Another solution for the expanding tank problem

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MartDude · #1 Post by **MartDude** » Sat Mar 16, 2013 10:01 pm

Found the link to this over on AF1.

http://www.ktmforum.co.uk/rc8-superbike ... blues.html

"common problem with plastic tanks if left off for a while, i get it on my KTM RC8 as do many others, i simply put a ratchet tie strap round the front of the tank mounting and round the rear tyre with it in gear or the rear brake on, then tighten up the strap and ratchet away till it comes in line with the holes "

#2 Post by **mangocrazy** » Sat Mar 16, 2013 11:56 pm

I read through to the end of that thread, and it sounds like the ratchet strap manoeuvre will work in some cases, but not necessarily all. One guy got to the point of doing this:

My problems eventually begun - when I tried to get the "bugger" back on the bike... My tank was definitely 1 cm to long!!! Even with squeezing - in screw drivers - I could not arrive to a point - where I could fit in the front screws into the threaded holes in the frame...

I then had a talk with a plastic specialist and with the painter - and together we found out a solution for curing the situation!

We bolted the tank - at the aft holes - into a solid wooden cradle... We then heated up the tank with hot air - comming from a big hot air fan that is usually used to dry out houses after he construction work... We then "squeezed" the tank together - with span - bands - until he was 3 mm shorter than the ideal measurement... We then bolted it also down to the wooden cradle - at the front holes... The tank was then subsequently filled up completely with cold water of 4° Celsius and brought back to ambient temp. It staid there - screwed to the cradle - for 2 full days... After that - I drained the tank and dried it out. Before it was mounted to the bike - it was flushed with a small amount of fuel - in order to get rid of the last amount of residual water...

Which sounds like a fairly hellacious amount of work to get one's tank back to workable dimensions.

How long before manufacturers start making fuel tanks in stainless steel if the current ethanol nonsense persists? It's about the only material that can resist the effects of this pernicious shit fuel.

blinkey501 · #3 Post by **blinkey501** » Sun Mar 17, 2013 7:19 am

I find that interesting reading mart. Are you looking at buying a KTM or something

I wonder if it would be worthwhile strapping the tank after disconnecting the bolts at the head stock when the bike is not in use. "Long term" over the winter months maybe.
With the mounting bracket having slots in maybe strap the tank until the tank is at the shortest hole? Or more?
I still wouldn't buy supermarket unleaded petrol or any standard unleaded for that matter even if this method works.
When myself and pete was at the 1000 bikes last year there was a flyer handed to everyone who attended, and one of the advertisements showed a miracle cure by declaring they had a solution in a bottle which with a few drops in each fill up made the ethanol content in the petrol miraculously vanish maybe this could be another solution to our problems

BikerGran · #4 Post by **BikerGran** » Sun Mar 17, 2013 12:34 pm

Frost are one of the most reputable companies selling additives etc - they have an anti-ethanol additive but their detailed description of what it can do has nothing about plastic fuel tanks, and does say that it doesn't cure all the problems created by ethanol.

MartDude · #5 Post by **MartDude** » Sun Mar 17, 2013 1:57 pm

blinkey501 wrote: Are you looking at buying a KTM or something

Not unless I win the lottery - RC8R with a Futura subframe, seat & panniers

wayno · #6 Post by **wayno** » Sun Mar 17, 2013 7:09 pm

I just undo the rear bracket that holds the tank down, then put the fronts in half way, the back one pivots so is a lot easier to get in.

falcomunky · #7 Post by **falcomunky** » Tue Mar 19, 2013 11:25 am

Funny, but I've never suffered this problem... Until this last week!

I ride ALL year round so she's never stood for more than a day or so, but after putting new plugs in last week I went to close the tank down and I couldnt get the front bolts in!
Remedy? I filed the front bracket down (to give more clearance as it passes the top yoke) and elongated the bolt holes.

Works fine (for now) but is it really the fuel/ethanol causing the problem or ageing neoprene?

D-Rider · #8 Post by **D-Rider** » Tue Mar 19, 2013 12:14 pm

falcomunky wrote:Funny, but I've never suffered this problem... Until this last week!
I ride ALL year round so she's never stood for more than a day or so, but after putting new plugs in last week I went to close the tank down and I couldnt get the front bolts in!
Remedy? I filed the front bracket down (to give more clearance as it passes the top yoke) and elongated the bolt holes.
Works fine (for now) but is it really the fuel/ethanol causing the problem or ageing neoprene?

Mine's grown (beyond the point of adjusting holes) and I don't wear neoprene.

über pikey · #9 Post by **über pikey** » Mon Apr 29, 2013 2:20 pm

I am in work 122 miles away from my garage, my garage has my motorcycle in which has had the tank removed for over 2 weeks, who thinks this might be an issue???

Dalemac · #10 Post by **Dalemac** » Mon Apr 29, 2013 3:20 pm

über pikey wrote:I am in work 122 miles away from my garage, my garage has my motorcycle in which has had the tank removed for over 2 weeks, who thinks this might be an issue???

If there is no fuel in the tank then it has probably shrunk. If there is fuel in the tank, expanded.

Dale

blinkey501 · #11 Post by **blinkey501** » Mon Apr 29, 2013 7:27 pm

Dalemac wrote:
über pikey wrote:I am in work 122 miles away from my garage, my garage has my motorcycle in which has had the tank removed for over 2 weeks, who thinks this might be an issue???
If there is no fuel in the tank then it has probably shrunk. If there is fuel in the tank, expanded.

Dale

I have just had a tank painted that has had no fuel in it for two months.
I had to fit the tank at the head stock first and then line the bolt holes up under the seat area.
The damage is done.

über pikey · #12 Post by **über pikey** » Tue May 07, 2013 1:47 pm

The Futura has two large rubber mounts at the rear of the tank, the only way I could get the tank back on was to trim the rubber mounts. With the tank back on and the bike refuelled I have inherited two other faults, oh the F****g joy....