250X starting Difficulty

[BigBoreDave250x]

I have a 88 TRX that on occasion won't start or show any sign of life. It usually starts or at least wants to on the first kick or two.

More often than not, it starts, idles good, torque & power is great, & it's a blast to ride. The tank, filter screens, & carb are clean.

When it doesn't start I pull the plug & its wet. The stop start switch is sloppy. How can I test it to make sure it is not the cause? I went through all of the connections to make sure that their clean, they are.

What else should I check or could cause this?

Thanks,
Dave:rolleyes:

[dork]

have you checked for spark when it won't start? follow the harness from the kill switch/handlebar switch unit down to the connector under the bars and disconnect and that will eliminate the switch. also check your key switch as well, you can just disconnect it also.

[Sjorge450R]

you said the plug is wet. Are you pumping the gas???

try to mess with the air screw.

[BigBoreDave250x]

Originally posted by dork
have you checked for spark when it won't start? follow the harness from the kill switch/handlebar switch unit down to the connector under the bars and disconnect and that will eliminate the switch. also check your key switch as well, you can just disconnect it also.

Thanks, I think this is the info I needed to rull this out. The kill switch is what could possibly keeping it from getting spark intermittently? My 88 does not have a key, the key is getting it started.

Thanks again,
Dave:cool:

[BigBoreDave250x]

Originally posted by Sjorge300EX
you said the plug is wet. Are you pumping the gas???

try to mess with the air screw.

No, I always start it the same. Turn on the stop switch, open the fuel valve, close the choke, & kick. If it wants me to ride it that day, usually does, it starts.

The pilot jet is set to factory spec & seems to have its best power
at that setting.

Thanks,
Dave:cool:

[bwamos]

Originally posted by BigBoreDave250x
Thanks, I think this is the info I needed to rull this out. The kill switch is what could possibly keeping it from getting spark intermittently? My 88 does not have a key, the key is getting it started.

Thanks again,
Dave:cool:

You have to reconnect the 2 wires back together to turn it on. ;) Just incase you didn't already know that.

I'd pay special attention to that stinking thumb kill switch. If it's not making good contact the quad won't start.

It's a normally closed circuit unlike most kills. Basically it just cuts off your 12v supply to the CDI when you flip it to either side and open the circuit. It doesn't ground the coil input like most kills do.

[BigBoreDave250x]

Originally posted by bwamos
You have to reconnect the 2 wires back together to turn it on. ;) Just incase you didn't already know that.

I'd pay special attention to that stinking thumb kill switch. If it's not making good contact the quad won't start.

It's a normally closed circuit unlike most kills. Basically it just cuts off your 12v supply to the CDI when you flip it to either side and open the circuit. It doesn't ground the coil input like most kills do.

No, I did not know about the reconnect,:confused: I will do that the next time this situation happens again.

I sort of thought that this could be a main culprit. Thanks for explaining about the closed circuit. I don't have a battery it must get its power from the magnito?

Thanks,
Dave:cool:

[dork]

bwamos, you're thinking of the 300ex kill switch and key switch. the 250x switches are normally open and if you unplug them it will run. the 300ex is a DC system and the 250x is AC.

[BigBoreDave250x]

Originally posted by dork
bwamos, you're thinking of the 300ex kill switch and key switch. the 250x switches are normally open and if you unplug them it will run. the 300ex is a DC system and the 250x is AC.

Just what I needed. Thanks for helping to keep me started!

Dave:devil:

[bwamos]

Aye I know the difference.

I haven't had the left side switch assembly apart on a 250x.. so I'll take your word for it.

So on the 250x the on/off key switch is a kill switch that grounds the circuit?

I know one's AC the other DC.. but the X still should have a rectifier circuit to convert the AC to DC. The CDI can not run off of AC.

Besides, AC/DC makes no difference in a kill circuit.

[dork]

the CDI's are completely different. the 250x runs everything on AC, including the lights. the regulator on the 250x is a 2 wire unit, it just regulates the voltage to the lights, real simple. the 300ex as you know has the regulator rectifier so it can charge the battery. the 250x switches are both open and grounded when closed(i have the manual). all atvs/bikes without a battery run the CDI on AC voltage. the CDI half wave rectifies it internally, not the regulator (if the model even has lights). the AC systems produce 100-400 volts from the stator to the capacitor depending on RPM, while the DC system has an amplifier to bump up the 12V to 250V+ so there is a constant max voltage no matter what RPM. other than that both system CDI's work the same(unless its digital).

[BigBoreDave250x]

Hey d, thanks for the break down. Is the stop swith rebuildable?
Is there anyway to clean the contacts, or is it a sealed unit? Mine appears to have some hairline cracks. I bet my coil, CDI & the like are all original 88 vintage pieces as well.

But, if it aint broke...................

Thanks,
Dave:chinese:

[Xater]

my 87 x had probems like that and it would only start sometimes.
i replaced the coil and never had a problem again.

[BigBoreDave250x]

My spark is only white in color so it could be suspect. I should be a dark blue. It was night when I rechecked the spark.

Is the coil for a 300ex the same as mine, 250X?

Thanks guys,
Dave:huh