Author Topic: KLX250 fork yoke dimensions...?  (Read 231 times)

0 Members and 1 Guest are viewing this topic.

Offline James P

  • Novice
  • *
  • Posts: 27
    • View Profile
KLX250 fork yoke dimensions...?
« on: November 27, 2017, 06:59:57 PM »
Can anyone help with dimensions for KLX250 fork yokes? I understand that all models have 36mm forks, but am unsure whether the yokes are the same for all models.

I am looking for a set of yokes (from any bike) to fit 36mm forks, which will allow the fork legs to pass up through the top yoke without hitting the handlebar. I've seen pictures of KLX250 yokes which look suitable, but I can't be sure without checking and measuring...or asking someone who knows.

I am looking for the following info:

1. Will the fork leg(s) pass up through the top yoke without hitting the handlebar?
2. If so, what is the distance between fork leg centres?
3. What is the offset (i.e. the perpendicular distance between the centre of the steering column and a straight line drawn through the fork leg centres)?
4. What is the inside diameter of the hole in the top yoke for the steering column?

I may have to modify positions of steering stops and make other minor adjustments to suit my application, but any basic info is welcome. If you are able to provide any details, please let me know the year of manufacture (if you know it) of the yokes you have measured, just in case there are any differences between models.

Thanks in advance & regards,
James


Offline LWC82PE

  • Superstar
  • ******
  • Posts: 5705
    • View Profile
    • PE motorcycles & SuzukiTS.com
Re: KLX250 fork yoke dimensions...?
« Reply #1 on: November 27, 2017, 07:04:18 PM »
If this is for your PE250, you can just use 1978 RM triples. They just bolt on, no mods required and allow forks to slide up though the top triple clamp. Offset is the same (30mm) and spacing is the same (175mm)
Other later  PE and DR clamps, although still have 30mm offset, have a longer stem and 180mm spaced fork centers and don't have steering stops on the top of the bottom clamp, so the 78 RM ones are the better ones to use.

Another option is Marzocchi clamps from 77-80 era approx with single pinch bolts. They have 5mm less offset (25mm), allow forks to be slid up through the clamp, but you will need to figure out steering stops, change the stem and bore the clamps from 35mm to 36mm. Theres plenty of meat in them to do this. Marzocchi use the same castings for the 35 and 38mm clamps.
« Last Edit: November 27, 2017, 07:13:04 PM by LWC82PE »
Wanted - 1978 TS185 frame
Orange Don Vesco/MS/Windsor tank
ADB Mags (vol 2 no.2) nov/dec 77& jan/feb 78 (vol2 no.3)

Offline James P

  • Novice
  • *
  • Posts: 27
    • View Profile
Re: KLX250 fork yoke dimensions...?
« Reply #2 on: November 27, 2017, 08:31:22 PM »
Thanks for the info Leith. The RM250 (C or C2?) yokes seem ideal - I'll investigate further!

I'd still be interested to know dimensions of KLX250 yokes, just in case I can't find any RM yokes.

Regards,
James

Offline LWC82PE

  • Superstar
  • ******
  • Posts: 5705
    • View Profile
    • PE motorcycles & SuzukiTS.com
Re: KLX250 fork yoke dimensions...?
« Reply #3 on: November 27, 2017, 08:44:19 PM »
Theres loads of these RM clamps out there. You wont have much trouble finding them. In fact all you would need is the upper clamp, the lowers are same dimensionally for 76-78 RM and 78-79 PE. 78's removed the pinch bolt at the base of the bottom clamp for the stem though. Please keep in mind to check your clearances between the lower triple clamp and tyre though when fully bottomed. If you slide the forks up through the triples too much you could find that the triple clamp/fender hits the tyre. Theres usually not a lot of breathing spacer here standard so pulling the forks up too much could create a problem. Take for caps off and springs out and collapse front end to see how much you can pull the forks up. Some people shorten the length by fitting spacers or extra/loner rebound springs too rebound.

RM250C has the bars over the fork caps and is the same as what you already have so you wont want that one. RM250C2 RM125C and RM400C are all the same clamp with the laid back bar mounts.
« Last Edit: November 27, 2017, 08:45:55 PM by LWC82PE »
Wanted - 1978 TS185 frame
Orange Don Vesco/MS/Windsor tank
ADB Mags (vol 2 no.2) nov/dec 77& jan/feb 78 (vol2 no.3)

Offline James P

  • Novice
  • *
  • Posts: 27
    • View Profile
Re: KLX250 fork yoke dimensions...?
« Reply #4 on: November 27, 2017, 09:09:10 PM »
Thanks again Leith. Yes, I will check the available travel to avoid the wheel hitting the mudguard, but I won't be doing any hard landings! As it is now a road bike, I'll be keeping both wheels on the ground ;D .

Regards,
James

Offline 80-85 husky

  • Legend
  • *****
  • Posts: 3437
    • View Profile
Re: KLX250 fork yoke dimensions...?
« Reply #5 on: November 28, 2017, 11:02:36 AM »
just be sure you have clearance as hard braking could inadvertently lock your front wheel and get you checking the bitumen for small stones.

Offline James P

  • Novice
  • *
  • Posts: 27
    • View Profile
Re: KLX250 fork yoke dimensions...?
« Reply #6 on: December 01, 2017, 08:45:34 PM »
Not KLX, but I had a look at some KLR250 (1989 I think) yokes today. The distance between fork centres seems to be 185mm, while the offset is somewhere in the region of 25mm (yokes still on bike, so accurate measurements difficult :-[ ). The important dimensions thus seem similar to the Yamaha IT (1977-1980) yokes which I also know about. Not absolutely ideal for my purpose but could be adapted, so the IT or KLR yokes will be my back-up option if I can't get the RM ones I want.

Regards,
James

Offline LWC82PE

  • Superstar
  • ******
  • Posts: 5705
    • View Profile
    • PE motorcycles & SuzukiTS.com
Re: KLX250 fork yoke dimensions...?
« Reply #7 on: December 01, 2017, 08:59:06 PM »
KLR250 are all the same 1985 onward. I can confirm they are 185mm wide and about 25mm offset. The stem is much taller than suzuki though. I once had some on a suzuki that uses the same series/dimension of clamps/head stem as what you currently have and it also required bearing addapters/taller inserts in the frame. It was already done like that when i got it might have been possible another way with a different stem. the stock steering stops did not suit suzuki at all and my frame had a welded on tab to contact a different part of the kawasaki clamp
« Last Edit: December 01, 2017, 09:02:56 PM by LWC82PE »
Wanted - 1978 TS185 frame
Orange Don Vesco/MS/Windsor tank
ADB Mags (vol 2 no.2) nov/dec 77& jan/feb 78 (vol2 no.3)

Offline djr

  • C-Grade
  • **
  • Posts: 76
    • View Profile
Re: KLX250 fork yoke dimensions...?
« Reply #8 on: December 03, 2017, 10:40:13 PM »
sorry if this is a silly suggestion , but if you need the handlebars out of the way of the fork tubes have you looked at offset handlebar clamps ?
there are various types for sale {ebay etc} and I have seen a few good home fabricated ones which move the handlebars out of the way.
or spacers under your existing clamps , if you don't want to slide the forks through a large amount this may work
{ I wish I could work out how to post photos}

Offline James P

  • Novice
  • *
  • Posts: 27
    • View Profile
Re: KLX250 fork yoke dimensions...?
« Reply #9 on: December 04, 2017, 10:52:45 AM »
...if you need the handlebars out of the way of the fork tubes have you looked at offset handlebar clamps ?

Pokey posted a photo and link to such clamps here http://forum.ozvmx.com/index.php?topic=42482.0. These clamps are certainly an option, but I'd prefer the end result to look both "standard" and "period", by using OEM parts from the same era (although much later yokes may not necessarily look too modern). Thanks for the suggestion though - I'm keeping this option as Plan C ;D .

Regards,
James