Fuel gauge reads too high and goes up with high rev

[XS11Hollywood]

Help please..... I installed a new tank sending unit today and it still floats slowly way above whats in the tank. It will kinda seem close then it slowly floats up.. with rpm.
I am going nuts Yesterday I installed a used ebay tach thinking it was the problem..

[randy]

Hollywood,

Welcome to the site.

On the back of the tach there's a little black box. That's the fuel guage regulator. It's probably fried. Too bad, because it's no longer available from Yamaha.

To test, pull the plug at the fuel sender and put a meter on the socket side (lead from the bike harness) you should read 7 volts while running, regardless of rpm. My guess is that you'll see the voltage rise with rpm.

Only fix is to get one that works. Sometimes (rarely) they come up on Ebay, last one I saw was two years ago. It was NOS and sold for $40. Most times, you'll have to get another complete tach and hope the regulator is OK.

Let us know the progress.

[skids]

You can use a solid state volt regulator. They are about as big as a nickel. I am not too sure where you can get one (Radio Shack?) Ask for a heat sink while you are at it, if you decide to do this.

Originally posted by randy
To test, pull the plug at the fuel sender and put a meter on the socket side (lead from the bike harness) you should read 7 volts while running, regardless of rpm. My guess is that you'll see the voltage rise with rpm.

[randy]

Sure,

5V and 12V regulators are a dime a dozen, but has anyone found a 7V one?

[XS11Hollywood]

Re: Fuel gauge reads too high and goes up with high rev

Originally posted by XS11Hollywood
Help please..... I installed a new tank sending unit today and it still floats slowly way above whats in the tank. It will kinda seem close then it slowly floats up.. with rpm.
I am going nuts Yesterday I installed a used ebay tach thinking it was the problem..

Thank You Randy... much appreciated

I wanted to say if anyone else decides to modify their old tach gasket, causing the casings to go much closer together, they need to make sure that the two threaded gauge lead studs don't touch/are insulated against the casing or they will fry that regulator.

The acorn nuts stop that from happening though you might use washers like me and they'll touch.

[DiverRay]

Randy,
A small board, 12V reg, and a trimmer to adjust to 7V.
This should be easy for someone with your skills
Ray

[andreashweiss]

I have a tach for the standard model that is complete glass good,black finish OK,I can beat ebay price by quite a bit, $15.00 includes shipping priority mail 2 day delivery. If it does not work and solve your problem will refund cost minus shipping. andreashweiss@yahoo.com

[randy]

I smell a challenge!

Maybe after I burn up my two spare guage regulators I'll delve into this. Right now, got no time, spring is upon us and WV is right after that! And i've already got a ton of mini-projects backing up:

Install my NOS Speedo and NOS Tach

Finish painting of the carbs and 140 mains

Polish the fork lowers

Clear coat the engine covers

Mount slotted brake rotors (thank you Andreas)

Lube driveshaft splines

Mount fron fender (thank you Bruce)


All this in the middle of reconstruction of the house due to a fire on Jan 26. Nobody hurt, garage untouched, but can't live in the house for 3-4 months!

Maybe i'll move in to the garage, where life is beautiful all the time!

[XS11Hollywood]

Re: Fuel gauge reads too high and goes up with high rev

Originally posted by XS11Hollywood
Help please..... I installed a new tank sending unit today and it still floats slowly way above whats in the tank. It will kinda seem close then it slowly floats up.. with rpm.
I am going nuts Yesterday I installed a used ebay tach thinking it was the problem..

Thanks Andreas!
I have emailed you...

[LoserShoes]

LM317 adjustable regulator, set the output voltage with two resistors.
Same shape and size as the fixed regs, TO220.
Steve