Author Topic: aero 250  (Read 2572 times)

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Offline Red

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Re: aero 250
« Reply #50 on: 28 Apr 2020 at 09:04 »
No. The only transfers are on the tank. We also have an Aero 600 which we haven't restored and that has transfers on the headstock, on the chaincase and on the rear mudguard, but they are all wrong. The Aero should only have transfers on the petrol tank. The 1936 model should be "Douglas" in white with gold edging - item 13. The 1937 model should be the winged Aero Douglas transfer in silver - item 30

Roy

Offline Cliffy73

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Re: aero 250
« Reply #51 on: 28 Apr 2020 at 11:37 »
Thank you for that I'll order some transfers from the club. Many thanks Chris

Offline Doug

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Re: aero 250
« Reply #52 on: 28 Apr 2020 at 22:01 »
But no stop (period) on the pre-war "Douglas" transfer.

-Doug

Offline Tazmantic

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Re: aero 250
« Reply #53 on: 24 Jun 2020 at 18:02 »
Hi all been a while with all this corona stuff going on and having to home school ive had no time but today I received a carb that I found on ebay (so back tracking to the start of my post)

I bought a 274/002 R/S (presume R/S is right side not race sport lol) it is the correct size according to the amal lists at 21/32 but is clip fitting not flange so I've made an adapter and fitted it...

I jetted it as values 60, slide 4/3, needle position 3 but still when i open the throttle quickly it spits fuel out the air intake and dies.......but if i rev slowly seems to be ok..(not road tested yet) I've used the float chamber off the old carb (2a) as it has a top inlet not the one that came with the new carb (3a) as it has a bottom inlet and is also smaller in diameter could the bigger diameter float chamber cause an issue?? or is there an issue else where..

Thanks

Offline Tazmantic

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Re: aero 250
« Reply #54 on: 19 Jul 2020 at 08:54 »
Hi can anyone confirm the magneto timing, is it 40° BTDC for a BTH magneto as the timing listed in my book is for a lucas mag/dyno but I'm assuming its the same.

Thanks

Offline Red

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Re: aero 250
« Reply #55 on: 19 Jul 2020 at 10:52 »
Both the 500 and 600's are 40 degrees before TDC with the magneto lever in the fully advanced position. This is with a BTH magneto. Hopefully someone will be able to confirm if this is the same for the 250 cc model.

Roy

Offline eddie

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Re: aero 250
« Reply #56 on: 19 Jul 2020 at 13:36 »
Hi All,
          Whilst the handbooks may state a specific figure for the ignition timing - that may not be appropriate for running on modern fuel. I would suggest it is better to time up the ignition about 5 degrees earlier - then run the bike, adjusting the advance/retard until you find the 'sweet spot' at which the engine is at it's happiest - check what the advance is, and re-time the mag to that figure when at full advance.

  Regards,
                 Eddie.

Offline Tazmantic

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Re: aero 250
« Reply #57 on: 19 Jul 2020 at 19:12 »
Thanks for the info, so go for 45° then find the sweet spot with the advance lever, I'm surprised that as the gear is keyed onto the magneto that there are no timing marks ...


Cheers

Offline Tazmantic

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Re: aero 250
« Reply #58 on: 30 Jul 2020 at 10:32 »
Ok so now trying to time in the magneto but am I missing something because as the gear is keyed onto the mag shaft I can only jump teeth so the means with 50 or 35 degrees BTDC  :cry:

Offline cardan

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Re: aero 250
« Reply #59 on: 30 Jul 2020 at 10:43 »
Often there is more than one keyway in the gear? If not, try 35 degrees, and if it wants more advance you can cut another keyway (almost) opposite the first, but offset by half a tooth.

It's always worth checking the valve timing while you're there.

Leon

Edit: Is the magneto gear on a taper? If so, just check that the tapers are in good order and leave the key out. I have played with lots of bikes that don't have keys on the magneto drive gear.
« Last Edit: 30 Jul 2020 at 10:49 by cardan »

Offline eddie

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Re: aero 250
« Reply #60 on: 30 Jul 2020 at 10:56 »
If the valve timing is right, and you only need to adjust the ignition timing (assuming the taper is good in the mag gear), re-time the mag without the key in place. The taper will provide ample drive for the mag. (On postwar machines, the taper also provides the drive to the dynamo!).

  Regards,
                 Eddie.

Offline Tazmantic

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Re: aero 250
« Reply #61 on: 30 Jul 2020 at 13:57 »
Cheers guys, checked valve timing and that seems ok tho lines all line up at TDC and they appear to be opening and closing at the right degrees.

Yes mag gear is on a taper and I just checked it with my otger bike (yes I do have 2 250 Aeros  :o) and that appears to be timed up the same must be why it seems to run better when I retard the lever slightly....

Think I might have another issue, magneto sparks fine when not bolted in and spun by hand or drill but once in bike I can’t see any spark at all.... li
« Last Edit: 30 Jul 2020 at 17:08 by Tazmantic »

Offline Tazmantic

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Re: aero 250
« Reply #62 on: 30 Jul 2020 at 20:25 »
Discovered problem its an anti clockwise mag and I need a clockwise one  :frown:

 

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