Fork stem issue

[NordieBoy]

I'm re-forking a 1981 GSX400F and can use either a pair of shortened KX125 USD's or DR650 forks.

I'd rather use the DR's forks and keep it Suzuki but...

The KX125 stem is 30mm at the bottom bearing and 25mm at the top.
The top bearing surface needs lowering by 5mm or so and it'd fit perfectly.

The DR650 stem is 30mm at the bottom and 30mm at the top.

The KX bearing will fit on the DR stem for the bottom
They can't find me a bearing to fit the DR stem in the top

The DR and KX wheels both use the same axle diameter so with some fiddling (spacers and caliper re-positioning) the DR wheel would work with the KX forks.

The KX sliders are 39mm.
The DR sliders are 43mm.

To use the DR stem it'd need the top bearing surface machined down to 25mm diameter and the top clamp bit down to about 20mm.
Catch is, it's hollow so I'm not sure about the 20mm bit.

Anyone pressed out a DR stem or know how they're fitted?
Then I could go KX stem in DR clamps?

If I machine the DR stem I can sell the KX front end complete and it pays for the machining.


Aaarrrggghhh...

[F5 Dave]

I briefly skimmed this, but I can't get past why anyone is doing anything with a GSX400 four.

[NordieBoy]

I briefly skimmed this, but I can't get past why anyone is doing anything with a GSX400 four.

This is why...

<img src=http://www.photostorage.nelson.geek.nz/sports/motorsport/mybikes/GSX400F/20100529%20Engine%20test%20fit/slides/20100529-153757-0009.jpg>

[T.W.R]

This the inspiration ?

http://www.trademe.co.nz/Trade-Me-Motors/Motorbikes/Motorbikes/Dual-purpose/auction-295357254.htm

[NordieBoy]

This the inspiration ?

http://www.trademe.co.nz/Trade-Me-Motors/Motorbikes/Motorbikes/Dual-purpose/auction-295357254.htm

Nah. This one...

<img src=http://pezz.smugmug.com/Other/CB-400-Four/IMG1171/824289013_tzm7y-XL.jpg>

[T.W.R]

Timken do a bearing that'd suit the KX stem to fit the DR dimensions (30x52x16) ; Timken # TRB 30205 (25x52x16.25)

Same with NSK, their bearing is # HR30205C

[NordieBoy]

The GSX stem hole is 47mm on the top and 56mm on the bottom.

Top bearing to suit the KX stem would be 25x47
Bottom bearing for the KX would be 30x56

Top bearing to suit the DR stem would be 30x47 - not enough room for the shells and races to fit in there.
Bottom bearing for the DR would be 30x56

Bottom bearing is no problem.
KX top bearing is no problem.

Looks like the KX stem in the DR clamps is the go.
The top bearing surface just needs to be extended downward 5mm or so and the DR top clamp just needs a sleeve to take it from 30mm down to 25mm.

Pressing the stems out.
You'd press from the top? Assuming they're pressed in from the bottom?

[T.W.R]

So you need suzuki part #09265-25019 bearing: RT 25x47x15 BRG

US price $33.97

pretty sure it'd be press out from the bottom

[NordieBoy]

So you need suzuki part #09265-25019 bearing: RT 25x47x15 BRG

US price $33.97

Yep - $20 from SKF. They've even got them on the shelf here :D


pretty sure it'd be press out from the bottom

We tried that with 2,000kpa but no movement but also no idea of how much it would take to get movement.

[NordieBoy]

Press out from the top - toward the wheel.

The KX stem is in the DR bottom clamp.

The bottom of the KX stem was a fraction of a gnats whisker smaller than the DR one so is held in by the spring clip and the bearing.

Sweet :D

[SS90]

This is why...

<img src=http://www.photostorage.nelson.geek.nz/sports/motorsport/mybikes/GSX400F/20100529%20Engine%20test%20fit/slides/20100529-153757-0009.jpg>

You know, that is actually pretty cool...it's not the sort of thing that I would build for myself, but I think it's cool!

[NordieBoy]

Thanks :D

At the moment apart from the front end, if you look at it too hard it'd fall apart. Everything is just sitting together.

[imdying]

You know, that is actually pretty cool...it's not the sort of thing that I would build for myself, but I think it's cool!Same here... It would probably eat me given my dirt experience, but still very cool!

[eelracing]

Any chance you would be entering this in the next Nth v Sth VMX round per chance eh?

Jeez you bloody southerners and ya 4 strokes will do anything to beat a northern twotanger.

I must admit she will be a looker when done,if a bit wobbly in the rough tho haha.

[NordieBoy]

Any chance you would be entering this in the next Nth v Sth VMX round per chance eh?

Jeez you bloody southerners and ya 4 strokes will do anything to beat a northern twotanger.

I must admit she will be a looker when done,if a bit wobbly in the rough tho haha.

Bloody mud islanders. Having to resort to smokers to beat mainlanders on proper bikes.

Disc brakes - vmx?

Only Suzuki could mix technologies soo badly. Damper rod forks and 290mm disc :D

Nothing I'm doing here is out of place really...

Wobbly? It'll be doing at least 1 laid back trail ride when it gets going. Also maybe at least 1 beach race too...

[F5 Dave]

Good luck with that. Suzuki 4 cyl are amongst the fittest & most reliable.


. . . except that model which is asthmatic & generally regarded as a bit of a lemon. The next gen Impulse were much better, probably retrofit easy enough if that poos itself. Won't be very inspiring to ride. How much is a DRZ400 these days?

[NordieBoy]

. . . except that model which is asthmatic & generally regarded as a bit of a lemon. The next gen Impulse were much better, probably retrofit easy enough if that poos itself. Won't be very inspiring to ride. How much is a DRZ400 these days?

Same HP as the DR650.

A DRZ would be more than the $685 this has cost so far and still wouldn't be an old school 4 cylinder adventure bike oozing character.

[F5 Dave]

Same HP as the DR650.
Delivered in such a way to make it feel like about 1/2 that.


. . . and still wouldn't be an old school 4 cylinder adventure bike oozing character.

ooz. yes I'm sure it will.


ok I'll bugger off now.

[Kickaha]

ok I'll bugger off now.

Yes bugger off and work on your two stroke, now there would be an adventure bike worth building :lol:

[F5 Dave]

Do you mean the bucket or the 500. Yeah the 500 would be a bit silly fer sure:blink:. Even just range with std tank would be bad enough.

As for the bucket, it wouldn't be the first time. I took my H out to The Lemming run at stone wall Cape Pallicer with just a pod filter added. The stone steps bashed the underslung pipe somewhat & the river crossing was interesting. Got up super early the next day, rode out & raced it.:Punk:

[NordieBoy]

ooz. yes I'm sure it will.

Bashplate - no stone or step induced oozing.