The Mobylette/Motobecane Forum UK - Flywheel Plastic Cover

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May 18, 2013, 8:50pm

The Mobylette/Motobecane Forum UK :: Technical information :: Technical information :: Flywheel Plastic Cover

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Topic: Flywheel Plastic Cover (Read 555 times)

av88
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Flywheel Plastic Cover
« Thread Started on Jun 8, 2011, 8:45pm »

Have been running an AV92 for the last couple of weeks on 40 to 50 mile runs. After a hour or so the engine seems to loose power as if it was running out of fuel then picks up again but keeps doing it every couple of miles. When I reached home, checked the spark by spinning the flywheel. i was suprised how hot the flywheel was. Is this the problem? Shall try it with the cover removed next trip. Anyone had a similar problem? john

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iant
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Re: Flywheel Plastic Cover
« Reply #1 on Jun 8, 2011, 10:28pm »

I doubt the cover is going to make much of a difference, that thin piece of plastic isn't much of an insulator. my guess is you are running a little lean or maybe your timung is a little over advanced. those stock set ups can take a lot of punishment though. How fast is your AV92? I have heard they have a little better top speed than the SP93, perhaps due to the larger wheels. .

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Re: Flywheel Plastic Cover
« Reply #2 on Jun 8, 2011, 10:28pm »

PS: 50 miles?! awesome work!

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av88
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Re: Flywheel Plastic Cover
« Reply #3 on Jun 9, 2011, 9:15am »

Thanks for your reply. Speed, bit subjective really, I would say 35 ish on the flat in still conditions, odly enough the speedo shows this speed, they usually read fast. My old AV89 was faster, 14mm carb. This would do the high 30s on the flat and just over 40 on an incline. I find the AV92 nicer to ride with its relay gearbox and the seat is a lot softer!
Wheel size, 2.25 x 18, is'nt this the same as the SP93?
I live in the country side, lots of back roads so easy to do 50 miles and still be relatively close to home. The plan is to get it reliable then take on a few NACC runs. Cheers John.

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Re: Flywheel Plastic Cover
« Reply #4 on Jun 9, 2011, 9:42am »

My AV92 has 18" wheels as well, but both of my SP93s have 17" wheels (and this is supported on the spec sheets as well so probably applies to all of them.

My AV88 is also faster than my relay box bikes, but I do like all the torque one gets out of the relay box. Brian Aplin told me that relay bikes never had the top speed of the 88s and 89s and that was part of why they weren't too popular.

I think they must have been made to compete with small motorcycles at the time because their frames and forks are so much more solidly constructed than any other Motobecane I have owned.

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Re: Flywheel Plastic Cover
« Reply #5 on Jun 9, 2011, 10:55am »

Here are the design specifications for the 92 and 93 models
AV92GT: http://docs.google.com/viewer?a=v&pid=ex....uthkey=CMbIhfEH
SP93: http://docs.google.com/viewer?a=v&pid=ex....uthkey=CKqXvscH

Man, according to this spec sheet for the 92, it also has 17" wheels, now I am really confused. I am going to have to check my 92 again -- maybe it doesn't have 18" wheels like the 88.

« Last Edit: Jun 9, 2011, 10:57am by iant »

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av88
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Re: Flywheel Plastic Cover
« Reply #6 on Jun 9, 2011, 2:38pm »

Thanks for the info. Motobecane do seem to do alot of mixing and matching of parts. I have a 1960 AV88, least I think is, but has a deeply valanced rear mudguard like the 89, small round headlight, very rough and origional. Havent been able to come across a picture of it in this configuration. My parts book for the 1960 AV88 shows a less valanced rear guard. God, am turning into a real anorak!!

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Re: Flywheel Plastic Cover
« Reply #7 on Jun 9, 2011, 3:50pm »

Mine is either a 1963 or 1964 AV88

[image]

AV88: http://docs.google.com/viewer?a=v&pid=ex....uthkey=CImE0e8P

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mobyjoost
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Re: Flywheel Plastic Cover
« Reply #8 on Jun 9, 2011, 8:29pm »

The model names stayed the same through the years, but the designs were adapted to changing tastes. The leading link fork on the AV89 was abandoned by AV89 MK3. First model with telescopic fork still had a rounded headlight. Then they changed to the big square headlight, also found on the second model SP98, the AV92, AV92 GT, SP93 and maybe more. So the longer a model was produced, the more versions there were. Basically, the older, the more rounded, more female shapes.
The AV92 and the AV92 GT are two different mopeds. The "normal" Av92 was equipped with the AV7 engine, the AV92 GT was the first Motobécane they used the AV10 engine on.
I like those tyres on your 88, Ian. Really sturdy.

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av88
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Re: Flywheel Plastic Cover
« Reply #9 on Jun 10, 2011, 3:06pm »

Thats a nice looking moped in very usable condition. I wish mine looked like that. Bought it out of a scrap yard after many years of exposer to the elements. I bought it because it is an early model, with more rounded features, round headlight, small oval chrome tank panels, simillar deep mudguards but narrow'er width because it uses 2 x 19 wheels. Its in many bits slowly being rebuilt. john.

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Re: Flywheel Plastic Cover
« Reply #10 on Jun 10, 2011, 4:22pm »

I ride it a few times a week, I think it might be the most reliable moped I have ever owned -- it's a tank! And I love the patina. It only had 78 miles on the clock (with a working speedo) when I got it but it must have sat in a shed for a long time.

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rebelmoby
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Re: Flywheel Plastic Cover
« Reply #11 on Jun 16, 2011, 3:52am »

I am glad to hear that other people are running their bikes on more than just the Sunday drives.
The older big bodied Motobecanes are surely a pleasure to cruise on - all day long!

Dont make a habit of grabbing onto the flywheel after a long run - they get hot - by product of producing electricity and not due to heat soaking from the engine and exhause in close proximity. The heating is the primary reason to relocate the condenser to a cooler area of the bike.

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