1998 VFR - Fuel Leak and Fuel Gauge Oddity

I've searched the forum for "leak fuel tank" to try and see if anyone has ran into this issue before, but didn't find it.

Long story short, my bike sat for a bit over a year and I had it revived at a shop nearby that has good reputation with older bikes. He removed the tank, drained, cleaned and treated the interior, and replaced the fuel pump gasket with an OEM honda part. I picked up the bike not too long ago and noticed that there's now a fuel leak (didn't seem to be one there before).

So I bring the bike back in and they cleaned the area thoroughly to examine the issue. Found that it seems to be leaking from one of the bolts (from an exterior inspection). So the initial assumption is that the gasket didn't have a proper seal, etc...

Drained the tank again, cleaned up the surface where the gasket mates to, reinstalled the gasket. Still leaking.
Tried to use a sealant as per mechanic on the seal surface, let cure for 24 hours. Still leaking.

As per the mechanic, he thinks it's somehow leaking from the bolt hole channel?

Is this a common issue? Heard of this happening before?

Another tidbit of info, which I'm not sure is related at all, is that the fuel gauge is not behaving oddly as well. I picked up the bike with 1 bar of fuel on the gauge. Went to fill it up and when I started the bike up the fuel gauge was still at 1 bar. It wasn't until a few minutes later that it sloooooowly started creeping up to a full tank.

I did see in one thread that someone mentioned cleaning the tank with citric acid caused an issue with the fuel gauge mechanism. Not sure if that could be related.

Any input is welcomed. Thanks!

 

Empty tank and take a look - generally if the gauge looks bad then that's how it will work...

I'd be tempted to add another gasket...

You may have a rusty fuel tank and although there are ways of fixing it they may be beyond your level.

 

It had a rusty tank and it was cleaned and treated by the shop prior to the fuel leak issue. I was wondering if there was some kind of precedent to that particular leak location. Thanks for the input!

 

how did they clean it & what treatment did they use ?

 

I never asked honestly but I'll put that question out there the next time I'm over.

On the fuel gauge issue, does it affect anything else electronics wise? Basically if the fuel gauge eventually dies, aside from the minor inconvenience of having to track trip mileage and peeping into the tank once in a while, is there anything stopping the bike from running properly?

 

I had a leak on my 1999 with a brand new tank, thought I was smart and could re-use the old gasket since a new one was on backorder. Wrong. But what I did find is that the flange was slightly bent and I gently straightened it up. My leak (externally) appeared to be from a stud also, but wasn't the case. New gasket fixed me up.....

 

Yeah I was hoping that would cure it too but it seems not to be the case, for now at least. Fingers crossed is all I can do for now.

 

Any bike with a reserve tap doesn’t really need a gauge.. Just drive till you hit reserve, switch over and get gas. Then switch the tap back to on.

 

Wait... 5th gens have a reserve? I wasn't aware of this.

This brings up another question, if the fuel gauge sender is bad (or the float is sticking), would it ever show the blinking fuel light/reserve light?

 

No 5Gs don't have a reserve.

The fuel sending unit is a simple varying resistance device operated by a moving float. When the tank is full, the resistance should be lowest, when empty it will be highest. The float arm could be stuck/sticky so not moving freely, or the variable resistor might be faulty. If there is a break in a wire or a connector, you will see high resistance and I assume the dash will show the flashing low level indicator. Any issue with the earth connection (green/blue wire) to the chassis earth will also cause high (or infinite) resistance and give a low fuel level, so it is worthwhile checking the electrical continuity between that wire at the plug, and the frame.

 

Thanks for the detailed reply Terry!

I specifically recall a scenario where I rode the bike and shut it off with a 3/4 full tank, and the gauge reflected that correctly as well. When I returned to the bike ~2 hours later the fuel gauge read 1 bar, and slowly started climbing up to read a higher (most likely actual) fuel level. Even if the bike was parked on the kickstand I doubt that the float would be able to sink down to "1 bar" level when the tank was relatively full. This makes me lean toward it being an electrical issue. I won't discount an issue with the float but for the time being it seems checking the wiring would be the easier route to troubleshoot. That is, once I get the bike back from the shop with the hopes that they sort out the leak.

Thanks again.

 

sorry didn't realise it was a 5th gen - my bad - didn't see the title on my pad at the time..

 

Fuel leak is sorted.

Looks like a third go at it took. With scraping the mating area clean, a bit of sealant, a new gasket, and a light touch... all was solved.

Fuel gauge is still wonky and I'll be looking at that in the next couple weeks when I have the time.

Thanks for all the input.

 

great news - keep us updated

 

The "breakthrough realization" you have to come to with a 5th Gen: The reality of a 20 to 22 year-old motorcycle is that every "consumable" item on the bike is now at or well beyond its intended lifespan. For the 5th Gen bikes the "maintenance honeymoon" is well and truly over. At this point anything that can fail will fail.

If you disturb a 22 year-old seal or gasket it will leak if you don't replace it.

 

Honestly... if this was a 22 year old GSXR or CBR... I'd have sold it for dirt cheap and just moved on to a slightly younger model.

But I genuinely love how unique this bike is. There's nothing out there that quite sounds like it (especially not at the price point), the ride is truly magnificent, it's relatively comfy (compared to my old 675 this bike is plush), and did I mention the sound? Ha.

Anyway, she's on her way to being mechanically very sound. She *feels solid at the moment, but I have a list going, in order of priority:

- Clean the decade of semi permanent grime on the swingarm + frame + motor +under tank surfaces. Toothbrush and simple green time.
- Will definitely swap out the R/R for a wire my bike kit w/ VFRness.
- Brakes are de-linked but the rear is still not very powerful, will stop the bike... but will not lock the rear under any amount of force. Front brakes are perfect.
- Rear brake flasher relay install.
- Throttle tube is so skinny. Long distance riding will be uncomfortable for me at some point. Will look into either a thicker grip or shorter turn tube + grip.
- Along the same lines, the throttle grip/tube/clip on get pretty buzzy above 7k. Wonder if they make model specific weighted bar ends for the 5th gen still.
- Upgrade to Datel for new voltmeter.