Triumph Rat Motorcycle Forums banner

1 - 12 of 12 Posts

·
Registered
Joined
·
255 Posts
Discussion Starter #1
My '06 Tiger was starting a little sluggish and the battery was only getting about 12.1 volts across the poles so I replaced it with new.
Interestingly it fired up great but when I measured voltage I found I was getting about 13.8 across the poles. As I revved the engine up it drops down to about 13.0-12.9 at about 4k rpm. When I let it drop down to idle it comes back up to 13.8.
This doesn't make much sense to me. I claim to know very little about electrical systems but it doesn't seem right.
 

·
Registered
Joined
·
1,722 Posts
There have been other similar threads - ISTR that generally this suggests a regulator / rectifier problem.
 

·
Registered
Joined
·
265 Posts
My '06 Tiger was starting a little sluggish and the battery was only getting about 12.1 volts across the poles so I replaced it with new.
Interestingly it fired up great but when I measured voltage I found I was getting about 13.8 across the poles. As I revved the engine up it drops down to about 13.0-12.9 at about 4k rpm. When I let it drop down to idle it comes back up to 13.8.
This doesn't make much sense to me. I claim to know very little about electrical systems but it doesn't seem right.
I am having a similar problem with my 06. Pretty much the same readings you are getting. I used my Midtronics battery tester (I own a automotive shop) on my battery and it was failing the test. Replace with a new Yuasa and the bike starts noticably better but the charging rate is still the same. Made me think charging system woes may be what trashed the old battery. In my automotive work, I have learned there can be real shortcomings using a DVOM for some electrical testing. I use a Fluke 192b DSO and low amp inductive probe almost daily and am comfortable with their use and decided to use them to check my charging system. The advantage of doing this is the system can be checked intact at various points without unplugging any connectors. Also I get to see a "picture" of whats happening in my charging system. First, I checked the three AC legs coming from the stator. All three showed good AC waves both at idle and 3-4k. No break up or differences between the waves so at this point I assume the stator is good. Next I connect the probe around the B+ coming out out of the RR going to battery positive. The waveform here should look like half of an AC waveform as thats what the RR does, clip half of the AC resulting in DC. At idle my DC wave looked just fine, but when the engine is revved, the wave gets very distorted with a bunch of garbage in it. Not good IMO. I would think from the wave I'm seeing that one or more of the diodes in the rectifier bridge are crapping out under high current load. I have another RR on order, will see what happens when it arrives.
 

·
Registered
Joined
·
1,722 Posts
..... Next I connect the probe around the B+ coming out out of the RR going to battery positive. The waveform here should look like half of an AC waveform as thats what the RR does, clip half of the AC resulting in DC. .....
I'd have thought we'd have full wave rectification, especially with a three phase alternator, so that the "negative" half would be inverted.

Something like:

 

·
Registered
Joined
·
265 Posts
Joe S.


Thats who I ordered mine from. I believe they have sent me the wrong one though ( by part number). Going to call them this morning and see if i can get it straightend out.


Iansoady

Actually yes, the last waveform is what properly rectified DC charging should look like and at idle mine looked like that. Sorry if I misguided with my statements.
 

·
Registered
Joined
·
265 Posts
On second thought Ian, I believe the third wave may be correct. I believe the diodes shunt half the AC to ground, thats why the RR has fins and tends to get hot. When I checked my bike, I had scope setting that did not expand the wave very well. When my regulator shows, I will test again and expand a little to see what it actually is.
 

·
Registered
Joined
·
1,722 Posts
Yes, it'd be interesting to see the results. My diagrams were based on what I would expect, not what I've actually observed.

However, it would seem very wasteful to chuck half the alternator power away, not to mention that it would get very very hot if the reg/rec was disposing of nearly half a kilowatt!!!

I would expect the reg/rec to get hot because of its regulating function, although I'm not sure how it does that.
 

·
Registered
Joined
·
265 Posts
Install the new RR last night and my Tiger seems to be a much better charger now......13.8-14.0 v at 4k rpm. The scope pattern behaves better too, no scattering or dropping out at elevated rpm. The charge voltage seems a little low at idle, around 12.8v. But after thinking about it, I think this is an acceptable level for idle. Automotive alternators are spun at 2 to 3 time engine rpm so they put out well at idle to handle things like air conditioning loads. Also autos have varible field current that adjust for various loads. The motorcycle systems are honestly quite crude in comparison......field is fixed by a set of permanet magnets that are spun at engine rpm only. Ian, after looking at the output wave after the repair, I really belive it is 3 wave half phase. It also looks like the RR may be using some kind of avalanche diodes which make sense sine the Tiger uses a ECM for engine control. Not sure about any of this really, just know that mine is fixed and I'm off riding.
 

·
Registered
Joined
·
178 Posts
Stay away from any products made by Electrosport, stator or regulator, and save yourself a headache.
 

·
Registered
Joined
·
255 Posts
Discussion Starter #11
I ordered a regulator/rectifer through my local independent dealer, for $110. Don't know who makes them, likely whoever makes them for www.regulatorrectifier.com I should think. Electrosport doesn't have them on their site.
In any case for far less than half of the pricey Triumph part, which lasted a whopping 14 k miles, it seems worth the risk to try aftermarket.
 

·
Registered
Joined
·
255 Posts
Discussion Starter #12
Finally got around to installing the new regulator this afternoon.
Runs at a steady 13.9 V at 4k which seems about right, certainly better than 12 something anyway.
 
1 - 12 of 12 Posts
Top