R80 Speedo over reading by too much

[Old Man]

I discovered last month that I had a space in my garage shaped exactly like a basic 1987 R80 and so I've found a very nice low mileage one to stick in there alongside my R100 GS-PD. The problem I've got is with the speedo and despite my searches I can't find the answer but I know that someone will know.
The speedo is marked as 1.186 (which I think is right but can't be sure) and the needle rotates very smoothly ie no jerkiness or fluctuating. However, it over reads by far too much. I've calibrated using my GPS and found that at 30mph it reads 45, at 50 mph it reads 65 and at 70 mph it reads 95.
Has anyone else had the same problem and what's the answer? Quite happy to take it to pieces and give it a clean up if necessary but do I need to?
Thanks for your help
John

 

[tuftywhite]

I have an R80g/s. My speedo isn't accurate and I was told not to worry about it.

Speedo - Actual

30 - 30

40 - 40

60 - 50

66 - 60

78 - 70

just map it and put little stickers on the clock if you need to.

Just an idea.

 

[(RIP) Proff]

Has Sir, perchance got a KPH speedo fitted

 

[Old Man]

Naah. That was the first thing I checked!!
Proff ..... you'll know. Is the1.186 the right speedo for an '87 R80?

John

 

[(RIP) Proff]

50 kph = 30 mph
80 kph = 50 mph
110 kph =70 mph
Thats what made me ask...
You say /87
You also say "Basic"
Two different bikes
Monolever or Paralever as an 87 can be either
basics" were 1997 iirc.
giz a clue, ffs I ain't a mindreader

 

[Old Man]

OK then. It's a 1987 R80 monolever in absolutely original condition. ie not messed about with at all so to all intents and purposes the speedo is the original, backed up by the last 20 years worth of MOTs unless, of course, it has been changed and the odometer altered to read the original mileage.
I did do the mph/kph comparison but the differences aren't consistent enough to be right.
I know I can ignore it or fit a gps but it just kinda niggles a bit.
Thanks
John

 

[piebaps]

try this thread OM.

http://www.ukgser.com/forums/showthread.php?t=192618&highlight=speedo

It looks like you have the wrong Speedo and you need a W1244 (if I'm reading this correctly.

If this is right just remember who helped - especially if you have a W1186MPH which is surplus to requirements

 

[(RIP) Proff]

I concur with Piebaps
Someone has swapped the speedo for {I think} a paralever one
Mine had a new speedo fitted in 1993 @ 22,000 miles 10 years old.. Damp wrecks the early ones..
I put a silicone crystal gel pack from leecy packing materials in the new one, still perfect thumb2

Piebaps has been looking for a para speedo for yonks !!!!

 

[Old Man]

Hmmmm. But according to this .... http://bmwmotorcycletech.info/ringgears.htm with a ring gear ratio of 32/10 (which it is) it should be 1.186. I've had a look inside and it's clean as a whistle, no rust, plenty of grease on the cogs and never been tampered with.
I think I'll tick it off to BMW quirkiness and invest in a GPS but thanks everyone for your help.
John

 

[piebaps]

I'm OK actually proff. Duncan lent me a MPH which got the bike through the test. My KPH works fine. That reminds me, I must get Duncan's back to him before he sends the heavies round!!

 

[(RIP) Arkwright]

Funny, I was just thinking about that!

Perhaps I should send

 

[(RIP) Arkwright]

Hmmmm. But according to this .... http://bmwmotorcycletech.info/ringgears.htm with a ring gear ratio of 32/10 (which it is) it should be 1.186. I've had a look inside and it's clean as a whistle, no rust, plenty of grease on the cogs and never been tampered with.
I think I'll tick it off to BMW quirkiness and invest in a GPS but thanks everyone for your help.
John

I use a GPS on all my Bikes all the time for precisely that reason!

 

[Beemerboff]

My G/S speedo is a long way out too.

I have simply remarked it on the rim with a white paint- a long stroke at 80 km, a shorter stroke at 60 and 100 km, and a dot at 50 and 110.

Actually works better than trying to read the numbers, particularly if it is raining.

 

[Old Man]

My G/S speedo is a long way out too.

I have simply remarked it on the rim with a white paint- a long stroke at 80 km, a shorter stroke at 60 and 100 km, and a dot at 50 and 110.

Actually works better than trying to read the numbers, particularly if it is raining.

That's a good plan. Thanks.