Big Tank

winger · Post by **winger** » Sat Nov 11, 2006 4:43 pm

I've had a couple of PM's asking about the tank conversion so here goes,have an extra piece welded on the bottom of the tank which gives an extra 4 litres so essentially gives you an 18 liter range and some,as the actress said to the Bishop that extra little bit makes all the difference!!!.

If you ABS then it's a no goer i'm afraid,you don't have the room as the abs pump takes up the room of the extension,if you have a big battery because of heated grips,then i sell you a smaller battery so you can have the best of both worlds,no worries about battery size,it's the difference between kill and overkill!!!.

As it's that time of year,i did a group/board deal some years ago for batteries,(I have them on sale or return)both big and small if thats the way your inclined!!!!!,the make(very well known) and price of which i'll tell you if you PM me,the hassle being your either collect,or ask Lloyd(Boxerpan) is he can deliver.

Almost forgot Sproggy,put your two peneeth in,i'm sure there's something i've forgotten,and of course the most important thing i've still got the check if i can get them done!!!!

Chris

sproggy · Post by **sproggy** » Sun Nov 12, 2006 6:18 pm

The big tank gives me about 170-180 miles range BEFORE the light comes on depending on how the bike's ridden. I squeezed 205 miles out of a tankful on Wednesday but that was only because I was on the M25 nowhere near services - 190 miles would have been less worrying. But when I filled up (with a modded fuel filler neck) it only took 19.8 litres so there was plenty left really. It really does make a huge difference.

QD (Quick Disconnect) fuel line connectors are a useful mod if you're changing the tank anyway as this makes tank removal and replacement much easier in future for servicing etc. They're quite expensive even from Motorworks. About £45 a pair, from memory - they were very apologetic when I ordered them as their supplier's just put the price up a lot.

I worried about needing a shorter battery strap when changing from my large battery to the smaller one that Chris supplied, and in fact I ordered one, but the replacement battery is such a snug fit that a strap really isn't necessary - you could turn the bike upside down and shake it and the battery would stay put!

quicksilver · Post by **quicksilver** » Sun Nov 12, 2006 8:31 pm

Hi Ian...What do you mean moded fuel filler neck and what does it do..

Cheers Andy

BockingBandit · Post by **BockingBandit** » Sun Nov 12, 2006 9:59 pm

Andy,.. a couple of neat holes drilled towards the top of the sleeve that enters the actual tank. It allows the air to exit the tank as you fill it. There is a photo of the mod somewhere here , .. i think.

Geoff

quicksilver · Post by **quicksilver** » Sun Nov 12, 2006 10:03 pm

Hi... Anybody got an idea where this picture is or by any chance sproggy can you take a pic or 2 and send them or if anybody knows where the link is that would be great..

Cheers Andy

sproggy · Post by **sproggy** » Sun Nov 12, 2006 11:04 pm

Andy, pictures aren't really necessary. You know the recessed filler neck (the bit you put the nozzle into when you fill up)? Well there's an air gap left at the top of the tank, the depth of that neck. By drilling 2 or 3 holes (about 5mm diameter - the number and size isn't critical) near the top of the neck you allow the trapped air to escape and be replaced with fuel. It doesn't give you much, maybe another half a litre at the most, but with a standard tank every little bit helps!

You also need to bend the overflow chamber upwards a bit otherwise you can't benefit from the extra capcity - most of the extra fuel will just overflow.

To drill the holes and bend the overflow you need to remove the fairings, tank centre cover and filler assembly to be able to then pull the filler neck upwards as far as it'll come. Plug the gaps with rag to stop swarf getting into the tank, and drill carefully. Bend the overflow (solid pipe with a plastic 'lump on the end) upwards a bit. Reassembly is, as they say, the reverse of disassembly. Grease the filler neck O-ring so that it slides into its seat as you tighten things up.

quicksilver · Post by **quicksilver** » Mon Nov 13, 2006 7:04 am

Cheers Ian.....next job then.....

Cheers Guys

Andy

Harry · Post by **Harry** » Mon Nov 13, 2006 10:03 am

I did mine with a single hole (on the rh side away from the side stand) - seems to work ok.

H

POB · Post by **POB** » Mon Nov 13, 2006 10:47 am

For an extra 1/2 litre?? Is it worth the bother? Aren't you better off removing race pipes / inducts / free filters and chips to get back to the OEM leanness and therefore economy?

When you do all take this sensible step, I will take any spare y-pieces, race pipes, inducts and chips off your hands for £2. And that's generous.

sproggy · Post by **sproggy** » Mon Nov 13, 2006 11:35 am

POB wrote:For an extra 1/2 litre?? Is it worth the bother?

That's up to each individual to decide. Half a litre is another 5 miles to find a filling station when you're touring. If this isn't important to you then it's probably not worth the bother. And you won't be interested in a bigger tank either.

POB wrote:Aren't you better off removing race pipes / inducts / free filters and chips to get back to the OEM leanness and therefore economy?

Why do you assume that making the engine run more efficiently by removing restrictions in the inlet and exhaust will result in worse economy?

With an SJ filter, Remus Y, Laser end can and K12RS pressure regulator I'm getting better fuel consumption (and tank range) than I did when the bike was standard despite the fact I know it's running rich at low revs. Fitting a PC will sort this and may improve the economy further.

BockingBandit · Post by **BockingBandit** » Mon Nov 13, 2006 2:06 pm

Ah, ... 'Bending the overfolw pipe upwards', .. why do I always manage to only do half a job lol. In my defence, I did the mod the day I bought the bike so had no idea if I was getting more fuel into the tank or not. I just sorta thought that they 'all' must overlfow like that, .. bugger.

Next job< ...... a little bending.

sproggy · Post by **sproggy** » Mon Nov 13, 2006 2:30 pm

The air gap in the top of the tank is there to allow expansion as the fuel heats up. If you do the filler mod, don't fill the bike right up to the top and then leave it on the sidestand full in the sun because it WILL overflow after a few minutes, even with the overflow pipe bent upwards as far as it'll go. So you should reckon only to use the top bit of the tank if you're going to ride the bike for a few miles straight away after filling up.

POB · Post by **POB** » Mon Nov 13, 2006 2:54 pm

sproggy wrote: Why do you assume that making the engine run more efficiently by removing restrictions in the inlet and exhaust will result in worse economy? With an SJ filter, Remus Y, Laser end can and K12RS pressure regulator I'm getting better fuel consumption (and tank range) than I did when the bike was standard despite the fact I know it's running rich at low revs. Fitting a PC will sort this and may improve the economy further.

Hmm - more "efficiency" isn't the same as more power and torque. You can't magic those figures up; the fuel supplies them. Allowing a bike to breathe better from both ends allows it to burn more fuel. Thus, a lean bike which creates the same number of "bangs" on a journay as a rich bike will use less fuel. I am of course assuming that you didn't change the gearing or the primary ratios? Thought not.

sproggy · Post by **sproggy** » Mon Nov 13, 2006 3:26 pm

I'm guessing from your previous comments that you've not modified your bike so you're riding around all the issues that make it less pleasant to ride than it could be, and are therefore not riding it in the 'most efficient' way. Do you have any experience on which to base the assumption that a modified bike must use more fuel than a standard one?

POB wrote:Thus, a lean bike which creates the same number of "bangs" on a journey as a rich bike will use less fuel.

That in itself is true, however here you make one huge but incorrect assumption - that a modified bike will create the same number of 'bangs' as you call them on a journey than a standard, lean-running one would. Well it almost certainly won't. One reason would be because a modified bike will pull more smoothly from lower revs and will run below 3000rpm on a light throttle where a standard one might need a lower gear to get the revs up into a smoother part of the rev range. Lower gear = more 'bangs'.

POB wrote:I am of course assuming that you didn't change the gearing or the primary ratios?

You assume incorrectly again. Because my modified bike will pull more smoothly at lower revs than your standard one I may well be in a higher gear, therefore I HAVE effectively changed the gearing.

Of course if I use all that extra power and torque (all 4 or 5 bhp of it) I'll almost certainly suffer worse fuel consumption than I would riding the same way on a standard bike, but for normal riding (commuting, touring, etc) there's no increase in consumption because the bike is more rideable.

Not that I really give a sh*t about fuel consumption (although I calculate it sometimes, particularly if I use the bike for work) - I've modified the bike so it's more pleasurable to ride and +/- 1mpg makes no difference to me. I fill it up when it gets empty and then just enjoy riding it. Having more fuel capacity lets me enjoy riding for longer before I have to stop to fill up again.