Guest Winchester300

Honda 450 es voltage regulator

5 posts in this topic

I am having a problem with my 450 es shift, have been going thru the steps in the service manual checking battery, etc. Can anyone please do me a favor and connect a volt meter to your battery, turn on the lights and rev up your engine slowly, my symptoms point to a faulty voltage regulator/rectifier, when I rev my machine up my voltage slowly drops, the higher the rev the lower she goes. mabye triggering an ECM fault, my year machine does not show the fault, you can reset by turning the key off then on and rocking the machine and using the es to shift back to Neutral to restart. I also disconnected the speed sensor and found that the voltage at the Blue/Black wire to GND was 11.25 volts dc, 1 volt less than the battery was showing, according to the manual I should get battery voltage. I have also done a leak test on the battery, 1.5 mA, which is under the 5mA by the manual, disconnected the Voltage reg. and was the same, manaul then says (faulty regulator) not sure if this is my shift problem but would sure appreciate if anyone can confirm the requests above

Thanks so much

Share this post


Link to post
Share on other sites


You're going to have variances with engine rpm on an atv. Most atvs I believe run 14.1-14.8 volts unless rpm is below the optimum rpm. With a draw it should not go below the battery voltage. It still could be a bad battery. You should have it load tested.

Share this post


Link to post
Share on other sites

Bad battery cables do wierd things too, try doing a voltage drop test. I think you are right about the regulator however.

Share this post


Link to post
Share on other sites

changed the v.r., no change, did not help

Share this post


Link to post
Share on other sites

My 300 fourtrax had similar problem with (lights dim) Discovered bad wire coming out of (one) of the two fuses near battery. Wire appeared OK (outside) Inside was bad so you may have to use OHM meter to check out

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now