Hey guys, i recently fitted some new progressive front springs to my Iron, after 800k's they needed more preload as they sagged, which is to be expected from any spring, no issue there, so i had the almost preload right for speeds upto 100kmh (put would feel like the tyre was too soft when going up and down driveways) , it would rarely bottom out so i knew i only need to add slightly more preload to be spot on! 

I went for a ride today and noticed that when hitting almost any bump at 105+kmh the bike would shake, the bars would wobble and ass end would move around also. This made the ride to be less than enjoyable. So upon getting home i put my thinking cap on. I had some screamin eagle heavy fork oil sitting in my shed so i decided to change it.

I jacked the bike up with the front wheel off the ground, i used a screw driver and a hammer to tap the drain screws loose, then put some tap over the holes with a gap at the bottom so i could direct the old oil into a measuring cup. It seems that from stock i was 50ml low in the right and 60 ml low in the left. i was going to add in some more preload on the springs but i decided not to make too many adjustments at once as i want to know what difference each step is going to make. I filled up the forks with 400mls of oil, and readjust the rear preload up one notch and lowered the dampening one notch.

I just went for a ride and i cannot belive how much difference i have made, the driveways feel normal and at speed of 105+kmh over bumps feel fine now, no more wobble, but im yet to try it on the bends! I found some bumps that i know make my bike bottom out and the bike isnt fussed by them now!

I just hope that its better on the bends now....

Regards Andrew - T1

i'm betting it will be. 10ml diffrence isn't a lot, but isn't a little either. Each fork would be trying to react to the bumps differently, setting up your wobble effect.

Good stuff Andrew!

yeah me too Jim, i used to get wobbles coming off the westgate freeway and onto the ring road at 110, the weekend really showed how bad it was setup. So hoping it will be ok now. Had the day off work today and went and got my neck checked out, seems i have a sprained neck, ffs doc wants me to stay off the bike for a couple of weeks!! Not sure im going to be able to do that.

yeah i went to the ostyo today also, told me the same thing, feel a little better. It started after i went to bright, 850k ride in one day might be a little too much.. and i havnt let it heal since.

Just putting it out there, if anybody has had experience with this, but i have noticed since changing the oil and putting the right amount in my ride height has come up 10mm, is this normal??
Regards Andrew - T1

i just went outside and decided to look into my forks a little more, i removed my bars and pulled my springs and measured the oil height, it was 69mm (spec is 79mm) so 10mm too much oil, the book says 407ml and i put in 400ml when i changed it. So i used a syringe to remove some oil and got it spot on 79mm. i took the bike off the jack and it had dropped in height, i went for a ride and it would bottom out on hard bumps just a little, so i came back and put in another 20cents in each side, seems to be ok so far, but time will tell, One thing i hate is setting up suspension (even on cars) as it takes allot of trial and error and there are so many variables, in this case its spring preload, oil viscosity, oil height, rider sag, rider riding style, and then even the rear plays a big part in how the front preforms. I think i might give this setup a few more months then maybe look into changing to ricor intiminators and back to stock oil and springs...i get the feeling that the progressive springs are too hard for my weight. (60kg at best)
Regards Andrew - T1

I went of a ride tonight and got a chance to test how well my suspension is performing on bends, on the same roads it feels fine over the small bumps, larger ones feel like im hitting a gutter, but i noticed on corners at 100k's and over bumps its much more stable....either way i have decided to get the ricor intimators and give them a try. I really think its my lack of weight and im not loading the suspension enough....not ya typical fat biker!!!
Regards Andrew - T1

 hi    them low late model sportys like the nightster  / custom have shorter fork tube's  on them & takes away the travel  by about 2" ,  they look cool lowered  but  have not as much travel ,    have you lowered the rear as well ? , also the late model forks do not like the heavy fork oil ,  10- 15 W      i use Race Tech Gold Valve's  & Race Tech spring's , try not to use the progressive  brand dual rate springs 

mate i will check my oil this weekend thanks for the heads up

Hi Andrew, we fitted racetech valves and springs to my wifes nightster. She is short and light, so we didn't want longer forks either. Very happy with the result. Good service from shocktreatment.com.au

hi ,   i just buy them off Shock treatment ,  i'am only 61 klg & 5.5 ft, & can reach the ground on a normal sporty  shorten suspension also shortens the travel  & travel  what you need on Aussie roads esp N.S.W.     you could try the longer damper rod's off the normal model sporty  but you have to make sure it dosn't bottom out under the bottom trippletreee,     i would have  normal travel set-up but with a modified seat shamfered & scolloped out for your possie that's what i did on both of my Buells that i had because i could only touch the ground with my toe's ,

either or just don't stop riding ?