old Rapide up to 100 miles/h and almost always together with my wife on the buddy.