external fork springs
- Thread starter Cbone
- Start date
Sorry a cant answer your question exactly. Both my bikes are factory equipped w ext springs. If you do end up making the swap, be sure to get all the parts associated w the springs. they have caps (seats) so the spring sits properly under the triple. Plastic tubes inside the springs, so springs dont rub and scratch the fork tubes. And seats between the springs and the fork seal jesus clips in the fork lowers.
o1marc
Over 1,000 Posts
Couple of questions,
Will the internal fork spring forks work correctly without the internal springs?
Do plan on removing the internals and running only the external spring?
Do you know the correct spring rate to use for the external spring?
What do you mean by "new CB forks"?
Are the tops of the lower legs made to accept the external spring, and is this feature on the internal spring fork?
Will the internal fork spring forks work correctly without the internal springs?
Do plan on removing the internals and running only the external spring?
Do you know the correct spring rate to use for the external spring?
What do you mean by "new CB forks"?
Are the tops of the lower legs made to accept the external spring, and is this feature on the internal spring fork?
the forks will work fine with out internal springs,the internal spring has no bearing on how the fork functions ,but to contradict myself,in fact the forks will work better without springs inside for a few reasons
if i was doing it i would just use some light rate beauty springs on the outside whatever fits that you like the look of just be sure they are not too stiff and also use a sleeve to protect the sliders such as on the earlier models
reasons to use a light spring
they are a lot less likely to coil bind allowing full travel
getting just the right spring rate can be difficult any spring will do a good chrome or ss hardware store spring
to make up for the rest of the springing you need to ride put some shrasder valves in the fork top caps and then you really have the ideal adjuastable lashup
tuning trapped volume of air by adjusting oil volume changes the compression ratio is one tuning deal
changing pressure is the other
the forks legs can each be tuned seperately with different pressures and volumes for another dynamic or link them to gether with a single shrader valve
this isn't crazy talk
all mc forks are partial airspring anyway. whether you realize it or not and this method i have described is EXACTLY(except for the external springs) it is exactly what motox fox developed back in 1975 for mx bikes and all factory racing teams were using light springs combimed with air pressure adjustement
if i was doing it i would just use some light rate beauty springs on the outside whatever fits that you like the look of just be sure they are not too stiff and also use a sleeve to protect the sliders such as on the earlier models
reasons to use a light spring
they are a lot less likely to coil bind allowing full travel
getting just the right spring rate can be difficult any spring will do a good chrome or ss hardware store spring
to make up for the rest of the springing you need to ride put some shrasder valves in the fork top caps and then you really have the ideal adjuastable lashup
tuning trapped volume of air by adjusting oil volume changes the compression ratio is one tuning deal
changing pressure is the other
the forks legs can each be tuned seperately with different pressures and volumes for another dynamic or link them to gether with a single shrader valve
this isn't crazy talk
all mc forks are partial airspring anyway. whether you realize it or not and this method i have described is EXACTLY(except for the external springs) it is exactly what motox fox developed back in 1975 for mx bikes and all factory racing teams were using light springs combimed with air pressure adjustement
no i wouldn't have any concerns about air bubbles or foaming oil on the vintage forks they are extremely crude and simple and if a few extra bubbles changes damping a bit then changing visc should be a cureGrazz256 said:
all this type of mods requires understanding patience and testing fun fun fun srsly cause test is another reason to get out and ride,air pressure can easily be jiggerd on a quick piss stop whilst riding take notes
i use the airspring/spring lashup and i love it cause i can stop and tweak(lower) air pres for a rough/washboardy section of fire roads etc
air getting to the seals has no ill effect if they cant seal air they wont seal oil
however air contains water the drier the air the better.dry nitrogen is the ultimate .water will over time cause the bare steel innards to rust in places even so if a guy or gal changes fork fluid on reasonable schedule,cuple times a year or so,then rust should not be an issue fork oil will stay cleaner on most because many internal springs rub metal to metal their whole length creating fine swarf and creating a slight drag and impedence to smooth action
fork oil fluid level can be higher without springs and a bit more oil should be used as the springs take up air and oil space,so raising the oil level helps maintain a similar to oem cr and submerge even more the piston/damper deaper under fluid win win
DohcBikes
Fuck You.
Some valves are there simply for purging built up air.
If using an air adjustable fork, be sure not to use unreasonable amounts of air, because as xb suggested boyles law is in full effect so a hard bump will really raise the pressure. Be sure to regulate the air supply or even simply use a bike pump to air them up. 2-12psi is generally enough and about all you want to ask of the fork seals.
If using an air adjustable fork, be sure not to use unreasonable amounts of air, because as xb suggested boyles law is in full effect so a hard bump will really raise the pressure. Be sure to regulate the air supply or even simply use a bike pump to air them up. 2-12psi is generally enough and about all you want to ask of the fork seals.
well boyles law is why air spring are so good very progressive so what i am talking about with a very light coil spring and air would require maybe 30lbs static going up from that when travel occurs
the seals can handle alot more than that ,the seal will not fail , if the seal is not secured correctly in its housing and or snap ring done wrong or left out then a seal could be pushed out .but like i said they always have pressure on them when in use .the only drawback to higher pressures is the seal is actually forced to grip tighter and can cause noticable decrease in small bump compliance,also if the stanchion tubes are pitted the seals will get ruined that much faster
this is one of the main reasons the mc industry has dropped the once more popular use of the air spring having a larger role, small bump compliance
that and a buyer/rider that cant be botherd with making any adjustements at all much less even understanding it
to many dealers telling honda these fuckers are to stupid stupid for air aDJUSTEMENTS
i carry and use a harley air shock pump best 20 dollers i spent on ebay that season
the seals can handle alot more than that ,the seal will not fail , if the seal is not secured correctly in its housing and or snap ring done wrong or left out then a seal could be pushed out .but like i said they always have pressure on them when in use .the only drawback to higher pressures is the seal is actually forced to grip tighter and can cause noticable decrease in small bump compliance,also if the stanchion tubes are pitted the seals will get ruined that much faster
this is one of the main reasons the mc industry has dropped the once more popular use of the air spring having a larger role, small bump compliance
that and a buyer/rider that cant be botherd with making any adjustements at all much less even understanding it
to many dealers telling honda these fuckers are to stupid stupid for air aDJUSTEMENTS
i carry and use a harley air shock pump best 20 dollers i spent on ebay that season
DohcBikes
Fuck You.
Wrong.
Making it sound as if anyone said the forks seals would be ejected from their seats is exaggerating.
A rough ride at slow speeds is certainly not the only drawback of using too high pressure.
Even most forks that are designed for air suspension will be very prone to blowing air and oil out the seals at 30psi static.
According to Honda Kawasaki Suzuki and Yamaha.
Uh oh someone said xb's wrong, get the tissues ready
Making it sound as if anyone said the forks seals would be ejected from their seats is exaggerating.
A rough ride at slow speeds is certainly not the only drawback of using too high pressure.
Even most forks that are designed for air suspension will be very prone to blowing air and oil out the seals at 30psi static.
According to Honda Kawasaki Suzuki and Yamaha.
Uh oh someone said xb's wrong, get the tissues ready
see,you got forks with oil, a front tire and brake pads right there just begging to absorb oil and a stupid fucker putting in seals wrong, what could possibly happen ? when they shoot out on :-\ the freeway ?
i raced motocross with no springs at all ,lots of us did this was a bultaco and a xl250 static was close to 40lbs never even leaked a drop, ever, much less have the seal itself fail
the air is simply putting oil pressure on the seals and ii is at the same time a gentle softer pressure,springy, not hard pressure like pure hydraulic
there is structurally almost zero diff between a quality fork seal and a hyd seal designed to handle _+3000psi
the only diff would be maybe a slighty more stout can (the metal part of the sealo body is the can )
i raced motocross with no springs at all ,lots of us did this was a bultaco and a xl250 static was close to 40lbs never even leaked a drop, ever, much less have the seal itself fail
the air is simply putting oil pressure on the seals and ii is at the same time a gentle softer pressure,springy, not hard pressure like pure hydraulic
there is structurally almost zero diff between a quality fork seal and a hyd seal designed to handle _+3000psi
the only diff would be maybe a slighty more stout can (the metal part of the sealo body is the can )
you either dont understand what psi means or just aren't thinking it throughDohcBikes said:
a simple single rubber oring in a groove can handle 20,000+ psi it must be majic BOO
the only part of a fork seal that is rubber is the sealing element the rest,the part that is structural is a formed steel can that the rubber is bonded to they are designed to handle many many many more times pressure than they would ever see, they have to be
i am never wrong when it comes to technical stuff because i only use facts already established by others and myself mostly by othersDohcBikes said:
if you like reading and learning right off the top kevin cameron is just about number uno and smokie unic cant freget him
I hope a lot of people read this thread because there is a real gold mine of great info about forks (actually shocks and an array of other similar stuff) that is rarely discussed. well said all around Mr. XB.
Have to say, 500 psi sounds like a lot, but I wouldn't be surprised if most systems actually can take it (a good idea if you want to know what your bike drives like with a rigid front end though!). Certainly 30 psi is seen in every conventional telescopic fork ever made - even those not air assisted. It's a small volume with a large percentage change when compressed so the pressure will skyrocket almost immediately, though I have never actually run any numbers.
Definitely one of the most overlooked areas of suspension fiddling anyone can do for next to nothing. Change your damping (dampening?) with fork oil viscosity, change your springing with oil volume and preload spacing. Fussy, fiddly (and messy!) work, but hard to beat for bang for the buck. Add charging with above atmospheric pressure (nitrogen? sorry - too exotic for me, you have to know what you are doing to use that!) and you have a lot of adjustment to play with.
Cool idea using the cosmetic springs, but seems likely you couldn't do it with so low a spring pressure that you wouldn't have to change the internal springs to compensate for the addition.
Have to say, 500 psi sounds like a lot, but I wouldn't be surprised if most systems actually can take it (a good idea if you want to know what your bike drives like with a rigid front end though!). Certainly 30 psi is seen in every conventional telescopic fork ever made - even those not air assisted. It's a small volume with a large percentage change when compressed so the pressure will skyrocket almost immediately, though I have never actually run any numbers.
Definitely one of the most overlooked areas of suspension fiddling anyone can do for next to nothing. Change your damping (dampening?) with fork oil viscosity, change your springing with oil volume and preload spacing. Fussy, fiddly (and messy!) work, but hard to beat for bang for the buck. Add charging with above atmospheric pressure (nitrogen? sorry - too exotic for me, you have to know what you are doing to use that!) and you have a lot of adjustment to play with.
Cool idea using the cosmetic springs, but seems likely you couldn't do it with so low a spring pressure that you wouldn't have to change the internal springs to compensate for the addition.
DohcBikes
Fuck You.
You hope a lot of people read this thread because you think you are taking the winning side of an argument that never happened.
I urge anyone to go outside and pump 100psi of air into their forks and see if it holds 100psi through the night.
If not, these guys are both wrong.
If so, still got 400psi to go to test their bullshit.
Put 30 psi In your forks that are designed for 2 to ten. See if there's more oil on the stanchions than normal after a hard ride. See if the pressure drops after a hard ride.
If so, these guys are both wrong. Plain and simple.
I urge anyone to go outside and pump 100psi of air into their forks and see if it holds 100psi through the night.
If not, these guys are both wrong.
If so, still got 400psi to go to test their bullshit.
Put 30 psi In your forks that are designed for 2 to ten. See if there's more oil on the stanchions than normal after a hard ride. See if the pressure drops after a hard ride.
If so, these guys are both wrong. Plain and simple.
