Mixing Fork Oils

I bought a bottle of Bel-Ray 7w fork oil today, I want to play around with my oil levels a bit, I'm still running my stock oil, is it ok to mix the two oils to test what oil level works best for me (i.e. I'm just going to top-up my current oil with the Bel-Ray)?

Any one done this before ?

[ January 04, 2002: Message edited by: Psycho426 ]

I would consider that a big no-no.... mixing two different oils might seriously impair the handling of your ride. I would just flush the stock oil and do your testing by putting the desired level of one specific oil type.

.02 ¢


I wouldn't mix either. If you're going to have it all apart to play with the levels then you may as well take the few extra minutes to go ahead and change it to the new oil, especially if have many hours on the stock oil. Just my $.02. :)


It's ok to mix hydralic oil. What you will get is a weight that is the average of the two.

Now that said, oil weight does affect your suspension. So, you may not know what is actual changing.

But, if you just change the oil height some, you should be ok.

Maybe this doesn't make any sense but I just changed the fluid in my used 01 426 came out green and real thick. The guy I bought it from said he had raised the oil from stock with another brand of fork oil (non-Yamaha 01).

I've been riding steady for over 10 years and I've dumped some oil that had been in forks for WAY too long and never seen anything like what I just dumped out of my 01 426. I mean, I've dumped oil that was grey/silver from particulate wear of the damping rods etc, and I've dumped oil that was fairly "clean" after some good useage but not green and thick. Something caused this, and without being an expert in Hydraulics I suspect some sort of incompatibility with the oils used.

Maybe technically you should be able to mix oils but I wouldn't do it. Just spend the $20 for a bottle of the Yamaha 01 and press on with life. When you decide to flush both forks in the future buy some good quality aftermarket stuff for half the price and live happily ever after.

I just put Bel Ray 5w HVI in mine, raised the level to 100mm and love it. I've had good luck with the Bel Ray stuff over the years but I will say the regular Bel Ray fork oil will wear down a bit faster than Yamaha 01 or the Bel Ray HVI.

My .02

Race Tech uses that as an excuse to get you to spend $26 per quart for suspension fluid. Their synthetic oil lasts longer before breaking down at the molecular level, according to them. I don't buy it, the story or the oil. Suspension fluids need to be changed WAY before they get to that level of breaking down, regardless whether it is synthetic or regular petroleum based. I've had excellent results using the Bel-Ray stuff. I'm pretty picky about what chemicals I use. I have a slew of different brands in my garage. The only bel-Ray products I use are their HV1 suspension fluids and their waterproof grease.

Just my opinion based on personal experience.

Thanx for the advice guys!bigok.gif Think it's a good idea replace the fork oil all together while I'm at it.

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