Fixing suspension for heavy rider on a budget

[zixaq]

Hi all, newbie to these forums. Had my 2004 FZ6 for a couple months. I love the bike, but I weigh about 240 lbs and the nosedive on braking actually feels dangerous. Doing something to the forks is super high priority, because surprise stoppies suck.

1) For those who have done the R6 fork swap, how much total did it end up costing you? I haven't been able to find a set of R6 forks for less than $300, and that doesn't include the brakes, axle or the little spacers that I'd need.

2) The option I'm planning on right now is to just do a spring swap with Racetech's recommended springs, but no emulators (budget!). I'm trying to figure out what viscosity fork oil I'd need for the stock damper rod for a guy my size. Any other big fellas that can chime in here about what works? There are a lot of kickass roads out here with questionable pavement, so being able to soak up the little bumps and still not nosedive is the goal.

I'm due for my 20k service and I'd like to fix the suspension while I've got the bike torn apart anyway. Any help would be awesome.

 

[FinalImpact]

Hi all, newbie to these forums. Had my 2004 FZ6 for a couple months. I love the bike, but I weigh about 240 lbs and the nosedive on braking actually feels dangerous. Doing something to the forks is super high priority, because surprise stoppies suck.

1) For those who have done the R6 fork swap, how much total did it end up costing you? I haven't been able to find a set of R6 forks for less than $300, and that doesn't include the brakes, axle or the little spacers that I'd need.

2) The option I'm planning on right now is to just do a spring swap with Racetech's recommended springs, but no emulators (budget!). I'm trying to figure out what viscosity fork oil I'd need for the stock damper rod for a guy my size. Any other big fellas that can chime in here about what works? There are a lot of kickass roads out here with questionable pavement, so being able to soak up the little bumps and still not nosedive is the goal.

I'm due for my 20k service and I'd like to fix the suspension while I've got the bike torn apart anyway. Any help would be awesome.

Hi and Welcome with 3 posts...

If I were you; add about 1.25 - 1.5" of 10wt oil and save your money for R6 forks if you ride the back roads. If this bike is just transportation; 10wt fork oil, 1.0 or more kg/mm springs and overfill the forks 1" or more and try it.

The bike has spirit and fixing the suspension is cheap compared to other bikes and insurance. I vote; do it right, love it, and have fun! You just have to hang on for the deal and LOOK!
Good Luck!

 

[Zealot]

Tie helium balloons to yourself before riding for some upward lift

(Or fork oil / fork + shock replacement)

 

[TownsendsFJR1300]

Another CHEAP and very effective option. Air assist. The stock springs/spacers
are still installed. Just added air to firm up the suspension.

*I do have bar risers, so you'd have to make sure the caps/valve AIR CHUCK will clear between the bars.*

I've had this mod on just over a year. Works great, infinity adjustable..

14 PSI in each fork, nose sits higher, dive is virtually nill. I haven't added ANY air or lost any oil.

I did do a fork oil change with 7.5 wt oil, I'd probably go 10 wt next time..

http://www.600riders.com/forum/fz6-mods/54803-air-assist-fork-caps.html

 

[tyvaj]

im on the same track as you. i like to do alot of agressive canyon riding on the weekends. so im going to try and save up some money and do the r6 fork swap but, for now im just going to change the fork oil out to a 15w and see how it rides.

 

[zixaq]

I ended up pulling the trigger on new springs. I'll let you know how it turns out once I get them in.

Going to try the 15w oil suggested by RaceTech, too.

 

[tyvaj]

congrats on the purchase and will wait for your update. ill give you an update on how just the 15w oil do.

 

[FinalImpact]

im on the same track as you. i like to do alot of agressive canyon riding on the weekends. so im going to try and save up some money and do the r6 fork swap but, for now im just going to change the fork oil out to a 15w and see how it rides.

Most have reported that 15 is too much (ride is to harsh while not fixing the problem) but it depends on who's oil you use! Some at 15wt behave like that of other makes 10wt... I'd suggest Yamaha oil and order 12.5 wt. Over fill as stated above and that will help nose dive.

 

[tyvaj]

My mechanic and i just got done changing the chain/sprocket and the fork oil. While changing the fork oil the fz6 decided to go with 10wt oil instead of 15wt. I happend to have some .95kg springs in it already and i was thinking about buying some. Thank goodness i didnt. Didnt get a chance to go up the hills but i noticed a huge difference in the suspension. The ride was much more firm and most of the nose dive have disappeared! Im lovin it and cant wait to hit the twisties! Oh and i also did the fz1 bar mod! Awesome!

 

[zixaq]

After two days of fighting with incompetents to get some freaking spacers cut properly (or at least close enough to make work), the front is together. The most embarrassing part is that one of the three aforementioned incompetents was me. I measured for the spacers with the forks compressed, which OBVIOUSLY did not work right.

Fortunately the second set of spacers was only botched somewhat horribly, so I was able to file them into square and only a couple mm different, which was made up with an extra spacer in the short tube. Yes, this is all stupid. No, I don't know why the dip**** couldn't manage to cut straight across an aluminum tube twice, but whatever.

I chickened out on going straight to 15 wt oil and put Motul 10 wt in, because I ride a lot of fun twisty roads that have bad pavement and I didn't want to limit the rebound. I haven't gotten to play on the bike much yet; I only took it for a spin around the neighborhood twisty street to make sure everything seemed okay. Hard braking seems to work a lot better, but more than anything else it accentuates how bad (soft) the rear suspension is.

I have the replacement spring for the back, which hopefully will go on tomorrow. Wish me luck.

Also curious if other people have slipped the forks up ~5-10 mm from stock position and how much difference it makes.

 

[zixaq]

Update after taking the bike up through some good twisties in Marin:

The extra spring rate is awesome under braking and keeps the bike much more level. That said, the bike geometry is different than what I was used to now, feels more leaned back. After the rear spring swap, if I still feel like I want the bike leaned forward a bit more, I'm going to try to drop the triple down the forks 5mm and see what happens.

I used 10W oil instead of 15W, and it was the right call. It's much rougher on bad pavement now, and I think the extra viscosity would have made it worse with the ****ty damping rod. I left the air gap a little short (120 mm) thinking it would be fine with the lighter oil, but I think I might go in with a syringe and pull 5 mm out and see if that behaves better. Still need to dial in my sag; hopefully I can get a helper to do that this weekend.

 

[thisisbenji]

Raising my forks 10mm through my triples was probably the second best mod I've ever done.

 

[FinalImpact]

Turn in is much improved sliding them up!
Careful going too far as highspeed stability can be compromised!
I've had them up 12mm and thats too much for my liking.
Settled on 8. 31mm front/29mm rear sag.

 

[zixaq]

The front felt a bit stiffer than I wanted, and the sag was a little tight, so I backed off one washer on the front preload and pulled out 7 mL of oil per tube (should be about 5 mm), which turned out to make it too soft again. Last weekend I put 4 mL back into each fork (only had 5W oil available of the same brand, but I figured 4 mL out of ~475 wouldn't make THAT much difference), and that made the front rebound and dive feel a lot better.

This weekend got my new rear tire and new rear spring put on.

Left to do:
Dial in the preload/sag front & back
possibly bring the forks up ~5 mm in the tubes.

 

[FinalImpact]

I've played with oil fill level a bit on the R6 fork and well, I just don't see 4 or 7mL (7cc or 1/2 tablespoon of oil) doing anything to the overall fork volume. Something doesn't add up.

In short, the fork fill level equates to a volume that is slightly more than the forks stroke length 5.1" (130mm).

Fill Level = 134.0 mm (5.28 in) vs Stroke 5.12" but then notice the spring collapsed length and the spacer above equate to roughly twice the stroke length. Meaning - we have a compression ratio of 1.5:1 so changing the volume by 4cc's just doesn't have any impact.

Did you change anything else while adding/taking fluid volume away?

 

[zixaq]

So, after a few days of riding around on it, I don't think I can recommend stiffening up the rear shock spring if you ride a lot of bad pavement like I do. It's uncomfortable now, and it feels less stable over bumpy pavement rather than more stable.

The rear tire skips around now over little bumps while in a corner. I don't remember it feeling like that before.

I still have questions about the front setup as well, but part of the problem is that I have no idea what a good suspension is supposed to feel like . . .

 

[FinalImpact]

What you are feeling in the rear is the lack of damping control and you are spot on!
Hence, once improvements are made to the front, one notices the back isn't worth a damn either.....
Basically the rear lacks rebound control and going over bumps it unloads kicking you in the butt giving you that sketchy feeling.... Thats not to say it has fovorable compression control as thats weak too.

 

[FinalImpact]

Another factor that in play is the higher spring rate is basically over working the shock... As in, it was compromised before and now with a greater load imposed on it, it has less chance of controlling it. So what you're explaining really does make sense.

Notice I fitted an R1 shock to mine. It is revalved compared to stock but some have simply resprung it and ran it as is...

 

[FinalImpact]

[MENTION=27568]zixaq[/MENTION] what happened here?

 

[zixaq]

[MENTION=27568]zixaq[/MENTION] what happened here?

I pulled another 5 mm from the front forks and tweaked the preload. I might pull a bit more to soften the front a bit. The rear still has the same problems, but those aren't fixable. I've also lost a bit of weight, so if I'm not carrying luggage or two-up, the rear spring is on the stiff side for me.

Right now my money and repair time are tied up with my wife's new bike (2002 SV650). Hopefully sometime soon I'll be able to do the R6 fork swap, then I'll start eyeballing a replacement rear shock. I also have a valve check coming up in 2k miles, which is intimidating.

One of the biggest hurdles right now to the R6 fork upgrade is finding the spacers. Does anyone have a kit solution for this? Is there an online place where it's easy to order the parts?