I believe that an overview of dampening rod forks is in order here. From prior posts I've made on this subject (borrowed heavily from RaceTech)...

Damping rod forks are used on the LS650 for one reason and one reason only; they are inexpensive to manufacture.  The design constraints of these forks have major limitations. For example, to create compression damping, oil is shoved through an orifice. Shoving oil through an orifice creates very little resistance to flow at low vertical wheel velocities as when hitting a dip or gully or applying the front brakes. This allows the forks to shoot through the travel fairly easily, diving or bottoming in these situations. On the other hand when the wheel hits something square edge, especially at speed, it needs a lot of oil to pass through the damping holes very quickly. Unfortunately the nature of shoving oil through holes is that as the wheel velocity increases the damping force increases with the square of the velocity. In other words if you double the velocity you get four times the force. This means the hole basically "hydraulic locks" resulting in a harsh spike. Damping rods give the worst of both worlds; they are both too mushy and too harsh at the same time.

With this understanding, the only condition you can create with a change in the oil viscosity is the point at which the damping rods will hydrolock. In all other conditions you will be under dampened - regardless of viscosity.

Oh, BTW, as long as you are going to obsess over oil viscosity, here's some info that will fry your brain. The amount of oil in the forks effects the rate of compression in the final 1/3 of stroke. To compensate for the poor compression of damping rods, Suzuki over fills the forks, only allowing a 75mm air gap in oil height. This large volume of oil contributes to the poor reliability of LS650 fork seals.

So is this something that you can improve upon? Can you reduce the amount of oil in the forks without blowing through the last 1/3 of fork travel? I know the answer (and have posted on this fairly extensively) but by all means, make your damping rods better then Suzuki could. After all, what do they know?

Verslagen and Gary, thank you for your replies. Gary, I really appreciate your contribution to this discussion. You really seem to be adding something here, especially since I have been wanting to add MORE oil than spec.  . I will certainly consider adding your ideas to my suspension design ponderings.

I really got frustrated (MAD!) at some of the people here. I kinda abandoned this thread for a while because of it. They don't seem to respect me or what I have to say. They can't handle it when some newbie comes in and questions their authority and conventional wisdom. If I have to blaspheme the mythical bike gods in Valhalla, then so be it.   I'm bustin' through. If they are really in authority, there is no question that can shake them anyway. That is what being a good leader is about. You're not a leader because you say so, but you're a leader because people find you fitting to follow. Conventional wisdom is good and all, but it only goes so far.

Here's what this discussion is worth-- No, really! Here is officially what this discussion is about: what kinds of oils can one safely use in the Savage front forks in order to accomplish a certain goal in certain conditions without unreasonable risk of mechanical damage or personal harm?

What kind of McGuyver fork oils are available off the garage shelf? What ingenious make-do oils can be used in the Savage front forks without unreasonable risks and problems Now, not all of them are going to be good for all conditions, and there could be sacrifices in quality since not every aspect is designed for use in motorcycle forks. But, seriously, do you actually trust manufacturers to give you something painstakingly designed for your motorcycle forks? Every single time?

Here's a wake up call to those who worship the industry and it's conventional wisdom: Fork oils vary WIDELY in their properties, at least from my perhaps shallow observation.

Look at this chart. http://mahonkin.com/~milktree/motorcycle/fork-oil.html

Some of these fork oils report rather mediocre viscosity indices, compared to ATF or good synthetic motor oil. A few have VI's no better than, or worse than regular hydraulic oil . Some of them have extraordinary numbers, though, so one can't make sweeping statements. I can say that when you try that next brand of fork oil only to find your forks stiff as a steel rod the next cold ride, you know you bought the wrong oil.

Some of you are going to pooh pooh this whole discussion away and call me a young fool. Well, those fellows can find another thread to play with. .

Let it be known, however, that if there were a good study/ experiment (probably not something for me to do in particular) done with various oils with proper research to back it, we could throw in an index of suitable oil mixtures, complete with their strengths, weaknesses,  pros, cons, side-effects, suitable conditions, contraindications, hazards, limitations, and the like, along with relative rank so that we know which ones are best all around. There could be a use for my musings. You could throw them in the tech documents.  

I tend to be OCD about things, but I have to admit, a lot of things, while not ideal, while possibly risky in theory and statistics, oftentimes-- don't mean a thing. Since Gizzo says I can put custard in it, well, I encourage him to ride the first custard-forked Savage! It might just work (for awhile, anyway ), and be funny too .

cheapnewb24 wrote on 02/08/16 at 15:53:13:


if you want to invest $199 for Gold Valve Emulators and another $125 for linear rate springs (plus shipping cost)- and spend some time fiddling with the settings, you might be able to improve on the ride quality of the forks and improve the handling a bit.  You have to change the springs with the emulators, as the valve mechanism does not work properly with the stock progressive wound springs.

http://www.racetech.com/page/title/Emulators



So....if you spend about $300 and some time fiddling with the valve settings and spring pre-load - you can make the forks a bit more modern, and maybe feel the difference. (I installed them last year in my bike....and so far I haven't noticed much of a difference.....I guess I need to do more fiddling with the settings)

And since you want to spend money on the forks...might was well buy some adjustable forks caps for $ 90, and a $ 165 fork brace....that way you can spend about $ 550 in an effort to make the forks work a little better!

JQAAOSwRLZT9kJ4&vxp=mtr" target="_blank">http://www.ebay.com/itm/Yamaha-FZR400-FZR600-others-Billet-CNC-Fork-Caps-with-Adjustable-Preload-/121884455697?hash=item1c60e13311:gJQAAOSwRLZT9kJ4&vxp=mtr

http://superbrace.com/shop/3335-suzuki-savage-ls-650/

Or....you can spend less than $ 20 and get some fresh fork oil (or ATF) in those aged forks..... and get a decent handling bike that will most likely meet your riding needs.

The emulator is a spring loaded valve.....the oil goes through tiny holes for normal riding, and then opens the spring loaded valve on bigger bumps.  The valve is adjustable and there are several different springs you can use....and the small holes can be modified to change the dampening characteristics on the small bumps - there is a lot of adjustment available.

Why do you feel that companies can design, do product development, buy materials, pay for labor/tools/equipment/insurance, manufacture and market things for pennies?  It required a lot of time and money for this company to develop their products, and they need to get that money back if they want to stay in business.  If you want somebody to make a cheap version that may or may not be an improvement - you might as well just use the stock damping rods and 15W fork oil or ATF (that works really well for 99.782% of the folks who own a Savage).

Is it worth it?  Not if you are still running that 8 year old, evil rear tire.

Dave wrote on 02/09/16 at 09:32:05:

cheapnewb24 wrote on 02/09/16 at 10:44:15:


If you ever own and try to run a business, keep employees paid, provide their benefits, have a warm place for them to work and a place to park their car, staples, paper clips, phone, internet, computers, software licenses, lights, paper, accounting, insurance, and then pay the Federal/State/County/City Taxes for the pleasure of doing this....you will begin to understand what it takes to pay the bills and keep the lights on.  This is not a hobby for these folks - they need to make some money doing it.

If this was a product sold by the millions - they might be able to get the cost down by gearing up for mass production.  However the market for these parts is small, they have to be made in a lot of different sizes and models to fit a myriad of different bikes......and it is expensive to make parts in small batches.

Oh, Wow, now I've even made Verslagen mad. Can't even speak my mind around here without stepping on everyone's toes, can I?