madeucer Posted September 26, 2014 Share Posted September 26, 2014 a you know I am rebuilding my xs 250 in my version of dirt tracker for the street and I was wondering what you might think of uprating the forks to 400 or 500 ones to add a little beef , well when you stop laughing let me know lol thanks guys Link to comment Share on other sites More sharing options...
slice Posted September 26, 2014 Share Posted September 26, 2014 It's all about geometry, if the forks are the wrong shape/length/diameter then your on a hiding to nothing but as long as you have the whole front end then should not be a problem, in my opinion anyway, the only thing is that it's usually better to use the brakes that the forks came with or your going to have to make up all sorts of brackets and crap to get the old brake calipers on. As long as your happy with the result and it's safe why should anyone laugh? It's been done by others before and most don't look like a frankenbike, it's usually only the anally retentive that whine about "it's not how it came out of the factory is it?" You should say "NO it's better, now fuck off!" Link to comment Share on other sites More sharing options...
dt502001 Posted September 27, 2014 Share Posted September 27, 2014 What you need to consider is the difference in weight between a 400 and 250,this is the most imporntant part if the 400 is close in weight then it shound be fine ( belive mostly just the top end is where your going to see added weight) then check that they didn't use the same front end with a spring up grade.No point in buying a whole front end if you can slip in new/used springs at a lower cost or to find it's the same alltogether. Check spring manufactuers and cross ref. the 2 bikes as the 400 and 250 are so closely built wouldn't suprise me if they share the same front end. As the 400 is mainly just a bored out 250. A cheaper way is to add a spacer of 5mm-20mm top the spring and heavier oil say 15w vs the 10w. People who laugh at up grades should be slaped alot has change in 30 years and lots of room for improvment on the old bikes. PS also I wouls up grade the brakes to dual piston and larger rotor over spending money on a new front end.IMO money better spent. Link to comment Share on other sites More sharing options...
Preload Posted September 27, 2014 Share Posted September 27, 2014 If you get a set of XS360 forks they have the mounting holes ready for an extra caliper I think the stanchion size is 33mm. I only mention this as I'm not sure of the stanchion size of the 400 & 500 bikes. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted September 28, 2014 Moderator Share Posted September 28, 2014 Aprilia rs125 forks fit 250 engines are slightly heavier than 400's but shouldn't make a difference http://www.xs400.com/forum/showthread.php?t=4481 Link to comment Share on other sites More sharing options...
Preload Posted October 1, 2014 Share Posted October 1, 2014 Looking nice. What spring weight are you using? Link to comment Share on other sites More sharing options...
Moderator drewpy Posted October 1, 2014 Moderator Share Posted October 1, 2014 Looking nice. What spring weight are you using? not mine, its cadxs from London, its finished now Link to comment Share on other sites More sharing options...
Preload Posted October 1, 2014 Share Posted October 1, 2014 Okay Drewpy Link to comment Share on other sites More sharing options...
Tommy xs Posted October 1, 2014 Share Posted October 1, 2014 hey Drew didn't you fit xs1100 forks to you old one Link to comment Share on other sites More sharing options...
Tommy xs Posted October 1, 2014 Share Posted October 1, 2014 I think the 400 forks are the same as the 250!! Link to comment Share on other sites More sharing options...
Moderator drewpy Posted October 1, 2014 Moderator Share Posted October 1, 2014 hey Drew didn't you fit xs1100 forks to you old one no dual brakes from an xs1100 I think the 400 forks are the same as the 250!! correct Link to comment Share on other sites More sharing options...
vayduh Posted October 1, 2014 Share Posted October 1, 2014 Darn just wasted/enjoyed who knows how long reading Cadxs entire thread. Building a bike in your flat is nuts (although I do know of someone who built a bike in his livingroom and then had to take out the windows to get it outside once it was fully built.) Link to comment Share on other sites More sharing options...
Moderator drewpy Posted October 2, 2014 Moderator Share Posted October 2, 2014 Darn just wasted/enjoyed who knows how long reading Cadxs entire thread. Building a bike in your flat is nuts (although I do know of someone who built a bike in his livingroom and then had to take out the windows to get it outside once it was fully built.) loved the bit where it started to cause the ceiling below to break and he had to hide the bike when the landlord came round to check Link to comment Share on other sites More sharing options...
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