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| 1975 MX 250 http://vintagedirtbikeforums.alp-sys.com/viewtopic.php?f=28&t=2186 |
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| Author: | giggyhurdle [ Tue Mar 03, 2009 8:32 am ] |
| Post subject: | 1975 MX 250 |
Hello. I purchased a 1975 MX 250 dirtbike, and the clutch doesn't engage (or disengage). I understand this won't be an easy fix, do you think a machanic would do this? And what do you imagine the cost being? Oh, and the bike also doesn't run. I think it needs the carbs cleaned, as I don't believe the bike has been ridden in 4 -8 years.. (last tabbed in 96) here are some pictures..  
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| Author: | giggyhurdle [ Fri Mar 13, 2009 11:54 am ] |
| Post subject: | Re: 1975 MX 250 |
Good news.. Bike runs good. I learned that all I needed to do was push start it to get the clutch free. Still doesn't idle, but it's missing the throttle screw set. |
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| Author: | Mikeee P [ Wed Sep 02, 2009 1:58 am ] |
| Post subject: | Re: 1975 MX 250 |
Do you know how to clean the carb? If not I can coach you through it and primarily the pilot jet which is probably causing you the problem. What do you mean by the "throttle screw set" do you mean the idle screw on the carb or ??? On your carb, just remove it from the bike - get legitimate "carb cleaner" not brake cleaner. Carb cleaner is much more caustic and will help to get crud out of the carb... Take out the mainjet, which should be right in the middle and the larger around of the jets. Make sure you can see through it, if not, you can spray it out with carb cleaner and/or get some fine needles and gently poke/scrape the main out - you don't want to harm any brass, just get out anything that is plugging it. On the pilot jet - it should be to the side of the mainjet - it's hole is much-much smaller. See if you can see through it, if not try spraying it out but realize that whatever is in there will cause the carb cleaner to "spray back" so be careful because if you get it on your paint, anything plastic etc... carb cleaner can eat it up. So be careful and see if you can spray out the pilot. It not, another trick is to soak it in a bit of gasoline so that the oils can all soften up whatever is plugging the carb which is prob varnish from old dried up fuel... you can try a very-very fine needle, but it might not be worth it because the pilot hole is tiny... try blowing it out again after soaking it - did it come clean? If not, spray it off and let the carb cleaner evaporate and prepare to tick your wife off - last step is to put it in boiling water in a pot and boil the living heck out of it. You can even put a lid on it so it gets hotter... the idea is to boil out whatever is in there. Have good reading glasses? You can also take the number and brand of carb - and go get another pilot jet at the motorcycle shop for under $10 in most cases... On the back of the carb are prob some small inlet holes - use the carb cleaner to spray into those and make sure there is no obstructions... you can do the same with any other openings on this 2 stroke carb... I know this isn't super direct info as I'm not 100% sure of the carb you have on there. Make sure the slide moves freely up and down - if not pull it out and clean anything on the inside body of the carb, and anything that might be on the slide. ........................ Do something about that airbox quickly - riding with it open can cause the bike to run erratically and if you suck sand, you'll tear up the engine. So get some type of filter in there somehow... Good luck and if you have questions just ask. Mike |
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