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Hi- new to this- may be going about it wrong but i am wondering if anyone knows how to adjust the lifters on a 1986 honda 250 4 stroke atv. we did it along time ago but i cant remember how i did it. getting old i guess. please help!
 

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If you want to check your valve adjustment do not do it after you have ran it. wait overnight until it's cold. Than remove all your front plastics, seat and fuel tank, remove the two valve covers.10mm bolts, remove the sight plug on the flywheel cover (left side sitting on bike about the size of a quarter and slotted.). It's the same one you looked through to find the "T" mark.remove the spark plug so you don't have any compression. slowly turn the engine over until you line up the "T" with the mark on the cover. check and see if your rocker arms are loose if they are tight rotate the engine one more revolution back to the "T" agian. now you are at TDC on the compression stroke. each rocker arm has a 10mm nut and a tiny square on top of the bolt, break the 10mm stop nut loose being carful not to turn the bolt. You want to see what the gap is before you start. and get out your feeler gauges and slide it between the valvespring and rocker check the clearance. I think you want somewhere around 8 thousands that's .008 you want them moveable but no slack if that makes sense you may go a bit lower 7 or 6 thousands. not real sure on a stock bike mine has a stage 1 cam so my tolerances are different.
Once you have completed the adjustment hold the little square and tighten the 10mm nut back up being careful to not move the bolt it will change your gap, the best thing to do is leave the feeler in place until you have tightened one rocker the do the same for the other 3. put it all back together start the bike up let it run for a min and ride it for about 10 min pretty hard not real hard but don't putz around. on your last run back to your work area open it up just before you stop shut it down don't pull in the clutch until it stops running. pull the plug check it and see if it's the right color, your looking for a medium beige like coffee with creamer. to light = to much air too dark= too much fuel.
Setting the pilotscrew on the carb is easy turn it all the way in until it just does seat then counting your turns rotate it out 2 1/2 turns that is the factory setting. Start the bike for 3000-8000 feet turn it back in 1/2 turn if your not above 3000 feet elevation your fine. the factory main jet is a 122 for below 5000 feet and a 118 for 3000 - 8000 feet above after you get which ever setting you need turn the idle down until it sounds like a nice low tone not just before cutting off though after that turn the pilot screw out 1/4 turn more and leave it alone. put in a new sparkplug and ride it agian for a bit pretty hard agian. shut it down the same way and check the plug.. I know this sounds like alot but it's all really simple. let me know what you come up with. than I will send you what i feel will help you out the best. Good Luck
 

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I've got the 86 250 blues too. but im in better shape thankfully. i just got this bike for cheap and it's smoking signifigantly from the breather tubes and such under the seat. im thinking the valves and provly just a top end rebuild. but besides that the idle fluctuates at idle. ive got cleaner and fresh gas in. it but don't want to do too mush until i can solve the smoking. any ideas besides the valves and a whole top end?
 

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More than likely you may have to rebuild the quad. but no worries it's pretty straight forward, just grab yourself a good service manual and you should be fine., I would definitely start with a compression test just to see where you stand.
 

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thanks got the chilton's in hand and a good machine shop @ hand. But ive got a good guy that'll do it for cheap.. I'll have to see what i think after compression and valves... Also what's your recomendation for the oil drain plug being stripped. When i took it out it wasn't leaking and now after going just past firnger tight it's done for.. is there a size to go to??
 

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It's a 12mm thread, mine stripped out so I took a 1/2 pipe tap and tapped it out and put in a pipe plug that was 4 months ago it works perfect no leaks, but you do need to do it with the bike sitting as it is crawl under it and tap it. then get yourself about 2 quarts of hyd oil and dump it through the oil fill leaving out the drain plug to wash out the crankcase. make sure you go really slow and use plenty of oil or lube on the tap take it out often and clean it too....good luck





thanks got the chilton's in hand and a good machine shop @ hand. But ive got a good guy that'll do it for cheap.. I'll have to see what i think after compression and valves... Also what's your recomendation for the oil drain plug being stripped. When i took it out it wasn't leaking and now after going just past firnger tight it's done for.. is there a size to go to??
 

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doin the tap tonight going with the Save a plug system which is gonna step up my drain plug too. i'll post results later maybe tommorow im suppossed to go out on it with some friends burn the carb out some and see how bad the oil burn is..
 

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Good luck!!!
doin the tap tonight going with the save a plug system which is gonna step up my drain plug too. I'll post results later maybe tommorow im suppossed to go out on it with some friends burn the carb out some and see how bad the oil burn is..
 

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doin the tap tonight going with the Save a plug system which is gonna step up my drain plug too. i'll post results later maybe tommorow im suppossed to go out on it with some friends burn the carb out some and see how bad the oil burn is..
Yeah hope all goes well>
 

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i have a 1991 honda trx250x and its has no spark from the plug or wire and i cant figure out why and i dodnt wont to spend a hole lot of money so please help out thank you
 

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i have a 1991 honda trx250x and its has no spark from the plug or wire and i cant figure out why and i dodnt wont to spend a hole lot of money so please help out thank you can you tell me some troulble shooting things i can do it would help
 

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pm me with your email I will send you the electrical test section of my manual.



i have a 1991 honda trx250x and its has no spark from the plug or wire and i cant figure out why and i dodnt wont to spend a hole lot of money so please help out thank you can you tell me some troulble shooting things i can do it would help
 

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ok did the tap worked great.. took out for a good ride and it blew oil everywhere.. can't find where it's coming from. I know it needs rings bc of cmpression. will that cause this amount of blow by. chiltons does not have the greatest troubleshooting section..
 

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Around what part of the motor was it coming from?
 

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X2 a little more info so we can put our brilliant brains to work for you. lol

Around what part of the motor was it coming from?
 

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back side im wondering if it has to do with the breather but im serious about the volume of oil. there are no obvious tell tale cracks in the blocks or oil coming from a seal. i am perplexed....a half a quart of oil in a half hour ride.?!
 

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I would say clean the case, fill it back up, fire it up and watch it. See if you can visually see it come out. Wear safety glasses.
 
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