NC35 ignition problem
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Please can you post items for sale or wanted in the correct For Sale section. Items / bikes for sale here will be removed without warning. Reasons for this are in the FAQ. Thanks
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MR835
- Settled in member
- Posts: 4
- Joined: Sun Mar 08, 2009 3:48 pm
- Location: Southampton
NC35 ignition problem
Morning all,
All was going well with the RVF until the other week I hopped on went to ride off and it seemed to really hesitate under acceleration and make a strange *brrrrr* (yes thats the closest approximation i can come up with!) as if it was firing on three cylinders. Since then I've changed all the plugs and swapped the coils with a new (to me) set from an NC30. The bike is fine when its up on the abba stand and idling, even revving the engine sounds fine. If you apply any load by using the back brake it starts to struggle, and sure enough if you attempt to ride it the instant the bike is rolling the jerky acceleration comes back. I had thought it was something to do with the anti-derestriction system kicking in, but that comes into play only after 4k right?
I'm checked over the electrics once, twice, thrice and the coils, HT leads and pulse generator are all within specification. The only suspect reading I am getting it the primary voltage to the coils. With the battery reading 13.0v across the terminals I get:
Front Coil Bu/Y wire : 11.76v (and 2nd time) 11.8v
Rear Coil Y/Bu wire : 11.85v (and 2nd time) 11.87v
...the service manual says this should be the same as the battery....so I've lost a volt somewhere along the line. Would this lead to a weakened spark? Can anyone confirm what readings they get on a working NC? Does this mean the ignition module is at fault?
much thanks!
All was going well with the RVF until the other week I hopped on went to ride off and it seemed to really hesitate under acceleration and make a strange *brrrrr* (yes thats the closest approximation i can come up with!) as if it was firing on three cylinders. Since then I've changed all the plugs and swapped the coils with a new (to me) set from an NC30. The bike is fine when its up on the abba stand and idling, even revving the engine sounds fine. If you apply any load by using the back brake it starts to struggle, and sure enough if you attempt to ride it the instant the bike is rolling the jerky acceleration comes back. I had thought it was something to do with the anti-derestriction system kicking in, but that comes into play only after 4k right?
I'm checked over the electrics once, twice, thrice and the coils, HT leads and pulse generator are all within specification. The only suspect reading I am getting it the primary voltage to the coils. With the battery reading 13.0v across the terminals I get:
Front Coil Bu/Y wire : 11.76v (and 2nd time) 11.8v
Rear Coil Y/Bu wire : 11.85v (and 2nd time) 11.87v
...the service manual says this should be the same as the battery....so I've lost a volt somewhere along the line. Would this lead to a weakened spark? Can anyone confirm what readings they get on a working NC? Does this mean the ignition module is at fault?
much thanks!
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MR835
- Settled in member
- Posts: 4
- Joined: Sun Mar 08, 2009 3:48 pm
- Location: Southampton
Re: NC35 ignition problem
BUMP, (my own thread?!)
Is there not a single working NC35 between the members of this board who can tell me primary coil voltage??! incredible...
Is there not a single working NC35 between the members of this board who can tell me primary coil voltage??! incredible...
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tk400
- Settled in member
- Posts: 19
- Joined: Sat Oct 18, 2008 3:04 am
- Location: Australia
Re: NC35 ignition problem
Ok...you should not see that much voltage drop but it should not be causing you trouble.
Coils are probably drawing 4 amps each so worst case is E=IR R=E/I R=1.2volts / 8 Amps
R = 0.15 Ohms
This is not to hard to beleive given stock wiring.
I would reduce my plug gap and see if that helps, if it does then post again.
cheers
Regards TK400
Coils are probably drawing 4 amps each so worst case is E=IR R=E/I R=1.2volts / 8 Amps
R = 0.15 Ohms
This is not to hard to beleive given stock wiring.
I would reduce my plug gap and see if that helps, if it does then post again.
cheers
Regards TK400
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jamie
- Settled in member
- Posts: 31
- Joined: Mon May 11, 2009 6:44 am
- Bike owned: NC30
- Location: Barrow
Re: NC35 ignition problem
Isnt that meant to be V=IR (ohms law) 
I have just done a write up today for checking ignition coils, here it is if you want to test them
Borrow a multi meter if you dont have one and set it to ohms, it might have different ranges on it so you will need to switch it to a range where you can measure up to the specified ohms for the test you are doing, you will find the values at the start of the ignition section in the Hanes manual. If its like mine you wont have all the different settings just the selection for ohms.
The ignition coil has 2 sets of windings. The primary, which is where the 2 wires connect and the secondary, which is the side where your spark plug caps (red leads) come off.
There are 3 tests you can do to determine if there is a fault
1. Disconnect the 2 wires on the primary side and put your meter probes on the contacts of the ignition coil. You will now have an ohms reading on your meter, Should be within 2.5 - 3.5 ohms. This test will prove your primary windings are ok.
2. Pull the caps off your spark plugs and put one probe down one cap and the other probe down the other so you are measuring from the cap end down the lead, through the secondary windings and back up the other lead. The contacts are quite far down the spark plug caps so make sure you push your probes in well. You should have a reading on your meter, the tolerance for this is around 14k - 25k ohms. This test proves your secondary windings and your plug caps and leads.
If this test failed you will need to do the next one to determine weather its your leads or secondary windings that are at fault, if it was within tolerence you wont need to do the next test and you will have a healthy ignition coil and leads.
3. Disconnect the red leads from the coil pack and put your meter probes accross the secondary windings, again the contacts are quite far down. It should read within 11k - 14k ohms. If the ohms reading is within tolerance that would suggest your leads are at fault and obviously if the readings are out your coil is faulty
hope this helps
Jamie
I have just done a write up today for checking ignition coils, here it is if you want to test them
Borrow a multi meter if you dont have one and set it to ohms, it might have different ranges on it so you will need to switch it to a range where you can measure up to the specified ohms for the test you are doing, you will find the values at the start of the ignition section in the Hanes manual. If its like mine you wont have all the different settings just the selection for ohms.
The ignition coil has 2 sets of windings. The primary, which is where the 2 wires connect and the secondary, which is the side where your spark plug caps (red leads) come off.
There are 3 tests you can do to determine if there is a fault
1. Disconnect the 2 wires on the primary side and put your meter probes on the contacts of the ignition coil. You will now have an ohms reading on your meter, Should be within 2.5 - 3.5 ohms. This test will prove your primary windings are ok.
2. Pull the caps off your spark plugs and put one probe down one cap and the other probe down the other so you are measuring from the cap end down the lead, through the secondary windings and back up the other lead. The contacts are quite far down the spark plug caps so make sure you push your probes in well. You should have a reading on your meter, the tolerance for this is around 14k - 25k ohms. This test proves your secondary windings and your plug caps and leads.
If this test failed you will need to do the next one to determine weather its your leads or secondary windings that are at fault, if it was within tolerence you wont need to do the next test and you will have a healthy ignition coil and leads.
3. Disconnect the red leads from the coil pack and put your meter probes accross the secondary windings, again the contacts are quite far down. It should read within 11k - 14k ohms. If the ohms reading is within tolerance that would suggest your leads are at fault and obviously if the readings are out your coil is faulty
hope this helps
Jamie
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tk400
- Settled in member
- Posts: 19
- Joined: Sat Oct 18, 2008 3:04 am
- Location: Australia
Re: NC35 ignition problem
E = IR is actually the proper convention for ohms law
http://www.electronics-tutorials.com/ba ... ms-law.htm" onclick="window.open(this.href);return false;
Although I agree that in forums V is probably more appropriate. cheers
Regards TK400
http://www.electronics-tutorials.com/ba ... ms-law.htm" onclick="window.open(this.href);return false;
Although I agree that in forums V is probably more appropriate. cheers
Regards TK400
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jamie
- Settled in member
- Posts: 31
- Joined: Mon May 11, 2009 6:44 am
- Bike owned: NC30
- Location: Barrow
Re: NC35 ignition problem
Never seen that before i wonder if we use different symbols as were in different countries
http://www.electronics-tutorials.ws/dcc ... dcp_2.html" onclick="window.open(this.href);return false;
i apologise
Jamie
http://www.electronics-tutorials.ws/dcc ... dcp_2.html" onclick="window.open(this.href);return false;
i apologise
Jamie