My 48mm Kayaba Project

[Ed Ventura]

Forks arrived today with clamps. Look like brand new. A steal at $275 on ebay.

Fork diameter's
45mm zoke 54mm 57mm
48mm kyb 2007 yzf250 56mm 59mm

I did not get a chance to mesure the axle offset and compare. I will in a day or so.

The Yamaha clamps will work with a yamaha top bearing 28mmx52mmx16mm. The problem with the yamaha clamps is the sterring stop , or lack of.


More to come over the next few days

Ed

[Cruiser]

My 97 GG used the contact of the forks to the frame as the steering stop.. there is a small ding on each side of the frame but its easy to move the bike around in the garage...

[Ed Ventura]

Originally Posted by Cruiser

My 97 GG used the contact of the forks to the frame as the steering stop.. there is a small ding on each side of the frame but its easy to move the bike around in the garage...

I think they are going to get into the radiators. I will put them on my 2011 frame tomorow night.

ED

[rpduc]

Thanks Ed,
Good score on those KYBs!

I'd have a pretty easy swap from my 50mm Zokes then. My top clamp is 58mm, bottom 61mm so 1mm shim stock would fix me up using my triples. Hmmmm...

I'll be watching with interest as you delve into this further.

[GMP]

Some Delrin or Nylon sleeves for the fork tubes of the appropriate thickness to act as frame bumpers should take care of that problem. I did that on my Ducati so a fall off the stand would not trash the frame from a broken wimpy steering stop.

[Anders]

Originally Posted by GMP

Some Delrin or Nylon sleeves for the fork tubes of the appropriate thickness to act as frame bumpers should take care of that problem. I did that on my Ducati so a fall off the stand would not trash the frame from a broken wimpy steering stop.

My Bimota Supermono has a thick rubber band around each for leg where it would hit the frame. That's the way they did it in Rimini.

[rpduc]

When I put open chamber 2000ish KYB forks on that '03 I had I used the Kawi triples. Had to have a spacer made for the Gas Gas stem to fit the larger hole in the bottom triple. Same deal with the steering stops on front. The stretchy rubber band thingies holding on the headlight assembly were conveniently located to act as bumpers on the fork tubes. It was close, but the tubes did not hit the radiators.

Not being a physicist I was a little concerned that in a BIG get-off one could tweak a fork tube or frame cuz of the leverages and point contact involved but I'm not sure how the stock steering stops would fare in that situation either. An additional hard rubber pad glued to the frame would have eased my mind a bit.

The guy that bought it from me was going to have the stock bottom triple bored to fit the KYB tubes so we didn't pursue it any further.

[Ed Ventura]

The axle clamp offset.

I was struggling with the best way to measure the clamp offset. I thought about a plumb bob with the string on the side of the lower tube in a few spots. Then the plumb bob down through the axle hole . Mark a sheet of paper then mesure off that.

In the end I just traced both sides of the lower tubes, found the center and ran a straight line down past the axle hole. I then traced the axle hole, found the center and mesured the distance to my fork tube line.

Dont take it as gospel but seemend to be prety acurate.
45mm Zoke 35mm center of lower tube to center of axle
48mm kyb 32mm center of lower tube to center of axle

So the kyb is 3mm closer.

The yamaha tripple clamp offset (25mm) is 3mm more, than the GG offset (22mm) which should put the front wheel at the same spot as it was with the GG clamps and zoke forks.

I was worried about the kyb forks hitting the frame, if you look at the pic below you can see the spot on the frame were my 45mm zokes were hiting



Here is a picture with the forks and clamps on the bike. If you look close you can see the upper bearing nut. I have not mesured anything yet but the nut is thicker putting the bars higher , but also the spacing between the clamps might be more than the spacing with the GG clamps. So with the forks being the same length if the the same amount is exposed above the clamps with the both setups the kyb flush with the clamps could be the same as the zokes up in the clamps (sticking out the top). That will be my next investigation





Here you can see the upper portion of the tube hitting the frame. It looks lie a rubber fernco pipe coupling will protect it .
The lower clamp bolts get into the radiator plastic louvers a bit. Will trim them.



All that is left is get a front wheel and caliper. I see no reason to mess with a GG wheel. Much simpler just to convert.

After talking to a few tuners the other day I have decided to send the forks and shock to Drew Smith at WER.

Hopefully I will be riding it by the end of next week



ED

[Ed Ventura]

The conversion is Done,, Just rode around my barn a little, seems to crave the inside line more than ever, I do have less sag in it. Cant wait to get on the trail, Crazy week at work with the storms.

[Ed Ventura]

Update on my FRANKIN Bike as my KTM friends call it.

By far the best rock suspended bike I have owned. I dont feel trail trash or roots.. Seems to carry a gear higher in rock gardens. Stays up in the stroke much better than any of my 45mm zoke bikes. A very solid improvement.

I cant compare them to the new 48mm zokes. i have not ridden them.

I am really looking foward to my next enduro with this setup, I have gone out to my practice area the last couple days and am very impressed. A click or 2 , it is close to perfect.

Thanks to Drew Smith at WER for his setup. I think he nailed it

ED