Front Suspension Issues

[rez]

I am dealing with suspension issues. Have an '88 VR purchased last August. Immediately I wasn't happy with suspension/ride...felt rough/'harsh' and bottoming out. I had a comparison bike in that my brother has an '85 VR..stock springs and rides very smoothly...and no bottoming out issues. So I replaced with progressives as many recommmend here...but still find a 'harsh' ride on sharp bumps and a sort of firm bouncy spongy action on other bumps. I have played with oil levels and different spring spacer thicknesses and tried no air to various air pressure settings....but can't seem to get improvement on my ride. I have had the forks off and apart and cleaned and done bushings and seals and dust seals. I have also added a fork brace. I use 10W fork oil. I weigh about 167 lbs. I even took the progressives out and went back to the OE springs to see if it was different/better but ended up putting progressives back in. As i said.....even now with everything i've done and tried.....the ride on my bike is not near the ride comfort level I feel on my bother's '85. Any help/suggestions/recommendations?? Am i missing something? Should i look elsewhere? I believe for this bike and weight of the bike...i should have a better level of ride comfort.

[Condor]

I am dealing with suspension issues. Have an '88 VR purchased last August. Immediately I wasn't happy with suspension/ride...felt rough/'harsh' and bottoming out. I had a comparison bike in that my brother has an '85 VR..stock springs and rides very smoothly...and no bottoming out issues. So I replaced with progressives as many recommmend here...but still find a 'harsh' ride on sharp bumps and a sort of firm bouncy spongy action on other bumps. I have played with oil levels and different spring spacer thicknesses and tried no air to various air pressure settings....but can't seem to get improvement on my ride. I have had the forks off and apart and cleaned and done bushings and seals and dust seals. I have also added a fork brace. I use 10W fork oil. I weigh about 167 lbs. I even took the progressives out and went back to the OE springs to see if it was different/better but ended up putting progressives back in. As i said.....even now with everything i've done and tried.....the ride on my bike is not near the ride comfort level I feel on my bother's '85. Any help/suggestions/recommendations?? Am i missing something? Should i look elsewhere? I believe for this bike and weight of the bike...i should have a better level of ride comfort.

 

Just a wild stab, but you might have loose steering head bearings...

[86er]

PSSSST! Swap bikes whit your brother when he ain't lookin'!

 

[Rick Butler]

Well Rez,

 

It certainly seems you know know your way around a set of forks now. For the most part what you have done would have already satisfied most everyone here.

 

If you are looking for the best that a set of 88 dampening forks can offer, then I would suggest installing a set of Race Tech Cartridge Emulators. But this means that you get to disassemble your forks again (but just the dampening rod and not the seals) and drill 8 holes in the dampening rod.

 

And even though Progressive Springs are readily available and pretty reasonably priced, they are not the end-all to fork springs. All of the fork tuners have gone to a constant-rate spring because you cannot get the full effect of a set of full length Progressive wound fork springs with a travel of around 5". These cartridge emulators take a set of dampening forks and turn them (functionally) into a set of cartridge forks for about 1/10th the cost. Or you could put a set of R1 cartridge forks (with adjustable preload, compression and dampening) on your 88?

 

I have been using and installing constant rate springs from www.SonicSprings.com for a couple of years now with complete satisfaction. The owner is a friend who was a past and is a present racer who started this company. If you want to do some research, I'd suggest checking out the tech articles on Race Techs web site:

 

http://www.racetech.com/SubMenu.asp?cMenu=4&c=Yes&cSubMenu=9&showPage=cruiser

 

As well as those on Sonic Springs that describe spring sag, preload, sag and spring rate:

 

http://www.sonicsprings.com/catalog/tech_articles.php?osCsid=87037da71e67e6fdf83d53a8173828b4

 

And speaking of spring rate, you will need a set of springs with a rate of 1.20 kg/mm. And the length of the spacer only changes your preload, more correctly your ride height. And the fork oil weight only changes the rate that the forks compress and the amount of oil changes the rebound rate. This is why dampening forks suck, but it's what we have to deal with.

 

Like Oprah says, knowledge is power.

 

Hope this helps,

 

Rick

[Condor]

Great info Rick. Tried to get on RaceTech's cruiser page and I think we've overwhelmed the server... I did find this info on Google. http://vmaxoutlaw.com/tech/cartridge_emulators.htm

[Rick Butler]

Thanks Jack,

 

I had seen this article previously but had forgotten about it. But you won't beleive what these emulators will do for a set of dampening forks, along with new springs. And when I talk about new springs, I mean right out of the factory, 1st gen and 2nd gen alike. In fact the best thing you can do for the ride of these Ventures is replace the stock springs with a heavier set. They just don't put heavy enough springs in any of these Ventures, regardless of how much the rider weights.

 

Then Cartridge Emulators is the next best step. If you don't know how they work, they are nothing more than a pop-off valve that sits on top of the damening rod. And this valve can be adjusted to control how quick it pops off and lets fluid flow on the compression stroke. Then as fast as it pops off, it closes so the reaction between compression and rebound is almost instantanious. This lets the forks react so quick that the reaction from bumps just goes away. I installed my first set on my 93 after a friend that I was conversing with up in Washington told me about them. After I did all the research that I needed I bought and installed a set and have been using them ever since.

 

Hope this helps,

 

Rick

[rez]

Thanks for the replies. Condor....I did check and slightly adjust steering head bearings......it wasn't a problem or related. Thanks Rick for the links and information...I will do some research and reading. Did you experience noticeable difference in ride when you did the modifications on your '93?? (I'm assuming it was a VR) Did you do the work yourself or send the shocks out?? What I don't understand is why my brother's '85 with no modifications and all stock (we have had his apart for seals) rides so differently from mine. I believe they are basically identical shocks. I bought my Venture/a Venture based on the ride comfort I experienced on his. Thanks again!!

[Condor]

Finally got on the website. I guess we did overload it... I noticed that it's possible to send them a set of forks and they'll do the installation. I do have an extra set off an '86, and since I'm not real well versed on fork know-how I though I'd go that route and give it a try?? I also noticed that they don't have any Ventures..1st or 2nd listed... for the dampner???.

[Condor]

What I don't understand is why my brother's '85 with no modifications and all stock (we have had his apart for seals) rides so differently from mine. I believe they are basically identical shocks. I bought my Venture/a Venture based on the ride comfort I experienced on his. Thanks again!!

 

Actually there is a difference. Hydralic vs. Electrical Anti-Dives. I wonder if you're having problems with the AD's not working???

[rez]

Condor.....Yes u are right about the AD's. And come to think of it on the '85 the AD's are removed...they were leaking i think...or some other problem. Although my bike was bottoming out on very harsh bumps...some driveway ramps etc........and not really on hard braking (dive). Unless the AD's are staying on??? I will check that. Rick.....how did you calculate the spring rate at 1.20 kg/mm??? I used Race Tech's calculater and came up with .917 kg/mm based on my weight at 170 plus some riding gear.....and made it 180 lbs. Do the emulater kits come with instructions on how and where to drill dampening rods etc???? Very interesting information. Thanks.

[rez]

Condor....try looking under 'Cruiser'......then 'Street Product Search' and you will be able to get information for 1st Gen. Venture.

[Rick Butler]

Rez,

 

I have never gotten their spring rate calulator to give me a straight number. And I don't know if they ask you for the wet weight of the bike besides your (and gear) weight. The one that Sonic has is much easier to use, once you have the weight of the bike. The point is that with just the weight of the Venture by itself, you need 1.20 springs.

 

And on the anti dive units, when you drill the dampening rode for the emulators you destroy these units. Afterwards, when the antidive activates, there is nothing to stop the pressure from the compression in the dampening rod.

 

And yes, they come with very complete instructions. And like I said, you do not need to disassemble the forks completely, just remove the bottom bolt holding the dampening rod and let it drop out the top after you remove the springs.

 

Hope this helps,

 

Rick

[rez]

A bit of an update on my suspension issues. Had recently installed one of the group buy Fork Braces. And then realized some of my issues developed around the time i installed it. Pulled front fork springs again but left forks intact on the bike.....removed front tire, fender and brace etc. so i could check forks individually for compression extension and binding etc. Both seemed to work fine when working them individually. Then installed group buy Fork Brace and found forks would bind when compressing....tried the same with OE brace installed and forks worked ok. Repeated this with brace and front wheel installed with same results. The group buy Fork Brace hole tolerances were excellent but the radius cut in the ends to fit around the fork tubes was 'tight'....and i believe 'speading' the forks apart. After 'massaging' these radius' and refitting the Brace the binding problem was gone....and after reassembling everything and riding I immediately noticed improved riding characteristics........and much happier with a more comfortable ride. I still am noticing a harsher ride on sharp bumps...maybe Sonic Springs would improve this??? Thanks for everyones input.

[Condor]

A bit of an update on my suspension issues. Had recently installed one of the group buy Fork Braces. And then realized some of my issues developed around the time i installed it. Pulled front fork springs again but left forks intact on the bike.....removed front tire, fender and brace etc. so i could check forks individually for compression extension and binding etc. Both seemed to work fine when working them individually. Then installed group buy Fork Brace and found forks would bind when compressing....tried the same with OE brace installed and forks worked ok. Repeated this with brace and front wheel installed with same results. The group buy Fork Brace hole tolerances were excellent but the radius cut in the ends to fit around the fork tubes was 'tight'....and i believe 'speading' the forks apart. After 'massaging' these radius' and refitting the Brace the binding problem was gone....and after reassembling everything and riding I immediately noticed improved riding characteristics........and much happier with a more comfortable ride. I still am noticing a harsher ride on sharp bumps...maybe Sonic Springs would improve this??? Thanks for everyones input.

 

Just saw your post Richard. Sorry the brace caused problems, that's generally not the case.. Just for the heck of it I took one of the extra braces i still have, matched it up to a Super Brace that I also have, and the foot prints are identical. Holes are perfect and the radius are the same. Even in Super Brace's installation instructions they say to loosen the axle nut and spread the forks. In a few previous posts on the subject some of the members mentioned they loosened the upper fork bolts as well. A couple of members, like you, reworked the radius with good results. Since the amount of relief or spread was only minimal, and fork flex happens quite a bit when the forks are working independantly, I'm wondering if there might be another cause for the binding?? Did you loosen the top bolts when you spread the forks the first time???

[Squeeze]

It's important to loosen the Axle and all four Pinch Bolts on the upper on lower Fork Yokes during the install of the Brace. Of Course the front Wheel has to be off the Ground during the Mounting.

 

Then install the new Brace but do not tighten down the Bolts on the Brace. When everything is lined up, thighten everything down from Bottom to Top. Axle first, Bolts on the Brace, lower Yoke and upper Yoke.

[Condor]

It's important to loosen the Axle and all four Pinch Bolts on the upper on lower Fork Yokes during the install of the Brace. Of Course the front Wheel has to be off the Ground during the Mounting.

 

Then install the new Brace but do not tighten down the Bolts on the Brace. When everything is lined up, thighten everything down from Bottom to Top. Axle first, Bolts on the Brace, lower Yoke and upper Yoke.

 

Thanks Squeeze. I knew I could count on you to chime in with the real scoop on brace installation.

[GeorgeS]

A bit of an update on my suspension issues. Had recently installed one of the group buy Fork Braces. And then realized some of my issues developed around the time i installed it. Pulled front fork springs again but left forks intact on the bike.....removed front tire, fender and brace etc. so i could check forks individually for compression extension and binding etc. Both seemed to work fine when working them individually. Then installed group buy Fork Brace and found forks would bind when compressing....tried the same with OE brace installed and forks worked ok. Repeated this with brace and front wheel installed with same results. The group buy Fork Brace hole tolerances were excellent but the radius cut in the ends to fit around the fork tubes was 'tight'....and i believe 'speading' the forks apart. After 'massaging' these radius' and refitting the Brace the binding problem was gone....and after reassembling everything and riding I immediately noticed improved riding characteristics........and much happier with a more comfortable ride. I still am noticing a harsher ride on sharp bumps...maybe Sonic Springs would improve this??? Thanks for everyones input.

 

------ I had the same problem with my Super Brace. The Bolt holes lined up perfectly, however I had to Remove some Metal from both sides so they would clear the Tubes. ( about 1/64 inch on each side as I recall )

 

This was with the tubes installed on the bike, and the Front Wheel Installed.

 

I can see if you tried to Install the Brace without the Axel Installed, you could probably Force it in without removeing the Excess Metal.

 

Obviously the Manufacturer has gotten his measurements Incorrect for this Particular Installation.

[Condor]

------ I had the same problem with my Super Brace. The Bolt holes lined up perfectly, however I had to Remove some Metal from both sides so they would clear the Tubes. ( about 1/64 inch on each side as I recall )

 

This was with the tubes installed on the bike, and the Front Wheel Installed.

 

I can see if you tried to Install the Brace without the Axel Installed, you could probably Force it in without removeing the Excess Metal.

 

Obviously the Manufacturer has gotten his measurements Incorrect for this Particular Installation.

 

And both of mine slipped right on. The '91 was a Super Brace replacement, and the '83 was an OEM brace replacement. Go figure.... Wonder why???

[Squeeze]

And both of mine slipped right on. The '91 was a Super Brace replacement, and the '83 was an OEM brace replacement. Go figure.... Wonder why???

 

The Pinch Bolts on both Fork Yokes allow some Room for Moving during Bolt Down Procedure.

[Condor]

The Pinch Bolts on both Fork Yokes allow some Room for Moving during Bolt Down Procedure.

 

OK, but would that mean that some bikes have forks that are not installed properly,and out of alignment???

[rez]

As I described earlier.....when finished I had everything bolted/fitted together....wheel (off of the ground), axle, forks and brace, etc. But I had left the fork springs out which allowed me to manually work the front forks assembly to full compression and extension. After I did this everything worked freely with out any binding. Progressive also discusses some of this when fitting your bike with their springs. This is what they say......

 

Fork Braces: We have found numerous cases of binding forksffice:office" />

due to improperly mounted fork braces. Our experience has led

us to conclude that even the slightest misalignment while installing

the fork brace will cause the forks to bind. If, after installing

the springs, a harshness exists (especially on small bumps and

freeway expansion joints), remove the fork brace and ride the

bike again over the same route. If harshness has disappeared, refer

to the fork brace installation instructions for proper and

concise installation to eliminate the misalignment. If harshness

still exists, your front end (wheel/forks) may be misaligned.

Consult your shop manual for proper wheel and fork alignment

[rez]

Sorry...some glitches in the copy/paste.

[Squeeze]

OK, but would that mean that some bikes have forks that are not installed properly,and out of alignment???

 

Yes ....

[greg_in_london]

Okay well I'm going to take the advice here and buy the 1.2kg/mm Sonic Springs.

 

I must admit that I'm a little worried about the massive difference between the strength of the Yamaha springs and sonic springs, but doing the maths, sonic seems right.

 

What I mean is, the fork travel is 5 1/2" (140mm)total.

The yamaha spring weight (according to the manual) is dual strength - for the first 4 1/2" (112mm) the weight is 0.4kg/mm and thereafter 0.8kg/mm.

 

1.2kg/mm is 50% more than the maximum spring rate and double the aggregate, whereas most heavy duty fork springs are quoted as being 15% heavier.

 

Having said that, though, even solo I found the suspension woefully soft, even more so with a sidecar. Over time I have increased the preload as much as possible - the only reason I haven't done more is that I couldn't push any more spacers in ! There is a little preload as standard as the caps screw down, but without dismantling to check I'm guesstimating that I have 2" (50mm) of preload at present.

 

Using the weighing figures from my last MOT test, the load on the front end is 165kg, or 82.5kg per leg.

This means that the loading/movement is taken up as follows:

2"/50mm preload ........ 20kg ...... zero movement

rest of .4kg.mm ......... 25kg ...... 2 1/2" /62mm

and either:

fork pressure 22psi ..... 12.5kg ..... zero movement

.8kg/mm ................... 25kg ....... 1 1/4" /30mm

****leaving (5.5-3.75) 1 3/4" /(140-92) 48mm fork travel remaining

or:

no fork pressure .......... 0kg

.8kg/mm .................. 37.5kg ...... nearly 2"/48mm

******leaving just over an inch ~ 30mm fork travel remaining

 

And that's what I've got - hardly any travel on the forks - admittedly I've added weight with the sidecar. Your bikes will probably weigh less, but I'm not taking the sidecar off to get a figure !

 

With 12kg/mm springs the weight will be carried by nearly 70mm spring compression (60mm with 22psi) in imperial let's say 2 1/2".

With the stiffer spring let's say the max preload I can use is 30mm (1 1/4") then I have a sag on the road of 30-40mm or 1 1/4 - 1 1/2" which is what sonic springs recommend.

 

It might mean that the springs are stiff over the remainder of the travel, but I've a lot of weight transferring on to the front end under braking and don't think that will be a problem. Hopefully I'll have better braking.

 

A big difference, but as I said, the numbers seem to stack up. Now, can I get it delivered and fitted before we go on holiday ?

Edited July 28, 2008 by greg_in_london

[rez]

If you do go ahead and buy/try the Sonic Springs I would be curious to know how they work for you. I have emailed Sonic several times with questions.....they are very helpful to give advice and information. If you have questions email them. They do recommend the 1.2 kg/mm rated springs for our bikes and also going to 15W fork oil (although your dealing with a side car which could make things different). I want to try them too....but am hesitant to spend more money on an 'experiment'. I have already gone the Progressive route and a total fork rebuild with 'mixed' results. Let us know how you make out.