Speedo Accuracy and Mileage

[Le_Fromage_Grande]

My Suzuki's speedo reads fast by at least 10%, does this mean that the mileage is also 10% over, ie; when the speedo says I've done 5000 miles, I've actually done 4500?

[dern]

Normally speedos are intentionally calibrated to read a bit high so the manufacturer can't ever be held responsible for any speeding tickets you get. I don't think that that means your odo is similarly inaccurate. The only way to find out though is to ride it a known distance and see what you get.

[Mr. Dazzle]

I can convince myself either answer is correct. There are about a million reasons it'd over read and it depends where the error comes in. FWIW if you've got a digital speedo I'd be inclined to think the odometer would be off by the same amount.

Get a GPS phone app and log it, then you know for sure.

[Le_Fromage_Grande]

Get a GPS phone app and log it, then you know for sure.

I'm not that bothered, it was just a thought I had.

[ChrisW]

Oddly enough I was reading the legal requirement for speedo accuracy this morning - it's no under-read and a maximum over-read of 10% plus 4km/h.

https://eur-lex.europa.eu/legal-content ... 0X0513(03)

[Mr. Dazzle]

Which means every speedo over reads. It's basically impossible to make a perfectly accurate one, at least as far as consumer vehicles go, so if it's unlawful to make one which under reads your only choice is to make one which over reads.

I'd bet they're all designed to be 5% over +/- 4.9999%, then the manufacturers are 'safe'. Nothing to do with avoiding liability for your speeding tickets, just complying with the build regs.

[The Spin Doctor]

The only bike I've ever knowingly owned with a speedo that was bang on was an XJ600 Divvie I had for a few months. I had a GPS to check it. Everything else I rode at the same time or since has over-read. The Hornet for example is showing 30 at a genuine 27 and at 70, the bike's only doing 63-64 mph. Still makes it feel fast

[Yorick]

So if you did your 4,000 mile service at 4,150 you'd still technically be in schedule

[Le_Fromage_Grande]

So if you did your 4,000 mile service at 4,150 you'd still technically be in schedule

That's what made me think of it, bike is due a 15000 mile service, but could I wait until 16500 miles?

In reality I know the mileage is only a guide and it's booked in for the 24th of October.

Also did anyone else have a 750 SRAD that would indicate 190mph, but reality was more like 160?

[Mr. Dazzle]

I did an indicated >160mph on a VFR750 (at Bruntingthorpe, not up the M1 ) but my phone said it peaked at 138.

[Le_Fromage_Grande]

I set the Koso Speedo up on my Kawasaki by measuring the diameter of the tyre, it's accurate, but what felt fast is disappointingly slow.

[Horse]

it's accurate, but what felt fast is disappointingly slow.

A colleague had a Cavalier SRI (or summat), kept banging about how fast it was, telling us its amazing top speed.

We checked his speedo, timed with him doing [speedo] 60mph over a measured mile*. Made the adjustment to his claim - exactly what the specs said it should do.

* 5 small circular signs in the verge or centre res, at 1/4 mile intervals. Haven't seen a set for a while.

[Mr. Dazzle]

In reality I know the mileage is only a guide and it's booked in for the 24th of October.

Loads of vehicles these days have so called condition based servicing anyway, intervals are based on how you use it. I don't know if any bikes do it though.

Back when I did a 45-mile-cruising-along-at-50mph commute every day my BMW would 'gain' thousands of miles of service interval. I'd take it to a dealer for a service and they'd reset all the indicators, then you could see the "distance to next oil change" mileage go up every day for a couple of weeks

[Le_Fromage_Grande]

My Suzuki's servicing is done by mileage, 15000 miles is valve clearances, I'm hoping tootling around in the middle of the rev range is going to mean the clearances will be good, otherwise it's cams out time, which will be expensive.

[Skub]

The cynic in me idly wonders if a lot of dealers bother with the work to check the valve clearances,but give them an 'aural check' instead and bill you anyway.

[Mussels]

The cynic in me idly wonders if a lot of dealers bother with the work to check the valve clearances,but give them an 'aural check' instead and bill you anyway.

I bought a bike from a big London dealer on condition that they check the valves, they agreed and put it in writing. They did a great job of checking them without needing to remove all those seized fairing fasteners.

[Skub]

The cynic in me idly wonders if a lot of dealers bother with the work to check the valve clearances,but give them an 'aural check' instead and bill you anyway.

I bought a bike from a big London dealer on condition that they check the valves, they agreed and put it in writing. They did a great job of checking them without needing to remove all those seized fairing fasteners.

Yeah,it certainly goes on!

I always did my own valve clearances and often those on mates bikes too,my ZZR11 was the last bike I checked myself,as modern stuff is far to tightly packed in and awkward to access. What used to be a quite enjoyable task,is now very unpleasant,so the past number of years I've farmed out the task to someone I trust.

Chances are,on Jap bikes,no adjustment will be required until north of 40k and maybe not even then,depending on use/abuse and oil changes.

[Le_Fromage_Grande]

The cynic in me idly wonders if a lot of dealers bother with the work to check the valve clearances,but give them an 'aural check' instead and bill you anyway.

How do you listen for tight valve clearances?

[Skub]

The cynic in me idly wonders if a lot of dealers bother with the work to check the valve clearances,but give them an 'aural check' instead and bill you anyway.

How do you listen for tight valve clearances?

They must have better hearing than me. It's all bullshit,since as thee knows shims wear tight,not like old tappets which got noisier.

Still,maybe it's part of the skill set needed by a franchised techy.

[Supermofo]

I doubt a GSXR 750 engine with 30 odd bhp lopped off is too stressed an engine. I'm hoping the 1000 is the same.

Quick perusal of the GSXS 1000 forum doesn't lead to many people checking em and only 1 I could find who had adjusted one.

If mine was in warranty I'd do it but by the time I get to 15k I won't be so doubt I'll get mine checked till later.

I know MT09s often need adjustment at 20 whenever there's is.