venny2522 Posted September 7, 2008 Share Posted September 7, 2008 Hey everyone. I've got a 1976 RD400C with an interesting steering problem. I'll try to describe it as best as I can, so please bare with me. The steering feels loose in general compaired to my other vintage yamaha bikes. On a sharp turn, even at slow speeds, the steering seems to want to come towards the bike (tank). It feels like theres a spot where any resistance in the steering seems to be lost. When the front wheel is hanging at full droop, the steering seems to be very non-linear. Is it true the RD400C has no steering damper? Could this be the cause of what i'm experiencing? Any help or input you could provide me with would be great. Thanks, Venny Link to comment Share on other sites More sharing options...
Moderator Airhead Posted September 7, 2008 Moderator Share Posted September 7, 2008 Hi Venny, Things to check are Tyre pressure is correct specification Steering head bearing is not rough or loose When did it last have fork oil changed, change as necessary Wheel bearings gone Fork stancheons are at correct position in the yokes and yoke bolts correctly tightened Wheel spindle nut correctly tightened Link to comment Share on other sites More sharing options...
JimR Posted September 7, 2008 Share Posted September 7, 2008 Hi Venny, Things to check are Tyre pressure is correct specification Steering head bearing is not rough or loose When did it last have fork oil changed, change as necessary Wheel bearings gone Fork stancheons are at correct position in the yokes and yoke bolts correctly tightened Wheel spindle nut correctly tightened Hi Venny, If its a wire wheel modal check the spoke tension also Regards Jim Link to comment Share on other sites More sharing options...
Moderator YamaHead Posted September 7, 2008 Moderator Share Posted September 7, 2008 The steering head bearings would be my 1st suspect. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted September 7, 2008 Moderator Share Posted September 7, 2008 I'd go for the swing arm bushes and upgrae them to bronze. Easy to check, bike on main stand and wiggle the rear side to side any play more than 1mm! = worn. Link to comment Share on other sites More sharing options...
yamahanut Posted September 10, 2008 Share Posted September 10, 2008 hi vinney i would go for the head set bearings also, if they are no good replace them with standard bearings as yamaha did not put tapper ones in and also they dont fit as ,i found out on my 400 dx Link to comment Share on other sites More sharing options...
Moderator mervin Posted September 10, 2008 Moderator Share Posted September 10, 2008 hi vinney i would go for the head set bearings also, if they are no good replace them with standard bearings as yamaha did not put tapper ones in and also they dont fit as ,i found out on my 400 dx Taper rollers do fit i have em on both my running Rd,s but you will need to put an extra o ring in the bottom headlight ear rings. the ones that go in the neutral light switch do the trick, problem is the bearings sit a little higher than the originals, but i honestly cannot say you will see much difference between originals and the tapers handling wise. so fit which ever you feel happiest with doing Merv Link to comment Share on other sites More sharing options...
Moderator YamaHead Posted September 11, 2008 Moderator Share Posted September 11, 2008 I had NO fitting issues with the tapered set I installed in my RD400F ..... But it seemed to steer a bit smoother as I recall. Link to comment Share on other sites More sharing options...
venny2522 Posted October 14, 2008 Author Share Posted October 14, 2008 Ok, so I have a set of tapered bearings now for the RD400C. How hard is it to change these in the garage? Do I need any special tools? Also if anyone has a guide or just some helpful tips for changing them, that'd be great! Thanks, Venny Link to comment Share on other sites More sharing options...
Moderator mervin Posted October 14, 2008 Moderator Share Posted October 14, 2008 place on centre stand, remove front wheel, muddie, forks, then undo the big nut in the middle of the top yoke/triple tree, then lift off top yoke with handlebars etc still attached put a thick cloth on your tank and rest them there, undo the castellated ring under the top yoke and the bottom yoke should fall out and ball bearings roll every where, careful you dont step on them and slip over. now drive out the old races form the top and bottom of the frame tube/headstock and remove the bottom race from the spindle on the lower yoke, these bits take a long punch and dome patience, then make sure the headstock is clean and free of rust etc where the new taper races fit and tap them in, then fit the bottom bearing to the spindle leaving the seal in place, push spindle through headstock put top bearing on thenm replace the rings and washer then rebuild in the opposite methid of strip down Merv Link to comment Share on other sites More sharing options...
Recommended Posts