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821 Monster 821 Overheat

Discussion in 'Monster' started by Jon Clarke, Dec 16, 2017.

  1. Hi Guys,

    Took the bike out today for a winter spin, the conditions just about being acceptable and, well, you know.

    Anyway went about 10miles on it, no troubles, if anything it was running a bit cold (50-60s), on the way back it seemed more nominal (in the 80’s - where it usually lives) but then hitting traffic back through town it was not a happy bunny. Every time stopped in traffic temperature would spike within about 20 seconds to around 105 at which point engine light would come on and the fans would kick in and just about stabilise it before moved again and presumably air cooling brought it back down to mid 90s, this repeated several times through lights.

    So I have two questions for yourselves...

    1. On this bike, from others experience what temprature do your fans kick in? 105 (when the engine light was on) seemed a bit late?

    2. Assuming it’s dropped it’s coolant somewhere, where/how would be the obvious place/way to check for a leak?

    Cheers!
    Jon
     
  2. I would assume that if the fans kicked in as they they should and "just about stabilise it" then it is working as designed. If any bike is stationary then it will get hotter and hotter till the fans kick in.
    Before bikes had temperature gauges and lights there was never any problem. Engines are more efficient when hot.
     
    • Agree Agree x 2
  3. Check engine coolant temperature in your manual, there was a post in UKMOC about this, 104 is about where the fans kick in when stationary. As to engine light not sure that should come on at the temp so maybe something more? I know mine came on when it was pretty hot and broiled my legs when it did.
     
  4. Here is my 1200R manual and I think that's about the same for the 821 too

    2017-12-16 15.45.23.jpg
     
  5. Thanks for all the thoughts chaps, really appreciate it - fully understand when it’s stood in traffic it’s going to get hot.

    Looking at it the coolant is dry, so I’m guessing it has a leak somewhere. Any ideas where might be a good place to start looking?
     
  6. If you had a leak then I would expect that you could smell the antifreeze as it evaporates.
     
  7. Fair enough, makes sense - any idea what other than a leak would result in the coolant running dry? Or is it just one of those things that needs refilling every now and then?

    Nb. If it sounds like I’m a bit of a noob it’s because I am, it’s the first bike for me and only had it a few months so just learning as I go - really appreciate the answers you guys have.
     
  8. Had the engine light come on a couple of times when in heavy traffic and really hot. Got home switched it off. Started fine the next day and no light on.
     
  9. The cooling system takes 2.5 litres of fluid so I doubt that it is dry. Are you checking coolant as per the manual, or just guessing where it should be in the overflow tank?
     
  10. So the manual for mine says to turn the steering to the left and check the level using the translucent window in the expansion tank. I was always taught to have the bike upright to do this check so I’ve done it both ways. I’ve done it hot and cold and in every way I can’t see any fluid in there, from what I can see it’s bone dry, but I’ll get the cap off today and double check - if there is no fluid in there then should I assume that points to a leak?
     
  11. There is only one person on this forum who can see or smell if you have a leak. Even if the little expansion tank appears empty, the engine will still be full of coolant as you cannot fit 2.5 litres into that expansion tank.
    I suggest that you visit your dealer and ask him if he can see a leak.
     
  12. Only ever had my bikes on minimum when cold as if filled to max mark it will poor out the overflow when warm.
     
    • Agree Agree x 1
  13. My inclination would be to top it up and then run it up to temperature and look for leaks. It would be fairly easy to see leaks, I'd expect. Would be worth checking all the hose clamps are tight.
     
    • Like Like x 1
  14. Hey guys,

    So had the caps off the rad and the expansion tank today - radiator full and expansion tank sitting pretty at the minimum. Great stuff, seems I was being paranoid. Sorry!

    It does still leave me a question though which is why does the engine warning light come on at the same time as the fans? Or to put it another way why do the fans wait until its so hot the engine considers it worth a warning light

    About 107degrees? Surely if the engine is getting hot enough it is throwing up a warning light then the fans should be cutting in sooner than that? As soon as the temperature drops back a couple of degrees then it flicks back off.

    Any thoughts on this?
    I wonder if they are meant to cut in sooner that that but are failing to do so through their normal sensor and are only cutting in as a response to the engine warning light itself.
     
  15. I seem to recall that the fans come on at 105 on my 1200. If I was getting an engine warning light I'd definitely be having my dealer check it out as a warranty issue.
     
  16. Also check the seals on your radiator cap. If the seals are worn the system wont pressurise fully and as water boils at a lower temp when not under pressure could cause you problems. There should be 2 valves on your rad cap. 1 to let water flow from expansion tank to radiator and one to flow from rad to expansion tank. Check both valves are working and free.
     
  17. So update on this, checked the fluids, all good, took the bike out again the other day and then parked it, allowed it to come up to high temperature and voila, the fans kicked in at 105c - no engine light, temp dropped back down, repeated a few times - all normal. Ran it in traffic (where had the problem before) and all good.

    It seems it was hopefully a transient problem and I've spent the rest of the afternoon giving her a nice sponge bath.... :)

    I'll ask the dealer to look into if theres anything noted for the engine light on the service in a couple of months.

    Thanks to the forum for all the help and suggestions!
     
  18. Maybe you had an airlock which has now cleared
     
  19. Hi guys,

    Gets weirder - okay so took it out again the other day and I've realised I only get the engine light coming on when the bike is in Urban mode..I'll ask Riders when I next visit what thats about but its very odd to me?

    In touring and sport mode then theres no bother at all, no light, fans on normal etc etc.

    How odd :thinkingface: If anyone else has seen this or knows why its happening please do let me know.
     
  20. My light came on in sport mode ? .
     
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