andus Posted June 15, 2009 Posted June 15, 2009 Hi, I have a DT125R 2002, which has been fine up until this summer, when it has started to overheat. Now, after about 5 mins riding (or 10 mins with the engine idleing) the temperature gaguge gets near the red mark. Things I have already checked/done: - Changed whole carb from another bike - Changed CDI from another bike - Checked water impeller - 2 stroke oil pump checked (and oil added to tank to double check) - Air filter checked. - Checked for leaks Still it is overheating. Does anyone have any suggestions of something I have missed, or perhaps something that is very likely, that I may need to check again. Thank you for your help, Andus
Moderator Airhead Posted June 15, 2009 Moderator Posted June 15, 2009 Hi Andus...Looks like you forgot to check the thermostat.. I dont know the bike but there will be a thermostat, this is closed when cold and opens up when hot to allow water flow to the radiator. The old way of ckecking them used to be to immerse them in a pan of water on the stove and witness them open up when the water gets hot. also they sometimes have the operating temperature stamped on them somewhere. so you can use a thermometer to check they work at this temperature. If its no good you may be able to run the bike without it until you get a new one. ...Paul
Timux Posted June 17, 2009 Posted June 17, 2009 Hi, i would of thought if the thermostat is faulty it would overheat all the time not just in summer,is the water actually being boiled out,if not it could be a faulty temp sender giving a false reading...
hippiebrian Posted June 17, 2009 Posted June 17, 2009 Hi, i would of thought if the thermostat is faulty it would overheat all the time not just in summer,is the water actually being boiled out,if not it could be a faulty temp sender giving a false reading... The timing could just be coincidence. I'd check the thermostat before anything else...
andus Posted June 17, 2009 Author Posted June 17, 2009 Hi Guys, Thanks for your replies. I forgot to mention on the first post that I've checked the thermostat - which seems to be fine. I've even run the bike without the thermosat fitted and still have the same problem. Also it seems to me that the bike is definately getting too hot (regardless of the thermometer reading), so I don't think that's the problem either. Thanks for the suggestions though. Any ideas what the next most likely culprit would be? Thanks Andus
Moderator Cynic Posted June 17, 2009 Moderator Posted June 17, 2009 Hi Guys, Thanks for your replies. I forgot to mention on the first post that I've checked the thermostat - which seems to be fine. I've even run the bike without the thermosat fitted and still have the same problem. Also it seems to me that the bike is definately getting too hot (regardless of the thermometer reading), so I don't think that's the problem either. Thanks for the suggestions though. Any ideas what the next most likely culprit would be? Thanks Andus Is the water actually moving round the motor? With the rad cap off (done cold) rev the motor and see if it affects the water. Over heating like you suggest is either water not moving or no water, how is the rad? full of cr@p? Is the cap OK. No leaks. Does the level drop quickly?
andus Posted June 18, 2009 Author Posted June 18, 2009 Hi Cynic, Thanks for the suggestion. I've checked the water system pretty thoroughly - The pump seems to be working fine, and the water is circulating. I've taken the rad off an cleaned/checked it - it was in v good condition. Do you guys think it could have anything to do with timing? I know overly advanced timing might cause overheating. As I mentioned I've tried a replacement CDI - so that's not the problem, but possibly some mechanical part of the timimg system? Thanks, Andus
Moderator Cynic Posted June 18, 2009 Moderator Posted June 18, 2009 Hi Cynic, Thanks for the suggestion. I've checked the water system pretty thoroughly - The pump seems to be working fine, and the water is circulating. I've taken the rad off an cleaned/checked it - it was in v good condition. Do you guys think it could have anything to do with timing? I know overly advanced timing might cause overheating. As I mentioned I've tried a replacement CDI - so that's not the problem, but possibly some mechanical part of the timimg system? Thanks, Andus I don't know where everybody's facination with timing comes from. I have NEVER heard of anybody having timing issues that they haven't caused themselves trying to fix something that isnt wrong. Aside from which you don't have any mechanical timing components. Right, its getting that hot in 10 mins. Is that actually an accurate statement or a guesstimate. TBH if you have a good rad/pump/and themostat and the water stays on the inside it can only be the gague, wiring or the temp sender. Check the gague by shorting the lead at the temp sender to ground , or check its resistances if you have the figures for set temperatures, . Run a jumper wire from the gague to the temp sender to prove the wiring. As for the gague its self unless you have the test figures for FSD (Full Scale Deflection)you will need a spare from somewhere to check it.
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