Honda ATV Forum banner

1 - 20 of 25 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter · #1 · (Edited)
ok i have a slight problem my 87 trx 250x wolnt start and its driveing me nuts well first ill start with what ive tried
rebuilt carb
retimed cam
replaced cdi unit and coil
did all resistance test in climer manual every thing ok
leak down tested at 2%
checked exaust and intake both clear
checked and rechecked timing and valve lash at least a dosen times
checked and rechecked for spark got it
rechecked carb settings
i'm geting spark fuel and compresson is there any thing i may be missing all ideas acceped and will be tried:confused:
 

·
Super Moderator
Joined
·
18,228 Posts
Welcome to the forums..
Make sure you have the little red switch is on....The key.... and you're not in reverse. if the reverse switch is bad it can be bypassed
 

·
Registered
Joined
·
2,735 Posts
Yeah simple things but it's happened to me half a dozen times.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #4 ·
key switch is missing and bypassed Red kill switch is ok as far as i can tell and i bypassed the reverse switch at least i hope i did it right
 

·
Premium Member
Joined
·
23,581 Posts
key switch is missing and bypassed Red kill switch is ok as far as i can tell and i bypassed the reverse switch at least i hope i did it right
All these things won't matter as long as you know for sure you're getting a good spark. If any of these things were the problem, then you wouldn't be getting a spark. Just make sure you're getting a good, bright blue spark and it's not jumping off the edge of the plug. It should be firing a strong, bright blue spark from the electrode to the electrode ground. If it is, then that's not your problem. You should be able to hear a distinct clicking sound, as it fires. If not, you have a weak spark.

Try pouring about a teaspoon of gas down into the spark plug hole. Screw the plug back in quickly, so the gas don't evaporate. Put the plug wire back on. Now see if it will start and run for a couple seconds, anyway. If it does, you have a carb problem. If it don't and you know for sure that you are getting a good spark, then you, more than likely, have a mechanical problem with the engine, such as a timing, valve, or compression problem.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #6 ·
well i have a good fat bright blue spark. i'm getting gas to the cylinder. ive checked the timing and valve adjustment many times always spot on ive checked compesson and cylinder leak down all ok to my clymer manual. my question now is could the ignition timing be off to where it woln't fire when it needs to
 

·
Premium Member
Joined
·
23,581 Posts
well i have a good fat bright blue spark. i'm getting gas to the cylinder. ive checked the timing and valve adjustment many times always spot on ive checked compesson and cylinder leak down all ok to my clymer manual. my question now is could the ignition timing be off to where it woln't fire when it needs to
The pulse generator or pickup coil is what makes it fire when it's suppose to and it isn't adjustable and it's probably not bad or you wouldn't be getting a spark at all. The timing advance is built into the CDI, so if it's not firing when it's supposed to, then it seems that the CDI would have to be the problem, but I'm just guessing, because I've never seen a problem like that before.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #8 ·
well i have a good fat bright blue spark. i'm getting gas to the cylinder. ive checked the timing and valve adjustment many times always spot on ive checked compesson and cylinder leak down all ok to my clymer manual. my question now is could the ignition timing be off to where it woln't fire when it needs to
The pulse generator or pickup coil is what makes it fire when it's suppose to and it isn't adjustable and it's probably not bad or you wouldn't be getting a spark at all. The timing advance is built into the CDI, so if it's not firing when it's supposed to, then it seems that the CDI would have to be the problem, but I'm just guessing, because I've never seen a problem like that before.
well me eather but knowing that it wouldn't spark with out the pulse generator helps and the cdi is new unless i got a bad cdi timing be dead on
thanks
 

·
Premium Member
Joined
·
23,581 Posts
well i have a good fat bright blue spark. i'm getting gas to the cylinder. ive checked the timing and valve adjustment many times always spot on ive checked compesson and cylinder leak down all ok to my clymer manual. my question now is could the ignition timing be off to where it woln't fire when it needs to
The pulse generator or pickup coil is what makes it fire when it's suppose to and it isn't adjustable and it's probably not bad or you wouldn't be getting a spark at all. The timing advance is built into the CDI, so if it's not firing when it's supposed to, then it seems that the CDI would have to be the problem, but I'm just guessing, because I've never seen a problem like that before.
well me eather but knowing that it wouldn't spark with out the pulse generator helps and the cdi is new unless i got a bad cdi timing be dead on
thanks
Sounds like you have everything covered. I don't know what else could be wrong.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #10 ·
well new devolpment i put my in line spark tester on it kicked it about 5 times it poped like it tried to fire then lost spark waited a few minuits tried it again did the same thing tried to start then lost spark again now im realy stumped:icon_cussing:
 

·
Premium Member
Joined
·
23,581 Posts
well new devolpment i put my in line spark tester on it kicked it about 5 times it poped like it tried to fire then lost spark waited a few minuits tried it again did the same thing tried to start then lost spark again now im realy stumped:icon_cussing:
Yeah, that just makes it more confusing. The bad thing about trying to diagnose the problem is that it's probably something simple. The simple things are the easiest looked over.
 

·
Super Moderator
Joined
·
18,228 Posts
Bypass the red switch too.
Also How did you bypass the reverse switch?
 

·
Registered
Joined
·
2,735 Posts
Maybe a bad cdi box.
 

·
Registered
Joined
·
2,735 Posts
I don't know either.
 

·
Super Moderator
Joined
·
18,228 Posts
No ground BRO! just put a jumper between the gray wires on the left side of the frame. unhook the reverse switch wire and put a jumper in its place. don't ground it.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #18 ·
No ground BRO! just put a jumper between the gray wires on the left side of the frame. unhook the reverse switch wire and put a jumper in its place. don't ground it.
ok will do tomorrow when i get back to it and will let you know if bypassing the red killswitch helped thanks
 

·
Super Moderator
Joined
·
18,228 Posts
Weak or faulty ground seems to be the most logical... relocate it...or clean the one you have:happy:
True...but if he grounded the reverse switch like he said above^^^ the he grounded his CDI out I hope he didn't cook it.
 
1 - 20 of 25 Posts
Top