Low alternator output (series-1)

AndyW

AndyW

Hero member
Cognisant that I've had to rely on a couple of gents in the Hills to push start the Mirage on the last couple of outings I thought I'd put a voltmeter across the battery terminals whilst it was running and give it a bit of a handful: no change (and only about 11.5volts..). So.. is there a better way of assessing the alternator output (i.e. am I missing something?) or do I need to replace/upgrade the alternator? If so what's recommended/available?  ??? ???
TiA
AndyW 8)
 
Better get it sorted before the next ride Andy. Don't want to push you all around the Hills again:D :D
Get the regulator checked by an auto electrician, easily done.
 
Hi Andy..if you check the two wires..yellow and yellow black that exit under the starter..be sure they are connected to that 1970s plastic bridge on the frame. If you are handy with a VOM, remove the wires from the bridge and check ohms to the engine case. One wire at a time, do not touch them together. You should have infinity. If not the "charging" coil is shorted to earth..no or little A/C volts available to the rectifer.

If the wires check okay..then set your VOM to a/c volts. Rig up some clips (with care) and connect your VOM to the two wires. Start the engine. You should have about 40 A/C volts, more or less. If much less..you have an charging coil problem.

You may still have that small rectifier on the right hand side under the tool tray? Those yellow and yellow black wires go there. That rectifier has a habit of burning out. Good time to change over to a real voltage regulator/rectifier. 
 
The Series I 180? Triples with CDI don't have a regulator which is why you need a big Ah lead acid battery on them.
This is a very useful device for checking batteries and charging systems:
http://www.sparkbright.co.uk/sparkright-eclipse-battery-voltage-monitor.php
 
I like that!!
Will check out what?s going on at the yellow & y/b wires this morning once/if the temp reaches double digits🥶🥶. Hopefully it?s just the r/r unit: plenty of aftermarket ones about..
 
The Sock said:
The Series I 180? Triples with CDI don't have a regulator which is why you need a big Ah lead acid battery on them.
This is a very useful device for checking batteries and charging systems:
http://www.sparkbright.co.uk/sparkright-eclipse-battery-voltage-monitor.php
Click to expand...

I did have a doubt.

Paul
 
its a Mirage, so IT WILL (very likely) have a rectifier/regulator, most series one 1000s do, and from about chassis#2899 (1975) aprox, variable, not set in stone.

1200's started in 1978, but there will always be someone who says 1977 and a few who (in the past) have tried to claim pre'72

CLEM
 
The very first batch of 1200s had CDI ignition, I think only a few hundred.
I have owned 2 of them.
They would have started producing the 78 model year when they came back from summer vacation in August 77 so some could very well be a 77 production.
The one I just restored (7th off the production line) was a 77 bike.
 
certainly agree on that grant, but did those CDI 1200;s have a reg/rect? no 7 for instance? which although numerically is no7 may not have been seventh off the line, as bikes were not always built in numerical order and in the beginning there may not have even been "a line" until chassis 20 or 30 even. protoype 1200's don't really exist as such and no7 could even be a pre-production, if there were any, the missing despatch records would help a bit on that one. If I owned it I would still say "seventh" perhaps pre-pro's had CDI? and productionised as BTZ, and I did say " very likely have a reg/rect" not definitely will have.
CLEM
 
It would have had the small rectifier box bolted under the tool tray.
Now it wears one of Red's finest 3 phase alternators, Ignitech ignition and modern r/r.
A deviation from original spec that is highly worthwhile.
 
"If the wires check okay..then set your VOM to a/c volts. Rig up some clips (with care) and connect your VOM to the two wires. Start the engine. You should have about 40 A/C volts, more or less. If much less..you have an charging coil problem."
Standard test of any alternator (without inbuilt r/r), you have to rev it up to fairly high revs to see what it puts out, not just start it. The Lav alternators at that time were pitiful. My 6v Ducati 450 had three phases and gave 85acv between any two at about 4500rpm, so I fitted a 12v r/r and never looked back.
 
... just additional comment on this - my 1200 (1977 # 2963 1263) has the standard Bosch alternator (and was BTZ's) however what perplexed me was the wiring. One induction coil seems to be designed for a higher voltage than the other (different winding) but are 'paired' straight out of the case. That seems just weird! So instead of a single pair of wires from the case, I have 2 sets that join up under the tank.

Any explanation would be appreciated but it does appear as if one coil would throw out 'voltage 1' and the other would throw out 'voltage 2'.

Doesn't identical coil winding seem logical?

 
Grant said:
It would have had the small rectifier box bolted under the tool tray.
Now it wears one of Red's finest 3 phase alternators, Ignitech ignition and modern r/r.
A deviation from original spec that is highly worthwhile.
Click to expand...

Certainly is.
Lusty, low comp motor combined with modern ignition makes for a fine, tractable and very useable triple.
One very happy owner :D
 
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