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

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, 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

The steering head bearings would be my 1st suspect.

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.

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

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

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.

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

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