Swapping RM Forks

[Enginerd]

Gents,

I'm working on swapping a set of 96-98 Suzuki RM forks to the front of my 1995 KX5. These are twin chamber, 49mm conventional forks made by Showa.  Lots of offroad guys really like these forks, so I thought I'd give them a try. 

However, I haven't found any record online of anyone who's performed the swap.  Have any of you guys done this swap, or seen it done? 

It seems to me that swapping the KX stem into the lower RM triple clamp will be the way to go.  I want to keep my entire 95 KX5 front end together, and set it to the side in case I don't like the RM forks.  So, I need a lower KX triple to get the steering stem out of.  What years and models are interchangeable in the KX lineup?

Also, if you have any tips or suggestions for me, I'd be glad to hear them.

Thanks,
Gary

[kxpegger]

Gents,

I'm working on swapping a set of 96-98 Suzuki RM forks to the front of my 1995 KX5. These are twin chamber, 49mm conventional forks made by Showa.  Lots of offroad guys really like these forks, so I thought I'd give them a try. 

However, I haven't found any record online of anyone who's performed the swap.  Have any of you guys done this swap, or seen it done? 

It seems to me that swapping the KX stem into the lower RM triple clamp will be the way to go.  I want to keep my entire 95 KX5 front end together, and set it to the side in case I don't like the RM forks.  So, I need a lower KX triple to get the steering stem out of.  What years and models are interchangeable in the KX lineup?

Also, if you have any tips or suggestions for me, I'd be glad to hear them.

Thanks,
Gary

Im pretty sure the stem is a press fit. My only concern would be the number of times you can press fit a piece of steel into aluminum before you run into some problems. I suspect this is why the OEM manufactures don't sell the stem from the clamp separate but as one unit. If the Suzuki stem uses the same size bearings but the stem is to long you could probably have it machined. If the stem is to short your out of luck unless you choose to press fit. I saw a post around here where someone had modified a KX450F set of clamps and forks for a KX500. Can't remember exactly what he did though!

[ID KX500]

I swapped forks on an XR650L from a CR500. kxpegger is right on the repressing of the steering stems,,, it should not be done. If the fork tubes are the same I'd keep it simple and just drop in the RMs in the KX. Do they fit?

[The Flyin Hawaiian]

Popular mod among a core group of enduro riders here on the east coast. You simply have a set of spacers made that will fit into the KXs triple clamps to make up the differance of the smaller 49mm forks. I am contemplating the same mod on my 500 using a revalved set of DRZ400 49mm forks. A machinest friend of mine is going to make the spacers for me. I spoke to Drew Smith from WER (Works Enduro Rider) and he said using spacers will work w/o any issues. Any machinest can make them and you can go back to stock easily. You will probably need the forks, wheel etc from the donor RM. I believe a DRZ wheel will work also

[CR480R]

stems press easy...thats the way to go if you can.  Most i've pressed had some type of factory anti seize on them...  do you know for sure the RM stem is a no go?  If you could find any info on CR to Rm swaps it would be useful because if a honda stem (USD models) will press into the rm clamp, so will a kx500/kdx stem. I know because i have some '95 cr500 forks with a kx500 stem in them.. identical press fit and i believe stems from most 90's jap motocrossers will too..   I had a kx500 stem with stripped threads, i replaced it with one I took from a kdx.. so that opens up more potential stem donors.  

It seems to me that swapping the KX stem into the lower RM triple clamp will be the way to go.  I want to keep my entire 95 KX5 front end together, and set it to the side in case I don't like the RM forks.  So, I need a lower KX triple to get the steering stem out of.  What years and models are interchangeable in the KX lineup?

[sandblaster]

Both the 95 K5 and the RM 49mm Conventional forks have a center line to center line mount of 102mm for the brake caliper.
Even though I have not tried it I think you can use the RM brake on your K5.
The RM uses a 20MM AXLE and the outside of BRG to the outside of BRG is 88MM,
The KX  also uses a AXLE OD 20MM - BRG TO BRG 89.5MM - (approx .060 difference)
Both use a 250mm brake rotor OD.
So, with a little bit of mods on the wheel spacers you might be able to use the K5 front wheel.
If you try any of this let us know if it works.

[Enginerd]

You simply have a set of spacers made that will fit into the KXs triple clamps to make up the differance of the smaller 49mm forks. I am contemplating the same mod on my 500 using a revalved set of DRZ400 49mm forks. A machinist friend of mine is going to make the spacers for me. I spoke to Drew Smith from WER (Works Enduro Rider) and he said using spacers will work w/o any issues. Any machinest can make them and you can go back to stock easily. You will probably need the forks, wheel etc from the donor RM. I believe a DRZ wheel will work also

This is an idea I hadn't thought of!  You are right, that this would make it easy to go back to stock, and it would also prevent any issues with the RM steering stops not working with the KX frame. 

I have two concerns.  The first is that the RM and KX triple clamp center-to-center distance may not be the same.  I do have both sets of triples and will have to measure when I get home (I'm working in N. Dakota for the next week) 

My second concern is that the insert bushings that go between the KX triple clamp and the RM fork tube could move/slip when the forks take a big hit.  However, if someone like Drew Smith thinks the use of the bushings will be OK, I think it probably will.  He has a bit more experience than me. 

Thanks for the idea!

[Enginerd]

Stems press easy...thats the way to go if you can.  Most i've pressed had some type of factory anti seize on them...  do you know for sure the RM stem is a no go?  If you could find any info on CR to Rm swaps it would be useful because if a honda stem (USD models) will press into the rm clamp, so will a kx500/kdx stem. I know because i have some '95 cr500 forks with a kx500 stem in them.. identical press fit and i believe stems from most 90's jap motocrossers will too..   I had a kx500 stem with stripped threads, i replaced it with one I took from a kdx.. so that opens up more potential stem donors.  

I've heard that swapping the RM stem into the KX lower triple is a possible route to go, but I'm afraid there might be too much difference between the RM style steering stops and the KX style steering stops.  I might get really lucky and the RM triples might go into the KX steering neck, and then it would be a super easy swap.  Unfortunately, I am not at home right now to look at the parts.

Thanks for the reply!

[Enginerd]

Both the 95 K5 and the RM 49mm Conventional forks have a center line to center line mount of 102mm for the brake caliper.
Even though I have not tried it I think you can use the RM brake on your K5.
The RM uses a 20MM AXLE and the outside of BRG to the outside of BRG is 88MM,
The KX  also uses a AXLE OD 20MM - BRG TO BRG 89.5MM - (approx .060 difference)
Both use a 250mm brake rotor OD.
So, with a little bit of mods on the wheel spacers you might be able to use the K5 front wheel.
If you try any of this let us know if it works.

This is great info!  Thanks, Sir!

[don46]

first, if you press the stem out, you must press it all the way through, in other words the long part has to go all the way through, there is a circlip in the bottom that keeps the stem from coming through the clamp.

second, Emig will make you a set of KX triples bored for the RM forks, it would be a bit pricey but would work

The spacers referred to would have to be split so when the clamps are tightened they would compress the spacers locking them on the clamp, I've done this before but only on the top clamp

[The Flyin Hawaiian]

All the guys running the 49s out here are using spacers. One of them is a AA enduro rider and ISDE vet. There is even one guy that swears buy 88 43mm CR forks and runs them on his 2010 KTM, also a ex AA and ISDE vet. His spacers are HUGE!

[The Flyin Hawaiian]

I believe later model DR350s (98-99) use the same wheel, just with the drive unit tabs. Also RMXs and DRZs.

[Enginerd]

first, if you press the stem out, you must press it all the way through, in other words the long part has to go all the way through, there is a circlip in the bottom that keeps the stem from coming through the clamp.

Good info, Don.  Thanks!

The spacers referred to would have to be split so when the clamps are tightened they would compress the spacers locking them on the clamp, I've done this before but only on the top clamp.

Should the split in the spacer be aligned with the slot in the triple clamp, or oriented 180 degrees from the slot in the clamp?

[Enginerd]

All the guys running the 49s out here are using spacers. One of them is a AA enduro rider and ISDE vet. There is even one guy that swears buy 88 43mm CR forks and runs them on his 2010 KTM, also a ex AA and ISDE vet. His spacers are HUGE!

This is good to hear.  It gives me a bit more confidence that the spacers will be plenty safe.

[Neli]

I too want to install a set on 1998 RM fork on my 1993 KX 500, I already have the complete from end from an RM including the triple clamps, and was hoping that I could just press out the KX stem, and install it on the RM triple clamps, as it seems at first glance that the RM stem is a bit short.
Any help or suggestions would be really appreciated!