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Race Tech .046 Fork Spring Install

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I'm getting ready to install a set of Race Tech .046 springs in the forks of my DR650. I have found a lot of info on the Eibach springs. Has anyone else used the Race Tech springs? I was hoping for a little guidance on how much PVC I should start with. This sure is a pre-historic method. I have the 10w oil but need to know about the fork oil level. I'm 185 lbs. w/o gear.

Thanks!

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I'm getting ready to install a set of Race Tech .046 springs in the forks of my DR650. I have found a lot of info on the Eibach springs. Has anyone else used the Race Tech springs? I was hoping for a little guidance on how much PVC I should start with. This sure is a pre-historic method. I have the 10w oil but need to know about the fork oil level. I'm 185 lbs. w/o gear.

Thanks!

A couple months ago I installed .48 Eibachs with Race Tech Emulators, and Jessie recommended starting with 2.5" pvc spacers and setting the oil height 6" from the top of the fork tubes. I don't know the difference in length/volume between the Race Tech springs and the Eibachs, but I don't think that they would be too terribly different (I've heard that Race Tech springs are actually made by Eibach, but I don't know this to be 100% true). Also, the Emulators I installed take up about 3/4" (+/-) of length in the fork tube. Since you're not installing Emulators, I'd start with a 5.5" oil height (stock is 6.5, but the stock springs are longer and take up more volume in the fork tube) and maybe a 3" pvc spacer. Folks say to shoot for 15mm-20mm of preload on your springs, so put everything together in each fork tube (springs and washers, minus the oil) and measure down from the top of the fork tube opening to the top of your spring/washer assembly. Then, add 15mm to that measurement. This total number will be the length of pvc pipe you'll need in order to get the 15mm of desired preload. Then, once everything is all together and back on the bike, measure static and race sag. If you don't have enough sag then you will need to cut your spacers down (try 3mm-5mm increments). Or, if you have too much sag, cut longer spacers and try again. It's not hard work, it just takes some time to get it all sorted.

EDIT: I was somewhat wrong in my above discription of measuring and obtaining the proper preload. You don't simply measure down from the top of the fork tube opening to the top of your spring/washer assembly and add 15mm in order to get the required pvc spacer length. You have to take into account the fact that the fork cap extends down into the fork a bit when it's screwed on and fully seated. You would have to subtract that "over hang," for lack of a better term, from the overall measurement obtained above. Please look near the bottom of this post here to see a visual of the measurements and another explanation.

Edited by DR Da-da
Correction to finding proper pvc spacer length (must account for fork cap protrusion into fork when seated)

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Why would you start with 5.5 inches of oil? Wouldn't that be more oil if measured from the top of the fork to the oil level?

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Why would you start with 5.5 inches of oil? Wouldn't that be more oil if measured from the top of the fork to the oil level?

Yes, you are correct. Aftermarket springs, like Eibachs, are shorter than the stock springs. Therefore, the aftermarket springs take up less volume in the fork tube. The idea is to add more oil to make up for the decreased spring volume. If you're installing Emulators or Intiminators (which take up more volume in the fork tube because the "bulk" of each is 3/4" +/-) with Eibach springs, Jesse recommends setting the initial oil height to 6" from the top. I threw out 5.5" as a swag for someone who was installing just the Eibachs without Emulators/Intiminators.

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Thanks, do the washers go on each side of the spring or on the top of the spring and then the other on top of the PVC pipe?

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Thanks, do the washers go on each side of the spring or on the top of the spring and then the other on top of the PVC pipe?

The washers "frame" the spacer. In order from bottom to top: spring-washer-spacer-washer-fork cap.

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The washers "frame" the spacer. In order from bottom to top: spring-washer-spacer-washer-fork cap.

Perfect, I better get to taking the forks off. Might be time to grease the steering stem bearings also.

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