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Odd starting problem


rhoderage

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Curious for your input on this one...

 

I've been chasing an odd starting problem over the past 2 summers.  With battery fully charged (via battery tender), sometimes when I press the start button nothing happens.  The dash lights will dim a little like its trying to crank but silence.  This happens sporadically, certainly not every time, and in 95% of cases after trying a few times it will eventually just fire up properly.

 

My starter relay was replaced 3 years ago with OEM, I've checked it and its good.  So is all wiring in that area, Honda replaced the battery harness and all that junk, and I've changed out the fuses and replaced the crispy wiring in that area.  This does not seem to be the source.

 

I also replaced the actual handlebar switch assembly, as the starter button was cracked in half when I bought the bike (just did the switch assembly this winter, I've had the bike 8 years and this problem existed before and after changing this out)

 

I've pulled the power lead off the starter and cleaned up the connection there, no issue.  Checked all the wiring to and from, no issue.

 

**What I noticed the other day - it was having one of these moments, and I put the kickstand up, and it started.  WTF.  I always start in Neutral with the clutch engaged.  In this exact state, raising the kickstand then allowed the bike to fire up.  Tried again a couple of times since when it was being finicky and by putting the kickstand up it has fired up immediately each time I tried, after failing to start with it down.  (80% of the time bike starts fine with kickstand down)

 

Maybe I'm misunderstanding the kickstand switch but I thought it would kill the bike, if it was faulty shouldnt I be having issues running not just on the occasional start? 

 

A little perplexed, interested in your thoughts.

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Sounds like your clutch diode might be faulty, OR, If your issue is more of an intermittent one, then it might be a dicky Neutral Switch. That means the only ground source for your starter relay is through the Side Stand UP and Clutch pulled in, which is the way you get around the problem.

 

Does your Neutral Light work normally when the fault is there? If when in Neutral it does NOT illuminate then it will be the Neutral Switch or its wiring.

 

Do you normally Start with the Clutch "Engaged" assume you mean pulled in, because without the clutch lever pulled in the Side Stand Switch has NO effect on the Starter Relay energising.

Provided the Neutral Switch and the clutch diode is OK, there's no need to pull the clutch for starting.

 

The ECM will kill the engine if it sees the side stand as Down AND the bike is NOT in Neutral.

 

The drawing below is only showing the Starter System, it doesn't show the inputs from the Neutral Switch, Side Stand Switch and Clutch Switch going into the ECM which it uses for Engine Kill logic.

 

If you look at the G/R wire (GROUNDING wire)of the Starter Relay it has two paths it can get a Ground from to energise the Starter Relay. 1 - via the clutch Switch (pulled in) then through the Side Stand up position. And. 2 - Via the Neutral Switch (In Neutral) through the upper Diode to the G/R wire.

 

Lets know what your Neutral Light is doing when your bike is playing up. It will help diagnose where your problem might be. NOTE drawing shows Clutch Switch in the clutch lever pulled IN state.

 

Hope this helps 

Cheers.

 

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Thank you for the detailed reply.

 

I always start the bike with the clutch lever pulled in, and always in Neutral, and in all instances referred to on the sidestand.  Neutral light functions properly at all times

 

I'm not great with electrical diagrams so any help in the right direction is greatly appreciated.  I do have a multimeter - havent used it much - but I can follow instructions

 

 

 

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On 13 July 2019 at 4:53 AM, rhoderage said:

Thank you for the detailed reply.

 

I always start the bike with the clutch lever pulled in, and always in Neutral, and in all instances referred to on the sidestand.  Neutral light functions properly at all times

 

I'm not great with electrical diagrams so any help in the right direction is greatly appreciated.  I do have a multimeter - havent used it much - but I can follow instructions

 

 

 

Ok, so if the Neutral Light is stable and doesn't flicker or carry on when the fault is present then the Neutral switch would appear to be OK.

IF YOU ARE ABLE TO CRANK YOUR ENGINE 100% OF THE TIME WITH SIDE STAND UP AND CLUTCH PULLED IN. Then other than wiring or connections it points to an intermittent open circuit Clutch Diode. 

You might have a poor connection at the Diode as it just plugs in like a fuse.

 

TRY THIS - Locate the Diode unit in your Fuse Box. Simply and carefully remove and ROTATE it 180deg and insert, hopefully if it's not keyed you can rotate 180deg. This will swap the two diodes around to see if this has any effect on your fault situation. Perhaps a squirt of WD40 on the Diode blades or the socket might help any poor connection.

 

If you can't rotate the device because it's keyed, then check the diodes with your multimeter. Select diode range on your multimeter and with the Black probe on the B point and Red lead on either A or C you should get a reading, and both A and C should read the same. Now swap your leads around (Red lead on B)and there should be NO reading for A and C. If it appears normal try blowing some warm air from a hairdryer to heat up the diodes and recheck with your meter.

 

If you have any doubts about the Diode, replace it with a new one, I really think your issue is associated with the Clutch Diode OR its wiring from the Diode to the G/R wire connection at the Starter Relay. You can check this by making sure you have good Continuity from the Diode Anode (G/R wire side) back to the Starter Relay.

 

The 2 photos are showing you what you should see on your meter when you check a Diode which is in effect a One Way Valve. First photo shows the Diode conducting, allowing current flow. Second photo with the meter leads swapped is the blocking effect ie no current flow. You should see the same results when you check your Diodes, if not you've found a dud Diode.

 

Good luck. Let's know how you get on.

 

 

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Just wanted to update and say thanks again for the detail... with the kickstand up eliminating my issue temporarily, I am feeling less rushed to do this... I'm waiting for a few electrical parts to arrive (gear indicator, voltmeter, USB port) and will probably get at this all at once and just pull the fairings and make a day of it.

 

When i get it done i will come back and post.  Again, appreciate the detail and I will be following the steps above.

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