alext Posted November 14, 2013 Report Share Posted November 14, 2013 Ok looking for someone with a bit of knowledge on (old-school) frame design.... I have a 350LC, to which I have fitted FZR400 forks, wheels and brakes... The front-end is FZR4003TJ, the rear is a 1Wg 18" wheel with a 3tj Rear brake caliper fitted into the standard LC arm. I want to fit the 3tJ rear wheel as its 17" and I can actually get tyres for it easily, unlike a 140/60x18. The problem is the 160 tyre on this wheel will not fit in the LC's swingarm - its too wide for the shock loop, so I was thinking about making a swingarm up to suit. I dont want to give it off to someone and be charged hundreds of pounds for it, I want to try to do this myself. I was planning to use a later powervalve arm's pivot (for the better bearings) and I know it will fit the frame, and attach to this some box-section of a suitable size and shape to clear the frame and tyre. What spec of steel box-section would be best to use for this? - my dimensions are set by the FZR internal wheel-adjusters I want to use, so thats no real problem, just the grade of steel I require. I cant weld Alloy unfortunately - dont have the experience or access to the necesary equipment. Thanks A. Link to comment Share on other sites More sharing options...
Superdunc Posted November 14, 2013 Report Share Posted November 14, 2013 http://www.steeltubedirect.co.uk/product_selector.aspx?shape=153 50mm x 25mm x 2mm would be what I'd use. £30 for a 3m length. Link to comment Share on other sites More sharing options...
2moto Posted November 14, 2013 Report Share Posted November 14, 2013 Most production frames, swinging arms, etc. are made from ordinary ERW mild steel. Presumably since you say you don't access to equipment to weld allow, you won't be using TIG, so probably MIG? If so, just use ERW, as Superdunc suggests. You can get higher grade like T45, but then you really should use a better welding method to make to most of it. Higher strength steel simply allows to make things lighter. Link to comment Share on other sites More sharing options...
porter_jamie Posted November 14, 2013 Report Share Posted November 14, 2013 or CDS. no point using anything posher as the main frame will be made from boat anchor anyway. if you check the specs the posh stuff isn't actually any/much stiffer, it's just a lot stronger which means you can go thinner gauge and make it lighter. but you wouldn't want to go much thinner than 16swg in any case because you still have to weld it Link to comment Share on other sites More sharing options...
Evilchicken0 Posted November 14, 2013 Report Share Posted November 14, 2013 Try finding an XJR400 wheel, its a 17" and fits the fzr400 1wg Link to comment Share on other sites More sharing options...
alext Posted November 15, 2013 Author Report Share Posted November 15, 2013 Thanks for all the replies - yes, it will be Mig Im using - need to build the jig first though, but that can be fairly agricultural. Im used to welding on mini bodyshells, so thin metal doesnt worry me too much, I had originally thought it would be around the 50x25x1.5mm stuff I would need. I need to get a good look at some box-section arms with internal chain adjuster blocks, as that will give me the size of tube I can use, as making up adjusters might be beyond me, so I might have to use some that exist already. Link to comment Share on other sites More sharing options...
Evilchicken0 Posted November 15, 2013 Report Share Posted November 15, 2013 You can use the TRX / FZR600 and 600R arms for that, they have square sections. Link to comment Share on other sites More sharing options...
phildawson8270 Posted November 15, 2013 Report Share Posted November 15, 2013 Are there no candidates for a much simpler swingarm change? Link to comment Share on other sites More sharing options...
kaighn80 Posted November 15, 2013 Report Share Posted November 15, 2013 Cbr 600 around the 1989 year had a steel box section swing arm might be worth a look to save a bit of time Link to comment Share on other sites More sharing options...
Evilchicken0 Posted November 16, 2013 Report Share Posted November 16, 2013 Are there no candidates for a much simpler swingarm change? I'd have though the FZR400 3TJ would be good then mod the frame Link to comment Share on other sites More sharing options...
willbloke Posted November 16, 2013 Report Share Posted November 16, 2013 I think the hot setup for a Valve is an FZ600 swinger , but then you'd have to mod the shock mounting linkage etc. But may be suitable for a donor ? Link to comment Share on other sites More sharing options...
alext Posted November 16, 2013 Author Report Share Posted November 16, 2013 I have been looking at the steel FZR600 swingarms... I dont want to mod my frame so I have to be able to weld a shock-loop to it (hence steel being my preferred option) looks like the 600 one will fit with 7and a bit milled off each side - but I would need to shorten it - its a lot longer than standard. Link to comment Share on other sites More sharing options...
phildawson8270 Posted November 16, 2013 Report Share Posted November 16, 2013 What about FZR400 swingarms? They're likely to be the similar width and shorter Link to comment Share on other sites More sharing options...
kens Posted November 21, 2013 Report Share Posted November 21, 2013 I have been looking at the steel FZR600 swingarms... I dont want to mod my frame so I have to be able to weld a shock-loop to it (hence steel being my preferred option) looks like the 600 one will fit with 7and a bit milled off each side - but I would need to shorten it - its a lot longer than standard. Just go for the USA Hayabusa look... Link to comment Share on other sites More sharing options...
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