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bike wont start
Posted: Mon Aug 30, 2010 10:46 am
by toby2003
ok i have a 1989 vfr 400 nc 24, i got this about 2 months ago and has worked brilliantly, however, it started not goin so well latley, first it would not start with the ignition switch some of the times, then it would turn the engine but would not start and finally now you push the ignition switch and the bike doesnt turn or do anything, the bike still runs perfectly fine i just have to bump start it each time, i've checked the bike for shorts and damaged electrics, and checked all fuses all are fine and i cannot find any reason why it would be an electrical fault thats causing my proplem. does this mean that it could be a problem with the starter motor?
Re: bike wont start
Posted: Mon Aug 30, 2010 11:19 am
by Neosophist
have you checked the electrical system with a multimeter?
you have classic reg/rec symptoms.
it is very common on the vfr's for the regulator to die, this stops charging the battery and the bike runs flat.
Don't keep running it like that, if the regulator starts to over-charge it'll buggar the battery up (probably dead anyway) as well as break the generator too.
Get the bike running and measure the voltage at the battery (DC Volts) at 5000rpm.
Next take the plug off the regulator that has 3 yellow wires, set your multimeter to AC volts and measure the voltage between each one at 5000rpm, should be 50v AC @ 5000rpm.
Re: bike wont start
Posted: Fri Sep 10, 2010 1:39 pm
by toby2003
hi sorry for not replying in a long time, i did some test which left the problem sort of pointing to the reg rectifier, so i got a new one how ever on recieving the new one i have found that the 3 yellow wirs to the alternator do not have a connector they have separate crimped pins, this is not so much a problem but the fact that the rectifier was removed before i could note down which one the plugged into is, so i now have 3 yellow wires with know markings which i need to connect to the reg/rec, does anyone know which yellow wire goes where??
Re: bike wont start
Posted: Fri Sep 10, 2010 2:58 pm
by CMSMJ1
doesn;t mater where the yellow ones go...
If you get ther other ones wrong you'll blow the main fuse. So, 50/50 on that

Re: bike wont start
Posted: Fri Sep 10, 2010 4:29 pm
by Neosophist
Yep.. it's 3 phase AC.. they can go in any order.
If the old ones have been cut off it is becuase they have melted the plug.. commmon symptoms but be wary of the reg/rec (test it first)
using an R6 reg-rec is much more reliable
Re: bike wont start
Posted: Sat Sep 11, 2010 11:12 am
by toby2003
yeah this is the thing the reg/rec i had in it before was an r6 one, this is why i thought it would be the starter motor that was gone???
Re: bike wont start
Posted: Sat Sep 11, 2010 11:52 am
by Neosophist
have you tested the generator? this supplys power to the reg/rec.. if this fails you can blow the reg-rec up
Re: bike wont start
Posted: Mon Sep 13, 2010 9:38 pm
by spooky
When you turn the key does the green neutral light come on and the red ignition light come on nice and bright? if only sometimes your ignition switch could be worn out. happened to mine a few months ago. ebay for new one will sort it. but before you do anything check your battery is ok.
Re: bike wont start
Posted: Tue Sep 14, 2010 3:13 pm
by toby2003
nah, green and red light come on bright everytime.
Re: bike wont start
Posted: Tue Sep 14, 2010 5:39 pm
by toby2003
if it was the switch that wasn't working would the starter solenoid still be engaging when you push the switch in???