what taper roller taper dt125R Head stock 1998 (USD convertion)

[YYHpilo]

Hello,
I am doing a USD conversion on my Yamaha DT125R 1998, with a Husqvarna 450 fork. The triple clamp axle is 25 mm, whereas the original DT125R triple clamp axle is 30 mm. I want to buy a new roller taper bearing for the underside of the headstock. When I measured it, I got 30x56x17. So, I looked for a bearing in the size 25x56x17, but there are none available. I then searched for the original taper bearing for the DT125R headstock, and I can only find taper bearings sized 30x55x17. Did I measure it wrong, or is my headstock somehow special?

[YYHpilo]

Or is there an easier solution for this?

[Calum]

https://dt125r.co.uk/topic/17/usd-conversion-bearing-cup-method

[YYHpilo]

yes I know, but those cups are exspensive to make and I was wandering if I can just buy a bearing that fits. so do you know the size of the lower headstock bearing? because the machine shops in my area all say around a 100 € per cup for those tolerantes.

[Calum]

That's the conversion problem isn't it!

The other thing I've seen people do is to press out the steering stem from the DTR triple clamps and into the conversion triple clamps of your choice. However if the stem diameter is different then you'll need a shim/cut to fit it into the conversion triple clamp.

This is quite a destructive process if you're cutting and you won't benefit from taper roller bearings up top. But it's an alternative approach.

The bearing cup method is the simplest approach and is easily reversible.

[YYHpilo]

Ok, thank you very much for the help. I am going to try some things. And pressing out the steering stem is a good idea, because the dt stem is 30 and the Husqvarna 25 so i can just mill the 30 mm stem to 25 and press it in. Thank alot.