Another KYB SSS Thread - 2013 EC250R

[fullthrottle]

Managed to pick up a complete front end off a 2006 yz450f for $250 including wheel brake m/c plastics t/clamps.

Just to confirm if I change the bottom head stem bearing and get a steering stop sorted I can fit the complete front end??

Forks will be revalved and new springs, what spring rate should I look at? Im 70kg no gear.

What is the measurements of the bearing I need?

Where will this leave me in terms of fork/axle offset compared to stock?

Thanks for any help

 

[Jakobi]

I haven't done a full front end swap, so can't comment 100% what's involved.

I can point you to this thread though!
http://www.gasgasrider.org/forum/showthread.php?t=14592
and this one too. http://www.gasgasrider.org/forum/showthread.php?t=12745&page=3

You'd have to check the offsets for that particular Yamaha model. The GG uses a 22mm triple, and 35mm lug offset if I recall correctly. YZ 2T uses 25mm triple and 32mm lug, so same same. I reduced total offset by 3mm with my fitment, and notice the difference in terms of force required to steer the bike, but don't find it bad at all (but that's on a 13 chassis too).

 

[_Hammy]

I thought that I'd tack this onto Jakobi's thread since he's mentioned the WR's in his original post

I'm looking at a set of KYB forks off an 08 or 09 WR450F

Does anyone have any opinions on whether these are worth the effort to swap with the sach's on my 09 ec300, or should I hold out longer (and more $) for a SSS set?

My intention is to use the gasser triples and front wheel (as it's set up with a tubliss system) and the WR axle, a braking brake caliper mount etc...

I've gotten myself confused with the various fork options, so some clarity would be appreciated

I'm not fast by any means, and the bike will be set up for technical bush/woods riding, but I also want it to be capable over woops, braking bumps/trail trash and not too soft for casual club MX

The other issue is that my top triple clamps are for 54mm OD forks, whereas the WRF's are apparently 55.5mm OD. I've had varying opinions on whether I "could" get them into my clamps, and whether I "should" do it given that it'll put some pressure on the tubes

 

[pscook]

The other issue is that my top triple clamps are for 54mm OD forks, whereas the WRF's are apparently 55.5mm OD. I've had varying opinions on whether I "could" get them into my clamps, and whether I "should" do it given that it'll put some pressure on the tubes

Don't force them, that would be bad. You could easily have someone bore them to match, I would think. Only 0.75mm off the clamp, shouldn't cause too much grief.

 

[_Hammy]

Don't force them, that would be bad. You could easily have someone bore them to match, I would think. Only 0.75mm off the clamp, shouldn't cause too much grief.

That'll be my plan I think if they don't fit. There looks to be plenty of material on the clamps so it shouldn't weaken them. I prefer this over swapping out the triples completely for the WRF ones, and then trying to sort out a steering stop



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[_Hammy]

Can any one tell me if when I measure the trail at the front axle, whether i measure from the axle centreline back to the centre of the fork leg , PERPENDICULAR to the fork leg, or PARALLEL to the ground?


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[(F5)]

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.

 

[Jakobi]

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.

I wouldn't decrease offset at all on the 2011 and earlier chassis. The change was noticeable on the 2013... Sure it adds some straight line stability, but what you notice most is the tip in effect. Takes a bit more input to initiate a turn but once it starts tipping it continues to follow itself quickly. Like a spinning shopping trolley! I think the short nimble 2011/10 might be too sensitive to such a change.

I believe the 46mm OC Zokes used an even smaller triple clamp than the 48mm Sachs/PFP Zoke. I'm sure I recall reading threads on people considering milling them out.

My guess is that your mate has tried to measure the ID of the clamp with the fork out and bolts backed off. Could see how that would get a few mm variance. I threw a set of calipers straight onto the fork tube... and can double check those measurements again for you if required (although my KYBs have just moved on, I have a new set on the new bike).

 

[(F5)]

Roger that. He's now chasing some 06 yzf450 which look from your list to be 35mm lugs. Throwing in the wheel too which is only any good if the disc is OK. But with 250 yz disc and 35 offset the GG brake caliper may be seated a bit rearward. I think.

 

[Brian]

I have an 06 and I'm trying to reason my way through the switch from 45 Zokes to KYB.

Are the stock lower clamps sized such that the YZ KYB forks fit? I got this impression some how. Could you use a YZ upper triple clamp and keep the Gas Gas stock clamp for the lower?

 

[(F5)]

Not for you ma boyo. Upper and lower and axle. My 07 change over should cover you. Can't remember if did as my own thread or think hijacked someone else's


Edit, erm heck I've forgotten the difference sizes, brain has gone soft. . .

The 450 conversion complete with YZ front wheel and brake was pretty seamless. Just the spring and valving are not ideal, rides quite high and stutters on bumps. Easily fixed if he would spend some money.

 

[swazi_matt]

I don't think so. I used a yz axle on my conversion and considering it stuck out about 30mm i suspect the yz tripples are wider than the gg ones (also not sure about the offset being the same)

I used the GG botom clamp and bought another gg top clamp and had it machined to the yz fork diameter. Then also used yz axle and specially made up spacers. Have a sketch of it somewhere

 

[Hooligan]

I haven't bolted anything together yet but comparing the GasGas triples to the YZ triples, the fork spacing looks to be very close. Maybe the YZ spacing is a bit wider but we are talking maybe 1/4" at most. No way is the difference more than an inch .... at least not with the parts I have.

 

[5valve]

Sourced SSS forks off a yz250f '09 with 105mm (22N/mm) ICS / free float piston spring.
Spring in at least one fork is broken at first bend from top. Haven't yet checked the other.

Standard spring for 2018 EC 300 is 20 N/mm @ 90mm long.
Wire thickenss on my spring is 3.8mm.

If spring wire thickness for 2018 EC 300 is also 3.8mm, then cutting and flat surfacing my springs to 90mm would also result in approx 20 N/mm force, so there would be no need to purchase a pair of 90mm's. Also quite pricey at 50eur/pc.

 

[(F5)]

Skim read, but if you heat that top coil and squeeze it you can then surface it better. Must be straight and take the space up with spacer.

 

[5valve]

That went easy, 90mm right there.

Used online calculator for spring rate, and stock 105mm, rated at 22N was actually 21N/mm.
Now that I cut it, it became 23.6N/mm.

Read somewhere on TT, that difference from using lightest 15N ICS spring or heavyest 28N spring results in difference of .01 to .02 in main spring rate, so having a .42, it becomes .43 - .44 of overall rate.
Considering this difference, since current springs in forks are .043, putting .42 inside should compensate.