OzVMX Forum
Clubroom => Bike Talk => Topic started by: Tom on January 07, 2009, 09:50:58 pm
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G'day all i picked up a 1984 xr250 the other week and we got it home we checked out the top end by having a little look see through the valve covers and it was dry as a bone it already had a full bottom end worth of oil so we added a little oil through each vale cover then we checked out the oil filter which had been put in the wrong way round so we fixed that up and gave it a kick plenty of compression started 3rd or 4th kick idles but blows a heck of alot of white smoke whats going on man? this is my first four stroke and its got me a bit puzzled maybe 2 strokes are easier :D
any help much appreciated thanks Tom
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i would of stayed well away from that model. they are one of the very few bikes i would not buy or own even if i was given one. 84/85 250 XL/XR and XLX hondas are notorious for the heads cracking. seen it several times and heard of it happening to many others. its a very common problem. They overheat badly and have a some design faults in the head design and they crack around the plug hole. re-designing fixed this in about 86/87 i think.
be very careful removing the spark plug. you may find that when removing the plug it strips the plug threads. this is because when the heads crack along the plug hole carbon gets in there. this builds up over time and gets into the plug threads. if the bike has been neglected and not serviced regularly ( not had the plug out for ages) this clogs up the threads and can strip the plug threads when taking out plug which will mean the head has to come off, but if its cracked it will have to come off anyway. Ballards used to repair/improve these cracked heads, not sure how successfull it is long term.
a quick cheap/bandaid fix that i did for someone who couldnt afford a proper repair is to fit a helicoil and loctite it in. it will sort of stitch the crack together. bike ran ok but still always seemed to overheat, and was gutless as hell. I dont really recommend doing this though. better to pay to get it fixed properly or get another bike. you will stuggle to find a second hand head for one of these if needed.
ive come into contact with at least 3 of these 250 Hondas and all 3 had cracked heads.
that older XL250 S you got would be a lot better bike engine wise.
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yeah when i first seen the bike all that popped to mind was every 1 saying how bullet proof they were and i thought u ripper and now i've done the deed im guna have to deal with it.The last person that owned it has replaced everything in the top ends besides a piston kit with brand new gear which made me wonder maybe the oil ring is no good and its letting oil go were its not spose to maybe like i said its my first four stroke an im really confused thanks for the advice Tom
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Yeah, the 84/85 weren't a bad bike, but good luck trying to start it after its been upside down on a hill....
The main reliability drama is over heating them, and having everything turn to pooh - cracked heads, sacked out valve springs, etc.
The 86+ bike is a heap better.
White smoke or blue? Smell like burned oil?
Easiest solution is to take it to the tip and get a 2-stroke! ;D
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its blowing a F@#$k load of white smoke nathan and yeah ur idea aint soundin to bad i've been told look after them new oil every month and they last forever but i spose it has to work properly to start of with :-[
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broken rings? valve seals shot? i havent looked into one of these for a while but is there any oil passages up the inside of the barrel? perhaps headgasket is leaking and oil from one of the oil galleries is leaking directly into cylinder?
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we havent taken a deep look inside yet to worried of what were guna find the bike has really good compression if its something to do with it being to much oil shouldnt it be blowing darker colour smoke this smoke is really white dad seems to think that buy putting the extra oil in the head we might have put 2 much in cause it was already full in the sump
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If it is smoking under power it tends to be rings/ piston area. If it is on start up it is more likely to be in the valve/ stems /seal area.
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ok so if it blows a little smoke when its idling and alot when its under power its guna need a new pistion and ring set so is it worth spending the cash on this bike knowing of there history with the bad head reputation? or best to sell it and cut my losses?
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Thats your call Tom. Can of worms comes to mind for me.
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I like most Hondas Tom, but take your last option young friend. Not a model that will be good to you. Cheers and if you can gives us info on any replacement machine you turn up, Lots of knowledge here and lots of people willing to help . good luck Tim754
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took the bike out for a buzz today and got it through all the gears winding out and by the end of it was blowing bearly any smoke but.......... im still gunna take your advice and move it on thanks for the help guys i'd say use have saved me alot of cash that i havent even worked for yet ;D Thanks again Tom
p.s has any got a nice roadtrail bike they would consider selling for a resonable price? dosent have to be modern just working :D