RichtheMac Posted May 17, 2011 Share Posted May 17, 2011 Does anyone have any advice when changing the head gasket on my DTR 125? I have performed this operation twice now and ,surprise surprise, it has gone again and is blowing water (shud be coolant-I know..!) back down the barrel and out the exhaust. I have used gasket sealant on both occasions. Should I get the head skimmed (the barrel has been rebored and new piston fitted) or am I doing something wrong when I am refitting the head. The gasket has been fitted the right way up and at first the radiator was not losing any water..Also -can I skim the heead and top of the barrel with a bit ov wet and dry?? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 17, 2011 Moderator Share Posted May 17, 2011 are you using a cheap after market all metal gasket or a pukka yamaha rubber coated one? Link to comment Share on other sites More sharing options...
RichtheMac Posted May 17, 2011 Author Share Posted May 17, 2011 Now then fella. Hope u r ok. I used a top end gasket set that cost about 15 quid mate.. Yes I think it was an aftermarket one.. Link to comment Share on other sites More sharing options...
RichtheMac Posted May 17, 2011 Author Share Posted May 17, 2011 I ll try and get a rubber one lol. It was a metal one Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 17, 2011 Moderator Share Posted May 17, 2011 I have used a cheap one once and sure enough it failed. I use proper ones now and run a thin film of silicone manifold sealant around where the bore is only about 7mm wide not the whole gasket (you have to get it off again sometime) do this both top and bottom. Your head may be warped though I cant comment on that but skimming should be done proffessionally in my opinion. At a guess place the head on a piece of glass and ensure it doesn't rock in any way. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 17, 2011 Moderator Share Posted May 17, 2011 Even a cheap one may work with the film of silicone as I said...I fitted it dry Link to comment Share on other sites More sharing options...
RichtheMac Posted May 17, 2011 Author Share Posted May 17, 2011 Much appreciated. I'll 'invest' in a yammy one and get the head re-skimmed If it need it. Thanks. Link to comment Share on other sites More sharing options...
YPVS TONE Posted May 18, 2011 Share Posted May 18, 2011 Are you using a torque wrench to tighten the nuts in a criss cross pattern and to the proper torque which should be 22nm or 16lb ft.I usually start of tightening to a lower setting in a criss cross pattern i.e 10nm or 7 lb ft before tightening to the final figure and checking again after the engine has got up to temperature and cooled down. As mentioned get the head checked to make sure it isn't warped and make sure the faces haven't got any old gasket left on them before putiing on the new gasket. You shouldn't need any sealant on the gasket providing the head isn't warped. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 18, 2011 Moderator Share Posted May 18, 2011 Are you using a torque wrench to tighten the nuts in a criss cross pattern and to the proper torque which should be 22nm or 16lb ft.I usually start of tightening to a lower setting in a criss cross pattern i.e 10nm or 7 lb ft before tightening to the final figure and checking again after the engine has got up to temperature and cooled down. As mentioned get the head checked to make sure it isn't warped and make sure the faces haven't got any old gasket left on them before putiing on the new gasket. You shouldn't need any sealant on the gasket providing the head isn't warped. Good advice Tony, some nuts can be torqued but the DTR gives too little clearance for sockets on some cyl head nuts, so a little guesswork with a ring spanner has to be applied. DTRs are renowned for blowing gaskets and so I will say again a thin line of silicone around the bore circumference (just 7mm wide) is of benefit and it cleans off quite easily, Link to comment Share on other sites More sharing options...
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