Sprockets and their teeth...

Hi all. Just got my first VFR a few days ago so my knowledge is pretty lacking at the mo.

I have a 6th Gen '06 and it came with new chain and sprockets. The owner said he had gone "-1 Front, +2 Rear".

Huh?

So I googleized and found out I need a speedo healer. Looked around some more and found a couple of sites where I can type in sprocket teeth numbers, tyre sizes etc to get the correct %age to enter into the healer to get correct speedo reading.

So, has anyone been through this and knows the correction %age required, assuming the previous sprockets were stock and allowing for the factory speedo error?

Or can anyone give me the OEM front & rear sprocket teeth numbers so I can do it myself via the websites I found?

What is the factory setting out by?
I've read anywhere between 5-10%.

I'm assuming OEM speedo settings and sprockets are the same worldwide - I'm in Australia if that matters.

Oh, and the first assumption I made is that the speedo works off the gearbox, not either of the wheels - dunno, gearbox just seems more Honda-esque.

Thanks, knowledgable ones.

 

First of all Congratulations on your new ride and welcome to The World!

Going -1/+2 (f/r) means that the PO lowered the gearing so your top speed will be less, but you'll have better "off the line" take off. In the states the sprockets sizes are 16T/43T (f/r) for the 6 Gen 2002-2009, which should be the same in AUS. The speed is read off of the front sprocket nut. There is a little nylon "cap" that goes over the sprocket bolt and a small slot on the back of that that the speedo sensor slips into. I'm not sure what percentage the speedo is off by but personally I really don't care, I typically use the 10% rule here in California in that if the speed limit is 65MPH, I allow myself a top speed of 71MPH on my speedo. Coincidentally, my speedo went out on me last weekend so now I have completely no idea of how fast I'm going! :wink:

Cheers!

 

Thanks, that's perfect.

I suppose I can confirm the old fashioned way by counting my sprockets teeth but I'm coming off a broken leg/knee reconstruction so I'm a bit limpy and ache-y currently. And no, it wasn't a spectacular 150km high side round a bend with the cops on my arse...fell off my bicycle.

Think I'll just allow 5% for factory error, which still leaves a bit of margin for "me" error

BTW - Your Cat av cracked me up; delighted and disgusted!!

Edit: for future thread searchers, -1/+2 change to 16f/43r sprockets requires a -10.4% adjustment entered into your speedo healer. Then add on as much % as you want to allow for the factory error. Like I said I'm going with 5%, which means my total figure will be -15.4%.

I was recommended speedoDRD:

https://www.motomummy.com/chain-kits-with-steel-front-and-rear-sprocket/12-oclocklabs-speedodrd/

Was told it was the cheapest and the best. Certainly won't weigh down ya ride heheh.

The same page has a link to their online error calculator...very handy!

 

The drd website has a calculator where you just punch in the sprocket sizes and error percent and it will give you what to punch into the healer. I don't have one (unfortunately) but I've installed one on a cbr and using an 8% OEM error rate, it was spot on.

-Drew

 

Yer I think that's what the motomummy page I listed is linking to. Too easy - and there are YouTube vids explaining how to program it, again very simple to do. I love powerful things in small packages, that healer is so tiny and unobtrusive.

I ordered mine last night - $70; + $30 international postage for something that weighs an oz is a bit rich though.

I was a little concerned though that they listed 2 different healer versions for the 6 gen VFR - one for 2002-2006, the other for 2007 on. I would have expected it to be 2006 on ie when they did the engine updates, smoothed the VTEC etc. Mine is a 2006, so I hope they don't have their model years mucked up, otherwise it's the 'returns to the other side of the world take forever' thing.

Did you check you healed speedo with a GPS? I don't have one (it's on the list) but I'm sure there must be an Android app that measures speed. I have a cycling app that displays current speed - maybe I can use that.

 

I use ulysses speedometer for Android.

Its got everything from total average speed, average rolling speed, 0-60mph 0-100mph and quarter mile times (in race mode) its a sweet app.

-Drew

 

I have speedo healer on my 2007. My conversion is 5.2. This a perfect match to my Garmin Zumo GPS.

Now here is the bad news. Looks like the speedo from the factory is 5.2% off but the odometer is right on. Now with the speedometer corrected and reading perfect my odometer is 5.2% too slow. Now when the GPS reads 100 miles traveled my odometer reads about 95. The speedo Healer gives plug and play setup so it bypasses the normal setup. Part of this wiring goes to the speedo and part goes to the odo. I read somewhere that the ideal setup would be to use the speedo healer wires that go to the speedo portion and leave the wires that go to the odometer portion in the original configuration. This would involve using the new connector and clipping two of the wires and connecting them to the original setup. I think this was a thread on VFRD. I decided it wasn't worth the trouble so I didn't do it, plus this should help the resale value. Ha Ha! Doesn't really matter, I'm never going to sell this thing anyway!

 

Hahaha the ole 'wind back the clock' cheat - digital style. Think of the $ saved on service costs too :tongue:

5% ain't much anyways. If I was buying or selling a bike, whether it had 20,000 or 21,000 wouldn't change the price.

But 5% out on your speedo can cost you $150 a pop - that soon adds up.

 

Ok...if anyone is vaguely interested here's how your work out the %age error to your speedo caused by changing sprockets from OEM:

1. Get your OEM sprockets teeth count and divide front by rear eg 16 front 43 rear is 16/43 = 0.372
2. Do the same for your new setup eg if you go "-1/+2" that becomes 15/45 = 0.333
3. Take these 2 figures and divide new by old and multiply by 100. eg (0.372/0.333) x100 = 89.6
4. Subtract 100 from that to get the error %age - 89.6 minus 100 = -10.4%. Enter this into your speedo healer (plus your estimated factory speedo error %age).
5. Grab a beer from the fridge to soothe your sore head from all that mathtrickery.