Rear Spring

[Viperpash]

Thanks to this forum I have repaired the E4 code problem but I think the Rear spring and or Shock are toast. It holds air ok and rises when inflated but bottoms out pretty hard especially with two up. Rate adjuster doesnt seem to do anything either. Is there an aftermarket replacement??

Viperpash

[GeorgeS]

First time I have heard anybody haveing problem with 1st Gen Rear End.

I assume you are talking about an 88 1st Gen.

What are you running for Rear Tire Pressure ?

[Viperpash]

Metzeler 880 Marathon tire 35 psi. I am near due for new tires which I have purchased. I was hoping to adress the spring issue when i change tires.

[Squeeze]

Metzeler 880 Marathon tire 35 psi. I am near due for new tires which I have purchased. I was hoping to adress the spring issue when i change tires.

 

 

This Pressure is a on the very low Side for the rear. 35 in front is fine, but on the rear you'd better run it on 42 psi, especially when riding 2-up.

 

 

btw, there is an Aftermarket Spring for the 1Gens Shock from Progressive Performance.

[GeorgeS]

Yes, you should be running AT Least 40lb in the Rear Tire !! ( Minimum )

 

When the Wheel is off, be sure to pull the 3 Cross bolts, for the Suspension Linkage under the Rear Shock assembly. Pull those bolts out and Hand greese them. They most likley be rusted, and worn. Good time to Install Zerk fittings so in future they will be easy to service.

 

Also on each side where the supension connect to the Swing Arm, be sure to remove and hand greese them also.

[Dano]

If you're pulling those links out, check the bushings and collars. Mine were so bad I replaced them and added zerk fittings. I will post pics tonite when I get home on the zerk locations. You can pick them up at Autozone for a couple bucs, and get an 1/8" drill bit for the tap size.

 

Now the bushings can be expensive, but mine had a LOT of slop in them, so I elected to replace them. Your choice.

 

Dan

[Gearhead]

Yup, the rear springs are too soft I think. If I ran my 87 with max air it was good for single, but 2-up we used most of the suspension travel just sitting there. You have two options from Progressive Suspension, and neither are real cheap. For 95 bucks you can get a replacement spring that fits on the stock shock and it supposed to be stiffer. Downside? What happens if, a month after investing in that spring your stock shock takes a dump, leaks air or oil or something? For about 350 you can buy a whole replacement shock/spring assembly which is what I did. It doesn't use air; preload is a manual adjustment that is hard to access, so you set it once and leave it. I ended up with the preload on max and it rides real nice 1 or 2 up, with no bottoming.

 

Jeremy

[Condor]

Thanks to this forum I have repaired the E4 code problem but I think the Rear spring and or Shock are toast. It holds air ok and rises when inflated but bottoms out pretty hard especially with two up. Rate adjuster doesnt seem to do anything either. Is there an aftermarket replacement??

Viperpash

 

 

There's a dampner adjustment on the left side of the bike just to the rear of the middle gear cover. Is it set on 4? If not put it there. And don't jump directly from 1 to 4 or 4-1, but 1-2-3-4 or 4-3-2-1. Should help with the bottoming out.

[Freebird]

There also is an after market replacement. Made by Works Performance.

[Viperpash]

What a wealth of info. Thanks to all. I'm pretty sure the spring is shot, and changing the dampner has no effect. I like this Bike enough to invest in the new suspension. Think I'll do the forks too. Keep hearing that Progressive stuff is good. Mama wants to tour Nova Scotia next year so I guess my plan is set.

[Cutty]

Thanks to this forum I have repaired the E4 code problem but I think the Rear spring and or Shock are toast. It holds air ok and rises when inflated but bottoms out pretty hard especially with two up. Rate adjuster doesnt seem to do anything either. Is there an aftermarket replacement??

Viperpash

Tire pressure has nothing to do with it bottoming out, i hope your putting air in the shock when the bike is on the centerstand. What is the pressure reading??

[Viperpash]

Yeah I have set the air at the high automatic setting and now it does not bottom but the ride is pretty stiff. Why does it need to be on center stand? Does it get more air in?:confused24:

[Condor]

Yeah I have set the air at the high automatic setting and now it does not bottom but the ride is pretty stiff. Why does it need to be on center stand? Does it get more air in?

 

I've thought about that myself. Maybe.... if you have a worn out side stand the bike will take a dump????? Or maybe... the psi won't be as accurate or repeatable with weight on the shocks. But.... the second gens don't have a center stand. Or maybe.... the added strain on the CLASS pump will do some damage?????

[greg_in_london]

DFaulkner springs will sell you a replacement spring for about £30 plus postage.

 

Their site is www.dfaulknersprings.co.uk/

They make a lot of performance parts (why has this turned green ?) From memory the standard spring is about 500lb/in and has an internal diameter of about 2 1/2 inches and is 6" long (free length). I think that you can check this in the manual, though.

By the time I tried a heavier spring my air assistance was toast - so I may have a heavier spring (650lb) lieing around.

PLEASE DO MAKE UP A SPRING COMPRESSOR AND BE CAREFUL WHEN CHANGING SPRINGS, THOUGH.

[Viperpash]

Well I'm still inclined to go for the new suspension. My experience with sleds and such is that shock technology has improved dramatically since this bike was built. I see some posts reflect that here to.

[greg_in_london]

Hey Viperpash - new suspension will usually be better than 25 year old kit, but air assistance should make for a much smoother setup if it is working well.

 

I had to upgrade my suspension because of lots of extra weight - sidecar and trailer.

 

The standard system may be pretty soft, but the original spring is preloaded and often left sitting withut much air and may be prone to 'sag' - so even if it was okay, years on it will be that bit saggier.

 

Just be aware that you will need at least 4" of clearance between the spring coils (total). If (as I did) you go for heavier springs, the coils will be thicker and there may be less clearance and they can go coil bound on full travel.

 

[Why 4" ? Well you'll need to work out the figure for yourself, but you will want to preload the spring by 1/2" or 1" (you work out what you need to replace the force provided by the air - 500lbf at 65psi I guess, plus standard preload of about 250lbf) and then allow for three inches or so of movement (check manual or your old unit). After this compression, DFaulkner say that the free space left should be a minimum of 10% the space you started with. If your spring has eight windings, there must therefore be more than 1/2" clearance between windings.]

[Gearhead]

I did some measurements once, but I don't think the rear shock displaces anywhere near 3" for the 4" wheel travel due to the leverage of the linkage.

 

CLASS centerstand issue: If you try this on the front suspension it's really obvious. The bike, when on the centerstand, compresses the suspension a little. (Front definitely, rear probably not as much). When you compress the suspension, you reduce the air space inside the fork or shock and drive the pressure up. Therefore, if you put 20 PSI in the forks on the sidestand and then put it on the centerstand you may only have 15 psi, with possibly a similar effect in the rear. On the centerstand, both suspensions are fully extended and unloaded, which is how the CLASS was designed to operate. I don't think it's hard on the CLASS to do it on the sidestand, it's just not consistent. Yeah, I dunno how 2nd genners are supposed to do it.

 

Jeremy

[Cutty]

Yeah I have set the air at the high automatic setting and now it does not bottom but the ride is pretty stiff. Why does it need to be on center stand? Does it get more air in?:confused24:

IF THIS IS A FIRST GEN BIKE: The air system is designed to calculate with unloaded suspension given all the varibles of not using the centerstand. The suspension needs some travel, start with you setting it 45 lbs. and a road test and increase by 10 lbs. To stiff is just as bad as not enough.

[greg_in_london]

I did some measurements once, but I don't think the rear shock displaces anywhere near 3" for the 4" wheel travel due to the leverage of the linkage.

 

Jeremy

 

Sorry - it would have been better if I'd checked the exact details before posting - but I was just giving a general warning as I used a heavier spring with a spacer I'd used with the standard spring and shattered the spring seat on a bumpy road while touring in Ireland - not helpul.

 

The TK has a longer spring, but the TDK has a 162mm spring (6 1/2") spring which is compressed to 115mm (4 1/2") to fit. The stroke is only 40mm (1 1/2").

 

When the shock is fully compressed, the spring is compressed 87mm (3 1/2"), so a total clearance of about 4" minimum (or 87 + 10% = 95mm absolute minimum) is still correct. The TDK spring weight is 7.25kg/mm (406lb/in).

 

[the TK spring is 481lb/in, 8.44" long compressed to 7.15", so it is precompressed by about 625lb force, compared with about 800lb for the TDK. The L/DL models are the same as the TK. I couldn't say why there is such a large difference. It will take about 1400lb force to fully compress the standard TDK spring, but only 1250lb force for the other springs. The mechanical advantage is about 3:1, so this equates to only 50lb difference on the back of the seat. The XVZ13DS has the same spring as the TDK.]

 

I still have that spare 6" 650lb/in spring.

 

Apologies to anyone bored by the detail.

[Gearhead]

That sounds right - 1.5" shock travel. I too broke a spring seat. Before I installed the Progressive shock, I was trying to be a cheapo and made a couple spring wedges to try to stiffen it up. They worked, but not as well as I hoped, so I made thicker wedges. I thought they were thin enough to avoid coil bind, but evidently I was wrong.

 

I bought the Progressive shock after that.

 

Jeremy

[greg_in_london]

I had a 1cm spacer which was okay with the standard spring, but not with the heavier spring I bought. I should have just bought a heavier spring....

 

I did like the air suspension, but the leaks kept getting worse and I was never sure if it was the CLASS or the shock itself.

[Viperpash]

Well the new Progressive rear shock & spring are in. Did the baffle-ectome on the exhaust while it was apart, and a new rear tire. Have'nt had 2 up on it yet but it sure takes the bumps better. I think cleaning and lubing all the pivots helped as much as anything. Wish it were'nt so hard to get to it to adjust the spring, I might back it off a tick.

I bought the front springs and will get into that later this summer too.

[Gearhead]

Cool, congrats. FWIW, I maxed my preload out per the supplied minimum distance between spring seats. At this setting it sits a little high with just me on it but a little low 2-up - so a nice compromise. I don't find the ride in the rear to be stiff at all riding single, so I'm not worried about it riding a little high. FWIW, I performed static sag measurements to determine this, with 1/3 static sag defined as optimal.

 

If it were still easily adjustable with the CLASS, I might find optimal settings for single and 2-up. However, since it's NOT easily adjustable as you noted, I set it at the max and forgot it.

 

Jeremy