1275LS was originally fitted with 145/70-12 tyres. If you have bigger section ones, yes it will under-read.

Cooper S and most Clubbies had 145-10 tyres stock. But since the late 70s many people have fitted 165/70-10 instead.

There is not much diameter difference between 145-10, 165/70-10, and 145/70-12.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I was going to say it was the tyre size that is causing the problem but the dia. of the 145/70-12 and the 165/60-12 is really very close and wouldn't make that much difference.

Check the tyre size. I've seen people fit 145-12s (which are 80 profile, = bigger) instead of 145/70s to these cars because they were cheaper and easier to find.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

whats wrong with cleaning with contact cleaner? I've done a fair few, not just mini's.

Posted: Thu Jan 15, 2015 8:10 am

If partially disassembled, you can then carefully clean out old gunk on the drive gear and odometer cam with contact cleaner (say) then sparingly coat with Moly Grease (do not over grease).

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"Show me the Mini!"

The tyre size is 145/70R12 which is what the handbook shows.

I will check the odometer next time I take it out and see if that is correct.

When I bought this car the previous owner did say it had a new imported engine from England,
so I am still thinking it's a problem with the speedo drive down on gearbox not being the right one.

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1967 Morris mini Deluxe
1968 Buick Riviera
1979 HZ Kingswood
1979 CM Valiant
1982 Jaguar XJ6 series 3
2002 VX HSV
2013 Mazda 6
2018 Gt Mustang

Yes if it's an import it's probable the drive gears are wrong.
But the engine really has to come out to swap these over.

I'd say eff it, and use a GPS. TomTom works for me.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Hi Kevin,

Like you said. I will live with it and use my Navman and if I ever pull the engine out I will fix it.

Thanks Felix

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1967 Morris mini Deluxe
1968 Buick Riviera
1979 HZ Kingswood
1979 CM Valiant
1982 Jaguar XJ6 series 3
2002 VX HSV
2013 Mazda 6
2018 Gt Mustang

or get the correct speedo head to match your UK box

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"Show me the Mini!"

But, then it won't be correct dials for a 1275LS, will it...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

are we talking Concours d’Elegance for the 1275LS here or "lets get the speedo reading right"

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"Show me the Mini!"

Well,
would you fit a `Chinese made copy of a Mk3 S speedo' to a Mk1 S? Similar concept, as the late Rover Mini speedos are Nippon Seiki or something, not Smiths!
Sorry sport, it's just not cricket.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Hang on Back the truck up Who you calling sport

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"Show me the Mini!"

Just took car out for a run and checked odometer with the navman.
Odometer reads 0.3km low for every 1 km on the navman.

And as said before the speedo is reading 10 km low for all speeds.

Therefore it must be the wrong speedo drive fitted to g/box.
So what size or P/N drive gear do I need to fit to g/box to fix this problem when I eventually pull motor out.

Just another note when I changed my fan belt I noticed timing marks on my timing case.I have never seen this on a mini
as it normally is in the clutch housing wre it also is on this engine.

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1967 Morris mini Deluxe
1968 Buick Riviera
1979 HZ Kingswood
1979 CM Valiant
1982 Jaguar XJ6 series 3
2002 VX HSV
2013 Mazda 6
2018 Gt Mustang

My daily runner Subbie has the same problem, but I don't stress, just drive to whatever the GPS says on the flat...have zoomed past others driving off there low reading speedos and plenty of speed cameras and cops without ever getting a ticket...

Don't you have other more pressing things to do? Like enjoy driving a Mini?

[Gawd! or the 1965 thunderbird!]

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"Show me the Mini!"