speedometer seems off

When I am on the highway and riding at posted speeds I find that I am passing everyone on the road. I am thinking my speedometer is not giving me the correct speed. I am guessing it is off by 5-10 MPH. One highway here I-295 the posted limit is 70 MPH is some points, at 70 I am in the left lane passing everyone. Now Richmond, Va drivers don't normally drive under the limit unless it is raining or there is a cop on the road. So, how do I adjust or check this issue before I see blue in my mirrors?

 

Yamaha's mechanical instruments are not noted for their accuracy.

That being said, it may benefit from cleaning and lubrication; see: http://xjbikes.com/Forums/viewtopic/t=15303.html

 

If you have an Iphone or smart phone you can download a speedometer app. Ride with your Smart phone and check. It is pretty accurate.

 

If you have, or can borrow a GPS it would indicate how far off your speedo is. Keep in mind that most juridictions don't recognize GPS as a speed indicator as their primary function is mapping. The size of tire in the front wheel will make a difference, if its bigger (outer circumference) than the stock tire, it will read slower than your actual speed. Check what tire you have verses what was supplied when new.

 

Yea I've kinda noticed this as well. I'm in California, no one ever drives under the speed limit, yet when I'm driving my XJ750, on city streets while trailing a car on a 40mph road, my speedo will say 40mph, on the freeway, even going interstate, I almost never hit over 55mph if there's a car in front of me, heck I was trailing someone driving a Porche 911 up in the mountains on I-80 with no one in front of them and it said 60mph, I have a hard time believing that someone driving a porche would be going 5mph under the limit.

I don't normally drive cars that often, but I made a delivery run for someone a few days ago in their car and hit the highway, traffic was going 75mph on I-80 according to the car's speedo, I drive that same highway every day on my bike and it never says over 55.

I think I'll try that GPS idea if I can get my hands on one for cheap, and assuming that lubricating everything related to the speedometer doesn't work, then what? Is there any way to adjust it or no?

 

I think for me it is the tire issue. The tires on the bike are not as wide as the factory tires, I believe. I downloaded a free speedometer app from my iPhone just need to find a way to rig it to my bike so I can see how fast it says I am going vs. the speedometer on the bike. I am guessing I am 5-8 MPH off on the slow side.

 

unknown; the speedo isn't really easily adjustable; they can be fiddled with but I've found that a proper cleaning and lube (see the article I linked) will often bring them back to their original stock optimism. If anything it should read high, not low.

doc; width doesn't have much to do with it; it's the overall diameter/circumference. A larger wheel turns fewer RPM to cover the same distance than a smaller one; so a larger tire will cause a "slower" reading and a smaller tire will "speed" things up.

The original tire on your bike was a 3.25-19 which is roughly equivalent to a 100/90-19; what is on there now?

 

I have a 100/90-19 on there... hmm I need to get one of those holders for my phone or find a way to do a quick and dirty velcro job for a one time test. I just don't want to get any speeding tickets I am proud to have a clean driving record.

 

So I downloaded a free app for my iPhone and tested it in my car it was on the money with my cars speedometer, so I tried it on my bike. My bike is 5.0 miles on the slow side, so when I am doing 55 MPH really I am doing 60 MPH -This is good info to have. If you are wondering the app was speedcheck and it is free there is a pay version as well but for what I needed for the free version was good enough!

 

The one I use is called SPEED-O-METER. really accurate as well. This one gives you average speed and top speed as well.

"if you don't have an Iphone well, you don't have an Iphone" LOL

 

Damn well my testing was done at slower speeds... It seems that it is 5 MPH off between 0 - 35 MPH but once you get faster it gets worse quick. When it reads 55 I am doing 70! How do I know, a very nice police officer was kind enough to pull me over and ask my why I was going so fast.. Grrrrr, but I will go to a place that does calibrations and get it tested then tear this one apart or buy a new one. Leaning towards a new one. But now I know why I am blowing everyone off the road at highway speeds... Damn last weekend when I was doing 70 on I-95 was I really doing 85? Or get a 12v charger rig for my bike and an iPhone mount and use my phone as a speed-odometer.

 

My speedo is off like that. It just doesn't go above 65, and that's on I-8 going down a mountain faster than everyone else. I know I wasn't going 65.

I've tried to clean it and lube it, but I think it's lost it's magnetism. Or the spring has stiffened up. The reason I think that is because there seems to be no extra resistance when I manually cycle the needle. It's clean and smooth the whole way through.

The kicker is that I had a perfectly good working speedo, but no tach. So I bought a new set off ebay, installed it, AND STUPIDLY PUT THE OLD ONE IN THE DUMPSTER!!!! Went back to dumpster dive for it the next day but the scavengers had already gotten ahold of it. Shoulda just kept it for awhile...I don't throw anything away anymore, at least not till I'm happy with it's replacement!!

I just downloaded Ulysse Speedometer...it gives alerts at certain speeds, so I don't even have to mount it on my bike, because I'm really not sure how I would go about doing that comfortably.

 

I got lucky after some good arguements i beat my speeding ticket with a defective equipment charge!

 

And for this you can be grateful! I have both Android (Galaxy S) and an iPhone G3. I have found the iPhone makes an awesome iPod!

I use the GPS on my Beemer all the time because those wacky Bavarians shipped the LT's with speedometer units calibrated to read 10% fast. 65 indicated is just under 60 mph actual. Because the speedo heads are electronic I just recently added 2 jumpers to the circuit board which is purported to make the unit spot on. I will button everything back up on my next day off and will soon know if it helped.

As an aside, RAM Mounts makes waterproof cases suitable for holding a smartphone to the handlebars of your bike. The product is called AquaBox and the mounts to put the box on your bike are varied and numerous.

Here is RAM Mounts web address: http://www.ram-mount.com/Products/AquaB ... fault.aspx

I have an older GPS made for motorcycles but would like to have one with a larger display so will likely go this way using a 4" + display automotive unit. I use a RAM Mount for my current GPS. The mounting screws replace the screws holding the front brake or clutch master cylinder cover so the install is very clean. The supplied screw color even matches the rest of the master cylinder.

Loren

 

MY bikes are both off about 10 KPH at 100 KPH. This is the mount I made for my GPSs. My son has the Maxim but it is the same. If you do this just make sure the Plexiglass isn't scratched or you loose the vacuum and the cup will fall off over time. This has been on for several week and is still holding strong. Moisten the cup before applying for best strength.

The link for inserting the pictures didn't work, but the link is OK The DSC01750 shows the plastic mounted to the mirror post.

Edited: Got the pictures to work




http://i974

 

Very innovative. Wouldn't it be safer to use stainless steel hardware and through bolt the mount to the plexiglass?

Up here in the Pacific Northwet we would only be able to use the GPS on the sunny days. There have been 83 days of .01" of rain since January 1st. 140 days of rain since Oct 1st 2010. MANY more cloudy days than sunny days.

Source: http://www.brucesussman.com/portland-we ... nd-oregon/

 

Probably would but I switch the GPS between my toys. Use a lanyard just in case it comes lose. Hasn't yet.

 

Call me sanguine but I honestly believe that is part of a plot by the manufacturers to get out of warranty obligations early. If you rack up recorded miles faster than the actual miles, your warranty expires early. To wit; my Subaru at 101K needed head gasket replacements. Since I was past the 100K warranty limit they refused to cover it. My speedometer & Odometer with new and correct tires was according to my two GPS units, recording 3% too high so I had around 2,000 more actual miles left to go before the 100K warranty limit but they go by the odometer reading and would not budge.

I do NOT believe this is only a Subaru issue, I think it's part of dirty cost containment methods by the vehicle manufacturers.

 

I have the police meter which uses the reid switch within the speedometer mechanism to translate to 'digital' pulses which the meter translates into numbers...

I put a new needle on my speedo... I've moved it twice and according to the police meter I've been low and high so far (yesterday I was doing 65Kph according to the police meter and the speedo was reading 80Kph whereas the last attempt when I was doing 70Kph on the police meter the speedo read 65Kph... painfull!!)

I would think the pulsing of the reid switch would only be altered by a faulty cable/mechanism and wheel size so that would be a good place to grab a reference point for an aftermarket electronic speedo alternative... I'm thinking.