St0fxxx Posted February 22, 2012 Share Posted February 22, 2012 hello peeps When I bought my 89 DT 125r the guy said that they guy before him had swapped the engine for a 2002 engine. Im looking to do the top end on it but obviously the piston sizes differ from the original 89 engine and the newer ones. Is there an easy way to see if the engine is different to the original (with taking the head off and measuring the piston). I use this bike everyday as it is my only mode of transport so i need to keep the downtime to a minimum to enable me to get work etc. I would like to be able to order all the parts and do it all at once. Could i take the head off measure the piston and then put it back on with the original gaskets or would they need to be replaced every time you take the head off? Cheers Link to comment Share on other sites More sharing options...
Moderator drewpy Posted February 22, 2012 Moderator Share Posted February 22, 2012 why not get the engine # off it and check that instead! Link to comment Share on other sites More sharing options...
St0fxxx Posted February 22, 2012 Author Share Posted February 22, 2012 That makes sense, do you know where the engine number is located? Also what do I check it against, will there be an engine number on my V5? Link to comment Share on other sites More sharing options...
Moderator drewpy Posted February 22, 2012 Moderator Share Posted February 22, 2012 usualy on the crankcase, its stamped on there, you may have to clean the engine first. if you google the first 3 numbers, if you do a search on here, there's been a few postings with codes to model/years Link to comment Share on other sites More sharing options...
St0fxxx Posted February 22, 2012 Author Share Posted February 22, 2012 Nice one drewpy. Thanks for you help mate... Link to comment Share on other sites More sharing options...
Moderator Cynic Posted February 22, 2012 Moderator Share Posted February 22, 2012 Look at the area above the crankcase filler... I'm pretty sure the pistons are the same size, just that at some point (not sure when) they changed from barrel induction to crank induction (so the piston doesent have windows). OG or whatever he is now will know for certain.. Link to comment Share on other sites More sharing options...
Moderator drewpy Posted February 22, 2012 Moderator Share Posted February 22, 2012 Look at the area above the crankcase filler... I'm pretty sure the pistons are the same size, just that at some point (not sure when) they changed from barrel induction to crank induction (so the piston doesent have windows). OG or whatever he is now will know for certain.. he's called dick head or something like that! Link to comment Share on other sites More sharing options...
Moderator Airhead Posted February 22, 2012 Moderator Share Posted February 22, 2012 he's called dick head or something like that! Cheers mate???? OG or whatever he is now will know for certain.. listen pongo or whoever you are it's 'Airhead' The engines from early/later bikes can easily be identified by their different oil pump covers. Engine# is stamped on the elevated part of the left rear section of the engine Link to comment Share on other sites More sharing options...
Moderator Cynic Posted February 22, 2012 Moderator Share Posted February 22, 2012 Cheers mate???? listen pongo or whoever you are it's 'Airhead' The engines from early/later bikes can easily be identified by their different oil pump covers Should be elephant with a memory like that.... Link to comment Share on other sites More sharing options...
Moderator Airhead Posted February 22, 2012 Moderator Share Posted February 22, 2012 hello peeps When I bought my 89 DT 125r the guy said that they guy before him had swapped the engine for a 2002 engine. Im looking to do the top end on it but obviously the piston sizes differ from the original 89 engine and the newer ones. Is there an easy way to see if the engine is different to the original (with taking the head off and measuring the piston). I use this bike everyday as it is my only mode of transport so i need to keep the downtime to a minimum to enable me to get work etc. I would like to be able to order all the parts and do it all at once. Could i take the head off measure the piston and then put it back on with the original gaskets or would they need to be replaced every time you take the head off? Cheers how is it obvious? you will have to take the head off to examine the piston crown to see if it's been rebored, scrape off the carbon and look for a stamped number, you would need to order piston and or rings at this same size assuming the bore isnt worn out. I have used quality head gaskets twice (the black ones) with a very fine bead of silicone manifold gasket just around the circumference of the bore on each side and had no issues, dont plaster it on all over and thick or you may find it difficult to remove the head next time. Oh and dont forget to drain the coolant first, yes i have heard of people filling their crankcase with the stuff!!! Link to comment Share on other sites More sharing options...
Moderator drewpy Posted February 23, 2012 Moderator Share Posted February 23, 2012 Cheers mate???? he he Link to comment Share on other sites More sharing options...
St0fxxx Posted February 23, 2012 Author Share Posted February 23, 2012 Thanks for the help guys. my engine number is IN23458 (I think, grabbed it before reading here and might have got the wrong one, it was behind the gear lever EDIT: its wrong ) Its obvious because when I have looked at purchasing one the 89 has 56mm and the later models have 56.6mm. How are the oil pump covers different? Link to comment Share on other sites More sharing options...
Screw Guernsey Posted February 23, 2012 Share Posted February 23, 2012 Thanks for the help guys. my engine number is IN23458 (I think, grabbed it before reading here and might have got the wrong one, it was behind the gear lever EDIT: its wrong ) I think you'll find that actually reads 1N23456, and indicates the gear selection order! (i.e. 1st, Neutral, 2nd 3rd etc). Link to comment Share on other sites More sharing options...
Moderator drewpy Posted February 23, 2012 Moderator Share Posted February 23, 2012 I think you'll find that actually reads 1N23456, and indicates the gear selection order! (i.e. 1st, Neutral, 2nd 3rd etc). never made that connection screw, nice one Link to comment Share on other sites More sharing options...
St0fxxx Posted February 23, 2012 Author Share Posted February 23, 2012 I think you'll find that actually reads 1N23456, and indicates the gear selection order! (i.e. 1st, Neutral, 2nd 3rd etc). HAHA! ...what a plank i am Link to comment Share on other sites More sharing options...
Moderator drewpy Posted February 23, 2012 Moderator Share Posted February 23, 2012 gave us all a laugh anyway! Link to comment Share on other sites More sharing options...
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