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XR650R Stability with USDs?

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Hey guys

I've got an 06' CRF450X front end going on this weekend

Currently have the triple clamp with the machinist.

Ive been reading on this forum there are some stability problems with the USDs, and requires spot on sag & dropping of the front end in the yokes.

I dont know much on rake/trail or whatever, but my question is, what do you raise/lower on a bike to give or lose stability at speed?

I would have thought lowering the front end gives it less stability, but ive read reports to the contrary.

Im getting my stock shock extended and with the USDs, i'm hoping i can keep my stock fork stability at speed.

Nothing worse than having the front end wobble at speed.

Cheers

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well stability also comes from wheelbase also, longer is more stable, when i would setup gearing for a GP/desert race i would extend rear wheel as far back as i could. Shorter wheelbase is oposite, better for tight turns like in MX/SX. Lowering and raising forks can help with weight transfer and i just played with it some and see if i can feel a big difference, never really moved forks up/down more than about 10mm myself, i couldnt tell alot from that myself but it does make slight changes. I know Borynack has said that the regular forks on the R help cuz they flex and with USD being much stiffer thats prolly why you hear about finicky setups. if you dont already have maybe a steering stabilizer will help your high speed stability on the front, i swear by them myself, on ANY bike too! Thats about all i can say about this LOL

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Measure the overall length of both fork sets,measure static and race sag of the stockers then make some marks where the USD's should fit in the triples.

Get the relative height of the new triples on the bike,set to the mark as opposed to the old height at the tree..

Measure the overall of the USD's again to the triple height again and go from there.

Try for the same static and race sag as a starting point,you lucky bass terd.

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Keep in mind that the CR forks are longer than the XR forks, so unless you do the XR/CR rear hybrid shock at the same time, the rake will have changed. That is why lowering the forks in the clamps probably helps some guys, it brings the bike back closer to stock geometry. The CRF clamp fork offset is the same as the XR clamp, so I would venture to say that the reduction in stability is due to the reduction in offset (4.5mm) at the axle for the CRF forks. Short of custom triple clamps or an eccentric axle, there isn't much you can do about that, which is one of the reasons I was motivated to figure out how to keep my damper with this conversion. It isn't so dramatically bad that you'll crash the first thing out, so just mount them up and go ride. If you still feel like you want something with more stability, you can always add the damper, have custom triples made or go back to the old set up later. Don't forget to take some pics and post your impressions after riding. GL

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I've got the hybrid shock, so I haven't noticed any issues. But I did the CR fork conversion first (about a year before the shock) and I did not notice anything goofy then either. But I also wasn't riding on the pavement either.

Even if it's a "little" unstable the R with a CR nose is still more stable than anything else out there.

XRs behave a little differently than other bikes as far as rear wheel placement is concerned. Due to the way different leverage ratio on the shock (ever wonder why are all looking at springs in the 10.0 to 11.0 range instead of a more traditional 5.2-5.6?) the rear wheel placement has not only an affect on the handling but also the shock action. With the stubby swingarm (compared to a CRF) and jacked ratio when you run the wheel in towards the back of the swingarm you may need to adjust the shock clickers accordingly.

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I've got the hybrid shock, so I haven't noticed any issues. But I did the CR fork conversion first (about a year before the shock) and I did not notice anything goofy then either. But I also wasn't riding on the pavement either.

Even if it's a "little" unstable the R with a CR nose is still more stable than anything else out there.

XRs behave a little differently than other bikes as far as rear wheel placement is concerned. Due to the way different leverage ratio on the shock (ever wonder why are all looking at springs in the 10.0 to 11.0 range instead of a more traditional 5.2-5.6?) the rear wheel placement has not only an affect on the handling but also the shock action. With the stubby swingarm (compared to a CRF) and jacked ratio when you run the wheel in towards the back of the swingarm you may need to adjust the shock clickers accordingly.

I have the XR/CR hybrid shock done too, and still I did notice a little decrease in stability. Ultimately, it's no big deal, and almost un-noticable when I use the damper. Besides, the better turn in when riding the tight stuff makes the trade off worth it, even without the damper . . . unless all your riding is WFO, 100mph across sandy whoops! You have a damper setup too, don't you? Do you have any pictures of your setup?

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