Topic: '73 cb500 triple tree question

[frob976]

hello,

     my project bike is a '73 CB500 and id like to replace the bars/gauges with that of the '90 GB400/500.  is it possible to replace just the upper triple tree clamp with the one off the GB500 and have it work?  or if i replace the upper and lower triple will i run into other problems with fork width etc.? 

thanks

efrem

[d3buttz]

ive never worked with a gb400/500, and no one else has chimed in so here is my speculation-
I doubt it will work, but if(and thisis a big if) the fork tubes are 35mm od like the 500, and if(another big if) the fork with is the same, and if, (a monster if) the distance of the centerline from the fork tubes to the center of the steering tube is the same, and if(astronomical if) the clamping id of the gb500 steer tube is thesame as the cb 500, And if,(you get where im going with this) the frames steering tube races are the same id, od, distance apart, yeah itll toatally work.
it might be alot easier to just swap the entire front end,  check out threads for the gxr front end swaps.  good luck and welcome to the forum!

[domer]

the fork tubes are the same diameter... but on top of everything else d3buttz said, you need to check to ratio's of the speedo and tach... if they dont match, no go!

[frob976]

thanks guys!

i found this although i dont really know what it means....

steering stem sizes (for berrings maybe?)
Upper: 26 x 48.5 x 15.2   
Lower: 30 x 50 x 14.4   

these numbers are the same for both the CB and the GB... does this help me at all?

i found that info here if it helps...  http://forums.vwvortex.com/zerothread?cmd=print&id=4596954
thanks again
cheers

[domer]

thats a start... now on to the rest, steering tube length, guages, and so on. its going to be kind of tough to figure out with out having them side by side...you will probably need the gb wheel and brakes to save some trouble.have you found a gb front end? there is a guy here in the bay that has a clean gb for sale...i laughed....$7500.

[frob976]

ha... wow so did i just now... im actually buying a GB from a friend thats in pretty good shape for less than $4k so that particular front end might be out.  although since i dont know what the numbers mean on the "stem bearing size" chart  #x#x# do you happen to know which figures i'm missing?  and i do have a gb at my disposal to measure from, but not to disassemble unfortunately.
thanks for all the help

[domer]

im not an expert on this, although id like to be! try measuring the steering tube, since the bearings are the same, as long as the length of the steering tube is the same, and you do a whole front end swap... you should be ok. another thing to check is (sorry for laymans terms) is the distance from the steering tube to the forks... i know someone on here is doing a gixxer swap and says the lock to lock on the steering is crap. other than that again check the ratio of the guages i know some of the later cbs are different than the earlier... oh and fork length is important to... hopefully someone else with more experience can chime in here. i think its possible, maybe not easy or cheap... but possible!