Changing Fork springs-- DD750

[Zenoches]

So I recieved my hyperpro Spring set from AF1-- A+++ to them.

I have the rear spring off to the powder coater as we speak and I am getting ready to tackle the front fork springs.

I have yet to dissamble the forks on this bike yet. I have replaced the springs on every bike I have owned due to being a gigantor...

Here is my question...

For those of you who have taken the fork apart or replaced the spring what should I expect?

I just replaced the springs on my R1 and I made a spring compress out of Steel tubing and threaded rod pieces. I do not know if that tool with work with these forks. I did take the fork top off the right fork to add a little thicker fork oil, and I remember it looking odd.

Anyone have tips, hint, or knowledge they woudl like to drop on me?

I used the search option btu did not find a lot of info.

Thanks in advance

[dk_dorso]

Going through the exact same pain right now, ordered the hyperpro front and rear springs for the DD, and i also bought this kit:

http://cgi.ebay.com/ebaymotors/ws/eB...OC%3AUS%3A1123

I am sure you could build the kit yourself, i just felt i would be nice to have anyway.. i am also changing the fork seals (one has been leaking)

The basic procedure is fairly simple once you have a spring compressor etc. and taking the legs of is a breeze.. its not going to be much different from your R1, unscrew the cap, compress the spring, place the lock nut holder thingy, unscrew the cartridge lock nut... remove cartridge and spring (optional at this stage is to pull legs apart and replace oil seals)... insert new spring and reverse order to put everything back together

[Tripyn69]

DK about covered it! I did mine a while back with a friends help and it took a couple of hours, a second pair of hands was helpful. The one key I missed is getting the oil level/air gap set correctly, we guessed at it but we did put the oil in after installing the springs (oppppps). I am about to switch back to the stock springs with heavier oil just to compare so I was looking at the same tool from E-Bay; the kit has everything you will need to get the job done.

[DownUnderDorso]

...I am about to switch back to the stock springs with heavier oil just to compare so I was looking at the same tool from E-Bay; the kit has everything you will need to get the job done.

Hi,

So reading between the lines, you found the Hyperpro fork springs too firm ??

I'm about to fit a set in mine so questions coming to mind:

DD or Shiver ?

What weight fork oil did you run in with them ?

What do you weigh ??


Cheers.

[Tripyn69]

Hi,

So reading between the lines, you found the Hyperpro fork springs too firm ??

I'm about to fit a set in mine so questions coming to mind:

DD or Shiver ?

What weight fork oil did you run in with them ?

What do you weigh ??


Cheers.

Yes, I find them a little firm for my weight so just for the sake of ruling it out I am going back to stock with heavier oil. To answer your questions:

Dorsoduro

15w

170lbs w/gear

[cpallen]

Yes, I find them a little firm for my weight so just for the sake of ruling it out I am going back to stock with heavier oil. To answer your questions:

Dorsoduro

15w

170lbs w/gear

15W Zowee!

Lets review.....
The oil controls the damping action of the forks. 5W is what Aprilia puts in it at the factory. Of course DD has adjustable rebound damping.....
Springs should be selected (and/or shimmed) to set the static sag.

Therefore, maybe you should experimenet with some lighter oil.
5W, 10W is pretty common. You can even get 7.5W at BMW dealers.

[Tripyn69]

15W Zowee!

Lets review.....
The oil controls the damping action of the forks. 5W is what Aprilia puts in it at the factory. Of course DD has adjustable rebound damping.....
Springs should be selected (and/or shimmed) to set the static sag.

Therefore, maybe you should experimenet with some lighter oil.
5W, 10W is pretty common. You can even get 7.5W at BMW dealers.

Thought about that too, 15w is what HyperPro supplied with the springs as a kit. My goal here is just to do some experimenting to see what works best but you do have a point there!



Zenoches, how did you make it out??

[abarth]

I have agip 7.5w oil in my DD. More rebound adjustment possible. With standard 1 turn rebound with 5w oil is like almost 2 turns with 7.5w. If rebound is less then 1 turn I can hear swoosh sound of rebound valve and forks are to stiff for normal riding.

[DownUnderDorso]

Thanks for the feedback....

I'm 190lbs in gear but I don't want it too hard.

I think I'll start with 10W oil with the Hyperpro springs rather than the 15W they came with...

[Zenoches]

I got the fat guy hyperpros since I am about 340 with gear... Finished installing them last night and went for a ride..Man what a difference..No severe front brake dive. No front brake chatter while aggresive braking. Better traction on Hard accel. More stabil in the corners. I did also raise the forks in the triple trees to show three lines and now it corners with less effort.

[spdu4ia]

Forgive my ignorance but If I were to just want to put in a thicker oil would I just take the right fork tube off and pour it out then add 10w oil to it and cap it off ? this is on a shiver btw. I read about airgap , what is that?

sorry if these are stupid questions.

[Zenoches]

Forgive my ignorance but If I were to just want to put in a thicker oil would I just take the right fork tube off and pour it out then add 10w oil to it and cap it off ? this is on a shiver btw. I read about airgap , what is that?

sorry if these are stupid questions.

Pretty much...

A few things

• when you empty out the forks pump the internal and the whole fork to get out as much fork oil as possible.
• You would not want to top off the fork with oil - the fork calls for a certain amount of oil and has to be even between the forks.( Which is the airgap people reference)

When I replaced the springs a couple nights ago I broke the liter of fork oil into two equal parts and without the spring in the fork and the fork fully compressed I measured the height of fork oil and swapped oil from one fork to the next until them were even.

Not a stupid question at all... Hopefully my post makes sense...

[Tripyn69]

For me it does make sense having been through this before, however what measurement did you use to get the fluid right? The shop manual states "air gap" which I understand but the Hyper Pro documentation states a different number. So my question is which did you use??

[spdu4ia]

so do i need to open up both forks to see how much to add to the right one and just make them even? Do I need to replace the oil in both ?

[Zenoches]

For me it does make sense having been through this before, however what measurement did you use to get the fluid right? The shop manual states "air gap" which I understand but the Hyper Pro documentation states a different number. So my question is which did you use??

Well to be honest I did not measure the air gap since I was planning on splitting the liter of fork oil into two parts and using it all.

Whatever the hyperpro manual says is what I would go with...But I typically as a fat guy always just split a bottle unless more is required. I like to avoid bottoming out as much as possible hahahaha

The fluid or "Air gap" measurement btw is not a definitive is a variable. It can be set to whatever a rider prefers. The shop manual is giving a measure to what it is stock, but not what is required

so do i need to open up both forks to see how much to add to the right one and just make them even? Do I need to replace the oil in both ?

YES....you must make them even or your suspension with be squirelly to say the least. Yeah you will want to change the oil in both you would not want to run stock 5wt in one and 10 or 15wt in the other. Different weight fork oil makes fork compress at different speeds and as you can imagine you would not want your forks compressing at different speeds.