BMW G650X Challenge Thread Index

Hello BMW XC riders!

I was wondering if one of you could measure the outer diameter of your fork tube under the lower triple?

I have been making some aux light brackets that clamp to the fork tubes and a few XC riders are asking me to build them for these bikes as well.

I don't know anyone near me with one I could measure so I'm hoping someone here can help.

I'm looking for an accurate measurement of the tube OD in the area under the lower fork clamp as well as a check for any taper. Prefer micrometers or decent quality calipers.

Can anyone here help out? I'd appreciate it!

Light mount thread if you want to see pics --> http://www.advrider.com/forums/showthread.php?t=942903

nothing happens, the clutch is fine, the engine rpm's stays the same, and literally takes a minute to speed up 1km an hour... when I back off the throttle to about half, the speed increases (very) slowly.

with the help of some local riders here, found a mechanic that has been able to start testing things.
compression is normal
the spark plugs had a nice red color, he said from poor quality of fuel,so changing the plugs
air filter looked ok, but I washed it anyway (same with pre filter)
1 exhaust valve was tighter then it should be, that's been adjusted

that's about it so far, Will check to see if there is a seal store here, that can supply the oil seal.

thank you very much for all your suggestions, really helps..

Are you still using the stock exhaust ? If so you might want to prod around in it with some stiff wire or something to check.
They are prone to falling apart internally and block most of the exhaust gasses.

Cheers, Ard

This isn't true though since mine did it on the F650 (EBC pades) and now on the G650x (Bendix pads). The back of the back is covered in copper grease. The brakes only squeal when applied gently. I can make them squeal when slowly pushing the bike (speeds far too low to cause chatter) if I apply a slight braking pressure.

I had a touratwat tank plumbed in by there recommended method. when I was crossing the amazon (north brazil) it was so hot my eyes felt like they were getting burnt out my skull but I never noticed a drop of fuel vaporizing.

I have a TT plumbed thru the main tank vent. I have never seen that kind of fuel loss. When it is warm and I park the bike vapor gurgles in to the TT tank, indicating that some vapor is generated in the main tank. I can hear that action. But it bubbles thru the fuel in the main tank, where it would get reabsorbed again. I do not get much vapor coming out of the TT vent. This vapor action actually helps getting the main fuel tank full, since as soon as it cools down liquid from the TT gets sucked back into the main fuel tank. I have seen this happen many times.

Regardless, the amount of fuel vapor that goes back to the main tank is not that much. The amount of vapor from 4L of fuel is huge. I have a hard time understanding how that could happen with my setup.

However, I understand your aux fuel is mounted almost directly against the engine. Maybe it is not ambient that evaps your fuel, it is engine heat. Do you have any kind of heat shield between the tank and the engine?

Is your fuel tank hooked up to the main tank vent? What is the height difference between the two tanks? How about a picture?

Just guessing (wildly), if your are indeed loosing 4L, could you be loosing liquid fuel thru your aux tank fill cap while you are riding?

I was thinking plugged exhaust, I had it happen on a car once. Not sure if the bike will run with muffler disconnected to test.

Wouldn't have the same pressure (and extra loud) but should start fine with just the header pipe attached. (Disclaimer, I am not saying you should do this just that if you did it should run). On that same note I would not hesitate to try it with the can off with a set of ear plugs... But I wouldn't say you should or shouldn't... Best of luck.

Earplugs are a must in that case. You'll be deaf otherwise. :eek1
Even on tickover is unbearable

I can confirm it runs without the can. last time I did this my neighbor came out to check on me. he thought something blew up.

good luck!

With the variable gas quality, is the injector plugged up? Maybe the throttle body butterfly is gummed up and can't open far enough?

seemed that (looking down on top of the motor) the right side exhaust valve was tight, needing adjustment, the other three were normal.
so we (well them) adjusted that, i cleaned the throttle body, it had had full movement, but did look like that there was much gum inside, cleaned the air filters, cleaned the little sensors on the throttle body. i asked about the injector, but they said that that wouldnt be a problem, maybe lost though translation... new spark plugs, and changed the oil.

took her for a drive.,..

idles very low, dies a few times, until warm, but still sounds like a low idle. slight tappet sound, but i guess that is the way its going to be...

was on the highway for a a terminal velocity test, slowly (emphasis on slowly) climbed from 100kmh to 119kmh, to where it stopped. i guess its better then before, throttle feels like there is something more then only half throttle. but as it sped up, still felt like there was some hesitation, rather then a nice steady increase in speed.
the clutch was (is) constant, no slippage.
leo vince exhaust, good solid putt putt blasts from the end cap, but the sound suggests that it is dying, has a bit of a "chirp" when giving throttle

i think for now, that this is as good as its going to get. in the morning, she starts up first button, dies as a result of low idle, but starts up again, without any hesitation, which is a plus

as always, i very much appreciate every ones help in suggesting ideas, when your out in the sticks, its great to have friends that are there giving ideas as to what to look for...

Is the oxygen sensor mucked up?

im just like you, i didnt believe it when a friend also said, that when you drive across kazakhstan (or other very hot places), you loose (at least) 100km from your main tank range, and did not heed his advice of carrying an extra 5liters in an old oil bottle, and when i ran out of fuel at 140km (from main tank) i felt like a silly twat..

as you can see, this is my set up, ali 10L jerry can, mounted to the side of Scheffelmeier skid plate, not directly to the engine.


side view

my extra tank is properly hooked up through the vent thing on top of the main tank, and a vent hose on the top of the extra tank.

when i say heat, im talking about extreme heat... my extra fuel cell does not leak, the bike gets so hot, that you can not touch (bare hand) the main fuel tank, can not touch the side panels, the heat from the radiator and the engine goes straight back and heats up the main tank, to the point of vaporizing the fuel. that when i did run out of fuel, i poured in the fuel from the extra tank, only to hear (and see) that the fuel was instantly vaporizing in the main tank, and blowing bubbles in the extra tank..

i know, it might be hard to understand, until you are there.
it happened to a friend, and like he said, it happened to me... im just wondering if anyone else has had similar experiences.

tomorrow, when i leave here and head towards mongolia, i have the vent on the main tank only venting, to see if i still run out at 150'ish km's, as a result of fuel vaporizing, to see if there is a difference

i did remove it yesterday, and (attempt to clean it), maybe that that wasnt a good thing to try and do? it looked red tinge in color

or better yet...

how does one clean it?

Sounds like it may have looked like your spark plugs, so it is still getting hot. If it was sooted up, then I think you'd have a too lean condition.

Now I'm just grasping at straws now, so I'd check the wiring for the TPS and fuel injector to see that the wires are intact. After that, I'd try to swap the ECU out.

i should say that i have no diagnostics skills, other then grasping at straws and hoping for the best...

but i feel that this is a fuel issue, as a result of my nasty introduction to kazakhstan, but im not pointing fingers at any one culprit..

valves are good, plugs are new, throttle body has been cleaned, filter has been washed and re-oiled, and it only becomes a problem after the bike is hot.... i think fuel pump. took a bit of convincing (pleading) for the mechanic to take a look. he hooked up a compression gauge to the fuel line coming from the top of the fuel tank to the injector. when the engine was cool, the pressure reading was 50psi, which he said was normal. fortunately on friday its was 40C, and took only a short drive for the bike to become very hot. with the gauge still hooked up while i was riding i could check the psi... and as the bike got hotter, the psi started to go down. at this point the fan was constantly on, too hot to touch the frame bare handed, and the pressure hovered around 30psi, when the bike stalled, while pushing the started button the pressure dropped to (around) 10psi, and the bike had a hard time starting...

auto shops are closed on the weekend here, so monday morning we are off to see if we can find a pump similar to mine that will fit.


the screen on the bottom of the pump looked to be clean, but the whole unit had a slight grey residue (powder like) on everything... the low fuel sensor looks to be fine, but as it is a sensor, they either seem to work or not, guess i will just have to keep an eye on the mileage...

I wonder if the fuel lines in or out of the pump are being affected by the heat? For instance - softening and expanding on the pressure side (like an aneurysm)?
Is there a input side hose and filter? maybe it is swelling, or crimping at a bend, starving the pump? The heat of the engine is most likely from the extremely lean running condition.

Has anyone tried to mount the F800 adventure, or 1200GS foot pegs with the removable rubber inserts on an Xchallenge. I thought that these might take some of the buzz out of the long highway sections, then when you hit the dirt you could just pop them off. I do not know if you can buy just the inserts, but if you can then maybe they could be ziptied on.