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Super weird starter issue


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Hi guys,


Problem is happening on my 1992 Bandit 400, not on my VFR 750 but I cannot find out what is wrong so I am asking for help to all tech gurus spending some of their time here ūüėČ


Bike is 26 year old, 101 000 km on the odometer. In the 8 years of ownership, I synch'ed the carbs many time (improving my technique  each time), I have rebuilt the gear box (faulty output shaft bearing) and more. Work(ed) like a charm until it spent one night outside more than 2 weeks ago (so late October): bike was under an external shelter, outside temperature at night was probably around 10 deg C, some humidity in the air. I live on French Riviera so temperature had nothing to look like Alaska nor humidity like Borneo or Java. It should not have been an issue.


Here are the symptom:
1/ most obvious: instead of requiring to press the starter only once, it now needs to press it 4 (long) times until it fires. Then it fires shyly to warm almost normally. So once started, everything seemed fine. 
2/ since that happened (almost 3 weeks now), I noticed it does not fire 100% correctly so I can ride it gently as usual but it does not rev correctly when I rev it hard (which I never do). 
3/ Now the super weird symptom: I have a C-Tek battery charger and a comfort connect indicator like this:
https://smartercharger.com/accessories/#CTEK Comfort Connect Indicator Eyelet
I noticed that once the bike is started, the Green LED is flashing (hopefully since the Reg is directly connected to the battery and is sending up to 15.0V to it's doing its duty) but at the same time, the RED LED is lightly lighting with intensity increasing with REVs (see the picture)... that is making me crazy. Battery is almost 2 years old and is cheap Chinese battery (less than 40‚ā¨).




Super funny: it is super hard to start with the starter but when I push start the bike, it fires within one second...


So I am leaving with it since 2 weeks and a half now. 
#1 made me think about an air leak but that would rather happen when hot, not when cold. Furthermore, the bike does not die when warm.
#2 made me think about fueling issue like enough to start but not the rev it properly but this is not really the case, I have probably ridden it for 200km since that. Poor fuel flow should have been more obvious (I think).
#3 made me think about a current leak. That happened to me once and was more obvious: some sparks were going out of the spark wire to the engine case and I had the bike that rattled. I saw it (I mean I physically saw the sparks going to the engine case), replaced the wire and that was it. 


I spent 3 hours on Sunday to find such a current leak but did not find. I exchanged/swapped all 4 spark plugs, the spark caps and the wire but nothing changed. The RED light is still ligthly lightening when the bike is running. I tested with the stator disconnected but then only the RED light is fully on because I am draining the battery to run the bike.


What I have not done is replacing the battery. I have no idea how I could spot some battery internal part that should  have been damaged. I have an old battery that have been replaced because it did not hold the charge anymore but I believe the internals were not damaged (no shortcut or something similar). I am charging it fully today and will try tomorrow to determine whether the battery might be the cause or this should be something else.


What do you think about my situation? Any clue about what could be the root cause?


Other options are:
- replacing the harness because I have another one in better conditions
- buy brand new spark plugs caps because those are old.  I also bought some NGK but they are too short, the angle is too close from the engine so they does not fit 100%.
- buy new coils? I have no spare.
- finish restoring my VFR (this is on-going)
- buy another bike


Thanks a lot in advance for your answer(s).

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may enjoy a new good battery, sounds like you might not have enough current for strong ignition, just enough to sorta operate starter & other loads

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Because the Bandit 400 is an older bike there's no computerized ECU to detect lower-than-normal system voltage during cranking and react/compensate by correcting (lengthening) spark plug dwell time to guarantee proper coil saturation before the spark is fired, so as the battery ages and begins to deliver less and less cold-cranking amps you end up with a weaker spark due to lower/incomplete coil saturation.  This alone might not create a hard-to-start situation, but combine this with something else like older spark plugs that have developed an incorrect spark gap or HT lines that are less efficient than they were originally, and these additive conditions can give you this sort of result.  But that only addresses the electrical side of the coin and as a B4 owner you surely know that those Mikuni BST32SS (or BST33SS) carbs are very small and their small passages get blocked very easily.


(Hello again, Benoit, my '93 B4 fuel injection project bike is still running great, pictured here out on the roads between Denver and Colorado Springs with my brother riding it during June of 2018.  He's a bigger guy so he makes the B4 look like a really small bike)



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Hi @GreginDenver,

So happy to see you here ūüėȬ†I see you are still enjoying both the your Bandit 400 and your VFR.¬†

I did not enjoyed my VFR too much (only 250 km until now) but that will change soon.


What you said is making sense (as well as @airwalk). Thanks a lot.


Some news. Bike gods were either against me today or they prevented me from going to something really bad, who knows... Anyway, when I got back to my bike today, I smelt gas and found that I let my petcock on PRI for the last 24h so obviously some leaked into the engine and contaminated the oil. If I was not completely stupid, I should have stopped there and called my wife to pick me.


But I tried to play my chance and come home gently (understand without revving the engine too much). And then... bam impossible to start the engine, like a real short circuit in the battery. That was it. I intercepted a colleague (and very good friend of mine) to pick me home and tomorrow, I'll go with a brand new battery and enough tools to make an impromptu oil change at work (not sure security will appreciate).


Then next on my (Bandit) maintenance list is: new spark plugs + new spark plugs covers (OEM) + new coil wires. 

I don't remember how old are my NGK Irridium spark plugs because I started my maintenance Excel sheet long enough after I installed them but they have a least around 24 000 km on the clock (maybe close to 30 000 km) which might be like (way) too much. 


I keep you posted.

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Some news from today and they are not good. I took my day off but went to work. I changed the battery and the oil. 

Then no more chance than yesterday night. And I noticed I did not describe properly how I ended.


Starter relay is clicking but engine is not cranking.

(note that the background noise is the building ventilation, not my bike).


More strange, it's impossible to jump start the bike because as soon as I release the clutch, the bike stops violently (like something mechanical preventing the bike from moving).


I googled/youtube'd "motorcycle relay clicking" and found the following possibilities (which I believe does not explain my originally RED LED flashing but nevermind) :

- bad starter relay

- bad connections between battery / starter relay / starter / ground

- bad starter 


Can starter be blocked and that prevents the bike to be jump started?


Thanks for your help.

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usual cause of a clicking relay with no start is a low state of battery charge.  starters themselves rarely fail.

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Had this exact issue in my ‚Äúother‚ÄĚ bike - dead battery. Fired right up after a charge.¬†


As as it gets colder a marginal battery will start showing its weakness this time of year. Either charge or replace. 

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Unfortunately, I don't think that's the battery. I just installed a brand new one (put the acid inside around noon, installed it in the bike at 03:00PM).

I just don't understand why I cannot push start the bike. I will remove the starter today and see if the output axle can rotate freely.

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The "click" you're getting from the stater relay sounds like a healthy, full-voltage click.  If the starter relay wasn't getting enough voltage to hold it in the engaged position it would probably make a rattling, ragged-sounding noise.  If I'm interpreting your short video correctly it shows you pressing the starter button twice and with each press you get a good, solid-sounding click of engagement from the starter relay, is that true?  If so, it could be that there's nothing wrong with the starter relay.


It would seem that you've checked off these items: Good battery and good starter relay engagement.  


Maybe there's just something preventing voltage from flowing through the starter windings, like perhaps the starter motor's path-to-ground (negative) wire has come loose?  Or maybe there's a problem at the main grounding lug on the engine?


But.... it's possible that your situation has nothing to do with the electrical system:


"More strange, it's impossible to jump start the bike because as soon as I release the clutch, the bike stops violently (like something mechanical preventing the bike from moving)."


This statement is a bit worrying.  You mentioned yesterday that you accidentally left the bike's petcock in "prime", I guess it could be possible that one (or more) of the cylinders is full of gasoline and you are experiencing Hydraulic Lock as a result.  Just a thought.

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OMG... that make perfect sense.

I hope I did not break anything like bending the valves...


At lunch time today, I removed the starter and checked it was freely turning. In the end, with the help of a fellow rider and colleague, we saw the starter working by bypassing the relay but I believe the relay might be fried now after all our attempts.


Will bring my spark removal tool tomorrow and see. Fingers crossed. 



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So I had an electrical issue to start with. And that might end in broken engine because I forgot to close this f... petcock... 

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IF this is hyudraulic lock...gas may have also seeped past the rings into the oil...right? If so, check your oil sight window as well.


IF it is the case you'll have to change your oil as well.  Could also loosen the spark plugs so there's a path for liquid to escape...




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@zupatun I had difficulties to start the bike for 3 weeks now. But it started. I described those symptoms in the first post. And by searching for the problem, I accidentally let the petcock fully open on Sunday night (Nov 11th). 


I asked for help on Monday during the day (the 12th). Symptoms were only difficult start and weird behavior of my charger connector. 


On Monday night, I noticed the gas smell and found I let the petcock opened and closed it. I also saw gas contaminated the oil but did not think some could have stayed in the cylinders... At that point, it was not possible to start the bike (only click on the relay) nor jump start it. That would be normal if there's plenty of fuel still in the cylinders.


On Tuesday afternoon (the 13th), so approximately 20 hours after I closed the petcock, I changed the oil for new oil and put a brand new battery. Same (new) symptoms: relay clicks (this is when I made the video )and no jump start possible.  At this point, we might expect all fuel to have gone into the oil and no more in the cylinders but there might be still some gas inside the cylinders. Let's hope that did not contaminate the fresh oil.


Today (14th), I believe I killed the relay (RIP) but I have another one that I will bring tomorrow and saw that starter is running when disconnected from the engine (when bypassing the relay). 


Tomorrow, I'll remove the spark plugs and see if with a new relay (or by pushing the bike) we can see gas getting out of the cylinders through the spark plug holes.

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Another thought: Even if it turns out that the issue isn't hydraulic lock I wonder if the current situation might still be a direct result of the accidental fuel bath the cylinders got.  If the cylinder walls were stripped of their oil film there might now be so much static friction between the piston rings and the cylinder walls that the starter motor doesn't have enough torque to turn the engine over (the starter motor is getting proper power but is "stalled" by the friction load).  It would effectively be a "cold seized-engine" condition.  This is just me thinking about the situation while I was running this morning.  I think it might be wise to test for this condition by carefully hand-turning the engine (in the proper direction only, of course) just the way you do it during a valve adjustment proceedure.  If it feels like the crankshaft cannot be turned with normal/reasonable force (I would assume that every Bandit 400 owner would be familiar with this from having performed valve adjustments, and would be able to judge this correctly) then I'd suggest spraying some engine oil through the spark plug holes into each of the cylinders.

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Thank you @GreginDenver¬†you were right with the hydraulic lock ūüėȬ† Cylinder #3 (according the the service manual page 1-3) was full of gas. I removed the spark plugs, put in the 5th gear and run it. I received gas on my face, in the eye and on my shirt... but I am ok.¬†


After I made everything necessary, it is running again... with the original electrical problem still there ūüė쬆so not as smooth as it should. The difference with my original post is that I replaced the battery with a new one and also the starter relay.¬†


So I am left with my original issue...


I made it run for a few minutes in order to warm it a little bit and see how it goes when warm. Let's hope I can come home without trouble tonight ūüėČ

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So I got back home with the engine not running perfectly . In fact, that is exactly like how I got to work on Monday morning ūüėČ


Gone is the hydraulic lock issue and I learned my lesson. Watch out the petcock when you put it in PRI...


I also have new clues about my electrical issue which is quite good.

Here is the thing:

- On Sunday, I removed my 25-30 000 km irridium spark plugs and put back my previous regular spark plugs (which I changed after 12 000 km) and were still ok. The one from Cylinder #1 was all black like my carbs were way out of synch (which I know is not true). The old one I put back into the engine had a "regular" brownish color.

- Yesterday, when I removed the spark plugs to remove the gas from the cylinder(s), the spark plug from Cylinder #1 was again all black after only 10 km (and a few tests on Sunday). 


Since I am:

- looking for a misfire issue

- I switched all spark plug

- I switched all spark plug caps

- I changed the spark wire on this cylinder (I know it)

this let me with a potential culprit which is the coil that is driving cylinders #1 and #4 - more precisely the output connected to  cylinder #1 


The quest continues...

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