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I could call Bruce, or maybe someone here knows..... How i would soften the front end of  230 Bruce suspension? My other bike, I have determined I like it's characteristics better than the 230. So I am wondering how I might change it?

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If you are still running the standard springs go heavier. Probably close to what you are running in your "other bike" or a little less

 

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 Mine has Bruces mods also including cutting 2.5" or so from the springs and installing a spacer. That was not what i was looking for in the rocks and square edge so I put the cut-off sections back in and adjusted preload with the 1/2" spacers. Still not happy, even drilled Bruces dampners 1mm larger per his recommendations and tried running 5, 7.5, & 10w. fork oil. Still not close to the xr650 or KDX forks.

Would like to hear your recommendations BTR.

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I played on my obstacles yesterday for an hour on my other bike, then after running out of gas, went and got the 230. It was like..... dang, harsh, brutal, compared to the other. I traded off with a stock 230, my old bike that I sold. It was much better for slow play, like jumps off skidder tires, logs, etc. I understand that stiffer in the front is better for higher speed, but this bike is now my family spare bike, and it will never be pushed hard again. I will have to see if I can find the paper work from bruce. I could call bruce and give him the serial number he stamped in it. 

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found it.

spring rate .30- .50 was stock.   .43-.50 installed

135mm oil level

oil weight 5w/20

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Just a note but 5W-20 isn't the same as a '5W' suspension fluid.

 

For engine oil, the 5W rating just means is passed certain cold weather specs,  the 20 is the 'weight' or rather grade of the oil.

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3 hours ago, mlatour said:

Just a note but 5W-20 isn't the same as a '5W' suspension fluid.

 

For engine oil, the 5W rating just means is passed certain cold weather specs,  the 20 is the 'weight' or rather grade of the oil.

All I recall was that he used an off brand cheap synthetic .

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2 minutes ago, 1gr8bldr said:

All I recall was that he used an off brand cheap synthetic .

Bruce normally uses Amsoil but he has been experimenting with multi-weight oils for quite some time.

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2 minutes ago, VortecCPI said:

Bruce normally uses Amsoil but he has been experimenting with multi-weight oils for quite some time.

I would prefer to have good oil in a motor, but for suspension, it would seem that one "synthetic" would be as good as the other. I don't know much about suspension.... is it partly just fluid [volume], but still working to lubricate?

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Fluid passes thru the orifices to control the damping, thicker more viscous oil = stiffer.

 

I'd have to look up the specs but that 5W-20 engine oil (actually a 20 weight oil that meets 5W winter specs) 

may be the same viscosity as 10W or 15W fork oil.  Rather thin ATF (auto transmission fluid) is about equal to 7.5W

 

Fork oil has lots of additives required to resist foaming (cavitation) when used in suspensions, really important!

Engine oil has some but also a bunch of other additives not required for this application.

 

Will it work in forks, yes

is it better than the right fluid, no.

Edited by mlatour

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All I recall was that he used an off brand cheap synthetic .


5w-20 Amsoil is what he has told me to use.
There is also 0-20 available

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Again, engine oil wording doesn't mean 0weight-20, or 5weight-20

both 0W-20 and 5W-20 are sensibly the same viscosity in above freezing temps, at normal operating temps they are both a 20 weight (grade).

0W and 5W are winter cold flow and pumpability ratings, the 0 remaining easier to flow and pump in extreme cold temps.

Edited by mlatour

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Again, engine oil wording doesn't mean 0weight-20, or 5weight-20
both 0W-20 and 5W-20 are sensibly the same viscosity in above freezing temps, at normal operating temps they are both a 20 weight (grade).
0W and 5W are winter cold flow and pumpability ratings, the 0 remaining easier to flow and pump in extreme cold temps.


Regardless, Bruce's designed, built/modified tested, recommended to me, damper rods, using 5w-20 Amzoil, and after 5 years of using RT emulators, fact is my bikes are so much more powerful than I ever dreamed of 5 years ago, and am now now, using Bruces recommend oil in my forks along with his modified OEM damper rods, are actually MUCH less punishing on my wrists, elbows and shoulders than ever before, that Im not really concerned about technical specifications on what ever oil he recommends for his OEM fork damper rod modifications on a 230f.

I can now travel at much higher speeds, through slippery roots, rocks, step ups and downs, steep down hills with much more confidence than ever before.
In fact, in a recent trip to Stonyford, CA., after a long winter of winter rain and flooding conditions, Bruce's damper roads and recommendations, along with his telephone, support, (he called me several times over many months) saved my ass several times going down steep hills at a speed that I was not personally comfortable with after a long winter of not riding, his fork mods and recommendations saved me, more than once that day from painful get off(s) that never happened.
I can assure you that I was not thinking about specific oil technology that day.
In fact I was thinking that if I still had emulators that day, I would not have been going to work for at least the next day for sure.

His design of emulator destroying damper rod modifications and specific recommendations for fork fluid works for me.
In fact my 262cc 230f is working/handling on a whole new level of performance, confidence and speeds over and above that it has ever worked for me before.
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Indeed, in the end what counts is the actual performance.

Perhaps not an issue in conventional forks, but a cartridge / closed chamber design would likely be more picky on proper fluid.

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17 hours ago, 1gr8bldr said:

found it.

spring rate .30- .50 was stock.   .43-.50 installed

135mm oil level

oil weight 5w/20

I would try putting more oil in it.  Try 100mm from top.  Sounds like some of your harshness might be coming from bottoming too easily.

When I went lower than the recommended 125mm, I could easily bottom my forks over small to medium stuff and the front end felt terrible.

Fork oil weight in our DR forks will mostly effect rebound.

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Use the brand and viscosity of oil the tuner recommended because viscosity can be inconsistent between brands.  

Oil level is much more critical than measured volume and an 1/8" can make a big difference in performance.  It needs to be just right because the volume of air is compressing like a spring.  Bleeding air out of the forks or adding one or two pounds pressure to the air column to bring up sag makes a big difference as well.

Also, 5w-20 is made from 5w base stock with viscosity index improvers VII added which stretch out when heated causing the oil to become 20w at engine operating temperatures.  I doubt forks get hot enough to make the oil like a 20w at operating temp.  These VII can get beat up when an oil gets overheated in an air cooled engine causing viscosity breakdown.  This is why we run 20w-50 in air-cooled engines in summer so we have at least 20w in the most extreme conditions.

Hopefully this won't become another oil thread.

 

 

.

Edited by Baja Rambler

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