Cooling issue
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Good morning went off road first time ever and my engine gets to hot when not going over 25mph the water pipe that goes to the radiator from the engine feels warm but the radiator it's self could be cold currently working today but got 3 days off just wondering what people could suggest to check could it just be trapped air? Is the water pump just under the 2 stroke injector are they easy to replace as I have 3 spare engines so should be able to just take from there thanks guys.
Kieran.
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Hi Kieran,
Yes the waterpump is beneath the oil pump.
It is driven by nylon gears from the crankshaft so you'll need to remove the clutch cover to get access to it in its entirety.
Naturally I would inspect the simple things first but I suppose it could be that the gear is broken. I have not heard of this being a problem in all my years, but they are nylon so it's possible.
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Thanks you for a reply so early pal I'm hoping maybe it could be a pressure problem if that could even be the case? I've never had a issue with the engine getting to hot as always going over 25mph I'll pop the top of radiator off and see where it goes from there would I notice any pressure when I take it off my self like would I hear anything?
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Thanks you for a reply so early pal I'm hoping maybe it could be a pressure problem if that could even be the case? I've never had a issue with the engine getting to hot as always going over 25mph I'll pop the top of radiator off and see where it goes from there would I notice any pressure when I take it off my self like would I hear anything?
@kieran-hutchison The waterpump drive gear could be broken as @Calum said, it's worth checking this.
The DT125R is a little prone to getting hot during serious off-roading. Compared to the twin radiator setup on the DT200R, the single rad with 2T oil tank opposite design is aimed more at youths messing about around town with perhaps a little bit of dirt riding occasionally. Near where I live there's a green lane which runs along a high ridgeline; to get onto it you have to go up a long steep unsurfaced hill where the farmer has added a lot of concrete speed humps to slow 4x4s down (which appears to have the opposite effect on dirt bikes). On three different DTRs I could literally watch my temp gauge go from 1/3 to 2/3 when enjoying myself up here, then when I reached the top where it was flat I'd go along in a high gear at low revs for a bit and it would quickly come back down.
If you're getting serious off-road it's worth looking at one of those Chinese pattern radiators which are about twice the thickness of the stock rad and look to bolt straight on. Also make sure your thermostat is working well (Haynes tell you how to test this) as one of it's functions along with the waterpump is to keep the water jacket around the cylinder pressurised which increases the coolant's boiling point (some competition bikes have restrictor plates in the cooling system to do this).
In the 1st instance I'd have a good visual inspection of your stock rad as the DTR is a bit prone to clumsy people bending the fins over when doing plug changes etc. which can reduce airflow by a fair bit. You can carefully use a thin screwdriver to straighten these and in extreme cases it can make the bike run cooler.
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Thanks bud will have a look later yeah I went out for my first time last night but was small trail where you couldn't go fast at as a couple technical bits probably was not the best place to start for my first time my mate breezed around it on his trials bike lol cheers lads for the info I'll let you know how I get on
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Morning guys I just popped of rad cap went for a ride and she's now staying cool cheers guys
