Why are motorcycle reg/rec's so unreliable?

[dyzio]

Might be a bit to harsh with the thread title, but:

My bike currently shows symptoms of a dead RR, there have been numerous threads on here on the RR faults on the SV. Triumph forums seem to be full of them as well, at least the 675's.

I spoke today at work with someone from the electronics department, and the person was surprised at the common* RR faults. A quick google revealed a diagram with a few diodes, so I'm surprised as well.

*) Of course, it might also be that I'm seeing a few dozen faults reported, however taken in perspective of the number of bikes sold, it's only a minimal percentage of units failing.

Is there any explanation what causes them to fail?

[Sid Squid]

They're not. The overwhelming majority of people have never suffered from this problem, they don't post up that it's working just fine, the opposite isn't the case though.

Go to a motor factors that does exchange alternators for cars and vans, they sell lots too.

[Bibio]

its not the RR its the grade of wiring going to and fro as its been noted that upgrading the stock wiring makes them run cooler.

just like a processor in a computer if it gets to hot it breaks.

[Bluefish]

I'm with Sid, never had to change one on any bike i've had, Yet ;)

[yorkie_chris]

It is a very common fault. They break much more than CDIs, or conrods, or ignition switches...

The MOSFET ones last much much better, not seen a dead one yet.

[dyzio]

Yet ;)

I said that 10 days ago ;)


The MOSFET ones last much much better, not seen a dead one yet.

I think the post 2009 675's have a mosfet, but I also think there have been a few mentioned of them going bad as well.


I've had a look through the other site and I found what looks to be a replacement reg for 1/4 of the price (Triumph are asking 230 pounds).
Is there a way of telling if it's a MOSFET unit? It's described as a direct replacement (for a Kwak RR):

[tonyk]

My reg failed at the ace cafe..............everyone that came to look said yep a common fault on the 675's..even the AA man said the same.
The 675 forum said a known fault...........bloody hell, just lucky i got fixed under waranty...
But sayindg that, i had a bloody leak for 2 years and 3 services later, untill they fixed that. "bolt too long fixed by adding some washers". And now every now and again the engine management ligt goes on..but the time i get it to the deallers it goes off.....

[BillyC]

I'd just like to report that my regulators have always been fine. Thank you.

[HoL]

Sids sig says it all, everyone blames the RR to begin with no matter what the electrical fault is.

[injury_ian]

3yrs 35,000 miles on my shunt wound 3 cylinder 675cc superstar.

Its had a hard life, year-round use, heated kit, track days.... the lot.

Whilst the R/R hasn't broken (yet) a lot of other stuff has!

[dyzio]

Yeah, I spoke to a few people before buying the bike, certainly also an element of "sh!t happens" there :/

[Dave20046]

Sids sig says it all, everyone blames the RR to begin with no matter what the electrical fault is.

... and the reason for this?
Maybe because it's quite a common fault :s

[keith_d]

I think it's the mode of failure which is responsible for their high profile. The most popular failure appears to be a blown diode, which then behaves like a resistor instead of a rectifier and discharges your battery.

If this happens in your car, you get a little red light and have enough battery power left for several miles (even with the lights on). On a bike you generally find out when your battery is flat and you're stuck in the middle of nowhere in the p***ing rain. That's why they get so much attention.

MOSFET designs are more reliable because they don't suffer from thermal runaway. Diodes which overheat conduct better, so they carry more current which makes them get hotter and hotter 'til they're fried. For reasons I've forgotten MOSFET designs don't do this.

[Owenski]

6 bikes - 2 suspected RR failures. One was the RR itself the other was a wiring fault somewhere between the 3pin RR connector and the battery, never took the time to determine if that be the RR itself or some dodgy wiring. Just replaced the RR and wired it direct to the battery, never skipped a beat since.
Considering that history I've got reasonable grounds to assume a 33% fail rate on suzuki RegRecs

[jambo]

Considering that history I've got reasonable grounds to assume a 33% fail rate on suzuki RegRecs
I have owned 5 road bikes and never had a Reg/Rec failure.
Based on 12 years and 100,000+ miles, I have reasonable grounds to assume that the number of failures must be approaching 0.

The trouble is even if someone came on here once a week with a failed reg/rec, it would make it the most likely diagnosis for a charging fault, but given there are SV650s out there from the last 13 years, and people posting here from all over the world, that wouldn't actually mean that a lot of them failed. It would just mean that we got to hear about a fair chunk of the ones that did.

If I wandered through a GP's surgery and did a quick straw-poll of the people in there that were ill I'd find an alarmingly high number of ailments, many of them the same for that sample of the population, but that's because I'm not adequately sampling the people that are fine, and have no issue at all, year, after year.

Jambo

[Sir Trev]

My 1983 GSX250EZ got through three in as many years... Suzuki electrics were notorious for them in that era. Having said that the wiring was getting pretty duff all round by the time it got written off in 1991 so they may not have all been the RR's fault.

Earlier this year I had the RR on my GSX changed under warranty. *Some* had been manufactured incorrectly so all were recalled for a dealer replacement. The original owner had not gone in to get it done but when it got registered in my name the records prompted a letter out to me. Result (I hope).

[dyzio]

Good stuff. I've asked at the dealers but there wasn't an RR recall for my bike.

There is however an outstanding recall for something else, so the bike will be checked over at the same time. See what they say, I'll know next week.

[Terah]

When I bought my '99 curvy at the end of 2010 it had just had the RR replaced. The next one went at the GM in 2011 and then another one has gone just recently. This strongly suggests to me that something else is causing the RRs to fail but I haven't been able to track it down yet.

I suspect it's related to excessive heat, and some of the wires on the most recent RR had started to melt, but not sure what is causing that heat. Presumably it could be either poor wiring/connections, or too high voltage coming from the alternator? When I checked the alternator outputs they all matched, but were higher than expected (around 90V).

I've now replaced the RR with a MOSFET one, put a new connector on the wires from the alternator, and put a new connector on the RR output which is now wired directly to battery. If I have any issues again I'll look at the alternator and the wiring from it.

[yorkie_chris]

Alternator producing too much power is basically impossible.

[BillyC]

There is, it seems to me, a right load of cobblers being spoken about in this thread.

Stop it, now, or I'll tell your mothers!

[dyzio]

Could you be a bit more vague please?