20/50 fork oil?

[johno74]

Can i put engine oil in my vf750 trike forks to stiffen them up?

Read about it being done but dont all the E numbers in modern oil dissolve the seals or something?

tah

[Big Pete]

Putting heavier oil in the forks wont stiffen them up. What it will do is make the damping much coarser. The answer is to put more oil than the usual specified amount in, Use automatic transmission fluid (ATF) or fork oil and add 20 or 30 cc more oil to each leg. this reduces the air gap in the fork leg and increases the effective spring rate (stiffens them up). The more oil you add the stiffer they will get, eventually they would go solid if you filled them right up. Dont go too mad though becuase it does increase the risk of popping a fork seal.

Of course the best solution is to buy heavier springs from someone like Maxton.

[johno74]

I'll try 25cc more per leg.

I would put heavy weight springs in ideally but they sound too expensive what about springs in between the slider top and bottom yoke- can you buy 'loose' springs to use?

tah

[IPC_Jules]

get some spacers made up to make the springs compress more and then use a slightly thicker oil to match the dampening?

Jules

[guydewdney]

an old trick is coins - 10p coins etc on top of the old springs...

washers?

or if its really bad - find an old valve spring in a breakers or somthing... they are about the right size...

[Big Pete]

Adding spacers doesnt increase the stiffness of the forks - it increases the preload and decreases the static sag (how much the forks compress under the bikes wieght).

The spring rate is what affects how much the forks dive under braking or when you hit a bump. Stacking two springs on top of each other will make matters worse (lower spring rate).

Putting external springs on will help (springs in parrallel=higher spring rate). More oil increases the effective spring rate.

you can get aftermarket heavy springs for about £80.

[IPC_Jules]

so putting spacers in would be the best bodge if you cant afford stiffer springs?

for a trike anyways ... all i need to do on mine is stop the forks dropping so much under its own weight. most of my trikes weight is the axle itself which isnt putting any load on the forks other than under braking when you have more kinetic energy to dissipate.

Jules

[trikerdan]

My reliant had standard xj650 forks on ;)

Handled a treat!! :D

[Big Pete]

so putting spacers in would be the best bodge if you cant afford stiffer springs?


No, more oil is the best




for a trike anyways ... all i need to do on mine is stop the forks dropping so much under its own weight. most of my trikes weight is the axle itself which isnt putting any load on the forks other than under braking when you have more kinetic energy to dissipate.

Jules

your trike would benefit from spacers if all you want to do is reduce the compression due to self weight, but it will still dive under braking, if you want to reduce the dive you need more oil or higher rate springs.

[IPC_Jules]

like i said in my other post... spacers and oil together? will have a play i think. need to get the damn thing finished first ;)

Jules