I'm a newbie here. New also to BMW Motorcycles. Not new to wrenching on bikes, having been the (sometimes) proud owner of Japanese, Italian, and British bikes for the past four decades.
My new to me R100GS has been acting up when well heated up. Idle RPM periodically goes off the deep end into the 3K range. Killing the ignition and immediately re-starting solves the problem every time. Research seems to indicate the automatic advance unit sticking a bit, so I took it apart. Note that I covered all the other bases before doing this - valve clearances, spark plugs, timing, carb idle setup - nothing solves this sometimes departure from normal idle.
The auto advance unit is in pieces and all cleaned up. My question is: what should I be using for lubricants in the re-assembly? There was lube on the shaft bearing washers (it's spread all over the inside of the canister now), or at least it was until I cleaned it up. There was another (clear-ish) lubricant on the advance weight plate. I'm inclined to use the minimum amount of lube in all of these locations and wonder if I should be looking at graphites or teflons or just plain dry under the weights. Some sort light oil should likely go into the fibre thrust washers.
Any suggestions? Preferably for products available in Canada as some that are mentioned on various websites are unobtanium.
Cheers,
March
Common sense isn't very common, any more.
Sad to say, Lubriplate Low-Temp is not available here in British Columbia (not completely true, I did find it in 5 gal pails). Many thanks to @8166 for the suggestion.
So I went ahead and tried to use the absolute minimum lubrication in and around the advance weights. I did lubricate the rotating parts, shafts, bearings and washers with TriFlow, again, very sparingly. This appeared to work fine as the over-revving problem went away. Unfortunately, it did not stay away. This afternoon, I went on a longish ride and got caught in afternoon traffic (yes, we do have traffic in Victoria). As the bike got heated up in the stop-and-go, the high rev problem came back. Not as bad as before - I was seeing 2000 rpm from time to time, easily controllable by bogging the engine before pulling in the clutch.
Now, I'm wondering if the problem can be blamed on weak springs in the advance unit canister.
Is there a Canadian or USA source for the two tiny bob-weight return springs?
I did find one in the UK, but I know better than to order from that source. Duties, taxes, brokerage, bull feathers, etc will drive the price of a couple of springs into the stratosphere. Usually a total waste of time, ordering from Jolly 'Ol England. I could be wrong, it's been a lot of years since the last attempt to get race parts for my Triumph T100.
I checked and the current price on the auto advance unit (BMW - 12111244088) is $641 CAD. YIKES!
Common sense isn't very common, any more.
@8166, Thanks for the advice.
I've given up on the stock bean can and ordered an Alpha unit, coil and plug wires from Rick at Motorrad Elektrik.
I did an extensive search for vacuum leaks, set the valve clearances, cleaned and re-balanced the carbs, checked cable clearances, and the Mayan Calendar. Still got the over-rev problem when hot. So, I'll just throw money at it and see if that helps. I'm also holding out hope that this will solve the rev-drop issue. As it stands, the engine does not like to drop down for shifting. It takes several seconds with the throttle rolled off for the revs to drop all the time. As the engine gets hotter, the revs don't drop at all unless I lug it down with the clutch.
Stay tuned - probably take a couple weeks for the parts to find their way up the coast to Kanukistan.
Common sense isn't very common, any more.
I am having the same problem with my 94 R100GS. Looking forward to your follow-up assessment.
@8166, As it stands, the engine does not like to drop down for shifting. It takes several seconds with the throttle rolled off for the revs to drop all the time. As the engine gets hotter, the revs don't drop at all unless I lug it down with the clutch.
Now to insult your intelligence, but did you lubricate all the throttle cables ? I like to use one of those aerosol can adapters that lets you inject oil down the full-length of the cable. On clutch and brake cables I use chain lube. On throttle cables I use RemOil which has PTFE.
See "Cable Luber"... http://www.amazon.com/Motion-Pro-08-0182-Cable-Luber/dp/B0012TYX9W
Hope this helps. 🙂
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Cable lube is something I (= royal "we") did religiously on our old Triumph, Norton, etc. bikes. The cable lube device you refer to is something I am very familiar with. In fact, there is one in my toolbox.
My understanding - and this may be flawed - is that modern, especially plastic lined, cables should never be lubed. That said, I have ordered new cables from BMW. Unfortunately, they have, thus far, delivered only one (32 73 1 454 584) of the two cables - still waiting for the other.
Common sense isn't very common, any more.
Received and installed the Alpha unit - good looking piece of kit. Simple install with the exception of trying to fit the (supplied) bracket for the electronics module. I took Rick's advice and binned the stock (grey) coil in favour of his unit. There's barely enough space for the two items and I did have to dremel-tool away a bit of the bottom of the heatsink to solve a minor interference problem. I elongated the mounting bracket holes in the vertical to get the bracket as high as possible, but still had to chew off a bit of aluminum.
It must have been an interesting challenge to design a bracket that covers as many models as this one does.
Problem solved! No more high idle when hot.
Common sense isn't very common, any more.
Advertisement
