Suspension Modification Advice. Help!

[Guest PIrat]

Squishy, mushy, nose dive... How do you describe the VFR's stock suspension... Ugh?

I LUV my bike and I'm not an ultra aggressive rider but I do tear up the twisties pretty good when I get the chance. So does it have to feel like a '76 cadillac in the corners? I'm not looking for a race bike suspension/feel just a good solid suspension that responds to rider input the way it should and doesn't wallow it's way through the corners.

To the point. I've done a bit of research and looked for recommendations in the forums but most of the recommendations I've found are Ohlins or Penske + Racetech .90 or .95 (180lbs) and gold valves. I'm thinking that even though I'll own and ride the heck out of this bike for a long time thats more than I need and I don't want to spend $1500.

So my other options are to have a company like Traxxion Dynamics, Racetech or Noleen (which I haven't heard of before) rebuild my front and rear suspension. Traxxion and Racetech are about $1000, Noleen is about $650. Are there any other good options for rebuilders? I don't want to go with a 929 rear shock because it would have to be rebuilt anyway (if I could find one).

Have I missed anything? Are there other questions I should be asking? Do I have any options other than what I've mentioned here? Will a semi aggressive rider be satisfied with a rebuild or is the Ohlins/Penske rear really necessary?

Any suggestions, comments or advice would be greatly appreciated.

BTW If anyone has heard of Noleen or has had experience with them or even knows what there reputation is, let me know. I think I'm leaning in that direction cuz they seem to know what they're doing (involved with race teams since '88) and also have a comparatively reasonable price.

[jeremy556]

You would probably be fine with a stock shock that is sprung and revalved for you.

[enzed_viffer]

If money is an issue, you could go with fork springs from Sonic Springs, and a slightly heavier fork oil, and shop around on eBay or wherever for a secondhand shock - Ohlins, Penske, or whatever. It needn't be expensive, and there's lots of info out there for you do do stuff yourself to save money, like setting up the sag properly, making sure your forks a re straight and level, the head bearings are sound, experimenting with tire pressures, adjusting the height of the front fork tubes, etc etc.

However, once you've ridden a bike properly set up for your weight and riding style, you'll realise that money spent on decent suspension is money well spent.

[Guest]

So if I decided to do the fork rebuild myself with sonic springs, who makes a not expensive but half way decent valve kit? I've rebuilt front forks before so I'm confident in that, but if I decide to have the rear rebuilt it would have to be done by a shop. Is a rebuild going to be my cheapest option to improve the rear? If so who would have a competitive price and decent quality? Or is there an easily attainable shock from another bike that would yield a solid improvement without time consuming modification or rebuilding?

I tried calling the number aftershocks lists on their website to see what their prices are, but that number has been changed and the new number doesn't work either. Whats up with that? Is aftershocks belly up or something?

Thanks for the input guys.

[Baileyrock]

If you have rebuilt/revalved before, I might be tempted to just add a shim here and remove one there on the stock valving. Honda's are usually under sprung and over dampened.

But actually for your weight and the spring(fork) you'll be using (1.0kg) the stock rebound stack might work fine, maybe add a little comp. dampening? :huh:

Of course I don't have a clue what I'm talking about, but someone here should! :fing02:

Again new oil and the correct springs will be a big improvement themselves.

[mechdziner714]

I can reccommend the Elka shock for the rear. You could do the 929 shock swap. I have one I'll sell you cheap along w/ the bracket needed. The problem will be getting the correct spring rate on the shock. The 929 has the same sprinrate as the OEM that way too light for me.

Dont go too stiff on the front springs. I went to .95's and they are too stiff for my 220 lbs. Most of the places that sell them reccommend a rate thats too stiff for street riding IMHO. RaceTech has the valves, not cheap tho.

Good luck, Ive done the Elka & front springs and its a much much better ride.

[Baileyrock]

Here's a few pages of threads on the subject that I found using the SEARCH function!

http://www.vfrdiscussion.com/forum/index.p...spension+set+up

[Guest]

Actually I've probably spent 5-6 hours in VFRD's suspension forum trying to answer my (probably asked before) questions.

mechdziner714- How much would you want for that 929 shock? Do you know if it's ever been rebuilt? Stock spring rate or other? It is definitely a 929 shock not a 954 right? I'm tempted to buy it and send it out to be rebuilt then do the fork springs (.90s) with a slightly heavier oil myself. Less total down time, more time riding :mad:

Can someone give me a quick and dirty synopsis on what it takes to use a 929 shock? Is it just the bracket that needs to be modified or are there other fiddly things involved. If it's not too much hassle then maybe I'll go that route.

Are there any draw backs to using the 929 shock?

Thanks for input guys!

Is shock travel the same on the 929 as the stock VFR shock?

[jeremy556]

I can reccommend the Elka shock for the rear. You could do the 929 shock swap. I have one I'll sell you cheap along w/ the bracket needed. The problem will be getting the correct spring rate on the shock. The 929 has the same sprinrate as the OEM that way too light for me.

Dont go too stiff on the front springs. I went to .95's and they are too stiff for my 220 lbs. Most of the places that sell them reccommend a rate thats too stiff for street riding IMHO. RaceTech has the valves, not cheap tho.

Good luck, Ive done the Elka & front springs and its a much much better ride.

.95 shouldn't be too stiff for your weight. Did you go to a heavier oil? If you switched out to a heavy oil, your damping will be too slow, giving a harsh ride.

A couple years ago I installed RaceTech .95 springs and upped my oil weight from stock. The fork was damn near rigid. About 6 months ago I installed gold valves, kept the .95s, and used 3.5-5 wt oil. Now it has a much softer, more compliant ride, and feels softer than stock.

[R_Cote]

If you are going to do heavier fork springs then reshimming the rebound valve is a must. I did the race tech 1.0 springs and my ride was very bouncy. I rode for 2 years like this and just revalved my forks 2 days ago and it is much better so far. I don't think the 1.0 springs are too heavy as long as you revalve it.

You may want to read this. However this topic is a bit lengthy.

Valving Modification

OOPS

Just noticed the link won't work.

Try to copy and paste this into your address bar. http://www.vfrdiscussion.com/forum/index.php?showtopic=18315

[SEBSPEED]

I'm around 200-215, ride very aggressively at times, and am very happy with the .90 RaceTech springs I put in my forks. I have stock valving in front, and an Ohlins in the back.

[Guest]

I'm around 200-215, ride very aggressively at times, and am very happy with the .90 RaceTech springs I put in my forks. I have stock valving in front, and an Ohlins in the back.

What weight oil do you use with those .90s? You didn't change the shim configuration on those stock valves did you? I'm strongly considering just using .90s in front (180#), maybe switching one shim from compression to rebound and uping oil wieght by +1 or 2 depending on recommendations. For the back I think I'll have either my stock shock or another stock Honda shock revalved and resprung by a suspension tuner.

Considering the stock setup is over damped and undersprung, I think these slight changes will balance out nicely and offer an appreciable improvement over stock.

Does this sound logical? Or am I blindly jumping off a cliff here. :blush:

[GP Paul]

I just lately got the full Racetech front and Elka rear. My suspension knowledge wouldn't buy a paperclip at Staples, but I will offer this: ride, adjust... ride, adjust... My dollars spent have increased my fun factor immensely. So far, I'm in the evaluation mode. It's all better, but I bet adjustments will increase my handling/safety/fun. Grande Prairie to Port Hardy (with diversions) and back next week will tell. Cheers.

Racetech .95 (210 lbs) gold valves, Elka 3-way, Pilot Road 2s - don't know what the heck I'm doin', but...

[jeremy556]

I'm around 200-215, ride very aggressively at times, and am very happy with the .90 RaceTech springs I put in my forks. I have stock valving in front, and an Ohlins in the back.

What weight oil do you use with those .90s? You didn't change the shim configuration on those stock valves did you? I'm strongly considering just using .90s in front (180#), maybe switching one shim from compression to rebound and uping oil wieght by +1 or 2 depending on recommendations. For the back I think I'll have either my stock shock or another stock Honda shock revalved and resprung by a suspension tuner.

Considering the stock setup is over damped and undersprung, I think these slight changes will balance out nicely and offer an appreciable improvement over stock.

Does this sound logical? Or am I blindly jumping off a cliff here. :blush:

Unless you are like 300lbs, stick with stock weight oil, or even go down a viscosity. With a much heavier spring AND much slowed damping (thicker oil) you will get a harsh ride and poor traction as the fork won't be able to move fast enough to absorb smaller bumps.

[SEBSPEED]

I'm around 200-215, ride very aggressively at times, and am very happy with the .90 RaceTech springs I put in my forks. I have stock valving in front, and an Ohlins in the back.

What weight oil do you use with those .90s? You didn't change the shim configuration on those stock valves did you? I'm strongly considering just using .90s in front (180#), maybe switching one shim from compression to rebound and uping oil wieght by +1 or 2 depending on recommendations. For the back I think I'll have either my stock shock or another stock Honda shock revalved and resprung by a suspension tuner.

Considering the stock setup is over damped and undersprung, I think these slight changes will balance out nicely and offer an appreciable improvement over stock.

Does this sound logical? Or am I blindly jumping off a cliff here. :mad:

Unless you are like 300lbs, stick with stock weight oil, or even go down a viscosity. With a much heavier spring AND much slowed damping (thicker oil) you will get a harsh ride and poor traction as the fork won't be able to move fast enough to absorb smaller bumps.

I used stock weight oil, Honda brand. :blush: I'd leave the shims alone for now if I were you; make one change at a time. How will you know for sure what changes made which differences if you make 2-3 changes at once? Just a thought.

[Guest]

Buy Andrew Trevitt's book, "Sportbike Suspension Tuning". Don't just read it, study it. That's what I'm in the process of doing.

I have tried to gleen advice from Phil Douglas, Jim Lindemann, Paul Theade, and Max MacAllister over the years. None of them agree with each other. So I have decided to try and figure it out myself.

First thing I'm doing is making myself a front wheel chock that will hold the bike up on it's on without any ceiling straps, center stands, etc so I can do some careful measuring with both wheels on the ground and figure out what I have before I decide where to go to next. The stand will have both wheels on the ground at the same time (hence why I don't use the SportChock). Once I get it done, I can start making accurate sag measurements, ride height measurements, etc by myself and with the aid of the wife. I have finally taught her how to read a metric ruler.

Luckily I have a good MIG machine, cut-off saw, and belt sander in my shop. BTW, the price of steel is going out of sight! I bought some 1" square tubing at Home Depot yesterday and I can't believe what it's costing.

My recommendation, figure out exactly what you have now and make one change at a time. I think my VFR handles good with the mods I've done to it so far but I think it can be made to handle even better.

I think the first thing to figure out with suspension is the correct spring rate. I don't think one spring can cover the range of 130# - 280 # riders (which is about the spread we have on this board). That is the source of my frustration with the suspension "gurus" (Douglas, Theade, MacAllister, Douglas, et al). None of them agree.

The springs provide the suspension for any vehicle. The shock absorbing mechanism controls the dynamics of the spring behavior. My opinion (and I could be wrong) is that too much emphasis is put on damping (both rebound and compression) and spring rates are more or less left to chance.

Read Trevitt's book. It will open your eyes to a lot of things. Did you know sprocket selection has an effect on suspension behavior? And I'm not talking about the change in wheel base but how it affects the squatting of a bike. Tires, shocks, forks, ride height, weight bias, etc - there are thousands of factors at work here.

Just my 2¢. I could be wrong.

[Rustbucket]

I know almost nothing, but swapped my stock rear shock to a 929 rear shock a couple of weeks ago. I weigh about 215, so it's seriously undersprung, but it was still a nice improvement in ride quality. For the time being I've got the compression damping turned pretty high to compensate a little for the spring rate.

If you're going to pay to have an OEM shock revalved it's worth it to get a 929 shock if only for the fully adjustable damping. Installing it was pretty easy (and I am by no means an expert mechanic). Just pull the old shock, grind out the bolt in the top bracket, get a longer (good quality) bolt, grind the head down for clearance, add spacers, and it bolts right up just like the original one did. If I were doing it again I'd buy a new top bracket from the local dealer (cheap) and modify that one, so there would be no downtime.

I'm planning to have the shock resprung/revalved for my weight over the winter.

[mechdziner714]

I dont understand the heavy spring light oil theory.

[jeremy556]

I dont understand the heavy spring light oil theory.

The spring supports the weight and absorbs bumps. The damping controls the motion of the spring.

Too much damping results in the suspension not being able to move fast enough to keep in contact with the road. Too little damping results in bouncing, ever see a car with blown shocks?

A stiffer spring will be harder to compress, if you add thicker oil (more damping) it will be even more difficult and slower to compress and rebound. Makes for a harsh ride, and in extreme cases the tire can leave the ground over bumps because the suspension cannot move fast enough to keep up.

[Baileyrock]

I dont understand the heavy spring light oil theory.

The spring supports the weight and absorbs bumps. The damping controls the motion of the spring.

Too much damping results in the suspension not being able to move fast enough to keep in contact with the road. Too little damping results in bouncing, ever see a car with blown shocks?

A stiffer spring will be harder to compress, if you add thicker oil (more damping) it will be even more difficult and slower to compress and rebound. Makes for a harsh ride, and in extreme cases the tire can leave the ground over bumps because the suspension cannot move fast enough to keep up.

Nice explanation Jeremy! :wub:

And on the other side of that(rebound) you will need more dampening to control the quicker rebound of a stiffer spring. That's whats hard about suspension tuning, you can have similar results with opposite ends of the spectrum. You will have the similar loss of grip with too much comp as to little rebound because the wheel is loosing contact(grip) with the road surface, but from different reason. :rolleyes:

Also like Pete M said, many tuners come from different directions on how they control the suspension. Race Tech seems to depend more on fluid dynamics then springs with their HUGE valve ports, this requires more from a Shim Stack then what company's like Ohlins do. Ohlins uses port sizes closer to OEM Honda to control certain aspects of dampening which allows the Shim Stack to only be responsible for fewer phases of dampening and in their mind provides better specific control of certain aspects of dampening.

Phil at Aftershocks (who build my forks) suggested the same .95 kg springs for my forks (200 lb) as another members forks with him at only 160 lbs. :fing02:

I find M/C suspension much harder to figure out then when I was racing both Open Wheel & Production cars. We always set the car up with lighter springs that would allow full travel of the suspension at each track then used the shocks to control transitions the way we desired. But just like with cars, bike riders sometime like a really stiff suspension because it fees better to their style, but when it lets go it's much harder to save.

Fun and confusing stuff. :fing02:

[Guest]

Well put Bailey.

To quote Keith Code:

The purpose of a motorcycle's suspension system is to provide maximum traction.

[Baileyrock]

Well put Bailey.

To quote Keith Code:

The purpose of a motorcycle's suspension system is to provide maximum traction.

That is the purpose of all suspension systems IMO, especially when racing or riding fast. On a bike you only have two contact points vs 4 with a cage so it's a little more critical. :fing02:

What's also funny is that people like Code would set their bikes up differently then what say a Freddy Spencer taught racer might want because they teach different riding styles that would require different tuning to provide the best results to match the riders style. :rolleyes:

It's endless! :fing02:

[Guest]

Well put Bailey.

To quote Keith Code:

The purpose of a motorcycle's suspension system is to provide maximum traction.

That is the purpose of all suspension systems IMO, especially when racing or riding fast. On a bike you only have two contact points vs 4 with a cage so it's a little more critical. :fing02:

What's also funny is that people like Code would set their bikes up differently then what say a Freddy Spencer taught racer might want because they teach different riding styles that would require different tuning to provide the best results to match the riders style. :rolleyes:

It's endless! :fing02:

That's why Baskin Robbins sells 31 flavors.

[Baileyrock]

That's why Baskin Robbins sells 31 flavors.

:fing02:

I like 31 Flavors and more! :fing02:

The problem is that with all the different approaches used it makes it much harder for us simpletons to understand and apply because you can't do it until you just choose theory and go with that concept. :rolleyes:

[ShipFixer]

The problem is that with all the different approaches used it makes it much harder for us simpletons to understand and apply because you can't do it until you just choose theory and go with that concept. :fing02:

From an engineering standpoint, there's really only one correct concept for tuning with linear springs as there's one equation of motion. It's a dynamics/frequency response problem. And it's close enough for the non-linear ones in my fork as well. It's the zillion and one mechanics, tuners, owners, and whoever who've come up with their own little way that "works" that muddy the water. The ones who are the most correct are one way or another coming up with a spring and damping system that a.) gives the right frequency response for the system inputs (bumps, potholes, squirrels, or whatever else you run over), and b.) resemble a critically damped curve at whatever section of the curve you're on (high and low rebound and compression).

I knew a vibration analysis professor in grad school who used expensive accelerometers to tune motorcycle suspensions. And I know mechanics who have no idea what the linear equation of motion is but just kind of push up and down on your bike at different speeds until it feels right. Both are really coming to the same answer.

I've watched people who prefer over-damped and over-sprung harsh suspensions because they think it's better or sporty or whatever. On mountain bikes it's pretty obvious that it's craptacular as their wheels go everywhere and they slide out in berms and such, but...it's their bike and their saddle sores.

Kind of like engine oil and break in theories on VFRD...I've only ever found one and only one acceptable answer in engineering journals and textbooks for each, but as many anecdotal references as you'd like on here to prove whatever