Archive of BMW Motorrad Club Cape (2006 - 2019)

headgasket?did they check for oil contamination?

Tubes inside radiator partly blocked?

Maybe deposits on inner surfaces of the tubes?

or corroded 

I'm going with the water-pump gears.  At slow speeds the water pump is obviously working better than at high speed.  You would expect the improved airflow at high speed to help with cooling, and the problem to manifest at slow speed when it is hot.  But it only occurs at high speed.

So I reckon that the teeth on the water pump gears are worn and end up slipping at high speed.  My guess.

Hi

Eerstens:  as die liggie aankom waai die waaier? Jy noem niks van dit nie.  As die waaier nie aangekom het nie is dit NIE 'n oorverhittings fout. 

Tweedens: wat is aan die fiets gedoen 'net voor die probleem begin het?

Derdens: As jy net die fiets start en laat loop (idle) moet die waaier eers na ongeveer 15minute aankom.

Charles, I don't think it is the gears.  If the gears 'jump' enough to reduce the rpm of the impellor to the point of such low coolant flow (at speed) it would be 'teethless' within a few kilometers.

I think?. As far as I know Andrew King is a qualified BMW meccie so dont think this could 'slip by' OIL LEVEL

The oil level on the 650 singles is a bit of a procedure to check.  Place bike on centerstand or prop it as upgight as possible wirh a brick under the sidestand.  WHEN COLD. Check the oil level on the dipstick IT MUST BE TOO LOW. now start the bike as is and let it idle UNTILL THE FAN CAME ON. This could take up to 15 minutes.  If the fan comes on earlier it could indicate 'low coolant flow' and point to the source of the problem.  When fan comes on switch the bike off and check the oil level.  If all OK it should have risen to the 'top lobe' of the dipstick.

If these procedure is not used the bike can be over filled and will have similar symptoms.  The 650 Rotax motor is a DRY SUMP motor and a lot of mechies over fill the oil if incorrect procedure is used. 

We rode over 400km gravel with an overfilled 650 with no problem.  It only cut out once we got on the freeway.  We siphoned more than 500ml of oil out and it was still a bit overfilled. The bike never gave any issues the rest of the trip.

Adie

Laat ons Stof maak

Did a trip earlier this year and my Mate's 650 Dakar developed similar problems. We stopped to refuel (smoke break), and the 650 refused to start. Prior to that stop the water light came on, and starting was more difficult than what it should have been. The guy who repaired the bike said it was a faulty water pump. The bike had also done about 30 000 km on ...

Hope it helps...

I'm with Charles on this one.  My Dakar has had about 4 water pumps ... it's a "feature" of the bike that they get "tired".  Sounds like the impeller is misbehaving at speed.

Adie gives great advice, and knows these bikes well, but I too think that water pump impeller needs to be thoroughly checked, to include or exclude it as part of the problem.

I know Andy Connell has a problem with Annie's 650 on a trip back from Namibia, and I know people discuss how these impellers need replacing at around 50-70,000km, and, just like the steering bearings, are one of 3 'common' faults on this otherwise trouble-free 650: side-stand switch + water pump + steering bearing.

See here, MAY help: http://www.bmwmotorcycleclubcape.co.za/f650gs-waterpump-strips-gears 

Does seem to be a 'wrong-way around' fault (!), seeing that some riders would have a problem at SLOW speeds, and no problems at faster speeds!

Good luck

Chris

Thanks for the feedback. I’ll pass it on. I’ll update when the problem is solved. It may take a while before I’m back on the bike again. I managed to break my wrist 2 days ago while mountain biking. Luck is not on my side this year. I go a lifetime with no broken bones, and then break my right foot and right hand within less than 6 months. Frustration just doesn’t describe it.

I’m not sure. I know they bled and replaced the coolant twice. Apparently signs of a shot head gasket is smoke (white or blue – depending on what fluid is mixing with what) when driving? My bike shows no signs of smoke. I’ll add head gasket to the check-list anyway.

The radiator was repaired 6 November this year by Radiator King. The invoice listed the following: clean & repair BMW motorbike radiator, remove bottom tank, clean out core, 30% blocked, test & spray. It made no difference to the bike’s symptoms. Either the radiator wasn’t the cause or it’s not what it once was. Your thoughts? How much will a radiator set you back?

Kingtek will have a good look next year, when there will be more time to take the bike apart. Hopefully it will end up being something this simple.

Ja. Kingtek het eers gedink dat daar dalk net fout is met die liggie self, maar dit lyk nie soos ‘n elektroniese problem nie.

Hy het al hierdie problem vandat ek hom gekry het. Die persoon wat die motorfiets aan my verkoop het, koop motorfietse, maak hulle reg en verkoop hulle as ‘n stokperdjie. Ongelukkig ry hy hulle nie (laai altyd op ‘n sleepwa) en het nie van die problem geweet nie. Die fiets was vir sy 30,000km service gevat na Shane by Yamaha voor ek hom gaan haal het. My kêrel sou die fiets vir my huis toe bestuur. Die oorverhitliggie het aangekom op die M3. Die ou wat die fiets aan my verkoop het, het die fiets teruggevat na Shane. Dit het gelyk of die problem opgelos was, maar ek dink al wat gebeur het was dat die spoed waar dit begin oorverhit net verhoog het. Omdat ek die fiets vir ‘n ruk gery het voordat ek dit vir die eerste keer op ‘n nasionale hoofweg geneem het, het die problem nie weer verskyn nie. Die M3 is nie lank genoeg om die probleem nou te wys nie. Dit vat nou omtrent 15-20 min van 120km/h ry voordat die liggie aankom.

Ek is gesê dat my waaiier nog goed/reg werk.

Ek wonder nogal of dit dalk die problem kan wees. Andrew het vir my gesê die ratte voel ok, maar hy moet nog goed na hulle kyk. Daar was nie kans om die motorfiets uitmekaar uit te haal voor die Kersfees vakansie nie.

Interessant. Ek sal hierdie inligting aanstuur.

From the general comments it seems that the focus should definitely be on the water pump gears and impeller. I found a bit of information stating that the impeller in the older model bikes (mine is 2001) is known to be brittle: http://faq.f650.com/FAQs/Water_Pump_Seal_Repair_FAQ.htm#Different Colour

If the bike is going to be standing for a while, I'd recommend you buy yourself an Optimate charger.  At least you'll have a battery that's in good condition when you want to start riding again. 

I think the battery should last. It's new (replaced May this year); one of the "second-hand bike niggles" I had to sort, along with front shock seals. When I busted my foot, the bike stood for 3 months. Started first time, no problems. I'll have someone drive it to Kingtek when they open on 5th Jan. I'm sure the bike will get some "exercise" there. I'm hoping that healing time for a wrist won't be as long as for a foot. It doesn't feel half as bad.

Just another thought came to the fore, Is the radiator fan turning in the correct direction? (I have experienced this on a new car some years ago.) I'm not sure that this can happen on today's form of transport. Some communication from others will be well received.

At low speed, even if the radiator fan is blowing the wrong way, there is not enough wind to counteract it, so it cools fine enough.  But once you have forward speed, the wind blowing through the radiator is strong enough to overcome the poor fan blowing the wrong way and you have overheating...

My wrist is finally healed and I took my bike in for a decent check-up yesterday (i.e. not seen to when there is spare time, but actually booked a day for it).

Long story short, the overheating light still comes on! The symptoms have changed somewhat though. In the past, the light would never come on at low speed, only at high speed (80km/h+) and only after a while. Then the intervals between light switch-on would get shorter, unless I decrease speed to below 80km/h. Now the light comes on at low speed in traffic as well. I always pull off the road, wait 2 min (3 min tops) and then head off again.

The bike has never actually boiled/ overheated and neither I nor the mechanic is in any mood to run the bike to see whether it does boil (obviously risk/ repercussions/ potential costs too high). I don’t want to risk engine damage.

In short, this is what has been done/ checked with my bike:

• Cooling system was pressure tested
• Radiator core serviced (was 30% blocked)
• Head gasket in good nick – no blue/white smoke, leaking fluids, etc
• Coolant bled/replaced 3 times (2 of them freebies at least)
• Oil was changed recently
• Yesterday’s service: water pump kit (gears, impeller, etc) replaced. All indications were that the previous kit was in good working order, but I though “F*** it. Replace, so that at least I can completely rule out that one. As an aside, I still have the old parts, so will sell them off at some point.
• Thermostat was swapped out with another bike’s working thermostat as a test – didn’t change anything
• Temp. switch works fine
• Fan works. Switches on at correct temp.
• Overheat light bulb replaced, along with other bulbs that weren’t working.

At this point, it seems as if every last damn mechanical issue has been checked and re-checked. The next step is to take it to someone who is a pro with motorbike electrics and see whether there’s something screwy going on there. Krog`s Motorcycle Service was recommended. I have also ordered a new radiator cap, as that may still be a culprit (the one that I have currently is non-standard).

FYI: It was generally very difficult for the mechanics to recreate the fault. The light wouldn’t always switch on when the bike is being run on the work-bench. I think it needed to run pretty hard and long before anything happened.

I am still commuting with my bike daily and experience no issues on my commute run: minimal traffic, 14km hop over Ou Kaapse Weg.

that is good news.  It means that eventually the fault will become permanent and easier to find.

The radiator cap is the glaring omission here.  Those caps have a pressure valve in them.  A non-standard valve may mean the pressure in the cooling system is not correct and you end up getting overheating.  (On the roof the enduro guys use the right caps to prevent overheating - and a faulty cap has put a number of people out of the race).

If the cap ever leaks or releases pressure it dumps the fluid into the reservoir so if the level there alternates or leaks it is normally a indication of a faulty cap.But still worth replacing as it is not that expensive.Though a genuine part probably would be.

I think a person shouldnt overlook the obvious tell-tale which would be that a air lock or bubble is present somewhere in the cooling system.A different appoach to bleeding should be taken.In other words a pressure bleed system maybe.

Just some thought.

Update: Strangely enough it seems as if my bike's problems has gotten much worse since replacing the water pump kit. I'm not sure if the timing is linked or whether the original cause is just getting worse.

The overheating light now comes on about 15-20 km into a ride, no matter if I keep my speed below 80 km/h. If I drive faster or more aggressively, it is sooner rather than later. I wait 3 min, head off, and can expect the light to come every 5-10 km thereafter, depending on what speed I drive, whether there is traffic and whether it's a hot day. Once it came on again after only 2 km, but that was because I was heading up a mountain pass and 3 min was obviously not enough to let it cool down thoroughly. This leads me to believe that it is not an electric problem, since the issue is temperature linked and not random. The overheating light does not come on during a longer drive (>30 km) when driving on cooler mornings.

The fan does work and is on when the overheating light is on. I am not willing to run the bike until it actually boils, as I do not want to damage the head gasket, etc. My bike still doesn't leak any fluids, has no problems starting and runs fine on short trips. I have been using it for my work commute almost every day this past month.

At the moment, for lack of a clear way forward, I am just replacing parts and seeing what happens. I have replaced the water pump kit and, very recently, the radiator cap. I will replace the thermostat on Monday. I am hoping this will solve the issue. A thermostat swap had been done with my bike back in the day to see whether this would solve the issue, but back then the problem had been intermittent and very difficult to trigger/recreate. It is getting worse, so I'm hoping the problem would be easier to spot/diagnose.

I am really hoping I do not need to replace the radiator. That will be pricey. The radiator has had a full service recently with a radiator specialist, so it should, in theory, not be the problem.

FYI: Two guys who have worked on this issue on my bike are now working with Donford Motorrad in Cape Town, so it's not as if there has been a lack of expertise.

My partner is telling me I should sell the bike, but I cannot sell it with a clear conscience. I do not want to load this issue onto someone else. I also love my bike! I want to get it fixed. If I do manage to get it sorted out, at east I will know that it is filled with a lot of new, shiny parts. I don't want to start all over again with another second-hand bike with its own set of unique second-hand issues.

You need to monitor the temperature of the top and bottom tanks of the radiator whilst the bike is running at normal operating temperature ( to make sure that the theromstat is open) and if checking whilst stationary, the cooling fan running.   I am open to correction here, but the thermostat should open somewhere in the region of 85 degrees C , so in theory this should be top tank temperature.    The bottom tank temperature should be around 10 degress C lower than the top tank.   Should the temp difference between the top and bottom tank be greater than the 10 dgrees C,  it indicates that the coolant is flowing too slowly through the radiator due to an internal blockage of the radiator, or a flow problem from  the engine (water pump,  internal blockage).   Should there be very little difference between the top and bottom tank temperatures it normally indicates an external blockage of the radiator i.e. insufficient airflow through the radiator core (you perhaps don't have an aftermarket radiator guard fitted?)   The hand is a very good temperature sensing device and if access to the top and bottom tanks is easy, and after assessing the risks, you decide to try this, you will feel the difference, or not, between the 2 tanks, but at the end of the day, the proper tools will be required to check the actual temperatures.   

Zanie,

I am sorry to say but there have been a lot of speculation w.r.t. the problem,

1. Gears. As I said in my reply to the gear comment. If the gear(s) are worn they WILL slip and slip IMMEDIATELY. And then they are GONE.  I just replaced Marinda's pump and gears after they stripped in robertson on our Gatsrivier trip.

2. Radiator cap. Be carefull, I can not remember but the 650 Rotax use a non standard pressure relief cap.

Ok, this time you mentioned that the fan DOES come on while to hot.  Maybe the waterpump was a bit of a money wast but at least now you ar set for another 20 000 km.

Did anyone do a FLOW test of the coolant?  It can be very easy to do albeit a bit messy if you want it to 'flush'

Run the motor from cold.  It should take a long time for the fan to come on. I cant remember but think it was 10 minutes??.  If it comes on quickly I will suspect flow.

Then, if you really want you can remove clamp on the INLET to the radiator (BOTTOM Left side of radiator.) Put the garden hose pipe on the radiator 'stub' where the hose was removed and open.  A CLOSED thermostat will 'direct' the water through the motor. Should freely gush out the hose.  If you removed the radiator cap there should be just a little flow visible from the thermostat bypass.  If water is freely flowing through the motor the thermostat/radiator is the only other culpret.  

Remember this motor use a TOTALLY different method to circulate water.  The thermostat is actually directing the water directly back to the motor (closed) OR through the radiator. (open)  the norm is the thermostat is a simple open/close valve.

NOTE: the radiator place can also do the flow test. They got (should have) a flow test system.

Interesting reading: http://www.bmwmotorcycleclubcape.co.za/f650gs-waterpump-strips-gears

Adie

Thanks for the update Zanie.

So glad you finally exorcised the gremlins and can ride with the assurance of no more overheating.

And now we can all defer to you for help on cooling systems as this has made you an expert in whatever may happen to a cooling system.

Viva!!

I have definitely learned more about a bike's innards than I expected to within such a short space of time!

Hi Zanie, so glad that your issues are sorted. Even though I don't have a 650 I followed this thread with interest.

Could you please tell us what the  dual temperature sensor does?

And a big thumbs up for Kingtek.

I went for my first breakfast ride with a large group of bikers today (the trip to The Goatshed). Despite being a newbie I ended up at the back by mistake, meaning I had to play catch-up as the group concertina'd. No biggie. Neels (I think?) kept an eye on me and made sure I wasn't left behind. I had a chance on the highway section to test out my bike at speeds ranging between 120-140 km/h. No overheating light.

I rode back on the highway after breakfast. By this time the temperature was nice and toasty. Still no overheating light. I have never, in the year-and-a-half that I've had this bike, been able to ride at normal highway speed for a length of time on a warm day. What an amazing feeling of freedom! The problem has truly been fixed.

Thanks for the info Zanie. I am afraid that it is all too technical for my ancient brain.