Suspension question

panjab · Dec 16, 2023

Hi all. I have a 1999 non-ABS 1100. First time I have riden her since purchase and rebuild. I fitted a YSS rear shock because the stock one was past it's best. I felt the bike was fairly stable on most roads but a little 'unsure' at the rear on bumpy corners.I have dialed in for approx 1.5" sag and put 10-clicks on the damping as a start point. I have left the shock length as it came from the factory but am aware it is possible to change that but need to know the effect on the front handling. Unfortunately, after the ride I found the right fork seal is leaking so no more tests until that is sorted. When I replace the seals, do I need to replace the bushes or are they usually OK? the bike has done around 60,000miles. Also, what oil is recommended? 5 wt or 10 wt? I weigh 100kg.

Any help/advice on setting up the front and rear suspension would be gratefully received.

TIA

ST1100Y · Dec 16, 2023

panjab said:
When I replace the seals, do I need to replace the bushes or are they usually OK?

Depends on usage, (in)frequent fork oil changes, etc...
You'll see the wear of the gray Teflon coating...
I'd get and replace the bushings anyway... + the copper rings for the bottom bolts...
O-ring set for the anti-dive...
Nylon bush & steel clip for the actuator...
I run Hyperpro springs and like 7W oil...

SMSW · Dec 16, 2023

IIRC, the 1300 shop manual shows wear patterns on the fork bushings - sort of a go-no go picture for replacement. Not sure if your 1100 manual has the same drawings. I had little visual wear on mine in the high 20''s to 30,000 miles when I changed the valves to RaceTech's Gold Valves. At 60K, I'd order and replace all wear parts as a matter of course.

Al st1100 · Dec 16, 2023

Bushing, seals and synthetic ATF (7.5w)

jodog · Dec 17, 2023

As to your question on handling, the lower the rear the less weight is on the front. At some point the front end becomes light, especially in high wind or following semi trucks and the handling will suck. The stock ride height was set by Honda for a reason. YMMV.

SMSW · Dec 17, 2023

IIRC, raising the rear will 'quicken' the steering. You can accomplish the same to some extent with more preload. This is why you set up the bike's sag to the stock configuration and then adjust the suspension to suit the rider and conditions. Experienced mechanics can dial a car (or bike's) suspension in for a particular race track and then fine tune it for the conditions of the race and the driver's wishes. They can come close, but there is almost always some final adjusting.

Larry Fine · Dec 17, 2023

jodog said:
The stock ride height was set by Honda for a reason. YMMV.

Understood, but there is no one "stock" ride height as everyone and their loads are different, which your "YMMV" alludes to.

To me, the goal is optimum handling, with minimal and equal steering effort required to both lean the bike over and to return it upright.

MidLife · Dec 17, 2023

panjab said:
I have dialed in approx 1.5" sag.......

Just to make sure: You are talking "dynamic" sag here right (may be difficult/impossible to get 1.5" static anyway!)?

https://www.emmearacing.it/static-and-dynamic-sag/rear-shock/

Nothing "dynamic" about this dimension but that's how most are calling it!

MidLife · Dec 17, 2023

jodog said:
The stock ride height was set by Honda for a reason. YMMV.

Larry Fine said:
Understood, but there is no one "stock" ride height as everyone and their loads are different, which your "YMMV" alludes to.

And the non-stock shock may come into play as well.

Even different tires often require redialing.

Larry Fine · Dec 17, 2023

MidLife said:
And the non-stock shock may come into play as well.

Even different tires often require redialing.

Exactamundo. I'm not going to set my suspension to a calculated setting if it results in less than the best handling for me.

JJames · Dec 17, 2023

ST1100Y said:
Nylon bush & steel clip for the actuator...

Are these part of the anti-dive or ....? (service parts) . My forks are coming off one of these days .

ST1100Y · Dec 18, 2023

JJames said:
Are these part of the anti-dive or ....? (service parts) . My forks are coming off one of these days .

It's where the front caliper bracket actuates the plunger when under load...
The nylon bushing eliminates rattle/knocking...

loc 39 (P/N 51545MJ0003, bushing) & 26 (P/N 51445MJ0003, ring stopper)

JJames · Dec 18, 2023

Thank You !