Hi gang, I'm new to the board, was searching for some info and came across this forum. I'm having a problem diagnosing my Dad's quad, here's a copy of what I posted on another forum, Help please!

"Help me out, I'm working on my Dad's quad, 96 Honda Foreman 400, has been very hard starting for a while, wouldn't start until you let off the starter button(crank it up, let off the button and hope it catches). So I'm checking it out, thought it'd be the CDI so I swapped it out with the one off my 02 Foreman 450 but no dice. So I've been going through the wiring diagram, everything checks out except for the pulse gen, it should have minimum of .7v cranking, get nothing until you let off the start button then you get a flash on the DVOM of 1-3v, and the quad will run so I'm having a hard time believing it's the pulse gen. I've even bypassed the ign switch, starter switch with the same results. No power to the coil while cranking except for a flash at the end. What am I missing!"

Norm

 

You cant check the voltages specified with a DVOM without a Peak Voltage Adapter.
Those specs given are in Peak Volts.

One thing to check, Take the spark plug out, install it in the plug cap, ground the plug to the engine, and crank the engine. Do you have consistant spark that way?
or does it only spark when you let off the start button? If it sparks consistantly that way, you may be having a fuel problem.

 

<div class="FTQUOTE"><begin quote>Originally posted by: HondaTechnician

You cant check the voltages specified with a DVOM without a Peak Voltage Adapter.

Those specs given are in Peak Volts.



One thing to check, Take the spark plug out, install it in the plug cap, ground the plug to the engine, and crank the engine. Do you have consistant spark that way?

or does it only spark when you let off the start button? If it sparks consistantly that way, you may be having a fuel problem.</end quote></div>

Maybe I wasn't clear enough in the previous post, there is no spark until you let off the start button, then it will spark once. Using a test light on the black/yellow wire at the coil show no cranking voltage until you let off the starter button, it will then flash the test light. Not getting power out of the CDI to the coil while cranking but yet if you time it right letting off the start button it will run, usually take a few tries. Once it fires it runs fine, you just don't want to shut it off.

 

Not sure how a test light would work there anyway, the voltage at the coil is 100 volt.
There were some of the mid 90s TRX300s that caused a similar problem, but they were the CDI.
You can try this trick that worked ALWAYS on the 300s.
When trying to start the machine, instead of pressing and holding the start button as you normally would, double stroke the button, I mean instead of just pressing the button (click) do it twice rapidly ( click click ). That would always work on the 300s that had this problem.

Good Luck.

 

<div class="FTQUOTE"><begin quote>Originally posted by: HondaTechnician

Not sure how a test light would work there anyway, the voltage at the coil is 100 volt.

There were some of the mid 90s TRX300s that caused a similar problem, but they were the CDI.

You can try this trick that worked ALWAYS on the 300s.

When trying to start the machine, instead of pressing and holding the start button as you normally would, double stroke the button, I mean instead of just pressing the button (click) do it twice rapidly ( click click ). That would always work on the 300s that had this problem.



Good Luck.</end quote></div>


Use the test light on the wires "feeding" the coil, that's 12vdc, the 100v side would be the coil lead going to the spark plug. Did this on my 02 just to make sure I wasn't doing something wrong, worked fine, test light flashed constantly while cranking.

I will try the double tap on the start button, if that take's care of it, what's the fix?

Thanks, Norm

 

<div class="FTQUOTE"><begin quote>Originally posted by: ntjordan

<div class="FTQUOTE"><begin quote>Originally posted by: HondaTechnician




Good Luck.</end quote></div>





Use the test light on the wires "feeding" the coil, that's 12vdc, the 100v side would be the coil lead going to the spark plug. Did this on my 02 just to make sure I wasn't doing something wrong, worked fine, test light flashed constantly while cranking.



I will try the double tap on the start button, if that take's care of it, what's the fix?



Thanks, Norm</end quote></div>

You need to have a look at the manual, the primary voltage(the two small wires going to the coil) on that unit is 100 volt
the secondary or "wire going to the plug" is in excess of 20,000 volt.
Im not saying a test light wont work, I said I didnt know, When in the service department of the Honda shop I worked at, we used a peak volt adapter for the multimeter, to read the peak voltage.
The peak voltage on the pulse generator is 0.7 volt.

On the 300s the only fix was to replace the CDI.

 

<div class="FTQUOTE"><begin quote>



You need to have a look at the manual, the primary voltage(the two small wires going to the coil) on that unit is 100 volt

the secondary or "wire going to the plug" is in excess of 20,000 volt.

Im not saying a test light wont work, I said I didnt know, When in the service department of the Honda shop I worked at, we used a peak volt adapter for the multimeter, to read the peak voltage.

The peak voltage on the pulse generator is 0.7 volt.



On the 300s the only fix was to replace the CDI.</end quote></div>


Hmmm...... well, OK the test light trick works then anyways, verified it on my '02 450, even swapped CDI's between quads, no change, even with the 400 cdi in my '02 it starts/runs fine. Luckily I wear my hair short enough, otherwise I'd be pullin' it out about now!!! Not sure where to go next, I do have a manual, if you want to call it that(clymers), just got it so I'd have the wiring diagram.

BTW, I tried the double-tap with the starter button, doesn't really seem to help.

 

Some TRX300's had the same problem and it was bad/loose connections at the voltage regulator/rectifier ...

 

Well I have a 94 TRX300FW same problem but mine will not start at all

Already pulled my hair out [img]i/expressions/face-icon-small-happy.gif[/img]


Also received it from my Dad he had replaced Cdi,Rectifier,Pulse Generator, Coil,Stator

I am considering ta new Wire Harness but thats just a hope try


The only reading that I have gotten that doesnt go with the Clymers manual I have
Is at the Diode It says to put the plus terminal on the + side of diode and - Terminal on negitieve side of diode and you should get a reading and then switch and you should not have any reading the results I get are opposite I would expect it to be either open both ways or closed both ways not reversed so it doesnt make any since to me unless there is a miss print in the manual even if not not sure it would cause this problem.. Haven'y tryed a new one yet

 

Replace the voltage rectifier/regulator located upper right rear frame above rear tire has 5 pin gray connector.Stator wires pass through volt/reg first then to cdi.
A 98 450s foreman had same symtoms and this was the cure.
Hope it helps. Mike