View Full Version : 85/86 5-axis 250r billet triples
Im wanting to make inverted fork Billet triples for 85/86 250r's and was wondering how much rake is built into the factory triples. Also how much total rake does the bike have? Thanks
Will be using CR125 forks for the first set. Also will be doing something a little different to drop the ride height, something nobody else on this site has tried but should work
Ive been a member since 2010 and need 10 posts also so if you have any questions about what im doing ask away
Also have a question of my own for the members that have done this, How did you fit the inverted forks without losing some steering? the factory tubes are already notched into the radiator grilles.
Red Rider
11-14-2014, 04:18 PM
You say you're going to use CR125 forks, so I'm assuming they are of the modern, inverted variety. If you want to run them in the "leading axle" configuration, like they were designed for, triple-clamps with zero rake built into them work out great, and are the easiest to make. But all that depends on your ride height too, which you say you are changing. To save wasted time/materials/money, my advice is to do your homework on the effects of rake/trail before you jump headlong into this project. Good luck with it & keep us posted on the progress.
Yes they are 01 CR forks that have the long non-tapering tops above the lower clamps. Im doing a trailing front axle and running rake in the triples, as close to stock as i can get it. This wont be a garage type deal, Im a CNC programmer and will be making these on a 5 axis mill.
Im aware of the rake/trail issues. I would like to get the feedback of the guys that have tried different combinations of this and get their feedback. What i'm really after i guess is the exact specs of the stock frame rake and the rake built into the triples. Thanks
Red Rider
11-14-2014, 05:58 PM
How did you fit the inverted forks without losing some steering? the factory tubes are already notched into the radiator grilles.When I did mine, I initially used the stock rake built into the triple-clamps, and with the bigger diameter forks, they will hit the radiator grills sooner than the stock forks will which of course limits steering radius. On the second go around, after doing the homework that I should have done prior to the first attempt, I went with zero rake built into the triple-clamps. Due to the steeper angle of the forks, the tops of the tubes are further away from the radiators, which provided an increase in steering radius for my application. Both attempts were done with the forks in the leading-axle configuration. In my opinion, running them in the trailing-axle configuration just doesn't look right, unless the forks were designed that way in first place.
I don't know the specs you're looking for, but with your setup, I would think it could be measured somehow.
And thats were im confused with some of the pics ive seen. some of the pics ive seen on here almost look like they put negative rake in the triples. And they just look goofy as hell. Are your non-raked triples hitting the steering stops before the grilles? What was the neck tube to fork offset, and how much trail is built into yours?
Red Rider
11-15-2014, 05:16 AM
Are your non-raked triples hitting the steering stops before the grilles? What was the neck tube to fork offset, and how much trail is built into yours?Yes, the triple-clamps hit the stops before they touch the radiator grills, and I've got more turning radius now than I did with the stock setup. I'm on the road right now, so I can't look at my triple-clamp plans to answer your neck tube to fork offset question. Since I'm using KTM 85SX forks, which are of comparable length to the stock forks, but with 10.8" of travel and 43mm diameter, I designed the triple-clamps to have the same trail as the stock setup, and I couldn't be happier with the steering/handling.
Ok thanks, i might try a raked and a non raked and see how it goes
Ill post some pics here when i get something goin
Red Rider
11-17-2014, 04:17 PM
Alright, looking at my notes, the steering tube to fork holes are 1.5" apart center-to-center.
That sounds about right. That would be looking down from the top, 1.5" in a Y-axis?
Red Rider
11-17-2014, 04:55 PM
You are correct sir. Yes!
Billy Golightly
11-18-2014, 10:46 AM
The last set I made, I did zero rake, and I just moved the center line of the fork holes out further away from the stem about 1/4in from what I remember (I did some calculation where I figured the amount of distance per mm of fork diameter for the stock forks/tree setup, just divided and averaged I think)
Cool thanks, does anybody know how much rake at the neck the stock 85/86 250r has
joe_foster
12-08-2014, 04:55 PM
Cool thanks, does anybody know how much rake at the neck the stock 85/86 250r has
You've asked this a couple times, I don't have a 250r to measure it but if you do you should be able to measure the degrees from vertical the head tube is. This should give you the rake providing the bike is sitting level.
RAKE: The angle in degrees of the steering neck from vertical.
Hope this is helpful, I did some digging and couldn't find the frame specs anywhere.
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