Just inherited a 1989 Moto4 250. rebuilt the carb, new battery but cant get it to fire, even with pulling. Looked at electrical diagram and holy crap what is with all the components and what are they all for? a starter, CDI unit, starter relay, rectifier/regulator, coil. should I treat this like a car and start with the starter?

how do I go about troubleshooting all this to see why no spark?

good thing this was free

 

Mine is an '86 225. These things are pretty well-made, but nothing can tolerate absolute neglect.

What's it doing? Solenoid click but no starter spin? Starter spin but no engine crank? Engine cranks but no sputter or spark?

Help us out.

The CDI is the electronic ignition box. It also controls ignition advance based on engine RPM.

The starter relay is a remote-mount solenoid, like on an old Ford.

The Regulator / Rectifier converts the stator's AC current to DC, then regulates the voltage down to about 14.5 VDC.

The coil provides the spark to the spark plug, on cue from the CDI.

 

thanks for quick reply

ATV is in Mexico near the ocean so lots of neglect, I am back in Phx so wont be able to check much for a couple of weeks just trying to understand how it all fits together, so you have helped.

OK it cranks but wont catch.

when pulled same thing, I wish it had a clutch.. pulled in higher gears but no luck

 

Okay, so your battery, starter, and starter relay are all good.

I know you said you rebuilt the carb, but are you sure the carb is right? Meaning to say, are you sure the engine is getting fuel? Funky old Mexican gas sitting there by the seaside certainly didn't do the carb any good.

Spray a couple quick shots of aerosol starting fluid into the airbox, then give her a go. If the engine lights, albeit briefly, you'll know it's a carburetor problem. But if it doesn't light off at all, you've no spark.

Keep us posted.

 

thanks for the idea. though I rebuilt the carb, I am no expert. new gas but hitting it with starter fluid is good idea. I need to check gas flow thru the hose and shut off too as I assumed it is OK

wont be able to check for a week or 2

 

well got back to Mexico and tried to start the 4 wheeler, It does try when I shoot ether thru the air intake, but does not catch once the ether runs out.

looks like I did not do the carb right. Going to trailer it home and work on it here, tried to avoid the haul but easier here, I can get help if needed

thanks for what I have learned so far
jim

 

Yep, sounds like a carb problem. Give 'er a nice soak in straight Pine-Sol (safe for plastic and rubber parts) for a couple days, then scrub indoors and out with a toothbrush and rinse, then blow everything out with compressed air. You can also use a single strand of copper wire to poke out the tiny holes in the jets and emulsion tube.

Here's a carb diagram, just in case... http://www.bikebandit.com/houseofmot...6701#sch131728

Keep us posted.

 

sorry I did not respond sooner

Put rebuilt carb on ATV, hit with starter fluid. It would kick off but not start. took apart carb. Had float upside down, fixed though it did not help. Fuel went into carb but still did not start. carb did not fill, it ended up the air tube for the bowl was clogged. Once I cleared it out with a piece of wire, the bike started right up and is running perfect

thanks for all your help
jim

 

Awesome! I love happy endings.