Can I use regular motor oil to clean my fork internals?

10 replies to this topic
  • Vegemite_luva

Posted April 09, 2008 - 09:09 AM


Hi All,

I am going to try to change my fork oil for the first time and one of the common steps I saw was to: Put fresh oil in the fork; pump the fork a few times, dump the oil; repeat 3-4 more times. I was wondering if I can use just regular motor oil for this cleaning process as it is cheaper and easier for me to get. You see I only ordered one bottle of fork oil and don't want to go through the trouble and added expense of needing to order a few more bottles. Also, can I use conventional oil or does it have to be synthetic?

I know the proper way is to take the fork internals out but like I said this is my first time just changing the fork oil, so I am learning how to crawl before I try to walk. Plus it seems there might be a need for some specialized tools which I don't have.



  • ophir

Posted April 09, 2008 - 10:25 AM


I use a couple of cans of cheap carb cleaner.

  • MotoGoalie

Posted April 09, 2008 - 12:40 PM


use some kerosene. ive done this and have had no fork seal leakage.

  • msgbean

Posted April 09, 2008 - 12:44 PM


You will need one quart plus a little more so you will need two bottles.

  • Vegemite_luva

Posted April 09, 2008 - 02:47 PM


These are great tips. But when using carb cleaner or kerosene are you saying I need to fill up the entire fork tube, pump the fork, and then dump? Do you repeat?

To be honest I am not sure what parts need to be cleaned and what contaminants are being removed? Is it just simply dirt from all the parts or is there some sort of varnishing and carbon deposits which would require the carb cleaner or kerosene?

Sorry, that my questions are so basic but my search results never showed what is being cleaned and why.

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  • pcmech2

Posted April 09, 2008 - 11:37 PM


i am not sure if this help any, but... it made me alot more knowledgeable about my forks...

  • MotoGoalie

Posted April 10, 2008 - 07:01 AM


Just put maybe a cup of kerosene in there and pump both the fork and the cartridge a bit to loosen up metallic SLUDGE then dump it out and let it drain thoroughly. Its the lazymans way of cleaning.

the sludge comes mainly from the springs sliding around on the fork tubes and can turn into a real mess over time.

I forgot to mention that ATF is a very good oil detergent cleaner for this application and might be better than Kerosene. I use Moblil 1 ATF synthentic Mercon V actually, for my fork oil. I'm pretty happy with my action right now. Do a search on this.

  • doctorchopper

Posted April 11, 2008 - 01:45 AM


I don't know if i would use keroseane as it leaves a film behind, brake cleaner would be a better option in my opinion as it tends to dry without leaving a film behind.

  • MotoGoalie

Posted April 11, 2008 - 06:18 AM


Brake Cleaner will destroy you seals and you'll wind up with leaky forks.:thumbsup:

There's no film to worry about with kerosene.

You fill the forks with oil when you are done anyhow.

I can guarantee you that if you use ATF to clean out/wash out the forks no harm will be done.

  • hillclimbguy

Posted April 11, 2008 - 06:28 AM


I agree with the ATF. And its cheap too. You will need two bottles of Fork oil though. Good luck. Take your time, you'll get it.

  • WR450FGreg

Posted May 10, 2008 - 02:16 PM


I've used the same method on all my bikes for the past 25 years.....

(I try to do the oil change after a ride so that any particles will be suspended in the oil to begin with.)

1. Drain the old oil.

2. Remove the top cap and spring.

3. Put a cup or two (depends on the capacity of the forks) of kerosene in the fork leg, pump it by hand for a few minutes then drain the kerosene out.

4. Repeat step 3 until the kerosene comes out looking as clean as it went in.

5. Put a cup or two of fork oil (any weight) in and pump for a minute or two. This cleans any remnants of kero out.

6. Drain the fork oil out overnight.

7. Fill the fork with the required amount of fork oil, check levels etc.

This has worked for me for years.



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