suzuki250 Posted June 13, 2012 Report Share Posted June 13, 2012 (edited) Just about to lengthen the swing-arm on my bantam project, anyone know how much I should lengthen it by? It’s a wider type sports cub swing-arm Edited June 13, 2012 by suzuki250 Quote Link to comment Share on other sites More sharing options...
suzuki250 Posted June 15, 2012 Author Report Share Posted June 15, 2012 Can anyone help me, I was thinking about extending them 3/4" ??? Quote Link to comment Share on other sites More sharing options...
old trials fanatic Posted June 15, 2012 Report Share Posted June 15, 2012 Your best bet is to go to a trial and measure up what is sucessful. Why do you want to extend them anyway? A short wheelbase is one of the few advantages that a Bantam has so depending on how much you have steepened the head angle i wouldnt go too long on the swing arm. Quote Link to comment Share on other sites More sharing options...
suzuki250 Posted June 15, 2012 Author Report Share Posted June 15, 2012 (edited) It’s now done, (cut and extended the tubes) I’ve extended it so the wheel has some clearance from the front of the swing-arm Edited June 15, 2012 by suzuki250 Quote Link to comment Share on other sites More sharing options...
bashplate Posted June 15, 2012 Report Share Posted June 15, 2012 yes, they do run very close as standard....and there's no room for the mud to 'escape' Quote Link to comment Share on other sites More sharing options...
old trials fanatic Posted June 16, 2012 Report Share Posted June 16, 2012 OK makes sense now. Never had much to do with Bantams so didnt realise. I knew they would suffer from the same width restrictions as cubs. Quote Link to comment Share on other sites More sharing options...
suzuki250 Posted June 17, 2012 Author Report Share Posted June 17, 2012 (edited) Progress of swing-arm One side finished, other sidw still needs filing down I think I’ll have a go at making some alloy Cub Hubs next (Can’t make up my mind if I’m going to turn them from billets or cast them, If I cast I will make a few sets ) Edited June 17, 2012 by suzuki250 Quote Link to comment Share on other sites More sharing options...
suzuki250 Posted January 27, 2013 Author Report Share Posted January 27, 2013 (edited) I’m now in the process of making my hubs and yokes, yokes are nearly finished just need to make the spindle and bar risers It’s taking a little longer than planed as don’t seem to have a lot of time at the moment (wifes just had a baby!) I will post some pics of the hubs soon Edited March 23, 2013 by suzuki250 1 Quote Link to comment Share on other sites More sharing options...
old trials fanatic Posted January 27, 2013 Report Share Posted January 27, 2013 nice work. Quote Link to comment Share on other sites More sharing options...
charlie prescott Posted January 28, 2013 Report Share Posted January 28, 2013 Hi Guys. Hi Suzuki. Bad Engineering practice extending the arm like that, now you have two welds to break? Do your homework on the hubs , it is far cheaper to buy some than to make your own. And you know the ones that are already tested work, been there as they say, Give Alan a ring. Regards Charlie. Quote Link to comment Share on other sites More sharing options...
suzuki250 Posted January 28, 2013 Author Report Share Posted January 28, 2013 (edited) Hi Guys. Hi Suzuki. Bad Engineering practice extending the arm like that, now you have two welds to break? Do your homework on the hubs , it is far cheaper to buy some than to make your own. And you know the ones that are already tested work, been there as they say, Give Alan a ring. Regards Charlie. I would disagree on the welding, I have inserted a bush into the swing-arm (see pic) even if they were butt welded I would be surprised if it did fail as most of the stress is transmitted though the shocks the swing arm acts more like a control arm than on a modern mono-shock bike (but I’m not the best welder!) I have worked many years as an Automotive prototype engineer / quality engineer, after serving a technical engineering apprenticeship so I would hope my work would be satisfactory But I would agree its not worth the time making parts, if you don’t have a CNC machine. But I’m in the process of buying one I’m sure you would agree most of the fun is making your own parts, I find it very satisfying Edited January 28, 2013 by suzuki250 Quote Link to comment Share on other sites More sharing options...
bikestat Posted February 3, 2013 Report Share Posted February 3, 2013 the reply regarding bad enginnering practice is outrageous you trained in prototype enginnering the same as myself and with 40 years in the game i see nothing wrong with that work at all.my bantam swinging arm has been extended by one inch by cutting the 5/16 flat plate where the spindle sits and welding one inch in no probs in five years.any time served welder would just laugh at that comment.you may need to heat and straighten the arm after welding though.one thing to be aware of is that a lot of people like to mig weld vertical to get a neat finish but you risk getting cold overlap doing that which will introduce a weak point. 1 Quote Link to comment Share on other sites More sharing options...
bantamsam Posted February 27, 2013 Report Share Posted February 27, 2013 Hi Suzuki Progress of swing-arm One side finished, other sidw still needs filing down I think I’ll have a go at making some alloy Cub Hubs next (Can’t make up my mind if I’m going to turn them from billets or cast them, If I cast I will make a few sets ) Hi Suzuki 250 What width and length did you lengthen the swing arm by because i am thinking of getting my swing arm altered? Cheers Sam Quote Link to comment Share on other sites More sharing options...
suzuki250 Posted February 28, 2013 Author Report Share Posted February 28, 2013 3/4" to 1" seems to give just the right amount make sure you have the wide type arm to start with Quote Link to comment Share on other sites More sharing options...
smelling123 Posted March 24, 2013 Report Share Posted March 24, 2013 I lengthened mine by 1.5" and it still turns great. I used to feel it wheelied too easily up steel hills and it seems to grip better with the longer arm. Used a scarf cut for strength and inserted a tube for strength - used for 2 years and lots of drop offs/rocky sections and no problems. Stu Quote Link to comment Share on other sites More sharing options...
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