Go Back   Horizons Unlimited - The HUBB > Technical, Bike forums > BMW Tech
Petrol tank modification Petrol tank modification
Register FAQ Calendar Today's Posts
BMW Tech BMW Tech Forum - For Questions specific and of interest to BMW riders only.
Photo by Andy Miller, UK, Taking a rest, Jokulsarlon, Iceland

I haven't been everywhere...
but it's on my list!


Photo by Andy Miller, UK,
Taking a rest,
Jokulsarlon, Iceland



Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 11 Dec 2006
Contributing Member
HUBB regular
  
Join Date: Mar 2006
Location: England
Posts: 37
Petrol tank modification
I have a 32ltr petrol tank off a R100 gs.My question is, can It be modified to hold an extra 2 imperial gallons /9lts,by welding some extra sheet steel to the bottom on both sides of the tank.If so,will the original tank be able to take the extra weight of fuel, or will it possibly split some where.
Obviously if that is the case,what mods are req to strengthen the tank and where on the tank.
Reply With Quote
  #2  
Old 11 Dec 2006
Grant Johnson's Avatar
HU Founder
Veteran HUBBer
  
Join Date: Dec 1997
Location: BC Canada
Posts: 7,313
Talking
I doubt you'll get a definite answer on this one - not likely anyone's done it before, though you never know.

My best guess - no problem - remember that the tank is strong enough to take a heavy tank bag, and I've NEVER heard of a tank splitting from a too-heavy tank bag.

You could always just add something in the center of the tank for support to be safe - kind of a rubber pillar in the center of the frame tube to add one more contact point.

There are loads of large tanks out there, might be worth a look before you start welding. Welding fuel tanks is not fun, you'll need a really good welder who's done tanks before.

Let us know how it works out!
__________________
Grant Johnson
Seek, and ye shall find.
------------------------
Inspiring, Informing and Connecting travellers since 1997!
www.HorizonsUnlimited.com
Reply With Quote
  #3  
Old 16 Dec 2006
Gold Member
Veteran HUBBer
  
Join Date: Mar 2001
Location: British Columbia
Posts: 246
Red face
Interesting project! I thought of doing this to the stock tank on my R80 G/S, which is very small (a whooping 23 liters if I recall correctly..). I think the reality of doing it would be quite difficult, even if you weren't to worried about appearences. One of the challenging parts is re-sealing the metal sufficiently to prevent rusting. If you go ahead with it, there is a product designed to seal the inside of the tank (The BMW tanks I have owned had it). This keeps corrosion to a minimum. I have done welding on tanks before - it is very difficult to get a good seal, as the metal is thin and even hairline cracks will leak a surprising amout of fuel.

Personally, if it was me, I'd sell the PD tank (which should be easy, they are in demand) and purchase an Acerbis 43 liter tank.

However, that is the boring route - much more interesting to modify you own tank! Good luck, I'm interested to hear how you get on with it.
Reply With Quote
  #4  
Old 16 Dec 2006
Contributing Member
HUBB regular
  
Join Date: Mar 2006
Location: England
Posts: 37
It is not impossible to expand(nothing is impossible as the saying goes) the capacity.I still have to see my welder to get his opinion on the practicalities of doing a satisfactory job.
I will let you all know what happens.
Reply With Quote
  #5  
Old 7 Nov 2007
Registered Users
HUBB regular
  
Join Date: Nov 2007
Posts: 22
it's possible
hi there,
the guy i bourght my r80gs had a photo of his first r80gs in his shed which had an expanded pd on it.
he said he bourght if of a guy who expanded it to do the finke rally in australia.
he couldn't remember how much it was expanded by, 40l ish.
he rode the thing all over australia with no problems, so i wouldn't be too worried about it holding the extra fuel.
chris
Reply With Quote
  #6  
Old 7 Nov 2007
AliBaba's Avatar
Registered Users
Veteran HUBBer
  
Join Date: Apr 2001
Location: Norway
Posts: 1,379
I'm sure it is possible, but maybe it's better to buy a 43L Acerbis? It is better attached to the frame and the cost is not that bad (500€).
Reply With Quote
  #7  
Old 7 Nov 2007
Registered Users
Veteran HUBBer
  
Join Date: Jun 2007
Location: Ripley, Derbyshire
Posts: 373
I had the same problem with my little Dakar (skinny calf that she is) now do I pay for the £1500 Touratech tanks, spends days fitting them OR do I buy and use 2 x 5lt jerry cans @ £5 fot both?

Which one did I go for? there are two kinds of project:

1. Much needed and balanced between usefulness time and money
2. The other is a waste of all the above for little gain

Decide which one this fits into in your view and work from there.

The voice of reason
Reply With Quote
  #8  
Old 7 Nov 2007
Guest2
Guest
  
Posts: n/a
Give some thought to the safety aspect. That goes for a modified tank and cans of petrol. The tank will be untested and could possibly fail in harsh use or accident with dire results. Cans of fuel can be holed if not carried correctly or pressurized in the sun.

Petrol is dangerous stuff if handled badly.

Steve
Reply With Quote
  #9  
Old 11 Nov 2007
Registered Users
Veteran HUBBer
  
Join Date: Jun 2005
Location: Cape Town / South Africa
Posts: 207
Quote:
Originally Posted by AliBaba View Post
I'm sure it is possible, but maybe it's better to buy a 43L Acerbis? It is better attached to the frame and the cost is not that bad (500€).
My thoughts exactly.
The problem with the BMW mounted tank is that it only rests on a small pipe behind the steering head and on two rubbers at the back. For the 19l tank this is more than sufficient but by the time you increase the weight to that of 32 litres of fuel I become doubtful of how secure it is. besides the mounting provide no support for sideways movement on the tank.
The Accerbis or HPN 43L tank have added supports that fit on the down tubes of the main frame and rest on rubbers on top of the main tube. It also bolts to the mounting in the back, much more secure than the flimsy wire clip on the BMW tanks.
It will not take any modification if fitted to a pre 87 GS and some work to the seat of Post 87 bikes and on the 100GS you will have to relocate the cooler.
The tank itself are fitted by mounting three bolt-on brackets to the main frame and can be done in less than an hour.
Reply With Quote
  #10  
Old 11 Nov 2007
Registered Users
Veteran HUBBer
  
Join Date: Aug 2007
Location: Sax, Spain
Posts: 901
my 2p's worth....
keep standard tank, carry fuel in jerry cans. that way if you have an 'off' its probably safer.
also if you have "modified" your tank or had it modded and not told your insurance company..........and it leaks and sets fire to your bike..... they wont pay. (Most Insurance companies are OK if you tell them what you do, but some get snotty and want engineers reports and then try to hike the premiums) anyway thats my 2ps worth... Jerry cans r less hassle!

Save the extra money for travelling.which is what a bike is for!!!!!!!!!!!
Reply With Quote
  #11  
Old 19 Nov 2007
Registered Users
HUBB regular
  
Join Date: Oct 2007
Location: Iowa
Posts: 16
just start welding! i would sugest maybe some internal bracing to reduce flexing, but dont see why it wouldnt hurt, also maybe make it a split tank so just in case one did tear or crack youd still have a spare tank.
Reply With Quote
Reply

« Previous Thread | Next Thread »

Currently Active Users Viewing This Thread: 1 (0 Registered Users and/or Members and 1 guests)
 

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
re-use petrol tank for water gozell Equipping the Bike - what's the best gear? 2 2 Dec 2006 02:04
Picture(s) needed: KTM LC4 620 Petrol tank mounting points. chris KTM Tech 0 9 Oct 2006 00:21
Aftermarket LARGE petrol tank Iain Yamaha Tech 18 7 Nov 2005 18:51
Wanted AF-Twin RD04 petrol tank chris TRAVEL Equipment for Sale / Wanted 2 28 Mar 2005 01:33
Large Petrol Tank andre Equipping the Bike - what's the best gear? 1 8 Jul 2000 03:30

 
 

Announcements

Thinking about traveling? Not sure about the whole thing? Watch the HU Achievable Dream Video Trailers and then get ALL the information you need to get inspired and learn how to travel anywhere in the world!

Have YOU ever wondered who has ridden around the world? We did too - and now here's the list of Circumnavigators!
Check it out now, and add your information if we didn't find you.

Next HU Eventscalendar

ALL Dates subject to change.

2025 Confirmed Events:

  • Virginia: April 24-27 2025
  • Queensland is back! May 2-4 2025
  • Germany Summer: May 29-June 1 2025
  • CanWest: July 10-13 2025
  • Switzerland: Date TBC
  • Ecuador: Date TBC
  • Romania: Date TBC
  • Austria: Sept. 11-14
  • California: September 18-21
  • France: September 19-21 2025
  • Germany Autumn: Oct 30-Nov 2 2025

Add yourself to the Updates List for each event!

Questions about an event? Ask here

See all event details

 
World's most listened to Adventure Motorbike Show!
Check the RAW segments; Grant, your HU host is on every month!
Episodes below to listen to while you, err, pretend to do something or other...

Adventurous Bikers – We've got all your Hygiene & Protection needs SORTED! Powdered Hair & Body Wash, Moisturising Cream Insect Repellent, and Moisturising Cream Sunscreen SPF50. ESSENTIAL | CONVENIENT | FUNCTIONAL.

2020 Edition of Chris Scott's Adventure Motorcycling Handbook.

2020 Edition of Chris Scott's Adventure Motorcycling Handbook.

"Ultimate global guide for red-blooded bikers planning overseas exploration. Covers choice & preparation of best bike, shipping overseas, baggage design, riding techniques, travel health, visas, documentation, safety and useful addresses." Recommended. (Grant)



Ripcord Rescue Travel Insurance.

Ripcord Rescue Travel Insurance™ combines into a single integrated program the best evacuation and rescue with the premier travel insurance coverages designed for adventurers.

Led by special operations veterans, Stanford Medicine affiliated physicians, paramedics and other travel experts, Ripcord is perfect for adventure seekers, climbers, skiers, sports enthusiasts, hunters, international travelers, humanitarian efforts, expeditions and more.

Ripcord travel protection is now available for ALL nationalities, and travel is covered on motorcycles of all sizes!


 

What others say about HU...

"This site is the BIBLE for international bike travelers." Greg, Australia

"Thank you! The web site, The travels, The insight, The inspiration, Everything, just thanks." Colin, UK

"My friend and I are planning a trip from Singapore to England... We found (the HU) site invaluable as an aid to planning and have based a lot of our purchases (bikes, riding gear, etc.) on what we have learned from this site." Phil, Australia

"I for one always had an adventurous spirit, but you and Susan lit the fire for my trip and I'll be forever grateful for what you two do to inspire others to just do it." Brent, USA

"Your website is a mecca of valuable information and the (video) series is informative, entertaining, and inspiring!" Jennifer, Canada

"Your worldwide organisation and events are the Go To places to for all serious touring and aspiring touring bikers." Trevor, South Africa

"This is the answer to all my questions." Haydn, Australia

"Keep going the excellent work you are doing for Horizons Unlimited - I love it!" Thomas, Germany

Lots more comments here!



Five books by Graham Field!

Diaries of a compulsive traveller
by Graham Field
Book, eBook, Audiobook

"A compelling, honest, inspiring and entertaining writing style with a built-in feel-good factor" Get them NOW from the authors' website and Amazon.com, Amazon.ca, Amazon.co.uk.



Back Road Map Books and Backroad GPS Maps for all of Canada - a must have!

Your ad could be here, on EVERY page of the HUBB, or the whole website, or as many as you like!

New to Horizons Unlimited?

New to motorcycle travelling? New to the HU site? Confused? Too many options? It's really very simple - just 4 easy steps!

Horizons Unlimited was founded in 1997 by Grant and Susan Johnson following their journey around the world on a BMW R80G/S.

Susan and Grant Johnson Read more about Grant & Susan's story

Membership - help keep us going!

Horizons Unlimited is not a big multi-national company, just two people who love motorcycle travel and have grown what started as a hobby in 1997 into a full time job (usually 8-10 hours per day and 7 days a week) and a labour of love. To keep it going and a roof over our heads, we run events all over the world with the help of volunteers; we sell inspirational and informative DVDs; we have a few selected advertisers; and we make a small amount from memberships.

You don't have to be a Member to come to an HU meeting, access the website, or ask questions on the HUBB. What you get for your membership contribution is our sincere gratitude, good karma and knowing that you're helping to keep the motorcycle travel dream alive. Contributing Members and Gold Members do get additional features on the HUBB. Here's a list of all the Member benefits on the HUBB.



All times are GMT +1. The time now is 19:37.

Contact Us - Horizons Unlimited Motorcycle Travellers Website - Archive - Privacy Statement - Top