problem electric or fuel

[polisher]

Hi Guys
Newbie here,
just brought 2009 GV125 Aquila the problem is this.
When off choke the bike will not tick over unless i higher the tickover. then when i switch the lights on it slowly dies again.
If i remove the rectifier the revs go high, so i turn them back down. but as soon as i reconnect the rectifier the revs drop and stalls.
I have replaced the rectifer (second hand) as it was getting red hot. but still the same. The only other thing i can think of is there is a short some where that is causing a massive current draw.
When the rectifier is disconnected the bike runs quite well and even with the lights on there is very little current draw on the battery
I have disconnected everything i can while the bike is running but still doing the same
Can any one help?
Thanks

[Islander]

You'll need a multimeter to test for shorts. Maplin stock them for about a tenner.

[polisher]

got one, but then how do you check?

[Islander]

A good place to start is measuring the voltage available at the battery terminals to get an idea of its condition.

[Islander]

Sorry - interrupted.

If you're happy with that then start checking the lighting circuits. You'll need a wiring diagram for the bike. Disconnect the battery, put the meter on the resistance or audible continuity range, clip one lead to an earth point and check the resistance of each of the lamp circuits after the switch - they should read lowish (you're measuring the filament resistance) but not zero.

[Daytona Dean]

Hiya....ive been having a look and these two links are intresting...the cbr one perticularly as it does say when lights turned on cuts out.. https://www.ehow.com/how_12016772_test-cbr-regulator-rectifier.html the second link is a step through thing like you had but pay attention to stage 5 6 7 https://www.electrexworld.co.uk/acatalog/pdfs/Troubleshooting-3P-PMG-&-RR.pdf last night when we were reading the voltage across the battery at idle it shouldnt drop below 13v nevermind 4v... do the tests in the links and see what comes up... after cleaning the pilot and bowls on the carbs something tells me the rectifier is playing up...like you say runs perfect when disconected..??

[DMCpro]

how long ago did you buy it, can you not take it back and complain...?
____________________
Honda CB-1, TS125X
VW Golf Estate

[polisher]

i am getting 13 to 14 volts on the battery. as for the cutting out part, when i switch the lights on it doesn't just cut out dead. the revs slowly drop then cuts out, but even with the lights off the tick over seems to vary quite a lot. you can set it to 1500 then after few secs it will rise then fall the perhaps cut out. I have been told that by removing the rectifier the bike revs would rise, but this seems not be the case with my other bike although it does run a bit rougher.
When it does cut out it seems to take ages for it to start with out a bit of choke.
as for taking it back unfortunately brought it private..
would holes in the carb diaphragm or inatke mounts cause it?

[polisher]

ok up date testing rectifier
with the positive lead connected to the earth terminal on the rectifier and the neg lead on the other connections my readings are as follows .781 .781 .775 this is set with the meter in ohms. both of my rectifiers read this so are they bad?
with the + and neg leads switched on the +/- terminals on the reg it is reading 1.7ohms

[Daytona Dean]

ok think ive got it...your rectifier is working...and when you take it off you adjust the idle to acommadate the extra rpm...but when you blip the throttle the revs still hang and dont fall correctly...so i would say you have an air leak on the carbs somewhere...put the rectifier on adjust tick over to 1,500rpm...then whip the carbs off and just check where they are seated in the barrel and where the airbox is connected...im pretty sure you have an air leak if there is an obvious sign like they are not seated on the rubbers correctly that is deffo the problem and check the diaphram while there off could ov gone brittle with the little use it had then split...100% air leak my man..!!

[Daytona Dean]

https://www.ehow.co.uk/info_8695392_symptoms-motorcycle-carburetor-manifold-leak.html before you take the carb off just make sure the header pipes on the exhaust are tight and sitting in there copper gasket correctly as it can suck air in from there if not sitting flush...

[Islander]

[polisher]

ok cheers,
one question though
why would the rectifier make that much difference to the rev's? when it is connected or not?

[polisher]

only got reading one way if i remember

[Islander]

[Daytona Dean]

the rectifier didnt make that much difference....when disconnected the rpm went up....so used the idle screw to bring it back down but when reved with it disconnected it still was taking time to rev and the revs were hanging at 2,500 for a few seconds before dropping to normal idle...i garantee its an air leak...mark my words....thinking back i had a rg125 that wouldnt idle revs hanged like yours...but i had a spare carb with rubber manifold replaced it and it run...and looking back the one i took off had a split where you tightened the square rubber mount to the head...didnt care at the time what was wrong because the spare one worked but looking back now that split must ov been why..!!

[Islander]

[Daytona Dean]

https://www.youtube.com/watch?v=XzjSEYB9RDU watch...your carb has come lose where it attaches to the engine and so there is a vacuum leak just check it...

[Daytona Dean]

https://www.youtube.com/watch?v=YH6306zM-Ug
https://www.motorcyclecarbs.com/Motorcycle_Carburetor_Troubles_W127C551.cfm read the part about hanging idle..!!!

[polisher]

cheers guys found a leak in the inlet manifold. Could here a chuffing noise
the clip that holds them together was pinching it somehow. put some ladder clamps on it and it runs like a dream.
the revs dont drop with the lights on either
very much appreciated. well happy