Scandal Posted February 5, 2011 Author Share Posted February 5, 2011 hi all got a new problem torqued the head and replaced the exhaust and bits , now the bloody thing has an engine oil leak could the oil seals have gone in the first place looseing compression and explain why it currently has not whats required compression wise , if so how big a job is it to replace the seals . Any help would be most grateful lol thanks in advance . Link to comment Share on other sites More sharing options...
Moderator Airhead Posted February 5, 2011 Moderator Share Posted February 5, 2011 Can you be more specific about the oil leak, I am thinking you mean crank seals but am I right? Link to comment Share on other sites More sharing options...
Moderator Cynic Posted February 5, 2011 Moderator Share Posted February 5, 2011 hi all got a new problem torqued the head and replaced the exhaust and bits , now the bloody thing has an engine oil leak could the oil seals have gone in the first place looseing compression and explain why it currently has not whats required compression wise , if so how big a job is it to replace the seals . Any help would be most grateful lol thanks in advance . DO YOU KNOW WHAT THE PREVIOUS OWNER DID DURING THE REBUILD? Very important question as a can of VHT, some SAE50 for the gearbox and a little bit of luck and a right boner of an engine can be made to look like a champion. More worryingly a rebuilt engine would have these seals done. It could be a genuine error. The Oring inside the primary gear is a popular forget, or the rebuild may have consisted of a rebore and a piston. Which can if they are already weak knock out crank seals due to all the new compression. The good news is a full bottom end re-build providing the crank its self is good and you know which end of a spanner is which, i'm not being sarcastic here either a competant DIY mechanic will find it perfectly doable. It can be done all in, with gen gaskets and seals/bearings for around 80quid. Cold comfort i know but you will be able to say you have eliminated all other problems then eh You say you have an engine oil leak? As in oil is leaking out, or its burning gearbox oil. If it is leaking out where from specifically. Did it run ok before it lost power. Link to comment Share on other sites More sharing options...
Scandal Posted February 5, 2011 Author Share Posted February 5, 2011 hi cynic the bike was running fine before it died the oil is leaking from the outlest under the carb from the oil tank and the oil overflow that area this is only a new prob in the last 24 hrs just assumeing its oil seals as still no real compression / could do with a bit more as far as i know only piston and rings replaced . the head is torqued the gasgets replaced and exhaust done and polished carb sorted fuel in cylinder and spark plug replaced the oil suggests to me oil seals . Dont want to take the bike in to a dealer as i dont want to waste money , would like to get it sorted soon other wise it will end up on ebay as a non runner lol. Getting to my wits end Link to comment Share on other sites More sharing options...
Moderator Cynic Posted February 5, 2011 Moderator Share Posted February 5, 2011 hi cynic the bike was running fine before it died the oil is leaking from the outlest under the carb from the oil tank and the oil overflow that area this is only a new prob in the last 24 hrs just assumeing its oil seals as still no real compression / could do with a bit more as far as i know only piston and rings replaced . the head is torqued the gasgets replaced and exhaust done and polished carb sorted fuel in cylinder and spark plug replaced the oil suggests to me oil seals . Dont want to take the bike in to a dealer as i dont want to waste money , would like to get it sorted soon other wise it will end up on ebay as a non runner lol. Getting to my wits end Not being funny but that discription sucks. So am i right in saying oil is coming from the gearbox vent under the carb? If so undoing the oil filler would result in oil coming out, at a bit of a lick too. Have you checked the oil level in the gearbox? and if its clean enough the colour of it compared to your 2 stroke oil? Link to comment Share on other sites More sharing options...
Scandal Posted February 6, 2011 Author Share Posted February 6, 2011 the oil that is comeing out is redish in colour and of a sweet smell its the same oil in my oil tank under the seat and its clean , it did look as though it had dropped a fraction level wise .?? Link to comment Share on other sites More sharing options...
Moderator Cynic Posted February 6, 2011 Moderator Share Posted February 6, 2011 the oil that is comeing out is redish in colour and of a sweet smell its the same oil in my oil tank under the seat and its clean , it did look as though it had dropped a fraction level wise .?? Got any pictures? did you take the barrel off or look up the exhaust port while the exhaust was off to check the piston condition. I say this because if its clean and sweet it hasn't mixed with the gearbox oil which is at least a dark brown due to clutch debris. Secondly i don't think there is physically enough oil in the 2 stroke tank to fill the box to the breather. Which brings me to the thought that the 2 stroke connections are wrong somehow hense oil starvation and possibly damaged rings(ie compression loss) the high temp from low oil may also cause the ally to expand causing the head to come loose. If you didn't ride it that far bar a set of rings all could be ok, my crank has taken spectacular abuse far worse than you have discribed and is still 'within tolerances ' Link to comment Share on other sites More sharing options...
Scandal Posted February 7, 2011 Author Share Posted February 7, 2011 hi cynic i will try to get some pics tomorrow as bike at my nans house im at a total loss as it it torqued and together properly still nothing my dad says he up for stripping engine but i think i might ebay it not sure what to do yet as all i wanted was a cheap run around not to spend money on !!! not sure weather stripping engine will do any good if we strip it i would replace the reeds head bolts and oil seals , i have a heynes manual so we could do it , i begrudge sending it to a dealer for such basic technology and have my arm ripped off.Is it possable an oil line has air in it and or blocked ? Link to comment Share on other sites More sharing options...
Moderator Cynic Posted February 7, 2011 Moderator Share Posted February 7, 2011 hi cynic i will try to get some pics tomorrow as bike at my nans house im at a total loss as it it torqued and together properly still nothing my dad says he up for stripping engine but i think i might ebay it not sure what to do yet as all i wanted was a cheap run around not to spend money on !!! not sure weather stripping engine will do any good if we strip it i would replace the reeds head bolts and oil seals , i have a heynes manual so we could do it , i begrudge sending it to a dealer for such basic technology and have my arm ripped off.Is it possable an oil line has air in it and or blocked ? You really don't need to get into that too much. To fix it so it works with gen bits would be 3-40 quid, to fully build it back up would be around 80, pluss a piston/bore if needed. My feeling is there is an oil issue coupled to mr rebuild man not being entireely honest about his skills and some buggerd rings. My engine before i rebuilt it had: Both crank seals worn, Both crank bearings worn, Output shaft bearing and seal worn Piston rings worn and passing gas Piston crown melted due to ignition/fuling error from some years ago Leaky head gasket Exhaust that was as much weld as metal and leaked spectacularily. With all that lot she still ran and would give around 45-50mph. Acceleration was hardly shocking and starting was an art but she ran, all it cost me was 90quid to replace all the seals/gaskets and bearings (with gen Yam stuff too)and drop on a good barrel and piston i had. Do it easily in a weekend if you set your stall out properly. The best bit, i now know when i'm going to work she will start. I can rely on it as i know its good. Ebay the bike as a non runner and you WILL lose more than it will cost you to fix, and may end up with another dud. You may even get away with just some rings, i think you would be mad not to at least investigate further. And as for basic technology, take away the electronics and there is nowt special about any engine. Just nuts and bolts. Link to comment Share on other sites More sharing options...
Scandal Posted February 7, 2011 Author Share Posted February 7, 2011 cynic you are right i think its oil its so frustrating ive come along way already , i will look at your list of things and see if i can replace the lot another few weeks off the road wont hurt, i was thinking of getting a dealer to look at it . I will shop around for parts my bike funny enough i was told to stick to 45 - 50 mph sounds familia hey lol .Keep the good advice comeing mate . Thanks in advance Link to comment Share on other sites More sharing options...
Moderator Cynic Posted February 7, 2011 Moderator Share Posted February 7, 2011 cynic you are right i think its oil its so frustrating ive come along way already , i will look at your list of things and see if i can replace the lot another few weeks off the road wont hurt, i was thinking of getting a dealer to look at it . I will shop around for parts my bike funny enough i was told to stick to 45 - 50 mph sounds familia hey lol .Keep the good advice comeing mate . Thanks in advance They won't know where to start. Oldschool mechanics would be able to do it in their sleep but the current generation of 'fitters' will have been trained to do just that. Fit parts. You would get a long list of could be's might be's and possibles that end up with the reccomendation that its all had it as they don't have the Yamaha manual to fix it. Very good place for engine/gearbox parts is TY trials, they actually specialise in TY bikes but the engines are VERY similar, 1 bearing and the gear change assy is all thats different i believe. Make sure your sitting down if you ask for the price for a gen piston though . Mitaka are fine and a quarter the price. Genuine bloke, will happily yap about their stuff if you are buying their bits for your bike. Good service too, they sent an incorect bearing to me and sent the replacement out as soon as i told them, no charge. With a "Send it back when you can" for the incorrect unit. Link to comment Share on other sites More sharing options...
Scandal Posted March 10, 2011 Author Share Posted March 10, 2011 HI all Just an update i have bought new top end gasket set , costic soda the exhaust blown the carb out some shit come out the jet , replaced one bolt that is loose on barrel purchased the origional dt washers and hexagon nuts , good news is it looks like the oil fuel mixture is now mixing in cylinder as before it was just fuel , i have set the spark plug gap correctly with gauges as the gap was too big ? another possable cause . Will put the bike together and see if it fires up , if not next is the piston rings then a strip down full bifta lol. cheers scandal Link to comment Share on other sites More sharing options...
Scandal Posted March 12, 2011 Author Share Posted March 12, 2011 hi all today i have found the problem it is a scored piston big big big time will post a pic as i cant believe it and a new barrel or rebore to 2mm i have aspare barrel will find out if it has been bored out , so far its new piston rings barrel and bareings . thanks in advance Link to comment Share on other sites More sharing options...
Moderator Cynic Posted March 12, 2011 Moderator Share Posted March 12, 2011 hi all today i have found the problem it is a scored piston big big big time will post a pic as i cant believe it and a new barrel or rebore to 2mm i have aspare barrel will find out if it has been bored out , so far its new piston rings barrel and bareings . thanks in advance I'd be wary of actually going to 2mm on the rebore as thats it, last one unless there is the same spectacular damage on the barrel? I'd sooner go with the spare that gives a bit of room as these barrels are getting v rare now. I have 2 and i'm not selling. Link to comment Share on other sites More sharing options...
Scandal Posted March 13, 2011 Author Share Posted March 13, 2011 hi cynic i have 2 now lol but was thinking of boreing out the old one to 2 mm then fit and sell bike and sell other barrel as i have now purchased an honda mxt 125 RHW 1990 model and am actually on the road with it !!! i would prefer the yamaha but dont have confidence in it any more ( more mentally ) i was thinking of purchaseing another dt 175 but a 2005 -2006 model import and have actually asked a dealer to source one . Would then get rid of both for it . As far as the old barrel goes i think its standard 66mm so should be ok , as far as barrels go wemco do brand new barrels on request for £112 i just want to get this bike ship shape and running to sell on ebay , keep the honda temp and get another yam 2 stroke 175 import or the DT200 not sure yet LONG LIVE YAMAHA Link to comment Share on other sites More sharing options...
Scandal Posted March 19, 2011 Author Share Posted March 19, 2011 Hi all Just an update ihave fitted the spare barrel and head new piston, rings ,bearing ,fitted the spark plug and nothing at first ,we then looked at the carb again and noticed the jet needle had the faintest of bends in it lucky i had a spare , fitted it and hey presto it kicked over but it was screaming its nuts off and wouldnt idle got it to 3-5 k then no idle so decided to go for a new / old carb from ebay lol . The other problem is the exhaust i fitted gasket and went to tightern the bolts the origional barrel has larger holes ??? does any one know what size they are as my DT 175 is a G ( 1980) model. dave Link to comment Share on other sites More sharing options...
Moderator Airhead Posted March 19, 2011 Moderator Share Posted March 19, 2011 Hi all Just an update ihave fitted the spare barrel and head new piston, rings ,bearing ,fitted the spark plug and nothing at first ,we then looked at the carb again and noticed the jet needle had the faintest of bends in it lucky i had a spare , fitted it and hey presto it kicked over but it was screaming its nuts off and wouldnt idle got it to 3-5 k then no idle so decided to go for a new / old carb from ebay lol . The other problem is the exhaust i fitted gasket and went to tightern the bolts the origional barrel has larger holes ??? does any one know what size they are as my DT 175 is a G ( 1980) model. dave A new carb may fix the problem or may not, sounds like a possible airleak, you should do the tests first with WD40 so as to not waste your money. If you do buy a new carb, make sure it is the right one for your bike...there were two versions. id's 2H500 for early bikes and 3U500 for later bikes. The original studs were 6mm. Many barrels have been drilled out to 8mm as the originals have snapped off or stripped. Link to comment Share on other sites More sharing options...
Scandal Posted March 26, 2011 Author Share Posted March 26, 2011 hi all i fixed the exhaust and put the bike back together it kicks over 2nd 3rd time goes on choke but as soon as i take choke off the bike wont idle , i didnt get the carb but foud the jet needle is 4j13 not 4j6 so have ordered a carb kit and will re do the lot sort the air screw and needle jet hopefully job done lol. Link to comment Share on other sites More sharing options...
Scandal Posted April 9, 2011 Author Share Posted April 9, 2011 Hi all I have referb my carb and bike is running / ideling about 1500 -2000 rpm , circumstances have played a major factor so now im forced to sell both my dt175 and honda mtx 125 my house needs work done to it . Great sound it makes i got to take it round the block is real sweet now only taken me 170 hrs and 150 quid all worth it thanks for all your help . Dave Link to comment Share on other sites More sharing options...
Cuda Posted April 11, 2011 Share Posted April 11, 2011 Hi all i purchased a dt175 last Saturday 3/4 of the way home it gradually died , i got it to my fathers house were we replaced the spark plug all fine with that , the next thing was the carb as the spark plug wasn't getting wet , so this weekend we stripped the carb which seemed clean we proceeded to put back the carb and try starting as normal , at which point we noticed once the carb was full it was constantly overflowing ( had done this before) but writed it self . This time we noticed the spark plug was get fuel as it was wet a good sign, the problem is the fuel overflowing . I shall point out the electrics tyres and everything else on the bike has been rebuilt the engine has a 1mm overbore and not fully run in yet. The floats were put in exactly how they were taken out just of note . We will take the carb off again and have another look not sure if we are on the right track , we tried bumping the bike and also noticed it wants to go and there is a puff of blue smoke out the back ??? along with backfiring . any help would be helpful thanks in advance Hi, be very careful you dont allow fuel from the overflowing carb to fill up your crank or you could end up with pre ignition and a bent con rod/knackered top end, the problem has to lie with your floats check they are set properly and this might sound daft but check you have not re fitted them upside down (ive seen this done before) a tell tale sign of the right way up is the little clean needle valve mark on the float tang,(also check the condition of the floats for any holes) while your carb is off again i would also suggest (just to be sure) another in depth check, take out all the jets including the idle jet that sits deep in the recess and clean them all out using a pin/needle the right size so as not to make the jet holes any larger then blow out the carb with an air line before re fitting everything and make sure you ha vent inadvertently turned up the tick over screw to much so it screams it nuts off when you start it Link to comment Share on other sites More sharing options...
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