Hi all, first post on here, son has just bought the fzr400 and first time out starts fine rides well turns it off and on trying to start again nothing is working as if the kill switch was off, lights dash etc all still work on investigating the ignition fuse is blown, so replace it again all good ride for 10 miles turn it off and again on turn on ignition the fuse blown again now need some ideas to find the fault,all help appreciated

OK - first a wiring diagram, go to this page http://400greybike.com/docs.htm and look at the Yamaha section theres a setup maunual for the 3tj SP the wring dia is there. This probably isn't the same as yours but it's a good place to start.

From what you write I'd say it could be a short - look at the all the thick red wires and then over the loom see if theres a rub on a wire or something touching the frame. Next we're look at a power spike which is probably the reg rec - put a volt meter over the battery terminals check the voltage with the engine off (13v) then running 14v then rev the engine the volts shouldn't exceed 14.6v. if it spikes up to 15-16 the reg rec is gone.
next - did the lad turn anything on or off just before it died - it could point to the circuit at fault, but I think it's either of the two things above

Hi, yeah have got some circuit diagrams printed off and have started looking for a short somewhere in the red and white ignition wires but so far nothing, seems strange he thinks it's after he's ridden it and switched it off hot, then when he's turned it back on after a while the fuse has gone, was hoping something easy, like fuel pump or relay may be doing it but seems wire digging is required, by the way the bike has been off the road for over a year so not been used, thanks in advance

I didn't know they'd invented relays when these were built

So, do you know the model of this bike ?
Single trapezoidal head light with para lever lamps (3TJ) or twin round head lights ?
twin round with air intakes above the lights (3en2) or below (3en1)
twin round, no air intakes, adjustable suspension (2tk) or without (Genesis)

Sorry I have no idea what model it is,all i know is its an English from first registration bike and says fzr400 4dx in the v5, it has the sharper looking fairing with twin round headlamps behind a one piece cover, it's got sv carbs on it and no intake tubes, would upload a picture but havnt a clue how to, also which way is reserve on the switch on the fairing as the local yamaha dealer hasn't got a clue

After doing a bit of searching think it's a 3tj exup

Check the main battery wires including the ground connection, and the connections to the battery posts.....I have seen this before

Bsamann55 wrote: ↑

Tue Jul 02, 2019 4:06 pm

Sorry I have no idea what model it is,all i know is its an English from first registration bike and says fzr400 4dx in the v5, it has the sharper looking fairing with twin round headlamps behind a one piece cover, it's got sv carbs on it and no intake tubes, would upload a picture but havnt a clue how to, also which way is reserve on the switch on the fairing as the local yamaha dealer hasn't got a clue

Ah - yes 4DX is the model. The 4DX was the official import version of the 3TJ … worth a little more than the TJ because it's not got the Japanese Speed restriction, theres also a MPH speedo, oil warmer (that flat thing under the oil filter), slightly different tail light to the 3tj …. and hooooge indicators should be white with dark red over it - nice bike.

Hooray think I've found the problem the reserve switch wiring was tucked in front of the headstock and the red and green had rubbed a small hole leaving a bare wire that was shorting on the throttle cable adjuster rerouted and insulated it properly, cleaned every connection and so far no problems

Sweet