trx 300 4x4 reverse light on

[crf250r]

good day everyone, 

                  new to this page. I need help with my 1994 fourtrax 300 4x4. the bike stop sparking for some odd reason so no big deal I order a new ignition coil, that was not it so I order a new cdi box. now I get sparks. by now the battery is low from cranking so much, so I boost it with the truck. the bike as the hardest time to start and when it does it runs rough, bogging, backfire,..., reverse light is on even if im not in reverse but in neutral. and the reverse light gets briter as I rev the bike.i clean the carb twice, remove the reverse sensor and check the ohm, reading 0.0 to 0.9. any idea, I need to get this bike going asap. thanks for your time

[davefrombc]

The reverse light switch (sensor) should read 0 ohms  or close to  it when  it   is  closed to  indicate the machine is in reverse.  The lights brightening  as you rev up the motor  is normal  as  the  voltage  rises  as the  motor  revs  faster . Check the voltage at the battery  when the  motor  is running It  should be  about  12.5  at idle and rising to a maximum of  between  13.5 and 14.2v . If  it  is  low  it could also  be  the source  of the rough running , although  the  rough running, bogging  and  backfire is usually  from the motor running  lean.  It  could be   from  a missed plugged passage  or just the  idle  air  mixture  out of adjustment.  Check  for  leakage of the  high tension wire to the spark  plug  and  try  a new  plug too as the spark plug  could be intermittent .

[Guest]

Where did you get the CDI box? I ran into this with a customers bike (more than one actually) which he replaced the CDI box with a cheap one from one of the big internet sites. I replaced the CDI with our "known good shop box" and the trouble was gone. The last bike i ran into this with was a TRX200D i think. I usually replace CDIs with stock Honda, or one from Ricks Motorsport Electrics,about the only ones i trust. I'd direct you to my website but i'm putting together a brand new one at the moment.     www.mettlers.biz in case your interested. As davefrombc stated above,rule out the reverse switch to be sure.

[crf250r]

Thanks for your help guys, so yesterday i tryed pretty much everything under the sun to get this bike going, finally i contacted my mechanic and that’s exactly what he told me about the cdi box, he said don’t expect much from a cdi box at 20$. So ill order a new one from Honda and ill keep you posted. Thanks again.

[crf250r]

Ok so i got a new cdi and coil from honda. Try them on and still no spark.... one thing the battery is dead but i boost with my truck to get the bike going, so lots of power to the battery there. What else should i be looking at. Thanks for your time guys

[Frank Angerano]

Start to look at the wire harness for any loose or broken wires.  Kill switch may have an issue.   If not there then the stator coil or secondary coil.   

If you know how to use a tester you can eliminate those parts to avoid buying them. 

[wanrep]

21 hours ago, crf250r said:

Ok so i got a new cdi and coil from honda. Try them on and still no spark.... one thing the battery is dead but i boost with my truck to get the bike going, so lots of power to the battery there. What else should i be looking at. Thanks for your time guys

Sounds like the regulator/rectifier is bad.  That will cause a no spark issue on those old 300's.  I'd get a new battery also.  Not a good idea to jump it with your truck ESPECIALLY a running truck.  Too many amps will reek havoc with the cdi and regulator.

[Frank Angerano]

It can also fry the stator coil.   

Edited February 25, 2019 by Frank Angerano

[jcboles]

Quote

hi guys i'm having the exact same trouble with my trx 300, i try to crank it over and the reverse light comes streight on? i have replaced the coil, cdi box, regulator,  stator/generator, tilt switch(the box next to the cdi with green plug marked HC04), new battery, all new fuses in wiring loom and a new spark plug of course. i've taken a good look at all the wiring on the bike and i can see anything wrong. ive heared about the reverse sensor located by the foot brake behind the metal plate going wrong.

Has anyone else experienced this issue?

 

[Finnforest]

Hello, i had a similar issue with my 300 TRX , no spark (1991) , thought it would be the CDI but it was the connections to the CDI that had some green crust on it. Cleaned it and runs like champ now.