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I've Been Forked!

A couple of years ago I bought some used White Power 5060 Extreme forks from Ebay Germany, with the idea to put them on the Camel. The front end on these BMW’s is not great and can be improved in all sorts of ways… Forks from KTM’s, Suzuki’s and Race Tech inserts.
I Wanted to stick with conventional forks, not upside down units, to sort of keep the original “look” of the bike.

I sold the yolks, (triples), that came with the forks as they were KTM items and I knew that they had the wrong offset and would smack into the PD tank.
They already had a BMW stem pressed into them, from a company called Roemer in Germany. A quick advert on UKGSER and they were gone, recouping some of the cost of the legs.

I tried to get an axle made locally, but, after three attempts they could not get it right. That more or less scuppered the whole idea, there and then.

At the end of 2010, I saw an advert from an English guy, Fraser, in St. Junien, which is about 40 minuets away. A trip up there confirmed he could do the machining I wanted for the axle, wheel spacers and disc spacer.

I decided to use the KTM size axle, 17mm and have the wheel spacers made as a combination of axle carrier dust cover and spacer. This allowed me to keep the original size of BMW wheel bearings. This also keeps to to only one piece per side.

New fork triples were needed. I tried getting some made using drawings that one of the guys on ADVRider had drawn up, but they required a CNC machine and my man does not have one. Mat of Boxer Toko sell a nice set in black. Not cheap, but really chunky and look the part. These were obtained.

So, at last I could hang the triples on the bike and slide the legs in to get the axle and spacer dimensions. A little tricky, but nothing too difficult to get everything centered. The brake now goes on the left leg so a new caliper bracket and rotor spacer were needed. Caliper mount is an off-the-shelf job from Mat and the disc spacer was copied from the existing one, but slightly fatter.

The handlebar clamps as supplied with the triples do not work with my Rox-Risers and I wanted to keep them. Although these risers are for Fat-Bars, the mounting bosses on them is for standard 22mm bars as fitted on the original BMW triples.
I found some Renthal bar mounts that were the size I wanted with 12mm bolt fixings, but again for Fat-Bars so I got Fraser to machine me a couple of split sleeves to reduce them to the riser size.

Originally, these forks are 100mm longer than the BMW items. Without being shortened, the bike would look, (and behave), like a chopper! The forks had to be sent to a specialist to have an 85mm shortening spacer put in, be re-sprung/valved for the bikes weight and a general check over and have any worn bushes replaced. This was done in Holland, through Boxer Toko.

The forks are pushed through the triples by 20mm to keep everything on an even keel. The triples are a lot thicker than the originals and the top of them fouled the PD fairing and dashboard. I got over this by taking ff the fairing support bracket and welding up the mounting holes and them re-drilling them 5mm lower. This pushed the whole fairing up by that amount and I now have clearance on the triples.

The steering stop also needed grinding down to almost nothing to get some lock back.

The bakes lines have been a little problematic. The caliper hangs on the back of the left leg and I have used a single braided line from master cylinder to caliper.
The line is anchored to the lower fork leg and at the top yolk. The problem is in the flexing part. It rubs the oil cooler and is wearing the outer casing. Its now strapped up with a rubber sheath and anchored at the lower yolk to reduce the amount that flexes. Will keep an eye on it!!

Does it all work? It does! The forks feel nice and plush and soak up all the bumps and undulations very well. The brake really works now, but I suspect that is down to the sintered bronze pads that Mat supplied!
The forks dive a good way under very heavy braking, but I have not managed to get them to bottom yet… which is good. I will experiment with heavier oil to see if that has any effect on the travel.

So far, so good and it looks the biz… IMPO.

  • 1
    Dave 3. June 2012, 19:34

    You’ve been busy then John – looks tasty!!

  • 2
    Harold 4. June 2012, 11:42

    Thanks for sending me the info John – most interesting.
    Are there future commercial possibilities with these mods?

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