comet

[ERIC BAYLISS]

 Hi can any one please tell me what engine parts are common to the 250 engine and the 350, as I now need quite a few parts for a comet engine,  eric

[Doug]

Eric,

So far as I know everything but the cylinders, pistons, and heads. I understand even the cylinder castings are the same, except the 250cc is not bored out to a 350cc. This made the 250cc engine quite heavy for the size.

Doug

[ERIC BAYLISS]

 Good morning lads, now I have got the engine it turns out to be what looks like a Aero, where the comet timing cover that was in the box has got the hole for the generator at the top, the engine has got the hole at the bottom in line with the crank. Has any one got any paper work on the Aero engine especialy pictures or can you please tell me where I might get some,as I have got nothing at all   Hope someone can help thank you    eric

[Doug]

Eric,

You can look up the engine prefix codes in the identification tables and determine exactly what you have. Follow the link in this post:
https://www.douglasmotorcycles.net/index.php?topic=489.0

A Comet (1935) model would be pre-Aero era. An Aero model (1936-38) could be a 250, 350, 500, or 600cc displacment. Though honestly, the 250/350cc was just a continuation of the 1935 lineup. I have seen parts lists (non-illustrated) for the 500/600cc 1936-38 models, but have yet to see anything like a handbook or mainitence manual for them.

Doug

[ERIC BAYLISS]

 Thanks  Doug  it lookes to be a aero 250 or at least its got 250 barrels heads and pistons, with engine no 25/b286. if there is no paoer work for these has any one got a aero in bits that could take some pictures of the timing cover oil pump and timing gears as. they are all missing and without pictures I dont know what I am looking for. hope someone will help.  eric

[Daren W Australia]

http://www.ebay.com/itm/Douglas-Timing-Cover-1920-s-30-s-Rare-Vintage-Motorcycle-/360461407177?hash=item53ed2c93c9&item=360461407177&pt=UK_Motorcycle_Parts&vxp=mtr is this what you need Regards Daren

[Daren W Australia]

some comet photo's from an old ebay sale

[Daren W Australia]

more

[Daren W Australia]

Hope this helps Regards Daren

[ERIC BAYLISS]

 Thanks  Dareen, can any one tell me what the oil pump looks like and where it is driven from   eric

[ERIC BAYLISS]

 Have just gone back through the last 13 pages and can not find a single picture of a aero timing cover and oil pump. hasnt any one got one.looking at my engine I can not see where the oil pump would be driven from eric

[Doug]

Eric,

There is a post on the timing cover coaxial with the crankshaft. On this rotates a worm driven by a dog clutch on the crankshaft timing pinion nut. This can be seen in the picture Daren posted above. The worm drives the oil pump, which is attached to the inside face of the timing cover. All the oil galleries, including pickup, are in the timing cover, and delivery is via a spraybay through a hole in the back wall of the timingchest, over the crankshaft. Hence with the timing cover removed no evidence of an oiling system.

Doug

[ERIC BAYLISS]

 Thanks Doug its all clear now. it a good job we have helpful peaple like you. Im a scott man rearly although I did have a EW back in the seventies, thats why every thing looks wrong when it isnt.  thanks again    eric

[Doug]

Eric,

Here is a post with a picture of a A32 timing cover and oil pump, same arrangement as the 1935 250/350.

https://www.douglasmotorcycles.net/index.php?topic=4288.msg15387#msg15387

Doug

[ERIC BAYLISS]

 Thanks  Doug  thats the same as the cover and pump I have got,it looks as if I am missing the worm gear. apart from the cams and gears and the plate that holds them in.     eric

[ERIC BAYLISS]

 Another question, how many teeth should be on the engine, gearbox, final drive and rear wheel sprockets.thank  you eric

[ERIC BAYLISS]

 I am still trying to find out how many teeth there are on the clutch, on both gears on the gear box and on the back wheel. dosnt any one know.