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Old 10-08-2018, 01:58 PM
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(F5) (F5) is offline
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Location: Wellington New Zealand
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Quote:
Originally Posted by Jakobi View Post
Good idea F5. We'll bounce this idea more when I get to it.

Forks should be arriving next week some time.
I have an axle from an 04 WR250F at my disposal (including front wheel and spacer). I was thinking I may be able to transfer the whole lot across, but thinking things through I will meet issues as the WRs use a 25mm offset lug so the brake carrier will still be out.

Working off this, I've found a better list of various KYB SSS forks and their dimensions.

YZ250F (02-06) 35mm lug / 56mm upper clamp.
YZ250F (07-11) 32mm lug / 56mm upper clamp.
YZ250F (12+) 32mm lug / 54mm upper clamp (fits stock 48mm triples).

YZ450F (03-07) 35mm lug / 56mm upper clamp.
YZ450F (08-09) 32mm lug / 56mm upper clamp.
YZ450F (10+) 32mm lug / 54mm upper (fits stock 48mm triples).

YZ250 (01-07) 35mm lug / Believe all use 56mm upper clamp.
YZ250 (08+) 32mm lug / Believe all use 56mm upper clamp.

WR250F and WR450F (02-13) 35mm lug - unsure which years inc SSS vs OC. Believe all use the 56mm upper clamping diameter.

So from that list, depending on what you want to achieve and whats available will depend whats required.

I intend on using the Stock Gas Gas 22mm offset triple clamps with the 12 YZ250F forks. The reduction in overall offset will be -3mm. If using forks with the larger upper OD, using KYB 25mm triple clamps will retain the stock geometry/overall offset.

Also, as I plan on using the Gas Gas front wheel which has a 260mm disc vs the YZF 250mm I will require an oversize caliper carrier for the particular forks (lug offset) that I will be using. Braking POW106. I have ordered one of these.

For the forks with the 35mm lugs the correct carrier is POW13.

The ideal solution IMO would be to source a set with 35mm lug from a late model WRF and have the upper triple clamped machined - I'm taking a risk with the -3mm offset for the ease of fitment. If the reduced offset ends up being too much I will be somewhat limited in my options as these late model Yamahas they come off all use 20mm offset triple clamps. I could source some older triples and shim the upper clamp. In my research I have read that many people would however sub out the stock 25mm offfset clamps for 22/22.5mm on the YZ250's for better handling.. I have also found the head stem angle to be similar between the 2 bikes, and that most new bikes run a similar angle with less offset. Glenn found the increased trail to be too much on his Beta 2T, however they already come standard with a 20mm offset clamp. Both bikes use a 27 degree steering rake angle.
Ok so I'm going in again, this time a mate's 2010 his marzocs are eating seals. It will fall on me to do everything so I want the laziest solution but still give him good forks, he loves mine.
He measured his forks and got 59mm lower clamp 56mm upper. Just like my 2006 YZ250 forks. Your chart indicated they should be 54mm. Should I go measure to be sure?

YZF450 seem most common over here for spares. The -3 lug if we go 08,09, Should be ok on the 10 do we now think? Do we need WR axle or mod YZF?
Cheers.
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