Honda CRF1000L Africa Twin Suspension Modifications

This magazine article was written a while ago and covers the same info found on our up-to-date featured bikes page. Check there for the latest updates.

In issue #23 we rode a trio of Africa Twins and thought the stock suspension was good. Then we rode a couple where the suspension had been sorted and tuned by Nick Dole at Teknik Motorsport and we were amazed that what seemed a good stock set up could be improved so dramatically. Nick was happy to share what he’s learned about Honda’s dualsporter...

In the last 10 years, the DR650 was the king of the hill in terms of the amount of them we upgraded the suspension on. That’s changed in the last 6 months. We now do more Africa Twin than any other bike. It’s not because it’s a bad stock, it’s just the sheer sales volume, 400 bikes are rolling off dealers floors each year. It’s selling well, lots of people love them stock, lots get modified. We do everything from changing springs, modifying OEM fork and shock internals, fitting Ohlins, Nitron and Andreani cartridges, to complete Ohlins forks. Ohlins shocks and now TFX shocks. There are a lot of companies making AT suspension components.

GOOD CALL

How does a typical Africa Twin phone call go? It’s varied. Remember a LOT of people buy this bike and love it stock. I get everything from “I read on the internet I should get it done” to “I bottom it so hard I may be in need of spinal fusion soon”. Clearly, we are dealing with a wide range of riders and uses.

If the caller is lost, just wants an improvement but doesn’t know why, asking what they use the bike for usually reveals why they are calling. Typical responses with my suggestions to no cost remedies are:

The forks are too soft and dive a lot.
Ok, have you adjusted the preload? Stock the fork has very little internal preload and you can make the fork sit a lot taller by winding 8-10mm (Turns) on the blue preload adjusters on the fork tops. I’d suggest you run the rebound adjusters on the fork caps at 1.0 turn out from full hard and the compression adjuster at the bottom 5 click out from full hard.

The shock gets hot and fades.
The AT has what I’d call a very active shock. I have heard your complaint before and done shock dyno tests at 30 to 120 degrees. The shock doesn’t fade any more than any other shock, it’s just that the level of damping the shock provides stock is very low, so any heat diminishes the damping and you quickly get out of “the window”, try running your rebound adjuster at 3 out from full hard and see if the problem is still there.

I have to run the shock preload at full hard all the time. I’m only 120kg, how could they have built a bike so soft?!?
(Suppressing laughter) The manufacturer has to target a weight range when they build a motorcycle, the stock rear spring isn’t suited to 120kg plus some gear. The shock’s damping targets aren’t meant for a stiffer spring so we are really looking at spring and damping changes.

So, what to do? Let's cover the OEM shock and fork because it’s the most popular to modify.

HONDA AFRICA TWIN FORK

The stock fork is a Showa 45mm USD unit. It’s closer to a late 80’s Honda MX bike than a 2018 CRF450R but that still puts it above or at least on par with its sales rivals. The stock springs are 0.54-0.56kg/mm progressive. That’s not a bad stock spring to have. A few shock dyno runs and some riding unearth who Honda designed the bike for. It’s made to be comfortable and do everything. It’s not supposed to be a CRF450R. The fork is approximately 30% lighter in compression damping than a KTM 1190R, while having a similar spring rate, so it’s aimed at a rider who wants a softer feel. As I said at the start, many AT owners love their bike, this is what we do for riders who want more performance and are happy to forgo the soft feel.

Our modifications to the stock cartridge are aimed at giving more damping support, so you lose the floaty feel. Brake dive is significantly reduced, feel is improved. You get more feedback so you know where the front tyre is. Getting some air becomes fun, not crashing back to earth.

I don’t change the stock springs for riders under 100kg. It’s a lack of preload that causes the sag, not a light spring. For heavier riders, we offer linear springs in 0.60, 0.70, 0.75kg/mm

What the stock cartridge can’t do. It’s limited on preload adjustment, only 10mm. Ohlins has 18mm. The compression adjusters at the base are quite ineffective. The rebound adjusters only have a small usable range, ½ to 1.0 turn out. They may have 3 turns but the adjustment is too course.

CRF1000L Upper Fork Tubes

The internet had a melt down over AT upper fork tubes wearing the anodising off where the lower fork clamp is, lots of talk of over tightening the lower clamp causing the wear. We measured it, checked every set of AT forks that come in the door and talked to Honda.

First, it’s not as widespread as the rumour mill claims.

Second, the wear is above the lower clamp, so it’s not tightening torque. The wear happens on the front of the tube so it’s the pressure of the bush causing the wear. If you spin the top tube 180 degrees the wear still happens at the front.

Third, the riders who seem to have the most issue are road rides where the fork sits in one place for a long time. Offroad riders don’t seem to have near as many issues.

Our answer to this is a performance coating called Kashima Coating. It is only available in Japan, Kashima coating consists of lubricating molybdenum disulfide deposited via electrical induction into the billions of micro-pores on the surface of hard-anodized aluminium to provide better lubrication and less abrasion and wear. This process can take some time to get done due to shipping time frames ex-Japan. We have 6 sets of exchange Kashima coated fork tubes in stock to allow a fast turnaround because no-one wants to have their bike in pieces for long periods of time.

In order for Kashima coating to be performed the fork tubes must not have any significant scratches or gouges as Kashima is microns thick, it won’t fill holes.

Of course, another option is to get a complete aftermarket fork such as the Ohlins CRF1000L Africa Twin Adventure Fork.

AFRICA TWIN COMMON REAR COMPLAINTS

The stock 46mm Showa shock is not a bad unit but set up very lightly for road touring with an emphasis on comfort. Although the shock spring rate (8.3kg/mm) is OK for an 85kg rider (According to the Australian Bureau of Statics the Average Aussie male in 2013 weighed 85.9kg add-on 10kg of riding gear, hydration system and possibly some luggage plus the fact that we aren't all average there is often a need for a heavier spring), the shock spring preload needs to be increased dramatically to help keep the ride height up.

Result Of Testing On The Honda CRF1000L Shock

Generally, our first step we take when we get a shock is to listen to a wide variety of riders, what they think, good and bad, then run the shock on the shock dyno and identify the rider feedback in the graphs so we know what we need to concentrate on.

Part of our testing process is benchmarking against aftermarket shocks to see where their R&D took them. Remembering some riders are very happy with the stock shock we can end up with 2 or 3 settings that give different damping characters depending on if you are majority road touring with some gravel, mostly adventure touring or ride it like a CRF450R.

The downside of the stock shock is an ineffective compression adjuster and a spring preload adjuster that is stiff to turn for springs heavier than stock, the 8.3kg/mm. the 9.0 we often use is OK but a 9.5 or 10.0 shock spring makes adjustments hard. It’s 1mm of spring preload for 2 adjuster turns. The Ohlins unit, by comparison, is 3 turns of the adjuster per 1mm of spring preload, so it's easy to turn with any spring.

We have done some extensive experimenting with stock preload and here is a snippet of our results. To help you interpret the graph below are a few key notes to be aware of:

• If you have the bike up on a lift, the suspension is "topping out", completely hanging free. This is called the free length and it's as long as your suspension gets.
• Now if you put the bike back on the ground, the suspension will drop a little due to the weight of the bike. The amount it drops is called static sag.
• And if you then sit on the bike, the suspension will drop some more due to your weight. Even further if you carry a lot of gear. The amount that the suspension has dropped from the free length is called the rider sag.
• A "classic" sag setting is 10% shock travel for static sag and 30% shock travel for rider sag, so here are the numbers for the CRF1000F: a total of 218mm shock travel, so an ideal static sag of 21.8mm and an ideal rider sag of 65.4mm.

So, as you can see from the graphs, the sag from stock is excessive. With no preload on it, the rear suspension is almost a third of the way through its travel before anyone even sits on the bike. When it's weighted up, with so much less shock travel to absorb any big ruts and thumps, the shock skips around and gets harsh quickly. We have added a spacer/collar to the spring to increase the initial pre-load, and now it's much closer to classic ride height numbers, leaving more shock absorber travel and a useable preload adjuster.

Simply, stock spring for under 80kg no gear, 9.0kg/mm for most riders up to 120kg, 9.5 and 10.0kg optional, depending on luggage. The Ohlins comes with a 95N (about 9.5kg/mm) stock.

Courtesy of Adventure Rider Magazine.