[LBZ_Duramax]

I had an old friend drop off his foreman 400 today. He says it Runs great for a few mins and then oil light comes on and motor immediately dies. You can leave it for 15 mins or so and it will run for a few more mins.

I’m thinking fan control or cdi problem. Has anyone had this happen before?

 

[Goober]

Great question this happened on my 00 450S the oil light would flicker but stay running
I would do the oil sensor test first cuz if the oil light is coming on and it’s not hot then it could be bad.
But the fan should be coming on when you ground the oil sensor lead—maybe different on 400 ?
In my case it was the Fan Control Unit $190

 

[mrbb]

I have a 99 400 foreman, owned it since new in 98
I have had 3 oil temp sensors fail on me and ONE fan control unit fail over the yrs
the oil temp sensor IMO gets exposed to a lot more possible things to damage it, and thus the weaker link
but there is a test to rule out the temp switch and FAN motor,
if you do and they pass, well, you got your answer on what is bad LOL

to replace oil temp sensor, you will pretty much need to drain the oil, so, make life easier if you time replacing with an oil change?

 

[LBZ_Duramax]

So I finally got the bike to my shop to play around with it some. It runs great, till it doesn't.... It will consistently idle for 15-17 mins each time. The oil light doesn't come on every time but when it dies I pulled plug and checked it. It had no spark. But after 30 mins or so I could check and it would have spark and run great. It has a red aftermarket CDI on it so I'm planning to order an OEM one unless someone has some better insight.

 

[mrbb]

ok, can maybe shed light on the CDI
I had running issue's I couldnl;t figure out, run great then NOT run, then run poorly
screwed with it for weeks, gave up, sent off to dealer, who had it for 2+ MONTHS
they finally installed a NEW CDI< CLAIMED OEM ONE
charged for OEM one
ran great for a few weeks then started same crap!
I pulled CDI and found a aftermarket one in ATV
HUMM Dealer lied and scammed me!
got NEW OEM CDI, and atv has run like new ever since(5+ yrs later now)
SO, IMO< Aftermarket electronic's are ALWAYS HIT and MISS, some times you get lucky, some times you don't!
I never BUY aftermarket OEM replacement electrical parts,. or NOT on NON sporty models
for what ever reason, SPORT models seem to have better results?(think MX racing atv's and or bikes or street sport bikes?
even aftermarket chips and such for vehicles
but utility atv's< aftermarket electrical parts seem to SUCK ! LOL

 

[fishfiles]

If you don't have spark when it kills and it starts back up after cooling off , you would think the CDI is getting hot ----

 

[LBZ_Duramax]

Replaced CDI with brand new OEM. Still no spark. I get a weak spark every now and then when grounding plug to head. I’m going to try a coil next, this plug wire looks dry and brittle and plug cap is cracked. Going to pull front fenders also and see if I can see any wire damage but the bike is one owner and never been apart. Everything I have seen so far is perfect.

 

[Goober]

Check plug number

Mine uses a resistor plug and some models use a resistor cap.

 

[fishfiles]

I know you must know about, unscrewing the spark plug boot , cutting 1/4 off the end of the spark plug wire , then re-screwing the boot back on -----spray WD-40 thru the straw into the kill switch while working the switch on and off ----corrosion in a harness connector

 

[Goober]

Something else. When it’s running and quits, does it start to sputter like it’s hot or just quits?

Mechanically I’m thinking worn SE (choke) valve–is the plug sooty?

Electrically to start, im thinking wrong plug, resistor cap fault, loose wire on or faulty Fan Control Unit, or faulty oil sensor.

 

[LBZ_Duramax]

Something else. When it’s running and quits, does it start to sputter like it’s hot or just quits?

Mechanically I’m thinking worn SE (choke) valve–is the plug sooty?

Electrically to start, im thinking wrong plug, resistor cap fault, loose wire on or faulty Fan Control Unit, or faulty oil sensor.

Will fan control unit or oil sensor keep it from having spark?

 

[Goober]

I thot it might but now not sure
Here’s a couple pages frim the manual

 

[LBZ_Duramax]

Something else. When it’s running and quits, does it start to sputter like it’s hot or just quits?

Mechanically I’m thinking worn SE (choke) valve–is the plug sooty?

Electrically to start, im thinking wrong plug, resistor cap fault, loose wire on or faulty Fan Control Unit, or faulty oil sensor.

Maybe you’re on to something with the plug. It has a dr8es plug in it. Supposed to be a dpr6ea. I will go by parts store tomorrow and see if they have one. The plug boot is cracked anyway so I have one of those coming.

 

[Goober]

Something else. When it’s running and quits, does it start to sputter like it’s hot or just quits?

Mechanically I’m thinking worn SE (choke) valve—is the plug sooty?

Electrically to start, im thinking wrong plug, resistor cap fault, loose wire on or faulty Fan Control Unit, or faulty oil sensor.

Maybe you’re on to something with the plug. It has a dr8es plug in it. Supposed to be a dpr6ea. I will go by parts store tomorrow and see if they have one. The plug boot is cracked anyway so I have one of those coming.

Sounds great
There’s a lot to know about plugs and there are a few plug threads here. I have been sold the wrong plugs several times—by well meaning folks. Here’s what may be another example; so the service manual can help you specify a plug, so long as the parts tech doesn’t try and talk you out of it

 

[shadetree]

bad fan control will stop it in a heart beat. safety feature honda put on all ( most ) atvs back In the day. if they fail..or going out ?, they stop all power to the c.d.i. and spark plug.

 

[mrbb]

bad fan control will stop it in a heart beat. safety feature honda put on all ( most ) atvs back In the day. if they fail..or going out ?, they stop all power to the c.d.i. and spark plug.

I am not so sure on this Shade, and only reason is, when my an control unit went, mine still ran, just fan wouldn;t come on anymore?
but could start atv no problem ?
SO< I don't know if mine was a freak deal or not, but its what it was for me?
and this is on the same model atv here(400 foreman, only a 1999 yr model!)

 

[shadetree]

bad fan control will stop it in a heart beat. safety feature honda put on all ( most ) atvs back In the day. if they fail..or going out ?, they stop all power to the c.d.i. and spark plug.

I am not so sure on this Shade, and only reason is, when my an control unit went, mine still ran, just fan wouldn;t come on anymore?
but could start atv no problem ?
SO< I don't know if mine was a freak deal or not, but its what it was for me?
and this is on the same model atv here(400 foreman, only a 1999 yr model!)

did you notice..i said ^^^ most ?!..lol.

 

[shadetree]

bad fan control will stop it in a heart beat. safety feature honda put on all ( most ) atvs back In the day. if they fail..or going out ?, they stop all power to the c.d.i. and spark plug.

I am not so sure on this Shade, and only reason is, when my an control unit went, mine still ran, just fan wouldn;t come on anymore?
but could start atv no problem ?
SO< I don't know if mine was a freak deal or not, but its what it was for me?
and this is on the same model atv here(400 foreman, only a 1999 yr model!)

and to further my statement, a lot of alarm boxes ( spec trx300's )..when they fail ?, they some how cut power to the c.d.i. boxes, I know this for a fact !.

 

[mrbb]

SHade, again NOT doubting you, as I know you know your stuff

BUT a lot of folks do remove the fan control units and then hard wire a on'off switch to fan?
so, wouldn;t that also be ?? here, saying, maybe no on if a fan control unit failed it would cause spark issue's
or is it when you remove from system, that it just allows things to work correctly again?

not ?? anything, just asking and learning!

 

[shadetree]

SHade, again NOT doubting you, as I know you know your stuff

BUT a lot of folks do remove the fan control units and then hard wire a on'off switch to fan?
so, wouldn;t that also be ?? here, saying, maybe no on if a fan control unit failed it would cause spark issue's
or is it when you remove from system, that it just allows things to work correctly again?

not ?? anything, just asking and learning!

from what I know of ?, they don't remove the control box, they just hard wire the fan to come on with a switch, what this does is '' fool '' the alarm box into thinking the fan is working..when in fact..its really not as the alarm should see it, but sense the fan is on when the switch is on, this keeps it cool. again..this control box does not work like I said on all makes/models from honda ?, but it should work this way on most of them. I do know for a fact, the trx300's that have this alarm box on them, and yet no fan ( optional fan kit can be installed...if you can find one ? )..if the alarm box fails ?, the c.d.i. will not work. a lot of things comes into play here, what all was bypassed ?, is everything oem ?. it all depends on make, model, c.d.i.. I just know on some models..if the fan conrol/alarm box fails ?, then the c.d.i. will shut down.