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1987 trx 250x issues

10K views 21 replies 7 participants last post by  hopedpocketts 
#1 ·
Hi
I am new to this forum, but not to quads. I have several others, but just picked up my first Honda last week. It is a 1987 trx 250x. It came with new tires, good plastics, g-force axle and DG exhaust (stupid loud) for $300. The former owner could not get it to run. I bought it, brought it home and with a little tinkering (adjusting the valves to spec)and cleaning, I got it to start (rough at first) and then was able to ride it. My problem now is that it won't stay running. It has great spark, new gas, I have totally cleaned the carb twice, new jets upped the main to a 130 and the pilot to 40. It is total bear to kick over. I see that the decompressor cable is attached to the head, but the bracket in front of the cam follower shaft is missing so I can't adjust the decompressor. It appears the motor may have been rebuilt not too long ago, or at least taken apart, because there are new gaskets throughout.
Now when I try to start it, it will fire briefly on the third or fourth kick, then die. There is fuel in the bowl, but when I pull the plug it appears dry. I have used two cans of carb cleaner to clean out all of the ports and crevices of the carb body. I adjusted the air/fuel mixture screw out to 2 1/2 turns to start. I can't figure out what else it could be. Could it be out of time? The T mark did not line up to the timing mark when I went to adjust the valves again. I am at a loss. Would not having the baffle on the main jet cause issues like this. When I pulled the carb apart I saw that mine was missing. Thank you in advance for any guidance you can give. I have been researching the forums to find the answers myself but am coming up without any fresh ideas. Thanks
 
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#3 ·
welcome to the forums. no way to adjust the float. if you take a pull bar and a 17mm you can hold the flywheel on the "T" make sure you are adjusting on the compression stroke too. try that and get back to us
 
#5 ·
The decompression needs the.bracket to be properly adjusted but that shouldn't affect it running? I've heard if it being deleted. I think your issue is in the idle circuit if you didn't remove the fuel screw and clean the orfices related to that area then you are shooting yourself in the foot. You need to remove the carb and dissemble it completely removing all the o-rings spray it out really good and blue out out with compressed air.
 
#8 ·
I did just that. I boiled it for about three hours, lots of crap floating in the water after. I was amazed especially because I had used two cans of carb cleaner before. After boiling it I blew it out with the air compressor. Hopefully this will do the trick. I am hunting tomorrow, so hopefully Monday I can get it put back together and see if I got it clean. I really am looking forward to riding it. Kickstarting sucks though, I have been spoiled with mt kfx400!
 
#10 ·
The acid in the lemon juice breaks down the contaminates. Personally I use a small HVLP gun filled with Laquer Thinner turn the spray pattern to a point and let her rip plus makes the carb look newer. lol
 
#9 ·
dd you do a compression test?
 
#11 ·
Okay, so igot it put back together......it still has the same issue. I pulled the plug after numerous kicks and it was barely damp. It wants to fire every three or four cycles, but nothing continuous. I kicked it over with the plug pulled and it has great spark. A little poof of fuel mist comes out of the spark plug opening. I then sprayed a little starting fluid Ito the plug hole, tightened the plug back up and fired up. Ran like garbage for about 15 seconds then shut down. The kickback from the kick start is ridiculous now. I still have the decompressor disconnected because I am missing the back bracket. I am going to have to try and make something that will work this weekend so i can hook it up and rule it out as a possibility. I am at a loss. The carb was very clean, I cleaned every nook, cranny, port, inlet,..... Boiled it for several hours, blew it out with compressed air. Could it be fuel pump not pumping enough fuel? The diaphragm looked good and appears to seal well. It looks like there is minimal strike on it. Is there a way to adjust it? Could it be a timing issue? Sorry for the dissertation, just frustrated with this darn bike! Thanks for any advice.
 
#14 · (Edited)
Check for good fuel flow, remover the drain nut in the bottom of the petcock and clean it I would break out the trusty multi meter and test all the electrical components just to be sure every thing is within spec. If so check the timing and compression.and try to get that decompression cable bracket
 
#19 · (Edited)
Thanks everyone, I got it to run yesterday. Picked up a known working carb, installed it, pulled pet cock made sure it was clean. The carb was off a 300ex. After a few kicks ( quite a few) it finally sputtered. Got it to run and idle. Idles smooth for about 30 to 40 seconds then dies. Kick it and it starts right up idles then dies. I bumped throttle and it dies and backfires out carb. I was able to feather the throttle and try to get her to roll it worked slightly but then stalled. I have pulled the valve cover and it appears timing is right on. New plug, and new Cdi.

When it dies after idling it just shuts off, like a kill switch has been pulled. Kind of strange. Any ideas. Wires appear good, only thing that seems strange is there are two wires spliced together into one going to the reverse switch located on the right case cover. Is this the way it should be?

On another note, when I first got it, I was able to get to run and ride albeit rough. It shifted fine through the gears up and down. Now the trans doesn't want to shift. I messed with the reverse lever not knowing what I was doing. Could I have screwed something up? It seems to stay in neutral, shifter lever moves very hard and when it does go in to gear it feels like one of the upper gears. Not sure if that makes sense.

Thanks, lots of questions, my $300 bike is really getting frustrating!
So went out today and it fired up ran for 3 to 4 minutes. Very smoothe, idling ver nice. The all of sudden it shut off, no sputtering, just off. Kicked it over again it fired and ran for a few seconds and shut off. I got out the ohm meter
Primar coil had very spoardic readings never did get the .1 to .2 ohms (not sure I have the meter on the correct ohm setting)
Secondary coil with cap 11.65
Pulse generator 303
Alternator exciter 180
Ign on sto switch on run no cont
Ign on stop switch off cont
Ign switch off cont
Reverse switch - not sure how to check this one. When I connect to the gray and green and white I get continuity, but not sure if the switch is on.

I have traced the wires looking for grounding out, bad splices, ..... I can't find any bad connections, except the reverse switch wires look a little sketchy. What are the signs of a bad coil? Thanks for your help in advance.
 
#20 ·
Well worked on it some more, cleaned all wire connections an put it back together. Got to run for 5 minute stretches over and over, I even got to ride it, albeit in 2nd or 3rd gear, what ever it is stuck in.....
Now it seems to just run out of fuel. Runs real smooth for about the same stretch of time, then sputters and dies. Wait a second, kick it over and it will run again. I am thinking it will run the fuel out of the bowl, die, refill then run again. The needle must be sticking or something along those lines. I ordered up a rebuild kit and will go from there. I also believe the pilot jet is smaller from the 250x carb to the 300ex carb. I need to change ht as well.
 
#21 · (Edited)
Today was the day! I re-jetted the pilot to a 40, changed out the needle put a new bowl gasket in and bam, kicked it twice and she runs nice and smooth. Adjusted the idle down a little, let her warm up and took off down the driveway in 2nd gear!! Runs great in 2nd gear, now I need to figure out why the transmission won't shift. Shifted when I got it, went through all the gears, up and down. Then started working on the fuel issues. Reverse lever is stuck and only have 2nd gear. I also had it kick it out of gear when I got it going. Bent shift fork? something in the case binding? Any ideas where to start? I have not had the side covers off yet and the clutch seems like it adjusted fine. No grinding when I go to put into gear.
 
#22 ·
rebuilt trx 250x runs great till its warm

Hello, im new to the forum, lots of great advice here.
Having a little problem, maybe you guys can help.


Have Jus got done rebuilding my 92 250x and it runs great until i ride it for about an hour.after that it does. Looses power and sputters out. Let it sit for a minute states after a bout 10 kicks. Goes for a wile it dies again. Let it cool for half hour 45 minutes.runs great for bout an hour.then all over again. New spark plug, inline filter. Fresh oil. New air filter. Maybe coil or cdi? Or bad ground not sure.

Thanks.
 
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