Leaky fuel cap fix

[Hammerhead]

Step #1: 

  Don’t blame me if this idea fails you & doesn’t work. (though I’d almost bet my bike it will)  My success does not = yours. Zero guarantees are made, nor should you confuse this with my recommendation that you actually do it. You’ll be increasing the thickness of your stock cap seal & it will result in  a cap requiring considerably more pressure to latch. It should also feel far more secure when latched.
 

  Now that little disclaimer is out of the way, proceeded to step #2; 

   Source an appropriately sized O ring from your local auto parts dealer to fit the inside & outside diameters of the spring loaded stock cap seal.

 

  Step#3;

Carefully slice said O ring into two halves like you would a bagel.(Canadians may be better at this). I created two small blocks of plywood with circular cut grooves (hole

saw) of the right size to clamp the O ring in with a razor knife thickness left between them. Accurate slicing was then challenging but doable. 
 

 Step#4;

   Place the flat sliced side of your bagel half against the cap seal & dry test to see it isn’t too thick for your cap to still be pressed into place. Considerably more pressure may be required to overcome the spring & get the cap latch dogs to click in. 
 

  Step #5; 

  Carefully fine tune & trim flat cut side of O ring bagel to adjust thickness till cap latches without excessive pressure being required. 
 

  Step#6; 

 Clean both surfaces with some isopropyl alcohol & then, using a thin coating of fuel safe flexible gasket maker, adhere new bagel gasket to your stock cap seal.

Install to tank to add even pressure.

Remove, check for & wipe away any excess sealer squeeze out. reinstall on tank for curing. Allow gasket sealer to dry as per product recommendations. 
 

Step#7; 

   Fill your tank with petrol & perform a test of your new seal with a simulated trail nap. (lay your bike down) Include wiggling your cap around & applying uneven pressure to it front to back & side to side. If you’ve nailed the bagel thickness, your cap should no longer have that half loose feel or have any spring left that allows you to still push it down when it’s latched.

 

   Step#8; 

Pick up your bike & go grab a cold beer to rejoice in celebration of home repairing a factory defect that’s been pissing you off since the first time you noticed it. Pat yourself on the back & forget about puking petrol on Mother Nature, your tank bag,

you or the bike ever again. 

 

 I nailed it first try, full tank doesn’t spill a drop. Good luck!

[Hammerhead]

Forgot the pictures

[Landshark]

My old KLR did the same thing.  If it tipped over, out would come lots of fuel.  I didn't know whether to run away for fear it would catch fire or to pick it and save the cost of lost fuel.  

 

[Hammerhead]

Unacceptable malfunction to this fuss arse. Worthy of repair one way or another.

[Neil]

I did a slightly modified version of Hammerheads fix. I tried slicing O-rings into bagels, but couldn't get an even enough cut to seal properly. So I used a 2mm thick M36 neoprene washer (trimmed to size). 2mm is the MAXIMUM usable thickness (I had some perfectly sized rubber washers at 2.4mm thick, and the cap would not close). Even at 2mm, it is an effort to get the cap to click back on (if you can get hold of 1.5-1.8 mm, that would probably be ideal). Watch you don't twist or snap your key when "forcing" the cap back on!! You have been warned!! I haven't glued the washer into place as it sits quite happily in the cap. I'll see how that one goes.

So, a big thank you to Hammerhead for the fix, I owe you a beer.

[Simmons1]

22 hours ago, Neil said:

I did a slightly modified version of Hammerheads fix. I tried slicing O-rings into bagels, but couldn't get an even enough cut to seal properly. So I used a 2mm thick M36 neoprene washer (trimmed to size). 2mm is the MAXIMUM usable thickness (I had some perfectly sized rubber washers at 2.4mm thick, and the cap would not close). Even at 2mm, it is an effort to get the cap to click back on (if you can get hold of 1.5-1.8 mm, that would probably be ideal). Watch you don't twist or snap your key when "forcing" the cap back on!! You have been warned!! I haven't glued the washer into place as it sits quite happily in the cap. I'll see how that one goes.

So, a big thank you to Hammerhead for the fix, I owe you a beer.

Where did you source the washer?

 

Thanks!

[REDHORSECA]

I've been looking for a rubber flat washer or O-ring that may work.

 

Found some rubber M42 rubber washer from UK that is about 2mm. Also eBay has silicon washers from China. The China washers don't have specific info on ID and thickness.  Still searching for a source in the US.

 

I measured out the T700 gas cap.

 

ID -1.68" / 42.75mm (metal at the widest by the rubber seal)

ID - 1.49" / 37.75mm (metal tapers down just above the widest point)

OD - 2.10" / 53.5mm (outside edge of the rubber seal, just before the lip)

 

From posts above, looks like 0.08" / 2mm thickness is about the maximum recommended before it gets too hard to close the gas cap.

 

 

[Neil]

Simmons1 : I got them online from a company based in the UK (as am I). I'll PM you the link of you are in the UK. If you are in the U.S or elsewhere, you'll  no doubt find something cheaper locally. Cheers.

[Simmons1]

2 hours ago, Neil said:

Simmons1 : I got them online from a company based in the UK (as am I). I'll PM you the link of you are in the UK. If you are in the U.S or elsewhere, you'll  no doubt find something cheaper locally. Cheers.

Thanks. I am in the US.

[Hammerhead]

On 6/10/2021 at 7:26 AM, Neil said:

I did a slightly modified version of Hammerheads fix. I tried slicing O-rings into bagels, but couldn't get an even enough cut to seal properly. So I used a 2mm thick M36 neoprene washer (trimmed to size). 2mm is the MAXIMUM usable thickness (I had some perfectly sized rubber washers at 2.4mm thick, and the cap would not close). Even at 2mm, it is an effort to get the cap to click back on (if you can get hold of 1.5-1.8 mm, that would probably be ideal). Watch you don't twist or snap your key when "forcing" the cap back on!! You have been warned!! I haven't glued the washer into place as it sits quite happily in the cap. I'll see how that one goes.

So, a big thank you to Hammerhead for the fix, I owe you a beer.

Cheers, mate! Glad others are finding success with this. Liking  your washer idea vs the O ring. Accurate slicing was indeed a challenge. Ideal thickness is paramount to avoid making it too tight for the key alright. If you do opt for glue, this is the goop I used. Still holding its own. If I ever wind up across the pond, i’ll take you up on that beer  (after a good ride of course!)

[Camel ADV]

Great fix @Hammerhead!

[Hammerhead]

 Cheers @Camel ADV, there’s  sure to be siphon for my future camel tank!

[chuckqc]

like this one ? mcmaster o-ring

just be sure to use the right material like BUNA (nitrile) some have fair or poor resistance 

Which Elastomer Offers The Best Oil & Fuel Resistance?

---

Our latest technical guide takes a look at which elastomer offers the best oil and fuel resistance for use when choosing base materials.

 

 

 

[Yammybound88]

@chuckqc I ordered these online.  After the order was completed they sent me this message:

"Due to the cost and complexity of shipping our products to Canada, we are only able to accept orders from businesses and schools. We’ve canceled your order. 

If this material is not for personal use, please resubmit your order online using the organization's name. "

 

Funniest thing I have ever run into.

 

I will try and source some from Canada.

 

Cheers

-Bob

 

 

[FernieT7]

Thanks for the tip. Love your disclaimer, BTW. I will give it a try and see how good my surgical skills are.

 

On the Yamaha note, I did mention to them in my email that this is a common problem and that I have now notified them in writing about it in the event that something bad happens in the future.  i.e. they were notified and did nothing about it so will be fully liable for damages.

 

Such a great bike, not sure why they put such a dumb cap on it. You'd think they would have field tested it before going commercial.

[Hammerhead]

Give it a go @FernieT7, good luck. I went with halving an o-ring ‘cause it was fuel safe. The flat washer would be easier if appropriate material of ideal thickness.

  To make such an affordable machine they had to cut some corners I guess. But agreed, it never should have passed factory QC, for numerous reasons. 

[TheFirePT]

Great fix, need to do it someday!

 

[DonaNobisPacem]

On 11/7/2021 at 2:26 AM, Hammerhead said:

Give it a go @FernieT7, good luck. I went with halving an o-ring ‘cause it was fuel safe. The flat washer would be easier if appropriate material of ideal thickness.

  To make such an affordable machine they had to cut some corners I guess. But agreed, it never should have passed factory QC, for numerous reasons. 

Do you remember what the dimensions of the O-rings you used are? I've read in the thread that the recommended thickness is around 2mm but I'm still confused about what the diameter should be.

[Hammerhead]

1 hour ago, DonaNobisPacem said:

Do you remember what the dimensions of the O-rings you used are? I've read in the thread that the recommended thickness is around 2mm but I'm still confused about what the diameter should be.

Negative. Never did measure, just went old school & took the cap to the local auto parts to size up one that fit. @REDHORSECAlisted some dimensions earlier  in this thread though.    
 

    Ideally you can find a 1.5 - 2mm flat unit to save the awkward slicing step. I wound up with halving the O-ring because. a) fuel safe material & b) all I could find that fit the cap dimensions but was way too thick. 
 

 Good luck!

[Camel ADV]

We've been testing a fix for this for a few months. It is basically the same fix as the o-ring solution above without the slicing. It is simply a flat washer cut out of Viton. 

 

I'm waiting to hear back about the bulk price from the place cutting them for us. We should have them on the site in a couple weeks.

[Bruincounselor]

I'm still waiting on my '22 to arrive so it's possible I'm not grasping the source of the leaky cap, but couldn't you source a viton o-ring of the right ID and cross section and be done with it? There's an infinite number of sizes:

 

 

Order O-Rings Quick and Easy X-Ring Seals Rubber Washers

 

[Hammerhead]

Update; 

   Camel tank install reveals this fix to be working a charm. Test ride siphoned straight from auxiliary & left the main tank full after a solid 100km. No shortage of vacuum created by a fully functioning seal. 

[DonaNobisPacem]

That's good to hear. I'm still waiting on the fix Camel ADV has coming in.  On a side note, when I went to fill up on gas the other day, a bit of fuel sprayed out of my tank when I popped off the cap. Scared me a bit, actually. Dunno what that was about, maybe the pressure my tank bag exerts constantly sitting on top of it has some effect?

[Camel ADV]

On 11/26/2021 at 1:07 PM, Bruincounselor said:

I'm still waiting on my '22 to arrive so it's possible I'm not grasping the source of the leaky cap, but couldn't you source a viton o-ring of the right ID and cross section and be done with it? There's an infinite number of sizes:

 

 

Order O-Rings Quick and Easy X-Ring Seals Rubber Washers

 

 

The issue is that O-rings are round (or square or D or x).... If the o-ring is wide enough, it's too tall and doesn't allow the cap to close properly. Because of that, the o-ring needs to be sliced like a bagel to get the width without the height. 

@Hammerheaddid the research and heavy lifting on this fix. Slicing o-rings with razor blades isn't the easiest task so we've made a plug and play seal for people who value their finger tips.

[Uncle M]

46 minutes ago, Camel ADV said:

 

The issue is that O-rings are round (or square or D or x).... If the o-ring is wide enough, it's too tall and doesn't allow the cap to close properly. Because of that, the o-ring needs to be sliced like a bagel to get the width without the height. 

@Hammerheaddid the research and heavy lifting on this fix. Slicing o-rings with razor blades isn't the easiest task so we've made a plug and play seal for people who value their finger tips.

@Camel ADV  Last summer I found my tankbag pressing down on the fuel cap stopped the siphoning effect for the aux tank to drain into the main tank, so hopefully your solution will fix that problem!