Fork Shortening

[TrailerRider]

I have a (what I think) is a 1977 Suzuki RM250 frame with forks setup. So to the mad scientists of the group is it possible to cut them down in size? I have not opened them up so I have no clue if it will work or not but are they spring loaded shocks? If so couldn't I just disassemble them and cut the spring down in size and cut the fork tubes down to match and then in theory the fork would be shortened right (replacing seals and oil etc..)? I will be retaining the triple tree and neck from frame.

Thanks

[El Camexican]

Not necessary to cut anything. Just disassemble the forks and determine what diameter of tube (preferably aluminum) fits inside the inner tube and has a hole large enough for the damper rod to pass through.

If you want to lower the forks 1” you just cut a length of said tube 1” long and slide it onto the damper rod before inserting it back into the fork tube. When you put the forks back together they will be 1” shorter. If you go more than that you may have to trim the spring as it will need to be compressed an additional inch when assembled.

Hope this make sense.

[robertc]

Sorry about the dislike El, I was going for the thumbs up when my finger inadvertently hit thumbs down.

[onformula1]

El camexican is correct but i use steet tubing because the top out spring will eat up aluminum

Remember the top out spring is a coil spring, when it compresses it turns and the two wire ends with tear stuff up

Thats why on PVC preload spacers or any material other than steel must have a steel washer on both ends.

[El Camexican]

Sorry about the dislike El, I was going for the thumbs up when my finger inadvertently hit thumbs down.

It may take a few weeks, but I'll get over it However, if you find yourself loosing sleep over it you can just click it again and it will go away.

[El Camexican]

El camexican is correct but i use steet tubing because the top out spring will eat up aluminum

Remember the top out spring is a coil spring, when it compresses it turns and the two wire ends with tear stuff up

Thats why on PVC preload spacers or any material other than steel must have a steel washer on both ends.

Good point. My experience has always been on drag bikes, not a lot of hard impacts on them and the aluminum was always high quality.

[onformula1]

Good point. My experience has always been on drag bikes, not a lot of hard impacts on them and the aluminum was always high quality.

Your right, but sometimes those walls come up quick!

[TrailerRider]

thanks for the tips fellas! So I will this summer be converting a little china quad to a 3 wheeler. I had the 250 frame and fork and figured I would just cut them down in size to fit the conversion. Looking at the length of the fork vs the quad frame I am thinking it would have to have at least 3 to 4 in cut off to work and look proper. Still possible to do this?

[TrailerRider]

oh yeah this is mostly what the quad looks like except mine is missing plastics:
http://thumbs1.picclick.com/d/l400/p...BUGGY-50cc.jpg

[El Camexican]

thanks for the tips fellas! So I will this summer be converting a little china quad to a 3 wheeler. I had the 250 frame and fork and figured I would just cut them down in size to fit the conversion. Looking at the length of the fork vs the quad frame I am thinking it would have to have at least 3 to 4 in cut off to work and look proper. Still possible to do this?

You can shorten the travel to zero, just don't expect a plush ride. I've done 3" drops before. I would leave at least 2" of travel and make sure the springs are well pre-loaded if you go that route.

[Racer-X]

How much shorter are you trying to go? You could always just loosen the triple trees and slide the forks up a little higher to lower it. Going with too short of a spring will bottom out all the time if its not uncomfortably stiff. Sliding the forks up into the trees instead will keep the same suspension travel

[onformula1]

How much shorter are you trying to go? You could always just loosen the triple trees and slide the forks up a little higher to lower it. Going with too short of a spring will bottom out all the time if its not uncomfortably stiff. Sliding the forks up into the trees instead will keep the same suspension travel

Until Mr. tire meets Mrs. fender.

[onformula1]

thanks for the tips fellas! So I will this summer be converting a little china quad to a 3 wheeler. I had the 250 frame and fork and figured I would just cut them down in size to fit the conversion. Looking at the length of the fork vs the quad frame I am thinking it would have to have at least 3 to 4 in cut off to work and look proper. Still possible to do this?

3" to 4" is not a problem to perform, I have shortened modern bikes in half from 12" to 6" because thats what the customer wanted. (Supermotard Bikes)

Remember a 1977 Suzuki RM250 did not have a lot of travel to begin with, I don't have the specs in front of me but 8'' to 9" must be close. I don't think you will need to do anything to the forks you will be in the "ATC" range stock. You did say 1977 correct?

[TrailerRider]

Yeah I believe its 77. I have also been toying with the idea of meshing the frontend from my old 85 110 frame is shot but fork and neck are good but I would prefer to use the suspension for sure. I think it would look better.

[TrailerRider]

I did a little photo chopping this past week and figured if I can cut the bends out of the side archs from the fork and reweld them up to the bottom of the tree it would possibly work. It would make for nice smaller tire for the front and might look kind of nice leveled out stance.

I would of course have to double wall the fork after cutting and welding to keep strength.


Original Fork


Modified Fork