How To Shim Top Of Shock On 5th Gen

[Guest heatmizr]

This was posted on another thread about mods; got no response so here is a new topic for you....

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(fallzboater @ Oct 12 2005, 02:18 AM)

FRONT SUSPENSION:

Mod:  Raise forks in triple-clamps

Benefits:  Improved handling due to steeper head angle, reduced trail

How to: 

Time:  20 minutes

Cost:  $0

Permanance:  Completely reversible.

REAR SUSPENSION:

Mod:  Increase rear ride height by shimming under top shock mount

Benefits:  Improved handling due to steeper head angle, reduced trail, increased cornering clearance

How to:  Add approximately 4mm of shims under top shock mount to raise ride height ~12mm.

Time: 

Cost:  $0

Permanance:  Completely reversible.

OK I finally got around to doing these yesterday on my 2000 5th gen. BUT had a problem:

I attempted to raise the rear of the VFR 6mm (which equates to 2mm at the shock) and lower the front 5mm to sharpen up the geometry. Well when I loosened the top of the rear shock mount enough to insert a washer underneath and thus extend the rear shock, I heard a metallic noise which I found was the bottom of the shock linkage dogbones hitting the exhaust collector(or converter I couldn't tell). So there really was not enough room to raise it a worthwhile amount. HOW are others doing this? Maybe this is strictly a 6th gen mod?

So I went and dropped the front 10mm instead! It did feel pretty nice underway, & I didn't encounter any clearance issues, although I didn't try any hard braking to get the front to dive much. I think I dropped the last VFR (4th gen) 10mm and I didn't have issues there either. As I am not a curb-hopper I don't expect any problems.

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So my question is, anyone with a 5th gen do this? What is the easiest way? Did you need to remove the exhaust collector first to gain enough clearance while lowering the shock to get the shim in?

BTW it sure is tight up in there trying to get a shim in above the shock mount...

[HispanicSlammer]

I don't subscribe to shimming the shock unless you ran out of preload and your scraping hard parts, in which case you need a heavier spring. Raising the center of gravity is what that does and takes more effort to flick side to side (pendulum effect) I have always believed that you should keep the bike as low as possible without having issues of bottoming out or scraping, in which case a click of preload should take care of that.

I have always leaned toward lowering the clamps on the forks, but 10mm is too drastic to me, I felt negative feedback and a hard sluggish feel at slow speed, as if I went too far. I liken it to focusing a magnifying glass in the sun, go too far and the image inverts.

You should always start by setting sag even on front and back, then work from there to find the best feel, just dropping forks or shimming shocks is a waste of time if you have the preload all wrong in the first place. something you can do by setting preload correctly right off the bat will save you a lot of time!

It is very easy to overdo this mod and go off the deep end raising forks and shimming at the same time? The vfr is very sensitive to sag settings, you want to try to keep the balance of load on the tires pretty even, too low in the front and your rear will will be stepping out in hard braking! Nothing like fishtailing when you are in an emergency braking maneuver!

It is sort of like sitting on a teeter totter, you gotta balance the load to keep traction on both tires.

[Baileyrock]

I would NOT do both (raise rear/lower front) and the 10mm you raised the front is most likely too much! 5-8mm on the tubes should be more than enough to get a good gain w/o starting to cause problems. One thing I noticed when adding more then the 5-8 mm was that countersteering effort increase which I did Not like. High Speed stability could also be negatively effected.

You could just cut a slot in the washers and slide them into place w/o pulling the shock.

[teleskier]

I would tend to agree that doing both is overkill. HS's suggestion of making sure your preload is set correctly first is a must. Then and only then if you still feel like you need more, drop the front but only 5mm to start with and that is assuming the front and rear are set to the same sag measurement.

I have my rear set at 27 and my front at 34 on my 5th gen with stock fork height but that is just where I like it with no adverse effects.

[Guest]

Thanks for the input guys. Please consider these comments:

- Yes, raising the rear by itself will raise the C of G a *little*, but if you are also dropping the front I would think it is cancelled out pretty well. This is one of the most basic and widely used ways of increasing turn in and reducing steering effort for any sportbike.

I agree you could go too far, but until I get a chance to really lean the bike over I won't know... My first guess was 10mm which isn't much different than the 8m recommended here, so I must be pretty close.

- I don't see how the VFR is any more sensitive to these changes than other bikes. In fact, I would argue that it is less sensitive, as it's geometry is set quite conservatively from the factory. The closer you get to that "sweet" spot, the more you will feel a given amount of change (say, 1 mm). If you are 10mm away from that sweet spot, and you go to 9mm, it will result in less change than from say 2mm to 1mm.

*I have worked out a very interesting spreadsheet showing all the VFR numbers and comparing them to the RC51 I also have, and what a given change in fork height do to each. If you like, I would be glad to email you a copy. Its pretty neat & interesting. Ask me at Tglasier@carolina.rr.com

- As a bike is tipped forward the counter-steering effort should *decrease*, not increase. Did you make any other changes? Also, high-speed stability is characterized by more counter-steering effort, not less, due to more trail and/or rake of the forks.

- I agree on the importance of setting your sag first; but preload is not quite the same thing as ride height. They can and should be set independently.

Preload allows the suspension to work over a optimum range for a given rider weight. Ride height in the rear has more to do with handling, and overall chassis geometry - in fact its primary function is to impact the front end by decreasing the rake & trail, and also to put more weight on the front wheel (a major factor in handling, thus all the fuss by the manufacturers to get more weight closer to the front - look at our side rads on the viffer).

Again, I agree, you can go too far, but the VFR is no where near the edge. On my 4th gen, I couldn't even get the proper sag measurements with the stock suspension - it was way too soft to even get into the 30-40mm range.

Re: the washer suggestion: Afterwards I did think of slotting the washer to slide in there without totally removing the shock bolt from the frame. I'll have to try that next. Its just very tight to get your hand in there.

Comments?

[Baileyrock]

I have to back track a little here, when I had 10mm drop in the front forks I also had my Ohlins on the rear raised 10mm or so and that combo was too much! Steering effort increased a bunch at speed and required a much higher effort on the bars for normal countersteering. So looking back at that info your 10mm at the front might not be too much and is a good aggressive change so the effect with be obvious.

You can make your 1-2 mm changes from there to attain desired feel. I still think 10 at the front and raising the rear will not benefit you in a positive way, but you can sure try and let us know.

Why everyone is so hard with the setting Sag direction is because as you know that's pretty much the only adjustment you have on our VFR's besides the minimal rebound on the rear shock. Rake like your playing with plays a major roll in how the bike handles. I'm don't worry much about the CG effect of raising the bike, I can change that with hanging off if needed.

I ended up happy with 6mm front end drop and the rear shock at stock length along with re-valved forks (.95kg springs) and an Ohlins rear running 19kg spring.

I ride very aggressive and weigh 195lbs. :blink:

[ULEWZ]

Raising the rear or lowering the front end both have the same affect with the following differences. Lowering the front decreases ground clearance with the pegs and other hard parts (not my first choise). Raising the rear quickens turn,in, increases ground clearance, but causes more lean when on the side stand (still, this is what I did), and increases the reach to the ground (not good for shorter types). With the VFR, you will be hard pressed to make enough geometry changes to cause a high speed problem (the geometry is just too conservative). One or two slotted washer under the shock upper mount is usually just right IMO. Setting the sag is a must before doing any of this.

[Guest]

ULEWZ - Agreed !

But I am sticking with the lowered front (possibly backing it off to 6-8mm instead of 10) until I scrape a peg or other...!

[Guest]

Raising the rear or lowering the front end both have the same affect with the following differences. Lowering the front decreases ground clearance with the pegs and other hard parts (not my first choise). Raising the rear quickens turn,in, increases ground clearance, but causes more lean when on the side stand (still, this is what I did), and increases the reach to the ground (not good for shorter types). With the VFR, you will be hard pressed to make enough geometry changes to cause a high speed problem (the geometry is just too conservative). One or two slotted washer under the shock upper mount is usually just right IMO. Setting the sag is a must before doing any of this.

Well this weekend's forecast is looking great, so I am finally going to shim my rear shock up tonight in preparation. This time going to slot the washer first and slide it in. I am thinking a normal large washer (approx~2mm) will give me a nice 6mm rise in ride height at the rear wheel.

Will let you know how it feels after this weekend.

Regarding the above, yup. Also a big deal is that the center-stand is a LOT more difficult to use when the front is dropped and the rear is stock height... I can barely get the bike up on it now, due to lack of leverage on the center-stand. Hoping this is alleviated when I raise the rear.

[Beck]

Try using automotive body shims, instead of washers. They're rectangular pieces of metal, in differing gauges with a "U" slot cut out of them. I got a set from an automotive parts supply store and installed them with the opening of the "U" facing the rear tire, to minimize any chance of them falling off if the top shock mount nut will ever loosen on me (Doubt if it will, cause that thing is tourqed down really good). I agree about it being hard to overdo these adjustments on the VFR unless you do it intentionally. I dropped the front about 13mm with no problems at all and the rear by two thick and one thin washer approaching 6mm. The bike is just approaching neautral handling at these amounts of adjustments, with just a very small, almost imperceptible touch if slow frequency wag at the bars when braking at around 45mph. Otherwise, my 4th gen has never handled better all these years. I can better feel what the front is doing and it raised my confidence on the front end 100%. I still need to re-do the sag settings on the bike after a half hearted first attempt, but after that, I think I pretty much reached the low budget limit on suspension adjustment to the bike. Only a new aftermarket high-line rear shock and an RC51 or similar front end, can elevate the bikes handling performance at this point.

The 5th and 6th gen bikes have a higher base performance platforms to work with and should be easier and cheaper to improve, but anything better might mean getting a different bike all together. Afterall, the VFR IS a Sport Tourer.

[enzed_viffer]

Ha ha ha! I'm bad! I did it ALL, and crashed and exploded and died!

Backtrackle a bittle....

When I got my VFR, the front fork tube thingos were raised to the sky and beyond. I think.

But I wanted MORE!!

Some time ago, I shimmed the back shock using the MentalVifferEasyShim method:

1. Get you a washer of some sort. The only sort I had around was a galvanised steel washer, about an inche in diameter, with a hole of about 12mm, and of about 2.5mm thickness (at a guess).

2. Cut a slot in the washer.

3. Undo the bolts at the rear of the tank, and prop the rear of the tank up (I used a cork sanding block on top of the airfilter housing).

4. Remove the swivelly brackety thingo (tech term) from the rear of the tank.

5. Loosen the bolt on the top shock mount about 5 or 6mm or so.

6. Using a telescopic screwdriver thingie (another tech term), lower the washer down next to the slot that's magically appeared between the top shock mount and the frame.

7. Push the washer into the slot, using your finger, a screwdriver, your small child's hand, a twig, or whatever.

8. Tighten up the top mount bolt till it strips the thread/snaps the bolts, then back it off a half-turn or so.

9. Put everything back how it was.

Then (well, later, actually), I got bored with this, and cut me a New! IMPROVED!!! Powdercoated black!! aluminium (like aluminum, only more betterer) bracket/spacer/washer thingo, and swapped the washer for that. This is about 4 or 5 or 6 mm in thickness. It works great!

So, to recap: I have maximum fork fiddle, and maximum hoisting in the air of the tail (exacerbated somewhat by a brand-new chain). I've also softened preload at both ends to allow the suspension more movement (because some of our roads are crap).

For a VFR, it handles well: less tendency to run wide than when I bought it, and quicker turn-in. A lot of this I would put down to the front tyre, which is an Azaro AV49-SP, running at 38 psi. Having everything jacked up in the rear, and hunkered down in the front has put more load on the front which it seems to like. Maybe I just adjust well or something? I dunno, but I could test that "don't shim and fork" thing by putting everything back to (ab)normal and see how it compares.

But (however!) I'm going to have to keep an eye on the top chain guide on the swingarm, as it is tending to rub, especially on slow-speed turns (like u-turns). Oh yeah - and that tendency to crash, explode into flames, and die. I can't say I'm particularly enjoying that, but I'm getting used to it.

Bring on the nay-saying! Flame away! (but keep clear of the gas tank).