SRX600 moving the oil tank

[guest1972]

Ello

I am working on an 'open' style SRX build - so no triangle panels and nothing between the engine and the rear wheel except frame.

To this end I am thinking of moving the oil tank - I believe that there is enough volume in the space behind the headstem (under the tank and aft of the frame junction/headstem) if I were to relocate the coil.

I don't think there would be any issues with pressure/delivery as XT engines have their oil tanks under the seat. Also I found some pics of a rather lovely XT600 flat-tracker conversion, where the builder has cleverly welded an oil tank into the triangular space under the fuel tank.



This is one lovely-looking bike so I'm going to add a full pic too:



I would need to get new oil lines made up though. I have a gas MIG and am reasonably handy with it, along with a small lathe and mill - was thinking of just getting some 1mm steel sheet and welding one up...

Anyone done this before or know of someone that has?

B

[guest1972]

Ah, just twigged that the oil tank under the fuel tank is standard on later-model XTs. Showing my age... darned new fangled machinery.

B

[guest1972]

Alright you crazy kids - it may be the paint stripper I've been using but I've had an idea...

I cut out some cardboard to see what sort of volume is available under the headstock - not enough, no matter how hard I tried to make there be.

So, I thought about... cutting into the tank. Yeah, that's right I just said that. Cut into the tank, make a cavity under which can fit a suitably sized oil tank.

I made a sketch, what do you think?



B

[SteveC#222]

Didn't some of the later SRX's have the oil tank on the front/bottom of the frame? - don't know if that would retrofit?

[Propellor]

I may be wrong but I think Ian's raspberry ripple 400 has the front oil tank. He's pretty clued up on these bikes so he'd be worth talking to.

The oil tank in the tank sounds a reasonable idea. Difficult to produce and guarantee integrity of welds to avoid cross contamination? Plus you'd loose some petrol capacity. I'm presently pondering the exact same dilemma on my xbr engined 250 RS framed project. One idea I had (just thinking out loud) was to make a separate oil tank and petrol tank, then cover them with a glass fibre (yes, glass fibre Mick!  ) outer cover, shaped like the original but slightly wider and higher. That said it'll probably just end up with something like on the ikuzawa racer. Or even where the xbr one sits. I'm still procrastinating. 

Good luck with yours. Looking forward to seeing it.

[Propellor]

What's that "box" sat above the cylinder on Steves attached picture? Would it go there? Be too hot up there probably?

[SteveC#222]

What's that "box" sat above the cylinder on Steves attached picture? Would it go there? Be too hot up there probably?

I'm guessing, but probably part of the airbox - if you think about it they'd have to move it , along with the oil tank, to fit the monoshock /linkage.

[guest1972]

Thanks for the input guys - I didn't know about the mono SRXs oil tank, looks pretty fugly tho... I am going to great lengths to remove clutter from the bike so a great lump of ally out front is out for me. There's also an oil-tank-shaped lump of ally where the oil tank goes on the twin-shock SRX.

About the tank within a tank, I was thinking to make a cavity in the existing fuel tank, and have a separate oil tank that sits in the cavity (bolted to lugs welded to the frame). So, you would take the fuel tank off to reveal the oil tank. This is necessary I think as you need some way to fill it, use the dipstick etc.

Heat dissipation may be an issue, as all the other stock oil tanks are out in the breeze, while this one would be encased on all sides but one with the steel fuel tank. Maybe a ally bottom plate which would be above the carb inlets and therefore get some breeze. Would be a bugger to properly attach to the steel oil tank tho.

Making the oil tank should be do-able as it's low pressure, and you could mostly weld on the inside corners - welding on the inside corners would be much easier than the 'pointy' outside corner, where a blow-through is more likely IMHO. And you could improve your chances of getting a fuel-tight cavity in the fuel tank by using mostly lap joints - where two pieces of metal overlap rather than meet only at their edges.

I made a more precise sketch last night and calculated the volume of the cavity as 2.3 litres - this is pretty spot on for size I think as it's around the capacity of the original oil tank, and will not reduce the fuel capacity too much.

Propeller - I had thought about the fake tank too, I think it would probably be easier in the long run. Could you just use the steel outer skin of the original tank - cut out the bottom? Then go to a local welder and get them to weld up two tanks. You could mock up the new tanks in cardboard to make sure they fit. If you wanted to DIY you could make the tanks yourself via brazing with a cheap MAPP torch and some flux/filler. I am using a gas MIG because I have one, and it's more forgiving than brazing for awkward joints.

All grist for the mill...

B

[Steve Lake]

The 'box' is actually part of the monoshock chassis... its beefed up all round there.. its a bloody heavy chassis compared to the twinshock (I have both)..  there is probably even less room there than on the twinshock.

as you can see on the pic, the exhaust headers are swept to the right and siamesed (actually... a nice touch... look better than the single pipes on the twinshock in my opinion) to accommodate the front mounted oil tank... which works well, and has a slightly larger capacity ( I think) also acts quite well as an oil cooler, but does get a bit of a battering from road crud.

nwo then... I think i may have one of these tanks, but not the associated pipe work... which I'd sell at a very reasonable price, should it be of any use....

good luck with the project

[Propellor]

Hi baz.

Splitting and rejoining the original tank had also crossed my mind.

I like the sound of your proposed method for your own bike, apart from the worry of reduced petrol volume? How much of the oil tank volume is free space? You'll defo need some! As you say, maybe make it from ally. How about slanting the bottom a bit and putting some ribs on there? Could you build in some free channels under the seat to get an airstream going?

Beats watching corrie 

[iansoady]

You could build it under the seat if you reduced the padding to about 5mm or so. Keep you warm in winter as well.......

[johnr]

id be concerned at the effect that a hot oil tank would have on already short lived modern petrol. the heat from an oil tank could well encourage the fuel to go off quicker as it evaporated the ethanol off quicker than normal essentially you are introducing a heater into the fuel tank which might have a negative effect on the fuel in there.

[themoudie]

Aye Bazmanout,

This maybe what your looking for?

The link for the site is this and the bike is the 5th image in the sequence:Monoconnection2014

Tidy job, BUT, I suspect the hump has something to do with the disappearance of the oil tank? and you won't be wanting to get the hump! 

The cast alloy oil tank at the front of the motor featured on the monoshock SRX also features on the SZR660. I'm not sure if the pipework is the same?

As for hot oil in the petrol tank? 

Complicated fabrication. Better off riding the bike! 

Messy for oil change and the chance of leaks into the fuel. SRX oil changes are not for the clean garage floor or monoblock driveway, the oil dribbles on the exhaust and then runs sideways afore gravity takes over.  I use ex-NAFFI baking tins for oil changes that are 1' x 2' x 3"deep, with a 5 litre plastic oil can to catch the bulk and the tin to act as a moat.

Pressurise your petrol tank, Sally's breather whistles and sighs after a good run and I can get vapour locking in hot weather. So, sticking 2 litres of hot oil in an adjoining tank, will heat the fuel to above 140°F, vapourising it!  Fine if you want to run a weak mixture, but rubbish if you are looking for 'poke', when you need the cool charge to maximise the volume of combustible mixture in the cylinder and you haven't even tried to put it through the carb, yet! Those early morning dewy runs are always the best 'cause the motor is getting a full charge of combustable mixture. 

As "johnr" points out, vapourising ethanol is likely to increase the condensation in the fuel tank as it cools and with the SRX 'pistol grip' tank 'design', it has lovely lines but is a lousy design, the two rear saddle tanks can't be drained unless you use a syringe and plastic hose to remove the fuel-water emulsion from them. Hence the paucity of second-hand SRX fuel tanks that do not leak from the lower rear tank seam.

You could go for the MuZ Skorpian 'belch bottle' under the seat, but that involved oil in the frame, readily belched oil all over the rear of the bike and made sorting out the oil level in the motor a fiddly pain.

Whatever you decide, I hope you have fun creating it and it runs well for you.

My regards, Bill

[deleted to save space]

[Propellor]

Aye up Bill.

Vaporising the ethanol will keep the oil cool! 

Unless I'm misunderstanding Baz, I think he's proposing to keep the two tanks completely separate? With a small air space between. Admittedly the air around the tank will heat up and transfer some heat into the petrol. How bad this effect will be.....? Don't forget, a lot of bikes have oil in frame designs, so must face similar issues? But then I guess the air stream will pass over those designs more efficiently? Or will it? Depends on how Baz designs the under seat layout.

So the risk would seem to be that if it proves a serious problem it completely scuppers the entire bike really. Tough decision to make!

What about fitting an oil cooler? This might allow him to insulate between the tanks. Not having to rely on the tank as the main means of cooling. Choice of pipe work?

Looking at my own project I think I'll be taking the safer route and having a special ally tank made. To fit in a similar position to that on the xbr, but more of a triangular shape.

[Mark]

Or you could start over with a wet sump engine.