87 Tenere reg/rec overheating

**jbw** · #1 11 Aug 2002

The reg/rec on my bike seems to get hot, is this normal? I've moved it down to the frame tube to be in the airflow, will this help ?

**POB/London** · #2 12 Aug 2002

That's normal I think.

**RichLees** · #3 12 Aug 2002

It depends how hot. the regulators job is to dump the excess voltage that the alternator makes at higher engine speeds so that the voltage stays around 14V and does boil the battery. it dumps the excess voltage as heat. does your design have cooling fins? if not, it must be using something else such as the frame as a heat sink so make sure it is in intimate (ie clean) contact with that other thing or it'll be hotter than it should be.
So, a working regulator will be above ambient temperature, but I wouldn't expect it to, say, burn your hand. if your battery is healthy, then I'd guess your regulator is healthy. Use a DC voltmeter to check the output with the engine running at different speeds and, just for fun, switch the voltmeter to AC to check the rectifier is doing its job of putting out nice, clean DC. You should see roughly 14V DC and zero AC.
Richard

**david lambeth** · #4 5 Sep 2002

The latest 4PT xt600e uses a reg/rec with proper heatsink fins. Yamaha have obviously accepted there is a problem with regulator cooling. I now use this item whenever I can.

**davidlomax** · #5 5 Sep 2002

does that mean I can change my 1vj reg/rec for a 4pt item? it would be good if I can as I am buying a new set of electrics for an xmas trip to the sahara......

**POB/London** · #6 6 Sep 2002

Dammit! About 3 months ago I bought a new reg. from Yamaha - the unfinned silver one for the 3AJ! Should I try to relocate it in the airflow? I don't think this would be a problem...

**david lambeth** · #7 6 Sep 2002

Hi.
The early xtz750 uses a similar plain reg/rec but it is mounted on an alloy heatsink plate. You could use a s/h one of these or make one similar. Always try to mount it in flowing air if poss.

David L.