Hi,

Are the regulators/rectifiers on the FZR400 a weak point? I have a FZR600 and upgrading the VR to a later finned one from a YZF600 is a highly recommended mod. The old style are prone to failing and burning out.

I'm working on my 400 doing some work towards the MOT so while I have things apart this would be a good time to swap the VR out if it has the same issues.

If anyone has done this are there any problems with locating the newer type VR?

Cheers

I've heard of one going and I've been on here for about 8 years. The reg rec isn't a problem.
I wasn't aware it was a problem on the 600 either, they're the same charging circuits although the batteries are slightly heavier on the 600. Sounds like somebody has had a scare and spread it round, I know Hondas have weak electrics and they use the R6 unit.

Thanks Evil,

On the 600 forums there's a lot of talk about failing VRs and guides on replacing them. My 600 had a fried VR so I am inclined to think there's something in it, but it may be more to do with the way they're mounted on the 600. Like you say both bikes use the same VR.

I couldn't find any threads on here about it so I guess it isn't a common problem on the 400s.

I've only ever come across one Yamaha reg/rec failure, ironically on my own R6 Turned out to be a fried generator causing the problem - the cover gasket had let in a bit of water.

There does seem to be a high number of failures of the 600 v/r esp on the US forums.
The fault is traced to a bad earth system (shunt type V/R's must be adequately earthed to prevent heatbuild up and consequent failure)
The original 600 unit is earthed through one of the mounting bolts to an alloy heatsink plate bolted to the steel subframe that then bolts to the main frame.Some have an additional earth tag at the V/R fixing that is part of the harness.Galvanic corrosion between the alloy heatsink and the steel subframe appears to be the units demise as it is also shielded from airflow by relays and the seat sidepanels.
If the earth path is good there is no reason to doubt the V/R on either 400 or 600.
The upgrade advised uses a later V/R with its own cooling fins and is not shunt regulated.

600 3HE


400 SP 2TK


Notice the earth tag on both at the fixing.
I reckon the problem is compounded by new owners reviving non runners, after corrosion has degraded the earth path with them standing and the V/R fails within days of first use.
If they do fail all manner of electrical problems ensue so owners tend to upgrade.

The later 3EN 400 models have the reg res mounted on the frame above the swingarm pivot. The 3TJ moves it up a bit.

I read some good material on a forum about the shunt style units overheating but I cannot recall where it was.
If you google this it comes up with kits that some sells on ebay.
SHINDENGEN MOSFET FH012AA REGULATOR/RECTIFIER KIT
Might be useful for future reference.

the 3TJ is also the finned variety for better cooling,

Thanks for the replies.

Does seem that the earthing and heat dissipation are big factors.

Here's a link to one of the 600 forums discussing the issues and fixes:

http://fzronline.com/wiki/doku.php?id=r ... conversion

Clanky wrote:Here's a link to one of the 600 forums discussing the issues and fixes:

http://fzronline.com/wiki/doku.php?id=r ... conversion

the reg/rec they say DO NOT USE in the 3rd picture down, looks identical to the 3tj jobbie