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Old 11-19-2008, 07:50 PM   #31
drivenbydiscovery
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thanks for that.

looking into it some more, i think the 2004+ Yamaha YZ bikes use the same bearings as the 2003 and older, so theoretically they should work. i actually stopped by a Yamaha dealer today but after posing this question, all i got was dumbfounded looks. so no help there.

only one way to find out i guess; buy a newer YZ triple tree with bearings and try to graft it on.

as one of my good mates always says; it's all just a matter of trial and error. with a little more error than trial.

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Old 11-24-2008, 03:40 AM   #32
johno
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Location: Mount Gambier, South Australia, Australia.
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WayneC1, just put a YSS rear shocker on my GSPD.
Will roadtest, and set it up 2morro.
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Old 11-24-2008, 02:19 PM   #33
mtothef
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this might help

when it comes to looking for bearing retrofits, the outer diameter and profile height of the bearings is what matters. if you go to pivot works website and search for the bearing application for your bmw. there should also be a specification for it somewhere, either listing the components of the kit including the bearing dimensions, or the bearing dimensions themselves.

now, go check for the same for whatever forks you are searching. if the profile height and outer diameters (both upper AND lower) match, then you are in bidness!

in some instances, the same bearing kit will work for several different forks ('frinstance, the xt600 i am restoring uses the exact kit that early 90s kx500s do, so that ended up being the front end i bought), so it's always a good idea to cross reference the kit number for your bike and see what else it is used in.

dealers are useless for this kind of info, because it involves a lot of back and forth cross referencing and may not always be absolutely clear. but with some digging on that one website, you should be able to figure this all out. good luck!

Quote:
Originally Posted by drivenbydiscovery
thanks for that.

looking into it some more, i think the 2004+ Yamaha YZ bikes use the same bearings as the 2003 and older, so theoretically they should work. i actually stopped by a Yamaha dealer today but after posing this question, all i got was dumbfounded looks. so no help there.

only one way to find out i guess; buy a newer YZ triple tree with bearings and try to graft it on.

as one of my good mates always says; it's all just a matter of trial and error. with a little more error than trial.

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Old 11-30-2008, 04:58 AM   #34
Brute
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What about the steering lock & ignition key setup . Did you use the same key setup ?If so how did you mount it ?
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Old 11-30-2008, 01:26 PM   #35
Salt fever
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Location: Yarra Ranges-Australia
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Husky Marzzochi Shivers

I kept the BMW post and had the bottom machined to suit the alloy triple from the 08 Husqvuarna as the post is welded into the factory steel ones. This way I also kept the BMW dual locking set up on the headstem. I run aftermarket risers for fat bars. I had to take off some of the metal either side of the plate with the holes in it for the steering lock as the bolts for the new handlebar mounts were hitting it ( not a very good steering stopper as it moves the bars heaps). I run an new Husky front guard and as its one piece it will be far more up to my standards of get offs ( I turned pro in get offs moons ago)≥ I had to run 3 washers between guard and triple at the back two mounts to give the correct angle on it to clear the frame spine and radiator shrouds.

I have yet to sort out front wheel/brake set up. I have a wheel from a new Aprilia which use the same forks and axle set up, however if I can machine up some spacers and end plugs (threaded one end) I can use the original wheel and rotor, or alternatly find new bearings for the hub to fit the husky/aprilia axle.

I too am having trouble trying to work out what to do with the ignition block. I will keep you posted as I am a resouceful bastard.


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Old 11-30-2008, 04:12 PM   #36
WayneC1
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Looking quite a mean beast there

Johno, Will be interested to hear how the YSS shock goes
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Old 11-30-2008, 10:56 PM   #37
Brute
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Thanks there salt fever . If all goes well I`ll probably have a set of forks & clamps off an 06 yz 450 very soon. I haven`t pulled my Dakar apart as yet but I was thinking maybe the only way to mount the ignition lock would be to cut the alloy mount off the old triple clamp & tig it onto the new top triple clamp & do away with the steering lock .
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Old 12-01-2008, 01:56 AM   #38
johno
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Location: Mount Gambier, South Australia, Australia.
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Just done a 450klm ride to Adelaide, and very happy with the YSS shock.
Will play a bit with it on the way home tommorrow.

Might have to change to a lighter oil in my forks. Running 5w at the moment. Standard Yammy is 2.5w. I dont have a lot of static sag with my YZ450 forks. Could have been set up firm by PO for serious MX.
Works better on rough stuff than smaller bumps.
Will give me something to play with
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Old 01-14-2009, 05:07 PM   #39
JDRadman
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Thumb

Quote:
Originally Posted by johno
Might have to change to a lighter oil in my forks. Running 5w at the moment. Standard Yammy is 2.5w. I dont have a lot of static sag with my YZ450 forks. Could have been set up firm by PO for serious MX.
Works better on rough stuff than smaller bumps.
Will give me something to play with
I am contemplating the same mod with the YZ forks on my Dakar.

I am curious about spring rates on your bike. Ski... said he thought his were a .52. Yama OEM or stock for KYB 48Us come with .46 or .44 for 450 and 250F respectively per Racetech (same on the 46U). The stock GS is .62 and Racetech thinks I need a .86 on the GS (160lbs no gear) but they don't make them. I am currently running the TT upgraded springs but don't know there rating.

So what's the story on race and static sag on the GS Dakar with the standard Yamie springs. I don't understand how a spring sooooo much softer than the stock BMW spring could be too stiff with too little sag? Damping would bleed down under the weight so what am i missing
Please help me understand this.

Great thread and I am looking forward to the upgrade...

Rad
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Old 01-14-2009, 05:32 PM   #40
floridasroadkill
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YZ in a R900 GS

Same bearrings but longer bearing stem.Huge improvment with longer rear shocks.YZ 400 from 1999.
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Old 01-29-2009, 08:33 PM   #41
JDRadman
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Location: In the Heartland
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In Process

I have begun the transformation.

I purchased a set of 03 YZ forks (46mm) and will fit the BMW OEM wheel and brake. I prefer to use the larger thicker 300mm disc rather than the Yamaha 250mm-stock rotor. Oversize 270mm off-road and supermotards kits get expensive pretty quick.

Confirmation for those contemplating such a modification on the bearing swap:

The Yamaha bottom bearing has a 30mm bore and uses a larger cup OD and is a bit taller than the 28mm on the BMW. It does however fit into the smaller OEM cup quite well. I used the stock Yamaha seal and bearing with the BMW cup. If you cut the rubber lip off the bearing seal it fits nicely into the recess left to create a good seal. Grease will complete the seal very close to as good as the stock BMW but not as good as the Yamaha OEM set up.

The top bearing is the same and I used the Yamaha top seal with a little bending to reduce the gap and greased it up well.

The fender mounts under the front triple within about 5mm if you cut off the number plate tabs and drill new holes. I also made a strap to reinforce the attachment of the front of the fender. The front mounting holes are very close to the front of the fender and not as wide as the OEM holes. It seems to work well so far in mock ups.

So now my challenges are
1)Key and lock mounting position
2)Spacer and new bearings for BMW front wheel
3)Hanger for BMW brake

I have some minimal machining capabilities at the house so I will start on those challenges this weekend.

If anyone has ideas on the key and lock would love to hear it…

If you completed this project and have additional details or ideas on any part of the process please share them.

Thanks,

Radman
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Old 01-29-2009, 11:44 PM   #42
farkleface
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pics

JD any pictures of your modification would be a huge help. I am still contemplating trying this. I have the 03 yammy fork and would like to use the bmw front wheel if possible. i don't have the ability or equipment to make custom parts.
if you are making a custom key mount and want to make another to sell let me know. there is a small picture of touratech's solution to the problem on their web site under wp suspension kit- and then kit photo- if that helps at all.
Does anyone know if I do use the yammy wheel and caliper will it work with my existing touratech ss brake line?
thanks
matt
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Old 01-30-2009, 09:31 AM   #43
farkleface
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steering damper

skibum any pics of your steering damper setup?
thanks
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Old 01-30-2009, 12:31 PM   #44
komatias
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Dude,

You are right to think that the 250mm rotor is under sized.

What I am really gobsmacked by is your mix and match of the steering head bearings. You cant interchange races and bearing cages just like that. It is dangerous. If the bottom of the axle is 30mm then get someone to turn it down to the 28mm required. Dont mess about with these things, its you life. Please do not be offended I am just trying to stress the facts.
If the steering axle is hollow then maybe that is a bit of a problem if it is aluminium. If steel then just turn it down.

You will have to turn the spacers and get a different front brake caliper. The brembo one is abit dated and you will have difficulty finding hangers for it.

The steering/ignition lock is a bit of a problem. Dont know what the yama clamps look like but avoid drilling holes in them like the plague if they look cast.

Just so you know I am not bulshitting you on the above points, I have spent 4 year(ever since I got my dakar) trying to find a quick way to add usd forks to it and I have done it.







Quote:
Originally Posted by JDRadman
I have begun the transformation.

I purchased a set of 03 YZ forks (46mm) and will fit the BMW OEM wheel and brake. I prefer to use the larger thicker 300mm disc rather than the Yamaha 250mm-stock rotor. Oversize 270mm off-road and supermotards kits get expensive pretty quick.

Confirmation for those contemplating such a modification on the bearing swap:

The Yamaha bottom bearing has a 30mm bore and uses a larger cup OD and is a bit taller than the 28mm on the BMW. It does however fit into the smaller OEM cup quite well. I used the stock Yamaha seal and bearing with the BMW cup. If you cut the rubber lip off the bearing seal it fits nicely into the recess left to create a good seal. Grease will complete the seal very close to as good as the stock BMW but not as good as the Yamaha OEM set up.

The top bearing is the same and I used the Yamaha top seal with a little bending to reduce the gap and greased it up well.

The fender mounts under the front triple within about 5mm if you cut off the number plate tabs and drill new holes. I also made a strap to reinforce the attachment of the front of the fender. The front mounting holes are very close to the front of the fender and not as wide as the OEM holes. It seems to work well so far in mock ups.

So now my challenges are
1)Key and lock mounting position
2)Spacer and new bearings for BMW front wheel
3)Hanger for BMW brake

I have some minimal machining capabilities at the house so I will start on those challenges this weekend.

If anyone has ideas on the key and lock would love to hear it…

If you completed this project and have additional details or ideas on any part of the process please share them.

Thanks,

Radman
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Old 01-30-2009, 01:12 PM   #45
JDRadman
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Komatias,
Thank you for your comments. I understand your concerns but I believe they may be somewhat overstated. What you say is applicable if the bearings were used in a high-speed application like a wheel bearing etc.

In a no speed - low load (relatively speaking) as long as the surfaces of the bearings and the cup meet as designed you will get satisfactory performance from the bearing. The 30mm bearing rides less than 1mm higher in the cup of the 28mm bearing and is within the machined wear surface of the bearing cup and still deep inside the steering stem. I believe it will work safely in this application.

Failures in steering head bearings occur over time and I have never heard of a sudden catastrophic bearing failure. They are usually attributed to lack of lubrication and infiltration of dirt and water allowing the bearing to beat themselves to death. It is witnessed by sticky or notchey steering and that is when it gets un-fun or dangerous. Letting that go is really bad.

FWIW, I am an Industrial Engineer by education, worked in the power-transmission and industrial automation fields for too many years to talk about. And I too have been doing this type of work...for about 40 years. It is not ideal because you have to buy 2 bearings to make it work but it is easier than pressing out and turning down the stem.

Your installation looks great. Thanks for sharing the album.

Are you using a KTM forks, wheel and aftermarket oversize off-road brake kit? If so, what manufacturer did you go with and how well does it work for you?

Thanks,
Radman
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