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xwhatsit
8th January 2008, 13:45
Fiddling about with bits of cardboard on the spare bike, trying to mock up a café humped seat. Coming to the conclusion my 250RS fuel tank won't work with the look I'm going for.

In Japan they make some wicked-sick aftermarket tanks for the GB250. GB250 is basically a CBX250 -- which is kind of a follow-on model to the CB250RS. Frames look similar. What are my chances? Does anybody have a GB250 kicking around that they'll let me try the tank on?

Fibreglass tanks. Now it's technically against the rules to change the standard tank in the first place, but a fibreglass tank -- is that pushing it? Eurodave?

Cheers.

imdying
8th January 2008, 13:51
Make a carbon/kevlar one. Carbon cause it's sexy and easier to work with (cut etc, you sand kevlar and it goes 'furry' so I've been told). Kevlar underneath for abbrasion resistance should the worst happen.

Wouldn't worry too much about the rules surrounding such things... they're minor trivalties. Apparenty a quality epoxy resin should do the trick nicely. Some people line them with something like POR15, but others don't.

It is something I'd consider giving it a crack in the future :yes:

xwhatsit
8th January 2008, 13:58
Make a carbon/kevlar one. Carbon cause it's sexy
No it's not, it's shit. :oi-grr:

Polished aluminium, now that's another matter. :drool:

I suppose I could just swap the original tank/seat combination back on for the WoF.

imdying
8th January 2008, 14:12
Hahahahah, basically it doesn't matter what fibre you want to use, fibreglass is going to easiest to work with, and you're using the same resins anyway for the most part. A tank/seat unit in one would be a fair undertaking, but definitely not impossible. Assuming no prior experience with body work and/or fibreglassing, it'll take you about 6 months from concept to final clear coat :) Dooo iiiit!

Mattzxr750
8th January 2008, 14:21
Youve got me interest in how this turns out, maybe my next project

xwhatsit
8th January 2008, 14:23
Can I do this with all the normal tools? A seat for me has seemed something I can accomplish eventually, as it's a simple open shape. In fact I was considering not even worrying about a plug (as it's only going to be covered in foam and vinyl/leather). However a tank is... hollow :laugh: Can you do this with the normal techniques, or are things like vacuum baggers and fancy things needed?


Youve got me interest in how this turns out, maybe my next project

Don't get your hopes up -- it's taken me about a year to get clip-ons, headlight, speedo and forks sorted :lol:

imdying
8th January 2008, 14:32
Yes, one of the beauties of working with composites is the ease of construction. Sure you're going to need a few specialised tools as you go along, but they're all cheap. Things like a DA or a power file are going to make your life easier, but you can buy them pretty cheap these days.

Get yourself another tank, make a 3 piece mold (left/right/bottom). Then lay the two top portions up, bond them together, and then bond the bottom in. Sounds easy eh :D

You won't need to vacuum bag it if it's out of fibreglass, the main thing the vac bag does is lower the resin/glass ration to the correct amount (for strength) when doing carbon work. You can (and I have done) vac bag fibreglass stuff, but it's overkill for what you're after.

Consistency in your layup and paying careful attention to rolling the layup in your mold is where the work will pay off (don't use CSM, get some woven glass, it's dead cheap).

I can point you at a guide if you want to see how it's done.

imdying
8th January 2008, 14:33
Read this. (http://www.bayarearidersforum.com/forums/showthread.php?threadid=145975) I blame tygaboy for my current addiction.

xwhatsit
8th January 2008, 14:40
I can point you at a guide if you want to see how it's done.

I would like that. Better that than ask endless questions on here :)

Not confident that this isn't beyond my skills :sweatdrop So many ideas in my head though, would be nice to have the power to realise them with some effort.

imdying
8th January 2008, 14:58
Read the link in post 8 first. It might be beyond your current skillset, but if you'd have asked me that 6 months ago, I'd have told you the same thing. Now, it's just a job with many little bastard steps. Approach it one step at a time, and you'll be sweet. You can't do nothing without a plug to take a mold from, start with that :yes:

Be warned though, you'll bleed money without actually producing any results for a while. If I were you, I'd start on some simple stuff, make a number plate hanger, or some trim for round your headstock, or whatever... you could dive straight into a tank/seat unit, but you'll probably find the numerous little set backs along the way will cause you to give up.

Mr Merde
8th January 2008, 15:45
... However a tank is... hollow :laugh: Can you do this with the normal techniques, or are things like vacuum baggers and fancy things needed?



....:lol:
Just a quick thought.

Couldnt you use foam, build the tank around it then pour in acetone to melt the foam out, leaving the tank cavity?


As said just a thought.

Wired1
18th January 2008, 22:01
I'm keen to give this a go. I went to the local bike wrecker today looking for an alternative gas tank and took along my XT550 on the back of the trailer so I could try them out. The XT is worse than the older TT500 in that it is extra wide in the spine of the frame as it has not only the oil tank in the frame it also has a hefty great monoshock up the middle too. The original tank is too blocky for me, a bit like the Volvo of gas tanks if you like (photo 1 below).
I was hoping to find something like the older TT500 tanks, more sleek (photo 2) but nothing came close to fitting. So all I got to do is make a life size blank out of something easy to carve, then make a mold from it, then make a tank from the mold. Sounds like a hoot. Photo 3 is the actual project bike.

xwhatsit
18th January 2008, 23:14
Well if you do it, Wired1, many many people would be very interested in seeing videos of the same quality and excellence as your restoration videos. Wish I had some of your skills :)

Must admit that XT550's tank doesn't really do it for me either.

Wired1
19th January 2008, 07:20
No I really should have bought an XT/ TT500 but couldn't find one, the XT550 just sort of fell in my lap.

imdying
24th January 2008, 18:26
I've started outlining what's required for DIY Carbon Fibre (http://nzsbf.co.nz/forum/viewtopic.php?f=49&t=1907&p=23942#p23942) over at nzsbf. There's more to come, but it takes a while to sort the photos and write the text :S

Wired1
11th February 2008, 21:14
I scored a genuine TT500 alloy gas tank the other day - it cleaned up OK but is a bit dented - thread here

http://www.kiwibiker.co.nz/forums/showthread.php?p=1421554#post1421554

I tried it on the XT550 frame but it doesn't come close to fitting but I could possibly use it for a mold for a fibreglass one - Ie use the TT500 tank for the outside shape and the XT550 tank for the inside shape.

Is this hard to do? - point me at the thread if you know of one.