Suspension THUMP!

[grbrown]

Ade,

Gulp! Need deep pockets - but then alternatively deep buttocks I suppose....

[Adrian]

Graham believe it or not I was very lucky kept looking at the scratched and dented and the bits missing sales on the American sites and got it for £450 ( if I remember correctly) but had to phone legend direct for the hose which cost about £30. Sometimes you fall on your feet but most times its butter side down. Ade

[banquo]

Well, all suspension systems will bottom out somehow, if the load exceeds the capability of the spring and damper combination. If there are no bump stops on the frame or swinging arm, then they're probably inbuit to the suspension units. Car and convenional bike ones often have a rubber bush on the damper shaft, which bottoms out on the mounting bush on full bump. Yours could have the same inside...?

There's something puzzling me; what do you mean by 1200 lbs...?
I hope that includes the bike, yes?
At 545kg, more or less, that is over half a ton of motorcycle.
I'm guessing the bike weighs in at about 325kg, which leaves 220kg or about 35 stone for rider, passenger and luggage. Not excessive I suppose, especially when they should have been designed to take a couple of burger boys... Is there a spec for maximum recommended load?

Three suggestions:
1. You won't like this, but if you remove both rear shocks, and raise the swinging arm until it stops, you will find out the ultimate limit of travel. If it's been hitting that limit, then there should be a bump stop on it. If not, it's not meant to hit it, and you should see obvious witness marks where the contact has taken place.
2. Not familiar with what your shocks look like but if shrouded, you might be able to stick Some Plasticene or BluTack on the body, to act as an indicator of how far compressed the units have been on any journey. Might give you an idea if they're simply bottoming out.
3. Probably irrelevant, from your description, but I've heard of big clangs from rubber mounted motors being casused by the motor moving under load, and something (usually the exhaust, I've heard) clanging on to the frame somewhere. Doesn't sound like your symptoms, but you never know...

Be interested to know what you find.

BTW - my Softail does it on any reasonably sized pothole, but the use of a Saddlemen Explorer seat has saved the passenger's back from damage. Best thing I ever bought!

[grbrown]

Ade,

Well done - compared with the current list price that is a real bargain.

Banquo,

On the weight front, the bike comes in at around 740 pounds (no apology for being Imperial old chap!), with full kit my wife and I each way around 190 and luggage about 60, which totals 1180 pounds to be precise. So yes, that is full rolling weight, or at least my best estimate, in the absence of suitable scales.

Thanks for your suggestions:
1. That's a good idea! Not difficult to do and I will certainly consider that. Following the suggestion by Old-Mo I have conducted a paper and visual check for bump stops and found nothing, but there is no substitute for experimentation.
2. These Fournales are air only shocks, no springs, so I could simply fully deflate them and repeat 1 above. The best answer to this I can come up with so far, prompted in part by your suggestions, is that the shocks are being fully compressed onto their own rubber bump stops.
3. Our experience is best described as a thump and I haven't detected any other sounds. Mrs' bum is the principle injured part here!

My shocks have chrome covers that can be screwed down (to gain access to their valves), hence I can inspect any rubbers to see if they show signs of having been given a bashing.

I'll also look at Saddleman seats. Have already sized up Air Hawks, following suggestions from elsewhere.

[grbrown]

Since I last wrote we have tried higher rear shock air pressures, which seem to improve ride and is promising, but we haven't travelled so far afield that we have found the same rough roads which gave us the thumps that prompted this thread.

I have also studied the bike intending to do the investigation we discussed above. With the shocks disconnected I suspect the tyre would simply touch the mudguard. I haven't actually dismantled anything, as when screwing down the shrouds on my Fournales shocks it seemed I had the answer in full view - the 'tide mark' on the shock stems shows their limit of travel.

With the bike sitting on its wheels and unloaded there is just 2 1/4 inches of travel to full compression. Studying the bike closely there is nothing in close proximity that the wheel or swinging arm gets close to, so I conclude that the source of our THUMP is simply full compression of my shocks. And probably insufficient air pressure!

As to improving our lot, we can continue to fiddle with these Fournales, or contemplate a change of shocks to an alternative variety. Air shocks are not supposed to compress fully, so we are presumably some way off an optimum pressure for our riding weight. Unfortunately the guidance from Fournales is sparse, except a suggested starting pressure. So I must be bolder in future and try higher levels!

The original factory shocks were air assisted, but on max recommended pressure they thumped very readily. These Fournales were an immediate improvement, give better ride and handling, and to date have been less thumpy (that's an engineering term! ), so they are a significant step forward. I have a degree of optimism that increased pressure will improve things further.



What this modest thread has emphasised is that Harleys have quite limited suspension travel. I imagine the travel available on the original shocks and any of the replacement brands is similar to my Fournales (I chucked the originals). I have already contemplated fitting yet longer shocks, to improve travel, hence give the things more chance of arresting an imminent thump!

I have also owned several BMWs and the suspension units that revolutionised them for me were Nivomats. These are load compensating and restore ride height under all conditions. So when setting off two up the rear sagged under the weight, however half a mile later they had adjusted themselves and ride height was the same as when solo. It is a shame they are no longer made for bikes, as if available for Harleys they would be my first choice. So much for progress!

Something I find very reassuring about this bike in its current condition is its handling. While zooming through Germany recently, travelling with friends on their BMW GT in the mid-80s/90-ish, we hit a stretch of road, in the outside lane of a dual-carriageway, also in a r/h bend, in which the surface was alternating patches of normal and scraped. In the past this would have given me apoplexy at those speeds, but the bike simply compressed and lifted equally at both ends, as we hit each scraped patch, and we didn't lose any ground to the GT. So there is nothing fundamentally wrong with it - just that occasional thump.....

Returning to alternative shocks, stock length is 13 inches, but there are 13 1/2 out there and Hagon make them even longer, so some of the manufacturers appear to make provision for extra travel. If all else fails I will look into that further.

That's enough for now! More news if I come up with anything else.

[DynaMik]

Hi Graham. I put a thread on here a while ago about changing my Street Bob. You suggested ''Pepping it up a bit''

Well I did, and part of the pepping was Hagon shocks. I got them to build standard shocks with springs to suit our weight plus 30mm longer and the difference is brilliant for £110.

It may be worth that relativley small cost to try these for elimination.

Just a thought. By the way thanks for the ''pep'' talk

[grbrown]

Originally Posted by MiKKiM

Hi Graham. I put a thread on here a while ago about changing my Street Bob. You suggested ''Pepping it up a bit''

Well I did, and part of the pepping was Hagon shocks. I got them to build standard shocks with springs to suit our weight plus 30mm longer and the difference is brilliant for £110.

It may be worth that relatively small cost to try these for elimination.

Just a thought. By the way thanks for the ''pep'' talk

Hi Mik,

Pleased to be of assistance and thanks for the suggestion! Stirs the little grey cells.

This all goes back to a trip my wife and I made to the USA in 2003 with this bike, for Harley's Centenary, when we did 3,500 miles over there. Nothing prepared us for the awful roads! So I vowed to do something and looked into various alternative brands of rear shocks.

We don't often do long trips 2-up (she has her own bike), so my research was leisurely and the Fournales looked a good choice. They may yet prove to be! Solo they are excellent and a great improvement over the originals, so for most of my riding I am very pleased with them.

However, if I find I cannot get these to work well for us, your suggestion prompts thoughts of an exclusively 2-up set of shocks, which is a serious possibility I hadn't previously considered. Hardly represents a huge expense! My current 2-up preps involve tyre and suspension pressures, both ends. No reason why they should not include fitting dedicated 2-up shocks! That is reasonably practical for our 2-week trips.

[grbrown]

I have been pushing forward the boundaries of research into Harley suspension since my last post. As Howard Messner of Motorcycle Metal says, there are hardly any high quality suspension manufacturers out there making products for Harleys, on the premise that we Harley riders don't want decent stuff! The MM website is a bit amateur, but has some very interesting words and other stuff and is well worth a browse. There is hope!

(Kindly refrain from promoting Brand X if they are from the cast of usual suspects.)

The first bit of the bike that hits a pothole is the front wheel, so let's start there. Most Harleys have damper-rod forks, which are decades old in design and mediocre. Their total abandonment by H-D is long overdue. Most sports bikes by contrast have been fitted with cartridge forks for a very long time and the good news is that Harley forks can be retrofitted with cartridge inserts. MM do them, branded as X-Factor and Axxion also make them. In both cases the original internals are discarded and the kit of new parts installed. Greatly improved ride quality is promised!

Moving to the rear end, MM also has a solution, in the form of either Penske and Ohlins brands. These are adapted from racing shocks (the Penskes are actually racing car shocks) and both brands can be had in a variety of configurations. Howard of MM gives the impression of working with both these firms to develop products expressly for Harleys and may well be adding worthwhile value not available elsewhere. His shocks get good reviews on US forums.

Hot off the press is news that I have found a source of Axxion, Ohlins and Penske in the UK, in the shape of Reactive Suspension. They can supply parts for both ends of my FLHS and are in easy reach of most of us, near York. Saves getting our feet wet, crossing 'the pond'!

So further to my previous meanderings I am now hovering between making do with my current Fournales (which I increasingly regard as interim, i.e. no more than adequate), buying two sets of shocks, one each for solo and duo use from a budget source, or doing the job properly and going for broke! Needless-to-say, that looks like costing anything from a King's ransom upwards!

The principle observation I wish to make is that there are sources of truly high quality alternatives to the mediocre stuff we are all riding around on at present. I am off to a darkened room now....

[Phil]

Graham, on your year & model check for any evidence of the top of the rear rocker hitting the frame.

Under weight the whole drivetrain can flex on the rubber mounts,, causing the top of the rear rocker to `KNOCK` on the frame for a second,even with new rubber mounts.

Is your S&S one of the `taller` models. This would make it a little more likely.

It would only do it when traversing a large bump or pothole.

[grbrown]

Phil,

Thanks, I hadn't heard of that! My 107 is the same stroke as a stock Evo, gets all its capacity from 4 inch bores. I have just got back in from the garage and there is stacks of room between rear cylinder and frame, and also no evidence of the two meeting up.

This is a problem that goes back into the bike's early life, made worst in some ways by the fact that we don't actually ride together very often, except on major tours (my wife has her own bike), which is when it really matters! So it predates fitting the S&S. The Fournales shocks I currently have are better than the originals, but their damping still leaves a lot to be desired, even solo.

My 'project' is admittedly being fuelled by increased knowledge, almost entirely due to the internet and with help from HDH. The first phase this winter is to fit a 2007 swinging arm, for which I have all the parts and will start shortly. This will provide a better foundation on which to build improved comfort and a generally better ride - funds permitting!

I'm determined to avoid working my way through all the brands of alternative custom shocks, as some correspondents in the USA have done and with the inevitable expense, but leap-frog them all to the top of the pile. More news as I uncover it!