front fork springs(1050)

[nickaprilia]

Hi all
Looking to upgrade the front end of my '06 1050 to stop it bottoming out!
Does anyone know the standard spring rate and oil viscosity/amount air gap etc.
or of a cartridge kit? I have around £300.00 to spend.

cheer's in advance:
Nick

[ralphus]

Originally Posted by nickaprilia

Hi all
Looking to upgrade the front end of my '06 1050 to stop it bottoming out!
Does anyone know the standard spring rate and oil viscosity/amount air gap etc.
or of a cartridge kit? I have around £300.00 to spend.

cheer's in advance:
Nick

I believe they are dual rate springs (the manual does not say). Most people replace them with straight rate springs. Check out www.sonicsprings.com or www.racetech.com they both have calculators for you to work out what the recommended spring rate for you and your motorcycle.

Ohlins, Racetech and Traxxion also sell valve kits for the Sprint. I am sure that there are companies in England that also valve kits.

Oil viscosity is SAE 10, 120mm air gap and 469cc per fork leg according to the manual.

Good luck

[oldndumb]

As stated earlier, fork oil viscosity ratings are not necessarily the same, brand for brand. The Triumph factory fill is Showa.

BTW, my +05 info says the oil is Showa SS8.

[Yimm]

If you like the spring and bottoming is your only complaint, just bump up the oil a bit at a time until it bottoms no more. It will have virtually no effect on the spring action or damping but it will keep you from bottoming out. Just move it up a little at a time.

[ricster]

Originally Posted by Yimm

If you like the spring and bottoming is your only complaint, just bump up the oil a bit at a time until it bottoms no more. It will have virtually no effect on the spring action or damping but it will keep you from bottoming out. Just move it up a little at a time.

I notice alot of people recommend this. I was told by several bike suspension experts that rasing the oil level causes the seals to leak sooner in their life. You increase the pressure by doing this..thus having seal failure sooner than you should.

[MuzTheInfidel]

Originally Posted by ricster

I notice alot of people recommend this. I was told by several bike suspension experts that rasing the oil level causes the seals to leak sooner in their life. You increase the pressure by doing this..thus having seal failure sooner than you should.

An old wives tale... raising oil level WILL help prevent bottoming by increasing progression, but it is no substitute for the correct spring rate. It will just in more harshness and reduced 'effective travel' if the springs are too soft.

[JTXR]

+1 for MuzTheInfidel!!!

No amount of oil willl fix a spring that is too soft. Your spring determines the bikes ride height which is crtical to get full use out of the amount of travel from your suspension.

Adding more oil or heavier oil, to compensate for too soft of a spring, will only make your suspension harsher. This is due to the fact that you are working with a shorter amount of suspension travel because it is starting low in the stroke due to the soft spring.

With the proper heavier springs your bike will ride higher in the stroke and be able to take full advantage of all of its travel without using heavier compression damping which will make for a more compliant ride. I know it goes against logic but a bike with the proper heavier spring will actualy feel lesh harsh than a bike with too soft of a spring. I have experimented with this alot with dirt bike suspension and found it to be true.

Springs are the first step, to get your ride height correct, and to get the most out of your suspension valving would be next.

Remember that when using a heaveier oil in you suspension that it will increase your compression damping and also slow down your rebound damping.

[DaveM]

Originally Posted by ricster

I notice alot of people recommend this. I was told by several bike suspension experts that rasing the oil level causes the seals to leak sooner in their life. You increase the pressure by doing this..thus having seal failure sooner than you should.

I have had this set up with heavier weight oil and more volume for going on towards 35,000kms with no ill effect. I have also done it on other bikes.

There is an improvement but it is minimal I grant you.

Heavier springs will also provide a firmer or more harsh ride.

DaveM

[Yimm]

Originally Posted by MuzTheInfidel

An old wives tale... raising oil level WILL help prevent bottoming by increasing progression, but it is no substitute for the correct spring rate. It will just in more harshness and reduced 'effective travel' if the springs are too soft.

I certainly agree with Muz here, though Nick mentioned that bottoming was the issue. If you use a zip tie to measure effective travel, you will see the effect is minimal, and, eureka, it eliminates the problem. I also don't understand why it would increase harshness and have not experienced this. So, while it may be a band-aid for a too soft spring, it is a very effective band-aid. But, as Muz said, it is surely not the proper fix for an under sprung front end.

[Katana Boy]

Nickaprilia, what is your weight and or what sort of load are you putting on the bike? Riding style? easy going or aggressive? How many miles on the bike? Time for front fork rebuild?.

I felt the need for a rebuild at about 20,000 miles. About 10,000 of it with a passenger. The bike started handling like an old car!

I'm 195 lbs., she's 140 lbs. I went with a .95kg spring, Gold valves set at c33, 5wt oil at 125mm, And increased rebound by 2 shims, Set preload at about 20mm, rider sag at 27mm. This setup would be considered soft race/stiff street. I also replaced the rear shock, setup with a stiffer setting to match the front.

The easy fix is to increase the preload by screwing in the slotted screw on top of the forks, providing the springs are not totally worn out.

I hope this helps.