Rough Rider

[brevas123]

Bought my 89 FJ the beginning of the season and have had all the regular maintenance issues taken care of including new fork seals and of course fluid. I really do like the bike but the fact that it rides like a log wagon is starting to aggravate me. I replaced the stock fluid with a 20wt. thinking that maybe a heavier weight would help, but if anything it just made it worse. Maybe I should say the bike has about 27,000 mi. on it, which looks about average from what I've read and seen. I  wouldn't mind buying the Progressive springs, if it was a absolute that this would make a huge difference in the ride quality. I will also say that I have the fork setting set on the lower end to try and soften things up a bit. Thanks for any info. Brevas

[Pat Conlon]

Do you have a budget?

The problem is your oem damper rod forks and your rear shock. The fork springs are soft, the dampening in your forks is dodgy and your rear shock was sacked out the day it left the assembly line in Japan.

I would save my money, don't mess with progressive springs or Race Tech cartridge emulators, go straight to the RPM fork valves and the appropriate straight rate springs....In the back we have been hearing good reports on the new RPM shock.

Do the front forks first...then save your money for the rear shock.

Cheers, Pat

[FJmonkey]

+1 on what Pat said, I did the RPM valves and .85KG straight rate springs and the only bad thing I can say is now the rear feels even worse. So I am saving up for an RPM rear shock as well. The RPM valves transformed the front end suspension, having the lighter oil (5 wt) do the work vs. the fork springs is superior technology hands down.

[Dads_FJ]

+2 What Pat and Monkey said^^ What tires and psi do you run?

[FJ_Hooligan]

If you want a more responsive suspension, then using 20wt oil was NOT a good choice.  Might as well just fill them up with cement.

Rough ride is the result of stiff suspension.  Stiffness can be caused by thick oil not allowing the fork to travel fast enough when it hits a bump thus sending most of the impact directly to the chassis and rider.

Weak (read: stock) springs can also cause stiff suspension.  The reason is with a weak spring you have to crank in a ton of spring preload to hold the bike/rider up.  This collapses the spring coils together (coil binding) to where you have very little effective spring left to work with.  End result is not enough spring travel to absorb bumps again sending most of the impact to the chassis/rider.

The cure is a spring of the proper rate for the bike weight, your weight, and the type of riding you do.  Next is the proper weight oil to control the rate (velocity) at which the suspension moves in response to a bump.  The oil damping should attenuate the movement without bouncing (oil too thin) or the suspension feeling harsh or packing down (oil too think).

As pointed out above, a damper rod fork has performance limitations.  The RPM fork valves were specifically designed for the FJ and are reported do go an incredible job of upping that performance to a modern level. 

Your main problem is deciding how much you want to spend on fixing the problem.

[1tinindian]

+3 you'll not get an argument out of me either.
RPM is your best bet for transforming the ride of your FJ.

I'm using the RPM fork valves and .80 springs with the 5wt oil.
Be careful, moditus begins with the smallest thing, and before you know it, your old FJ will have been reborn!

Leon

[yamaha fj rider]

If you can't do new springs and RPM stuff now. Change the oil to a 10W this will give an improvement over the 20W. I like synthetic oil in the suspension. When I changed the fork oil there was less of a pause as the forks changed direction with synthetic over conventional. Hope this helps and welcome to the forum.

Keep the wheels turning.
Kurt

[CelticTiger]

Hi brevas, as an interim measure, I have recently done the progressive spring upgrade, that was before I read about the RPM fork valves on here. It certainly helped, but I believe the RPM solution is the most cost effective option in the long run.

Another job I did is to service a pair of engine mounts, which has helped reduce the handlebar vibrations that used to turn my hands numb after 30 minutes riding!

By the way, does anyone know which of the three fork settings for a fully grown Irish guy of 260 lbs

Safe ridin y'all,

Conor

[CatTomb]

+4  RPM fork valves tranform the front end. You might also consider the RPM fork brace. After installing the brace I noticed a marked improvement in handling at speed even before I ....err ah Baldy and Randy...  changed the fork valves and springs.

[Bozo]

+5 definitely the best money spent.

[brevas123]

Thanks for the information. I'll do some homework, (it's not my only rider), and sounds like it could be a project over the winter.