Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 So that set up would give me more fuel and less airflow ??? In your opinion should I fit the 160 jet and look at getting an oiled filter, (any suggestions where from would be greatly appreciated) Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 31, 2012 Moderator Share Posted July 31, 2012 just oil your filter yourself, get a paintbrush and spread some engine oil all over it, knead it in then let it stand a while, then squeeze out any excess and fit (do not wring it, it may tear if you do), I am a bit unsure about your airbox picture I can see a square swing arm (mk2)yet the airbox looks like a mk1, somehow the back of the airbox (left of the picture) looks a little unclear? I will have to guess that the original 160 jet was correct, I would re-fit that one for now, what jet size is in now...did you say...did i miss that? anywaywere getting sidetracked here talking about main jet sizes, main jet size isnt causing your issue with engine racing and dying with the choke off do the oiling and exhaust gasket and air leak checks for now Sam Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 After buying it and putting an mot on it I have only done 11 miles before it blew a hole in the top of piston. Think its had a hard life. Its a 1979 frame but with a later square section swing arm fitted the bottom of the engine is 1 1981 DT 125 with the 175 head fitted, im afraid its just one of those bikes, poor thing. In my hands it will never be the smartest but I will use it as it was intended, I assume the plastic fitting between the airbox and inlet rubber is not standard because it is attached with silicone and self tappers Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 31, 2012 Moderator Share Posted July 31, 2012 it burned a hole in the piston because it was seriously lean...either from a bad air leak (unlikely because you would have noticed the engine racing)...or the jetting was lean, yeah I would say around 150 / 155 /160 with the Gianelli because mine runs ok with a 150, so can you post a pic of the airbox butchery? Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 these are the pictures I have of the airbox and carb inlet I have since re sealed the silicone around the join I have no idea what model/year these are Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 These are pictures I took in April straight after I pulled it out my shed, it had been sitting there for 2 years, I can take some more tomorrow if it helps Link to comment Share on other sites More sharing options...
Moderator Airhead Posted July 31, 2012 Moderator Share Posted July 31, 2012 you need a new (used airbox) that one is completely untrustworthy in my opinion, no wonder you holed a piston, am I right in thinking thats a big hole near the rear stop switch? and you downsized the main jet with this airbox? Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 yeah it is a little bit of a concern, guess I need a 175 airbox, I assumed this was a 125 box with the 175 outlet stuck on, if i plastic welded the outlet on and made sure there were no leaks do you think it would do for now Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 you need a new (used airbox) that one is completely untrustworthy in my opinion, no wonder you holed a piston, am I right in thinking thats a big hole near the rear stop switch? and you downsized the main jet with this airbox? I have scince stripped off the silicone and re sealed the air box with some instant gasket and put new fixings in. the hole shown appeared with a little pressure on the outlet, I may have opened it by removing the carb but im not convinced the seal was good before this action but with the pressure released there were no obvious holes Link to comment Share on other sites More sharing options...
Migthy Mule Posted July 31, 2012 Author Share Posted July 31, 2012 cant find any dt 175 airbox listed on ebay in the uk, International ones seem like a lot of money and lots seem as bad as mine (Nearly) could try my local breaker but parts like this seem hard to come by. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted August 1, 2012 Moderator Share Posted August 1, 2012 i didnt realise there wrere differences between the 125 and 175 airboxes, I must say that your picture did look a little unfafiliar at the left hand side (air intake)? but the picture wasnt clear enough to see properly I'm away on holiday at the moment this week and next but I think I have a spare airbox at work Link to comment Share on other sites More sharing options...
Migthy Mule Posted August 1, 2012 Author Share Posted August 1, 2012 I have (not very tidily) sealed the airbox with a souldering iron and a couple of melted zip ties and tested it by filling it with water, its not pretty but seems to have done the job, not sure if there are differences between the 125 and 175 airboxes but this is what mine looks like Thanks again Im working away next week for about 2 weeks though back at wkend, was hoping to get the bike up and running before I go so I think this will surfice, gasket should arrive tomorrow Link to comment Share on other sites More sharing options...
Moderator Airhead Posted August 1, 2012 Moderator Share Posted August 1, 2012 yes thats a standard mk1 airbox and looks the same as a 175's, If its holding water it looks like you have it sealed up ok Link to comment Share on other sites More sharing options...
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