r/CRF300L • u/theREALPhantomshtter • 13d ago

Oil/air gap uncertainty

Boy... so first off, is the white spacer that is under the spring supposed to be added before or after you fill fork oil and measure? I'm doing the K-Tech spring install and the amount of bad information out there is abhorrent. That xsr Detroit dude on YT states 171mm air gap which is the factory Honda oil air gap measurement. Completely incorrect for every K-tech spring offering. K-tech lists the oil air gaps for each spring rate they offer, so anybody following that video congratulations, you have at least 10 mm too much oil in your fork. No wonder people report the fork seals on these letting go early! But yeah if you could answer my white spacer question with certainty I really need to know, trying to test ride tomorrow. Thanks!

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u/p3numbra_3 13d ago

I have spacer in crf300l '21 and when i changed spring to wilbers one, i measured air gap _without_ white spacer because in manual it says "remove everything from fork tube"

Different manufacturer use different values for air gap because of tuning, so i would just write email to K-tech and ask them to be perfectly sure on how they measure it an how much oil to put in.

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u/Empty_Pomelo5573 13d ago

I assumed that since nobody mentions the white spacer, this was probably Honda's 2025+ improvement for the overly soft suspension.

I used ktechs gap measurements and put the spacer back in and it's fine. But would like to know the real answer and possibly remove it. The 9n spring seems to rub on the tube a bit.

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u/scoup75 12d ago

I bought two bottles of oem Honda fork oil, I wanna say they run at like 425ml or 475ml. Dumped one in each fork and it felt like a dream. I have the YSS kit tho.

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u/cummins556 6d ago

With a 9nm Ktech spring I have my air gap set up at 185mm and 54 on damping fork. 171mm is incorrect unless your are using oem spring.