Speedo sensor
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Road Warrior
Joined: Aug 2005
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Speedo sensor
So, I've noticed that my Speedo on my 1996 flstn is reading anywhere between 5-8 MPH over true speed. I expect 2-3, so this seems a bit much. Should I just clean the speed sensor, or is this a sign that the Speedo itself is starting to go. Thanks for any advice.
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Joined: Jun 2007
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From: Bedford UK
Have you just checked this for the first time, or has it changed recently? Frankly it sounds about right to me. Speedos are not inherently accurate things on normal production vehicles, especially from the era of our Evos. If you expect it to be as close as 2-3% then you have unreasonable expectations IMHO! Typical tread wear from new to replacement time on a front tyre is around 1.5%.
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Road Warrior
Joined: Aug 2005
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Thanks GR. I think I wrote 2-3 mph, not percent. 3 mph going 60 mph is 5%, but of course 6-7 mph off would be 10%+. Don't know how accurate these speedos are. I removed the sensor last night and cleaned it. There were some metal shavings, which I expected. I'll see if that makes a difference. If not, I'll just ride and forget about it. Thanks.
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Joined: Jun 2007
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From: Bedford UK
Thanks GR. I think I wrote 2-3 mph, not percent. 3 mph going 60 mph is 5%, but of course 6-7 mph off would be 10%+. Don't know how accurate these speedos are. I removed the sensor last night and cleaned it. There were some metal shavings, which I expected. I'll see if that makes a difference. If not, I'll just ride and forget about it. Thanks.
IIRC speedo accuracy used to be zero to +10%, in other words at a given speed the speedo can only indicate a higher speed than the vehicle is actually doing, it must not allow the vehicle to go faster than the speed indicated. I believe that recently that margin has been tightened to +5%, but that won't include our older bikes or other vehicle of similar age.
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From: Ohio
Thanks GR. I think I wrote 2-3 mph, not percent. 3 mph going 60 mph is 5%, but of course 6-7 mph off would be 10%+. Don't know how accurate these speedos are. I removed the sensor last night and cleaned it. There were some metal shavings, which I expected. I'll see if that makes a difference. If not, I'll just ride and forget about it. Thanks.
https://www.dakotadigital.com/index....d=115&mode=cat
Seasoned HDF Member
Joined: Mar 2010
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From: Poolville
Yeah, they are not a accurate as we would like.. I know the auto industry has a 1-2% variance.. I use a Thunder Heart speed sensor.. had it now for at least 5 years and never an issue...
https://www.jpcycles.com/product/570...E&gclsrc=aw.ds
https://www.jpcycles.com/product/570...E&gclsrc=aw.ds
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Road Warrior
Joined: Aug 2005
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Thanks for the additional information. I'll see how accurate it is now that it's been cleaned and go from there.
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You can use your satnav to check accuracy. I use ours with 5 different vehicles and none of them are accurate!
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3rd Gear
Joined: Apr 2017
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From: Kent, England
Sorry folks, I figure I wasn't clear. The needle isn't just 'off' or just giving me an under/over reading it bounces back and forth between the speeds while riding at a constant speed, so it won't just read say 80 while doing 70, it will read 65, 66, 67 etc. till it hits 80 then drop an read the lower speeds, and this would be within a second and constantly bouncing between values. Sat Nav will happily say a constant 70 while the speedo would be anywhere between the upper and lower limits of this 'bouncing', and constantly changing.
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From: Brighton, MI
"Sorry folks, I figure I wasn't clear. The needle isn't just 'off' or just giving me an under/over reading it bounces back and forth between the speeds while riding at a constant speed, so it won't just read say 80 while doing 70, it will read 65, 66, 67 etc. till it hits 80 then drop an read the lower speeds, and this would be within a second and constantly bouncing between values. Sat Nav will happily say a constant 70 while the speedo would be anywhere between the upper and lower limits of this 'bouncing', and constantly changing."
What year and make of bike? Electronic or cable driven speedo? Sounds like the inner drive cable for the speedo is binding up.
If it's cable driven, the first thing I would do is clean and lubricate the cable.
That is only if you have the cable drive type from the speedo to the front wheel. There is the drive unit on the front wheel and while it takes time, you can pull the drive unit, clean and re-lube using a good grease. The inner drive of the cable can be wiped down and then relubed with graphite powder.
What year and make of bike? Electronic or cable driven speedo? Sounds like the inner drive cable for the speedo is binding up.
If it's cable driven, the first thing I would do is clean and lubricate the cable.
That is only if you have the cable drive type from the speedo to the front wheel. There is the drive unit on the front wheel and while it takes time, you can pull the drive unit, clean and re-lube using a good grease. The inner drive of the cable can be wiped down and then relubed with graphite powder.