I've lost my balls

[jimson]

G'day viewers what size ball bearings do I put in the triple tree of a twin shock DT400  I need the size for top and bottom and how many each end. I pulled this thing apart years ago and can't find the original ones anywhere  jimson

[Nathan S]

Bottom: Eighteen 6.30mm balls.
Top: 22 or 23 4.75mm balls.

Sorry for the vagueness. I was putting my MX250 together tonight. After carefully counting the number of top balls, I put the triple clamps in, and instantly forgot whether it was 22 or 23 balls in the top....

[Colin Jay]

The DT400D (1977 model) runs the same steering head bearings as the XT/TT500's (and proberbaly most of the other Yamahas of that era).

For some reason, Yamaha use imperial sized balls;

22 x 3/16" in the top race

19 x 1/4" in the bottom race

I have always bought my balls from CBS in bags of 100. They cost about 8 - 10 cents each which is a lot less than what Yamaha caharge for them as a genuine part.

CJ

[Nathan S]

The DT400D (1977 model) runs the same steering head bearings as the XT/TT500's (and proberbaly most of the other Yamahas of that era).

AFAIK, the Yamaha dirt bikes with the loose balls in the steering head, all use the same cups, cones and bearings.
Athough its possible that minibikes are different to the adult bikes?

[211kawasaki]

HOW DO YOU GUYS KNOW THIS SHIT! I'm impressed that someone actually knows that Yamaha used imperial balls, theres depth in this movement and Im sure that in 100 years from now some PHD student will be doing a full thesis on it. Its going to be a study subject like Egyptoligy is now.

[Colin Jay]

The fact that Yamaha used/use imperial balls for the head race bearings is easy to determine, as  the size of the ball is given as part of the description in the spare parts manuals (well it is in all the 1970's books that I have, I am not sure if the modern electronic/online ones list the ball sizes).

The fact that the head race balls are imperial has all was been an oddity to me, as all the other bearings on the the chassis and engine are standard metric bearings. Of course it could have just been a case of leaning towards to their biggest market, the USA, which uses imperial measures, and thus imerial balls would be easier to get than metric ones.

CJ

[Tim754]

Blue pills will not help those old balls.....

[TT5 Matt]

you can buy 3/16 and 1/4 balls at cycle repair shops

[jimson]

Thanks everyone for your help  jimson