14 members (IcePack, bmgermany, Bishmog, KennethM, Rovert, Redfate, MJF, Peter G3VNH, Tresco, Grumpy2, Morganmike, +8Rich, teknome, ajg141),
274
guests, and
41
robots. |
Key:
Admin,
Global Mod,
Mod
|
|
Forums34
Topics48,349
Posts813,108
Members9,212
|
Most Online1,046 Aug 24th, 2023
|
|
|
Joined: Jun 2012
Posts: 2,141 Likes: 43
Talk Morgan Expert
|
OP
Talk Morgan Expert
Joined: Jun 2012
Posts: 2,141 Likes: 43 |
Some time ago I mentioned that a method of correcting the built in inaccuracy of the M3W speedometer has been found. The details of how to do this are in an article in the Morgan Three Wheeler Club "Bulletin" magazine and a link to that is here: https://www.mtwc.co.uk/wp-content/uploads/2020/01/Bulletin-December-2019-speedo-calibration.pdf. This is free to view, even if you are not a MTWC member, although there is a lot more information about M3W's available to members if you look at the list above the article. The speedo correction is easy to do, once you know how and is essential if you plan on using lower profile motorcycle tyres, as the speedometer error will be in excess of the 10% over read error permitted for UK MOT's. It's worth doing even if you retain the standard size tyres, an error of about 6% is just not useful. As you will see, the most difficult part is locating the calibration plug.
|
|
|
|
Joined: Aug 2019
Posts: 945 Likes: 16
Talk Morgan Regular
|
Talk Morgan Regular
Joined: Aug 2019
Posts: 945 Likes: 16 |
Excellent info! Thanks a lot Planenut! 
|
|
|
|
Joined: Jun 2016
Posts: 432
Learner Plates Off!
|
Learner Plates Off!
Joined: Jun 2016
Posts: 432 |
Thanks! I have the December MTWC Bulletin sitting on my "to-read" magazine pile in the, ahem, reading room... but have not opened it yet. I'd also suggest folks consider joining the MTWC. They are making a good effort at including info and articles on 5-speeders. The actual VDO instructions, as pointed-to in the article, are an incredible find, link re-posted here for future reference: VDO Installation Instructions
|
|
|
|
Joined: Apr 2015
Posts: 450
Learner Plates Off!
|
Learner Plates Off!
Joined: Apr 2015
Posts: 450 |
It is news to me that MOTs cover speedos - never used to be the case but I am an old fart with too many memories and not enough up to date facts! In any case, how do they carry out the test?
2013 M3W 1960 Velocette Venom and the Landrovardo!
|
|
|
|
Joined: Apr 2017
Posts: 1,799 Likes: 3
Talk Morgan Enthusiast
|
Talk Morgan Enthusiast
Joined: Apr 2017
Posts: 1,799 Likes: 3 |
I guess they could do something on the brake test rollers but it would be very rudimentary.
I was also not aware that they checked the speedo accuracy but IIRC they do check to see if it is working.
Bob
2009 Black Roadster 1999 4/4 2 litre Zetec
|
|
|
|
Joined: Aug 2016
Posts: 415
Learner Plates Off!
|
Learner Plates Off!
Joined: Aug 2016
Posts: 415 |
After a bit of research I’ve found this from the MOT Inspection Manual https://www.gov.uk/guidance/mot-ins...ht-commercial-vehicles/7-other-equipment7.8. Speedometer You must check the speedometer of vehicles first used on or after 1 October 1937 with a maximum speed above 25mph. You do not need to check Class 3 vehicles. If a road test is needed, for example to carry out a decelerometer test, you must check whilst driving that the speedometer is working. If a road test is not necessary, you should only reject a speedometer if it’s clearly not working. Speedometers do not need to be lit on: vehicles with no front or rear position lamps vehicles that have front or rear positions lamps that are permanently disconnected, painted over or masked You can accept a tachograph as an alternative to a speedometer if it satisfies the requirements of this inspection. Defect (a) Speedometer not fitted where one is required .... Category .. Major (b) Speedometer: (i) operation impaired ..... Category .. Minor (ii) not working .................................. Major (c) Speedometer: (i) not sufficiently illuminated ............. Minor (ii) not illuminated ............................... Major
Last edited by Ricardo; 26/01/20 06:09 PM.
|
|
|
|
Joined: Jul 2018
Posts: 1,031 Likes: 2
Has a lot to Say!
|
Has a lot to Say!
Joined: Jul 2018
Posts: 1,031 Likes: 2 |
Speedometers are permitted to over-read by up to 10% (I think), but it is illegal for them to under-read. The MOT tests whether they are working at all and could pick up an under-read as a defect (but I doubt that it would be spotted).
|
|
|
|
Joined: Oct 2018
Posts: 30
Just Getting Started
|
Just Getting Started
Joined: Oct 2018
Posts: 30 |
Thanks for posting this! It took less than 10 minutes bonnet-off to bonnet-on, and it will solve an irritating situation!
Phil 2013 Sport Blue/Black Leather
|
|
|
|
Joined: Apr 2019
Posts: 488
Learner Plates Off!
|
Learner Plates Off!
Joined: Apr 2019
Posts: 488 |
Is this the right plug? Late model year ![[Linked Image]](https://www.tm-img.com/images/2020/03/06/79A71808-3950-45D1-A7EE-BE7BCD6920AF.jpg)
|
|
|
|
Joined: Feb 2016
Posts: 2,027 Likes: 23
Talk Morgan Expert
|
Talk Morgan Expert
Joined: Feb 2016
Posts: 2,027 Likes: 23 |
Interestingly my Aero over-reads as well, and if I recall is a very similar procedure (once you are into the speedo settings). I shall have to see how accurate (or not it seems) the M3W one is!
Thanks for posting.
Aero 8 GTN #11
"What we do in life.. echoes in eternity."
|
|
|
|
|