The Gradual Morphing of My F650GS

Well here it is in all it's factory lowered glory. A blank canvas I feel.



The first thing I did was get an 18'' wheel for the rear. That way I can run the Michy Desert rubber that seems to do the trick for the type of riding I'm into.


A set of 48mm WP forks are going onto the front. They give 275mm of travel so it was obvious that something had to be done about the rear suspension travel. I made up a telescoping strut and put it into the bike in place of the rear damper unit. With the bike on a stand I moved the swingarm through its range and determined the stroke length and shock length that would be acceptable. I marked the strut to find the measurements. I then contacted my Hyperpro man and he pulled a Racing Shock apart and modified it to my specifications. The result is something around 280 to 290mm of travel at the wheel- a bit hard to be specific because you can put in different size bump rubbers and who can tell what thickness they compress to in a "bottom out" situation.

More! More!!

Once the rear end was sorted I moved onto the front of the machine. My G650X Challenge had all the good gear on it so I transfered it to the twin. That is a 21" Exel rim I spoked onto a KTM hub with a 300mm Galfer rotor bolted on. A new caliper (KTM 690) was fitted to the 48mm WP forks. These forks are in a custom triple clamp with 25mm offset to match the X Challenge upper clamp that I'm borrowing for a while.



The front mudguard is a UFO made in 1984 but it will do for now. What I'm after is an Acerbis Teknic but they don't appear to market the silver/black one I'm chasing any more.
I still have the original bars on but will later replace these with Renthal RC High or similar with Barkbusters.
As this bike came fitted with ABS I had a new brake line made up but had to route it in an unusual fashion over the bars.


So now the bike was pretty well set up with decent suspension although aspects of the triple clamp arrangement are temporary- that top clamp has to go back on the G650X!
She sits up a bit higher now revealing this problem-


Fabricating a new sidestand was a bit of a task but it came out ok.


Some engine protection is the order of the day so a bit of Hyde Racing plastic went on. When we are thinking protection the radiator comes to mind- well in this particular case anyway. So it was out with the tube bender and oxy again.




So that is the state of play so far. I've taken it out the 4wd tracks and through soft coastal sand and on the beach without the big girl spitting me off. I was a bit worried the 25mm offset may make the steering a bit light and twitchy (reduced trail) but it seems ok. I know the F800 has less than 25mm offset- Does anybody have accurate, confirmed information as to this measurement? I need to take a mates 800 for a ride to see what it feels like.
Probably the next job will to be to make up some bodywork for the airbox area out of kevlar/glass as I'm not a fan of the beak and fit a sensible seat- that lowered one is of no use to me.

I'll say it again, that thing is sexy! I look forward to seeing what else you do with it.

Nice work! Now there is two of us with WP 48mm forks on the F650GS twin. Will be interesting to see what your ride height is going to be with that much travel. What total length and stroke did you have the shock built too?

I currently put on dual discs but will probably switch to a single 4 piston Motomaster caliper with a 320mm disc. Do you have ABS on your bike?

Oh, forgot to answer your question: The F800GS uses an 11mm offset triple clamp. Axle clamp offset is the same as on the WPs, IIRC 25 or 35mm.

I am using 14mm offset clamps on mine, they are available from KTM and the closest match I could find unless going with custom ones ($$). A bit better turn in than stock, but not too twitchy. I like them.

Awesome, "A"!!! (I sound Canadian).

With all of these off-road oriented upgrades, and looking at your stellar fabrication skills, do you plan on doing anything to support the upper shock bolt?

Nice jobs!

@Lukas
Have you ever posted your impressions of how your bike rides? Also what is the spring stiffness you are using up front?

No I haven't posted anything yet, want to get some more riding time before I do. So far I have only been on the street using the 19"/17" wheel set, still have some work to do so I can use my 21"/18" 950 SE wheels (i.e. switch to the Motomaster caliper as it's only a single disc front hub, and some custom spacers for the rear).

My forks are from a 990 ADV but have modified 950 SE internals with .56 springs that I got from PowerCell. They feel good, pretty plush but not too much brake dive.

Thanks. I'm happy with the rear suspension. It worked well on my ride down the coast and handled whoops nicely with a controlled ride and getting a bit of air without bottoming. I havn't hammered it hard core yet but it certainly put a smile on my face. The front WP forks have been re-valved but need heavier springs so I'll do that before deciding if different offset triple clamps are neccessary. I reckon the 14mm you have is probably a good thing.
My bike has ABS hence the over the bars routing of the brake line. I was a bit worried a single 300mm disc would be inadequate but the Galfer Wave can certainly make those knobs squirm! I almost put on a 320mm disk but went for the smaller option first. Currently it doesn't have a disk fitted for the ABS sensor but I'll put one on sometime in the future.
The Hyperpro 467 shock has a total extended length of 440mm and 86mm stroke. Not all of that stoke is used because of the bump rubber.

Thanks mate (I sound Australian).
I will do something about that bolt but not not certain at this stage if I will come up with my own solution or use one of those mentioned in the upper shock bolt thread (be nice to have a single page summary of that- I gave up trying to read it all). The Indi (?) idea looks good. In some ways the frame BMW built is a strange mix of good and bad design. It seems to be a fairly heavy structure with a crazy idea for the upper bolt mount. Also in another area there is a short tube on the LHS between a couple of engine mounts that appears to be largely cosmetic- the back of it is cut out.

This is just cool.

Looking forward to hearing more details and riding impressions.

[QUOTE="A";15250436]Thanks. I'm happy with the rear suspension. It worked well on my ride down the coast and handled whoops nicely with a controlled ride and getting a bit of air without bottoming. I havn't hammered it hard core yet but it certainly put a smile on my face. The front WP forks have been re-valved but need heavier springs so I'll do that before deciding if different offset triple clamps are neccessary. I reckon the 14mm you have is probably a good thing.
My bike has ABS hence the over the bars routing of the brake line. I was a bit worried a single 300mm disc would be inadequate but the Galfer Wave can certainly make those knobs squirm! I almost put on a 320mm disk but went for the smaller option first. Currently it doesn't have a disk fitted for the ABS sensor but I'll put one on sometime in the future.
The Hyperpro 467 shock has a total extended length of 440mm and 86mm stroke. Not all of that stoke is used because of the bump rubber.[/QUOTE]

Yeah, for mostly off roading the single 300mm disc should be fine - if not actually better than the dual discs. That's what the 950 SE runs as well, with the same 2 piston Brembo caliper.

Maybe between the two of us we can figure out us how to make the ABS work with the WPs. I can already tell you that the slotted sensor ring from the 990 Adventure will fit on any KTM front hub (all have the same bolt circle), and it has the same number of slots as the BMW. Whether that's a good thing in your case I am not sure, as your wheel speeds will be different with the 21" wheel vs. the original 19". F800 riders who have gone the other way are not reporting any problems however.

Then you would only need to fab a mount for the ABS sensor on the axle clamps, shouldn't be that difficult to bend something up from a sheet of aluminum. My forks actually have a ABS sensor mount, so I was considering splicing a KTM sensor into the BMW harness. Not electrical enough to know if the signal it gives will be compatible however - any idea?

Lukas

Thanks Lukas. That KTM 990 info is good. I'll use my BMW sensor and fabricate a mount for the 690 forks I'm using. I don't know if the KTM sensor is compatible with the BMW control unit. If the sinusiodal voltage is similar and the KTM ring has the same number of slots as you mentiond then I suppose it should work. I have no real experience in this field though.
When I rode my bike in the dirt with its original wheels I was surprised how soon the ABS cut in. I immediatly got the feeling that I would have been braking harder with the ABS switched off. It will be interesting to see how it performs with the ABS working in similar conditions when I get it set up with my new 18"/21" wheel combo.
I did some more sand and gravel surface riding this weekend. This bike is fun but reminds me that I must put some stiffer fork springs in as soon as possible.

[QUOTE="A";15348969]
When I rode my bike in the dirt with its original wheels I was surprised how soon the ABS cut in. I immediatly got the feeling that I would have been braking harder with the ABS switched off. It will be interesting to see how it performs with the ABS working in similar conditions when I get it set up with my new 18"/21" wheel combo.
[/QUOTE]

I have always felt the ABS engages too quickly, especially in nice soft terrain on steep descents. If it just waited a split-second longer, it would allow the weight transfer required to improve traction and thus braking force, but it's just not dialed in that well.

I need to get the top clamp I borrowed of my 650X back onto it so I made a new one.


Because this bike came with a lowered seat I carved out some foam to work out what may be a suitable shape for when the job gets done properly.



I have a list of lots more to do-
Heavier fork springs
Bodywork- make a new fake tank, no beak
Upper shock mount fix
Lower the gearing
Protection for lower part of rear shock
Renthal Fatbars or similar
Barkbusters
Mount front ABS disk
Re-upholster seat
Fit a more modern looking front fender
Lighter, narrower muffler
Make some soft pannier racks
Cut off the pillion pegs
Make a headlight protector
Fit a lighter battery

I wonder if all that will actually get done!

just wondering why you didnt just buy the F8GS? It seems it would have been a bit easier and accomplish the same thing with alot less mods? Is there something this custom will do better?

If you want a good offroad bike you would change most of the parts the F800 has different from the F650 anyway. Forks, shock, wheels, etc are all mediocre quality at best. So if you can get a good deal on a F650 you can end up with a bike that is better in most regards for less money. Now if somebody finally did the cam upgrade to get the same power...

I'm not sure that that would truely be an advantage for offroad then you'd have the snatchy throtle and i ride offroad more below 5,000 rpm than above so i don't see the advantage.