I'm at the end of my rope with this ongoing issue! My 2004 790 Bonnie has the classic no spark problem so up to now I've replaced the coil and the pick up coil, each time it seems like it's solved the problem only for it to recur the next day!
Here's how it goes...replace or check component bike starts and runs...in my shed, not ventured to road test it yet! Next day bike doesn't start, nothing touched or altered in any way from the previous day.
A couple of weeks ago I took the ignition switch apart to check it, all contacts undamaged but a couple had slight corrosion deposits. Cleaned them up to shiny new copper, re-assembled and happy days she fired up and ran no problem. Left it at that and went off on hols, came back and went to start her up...nothing not a cough, splutter or fart!
First question is regarding the safety switches, clutch, neutral, side stand. Given that they work correctly and prevent the engine from turning over do they have a separate function that stops the ignition from working while still allowing the engine to spin?
First question is regarding the safety switches, clutch, neutral, side stand. Given that they work correctly and prevent the engine from turning over do they have a separate function that stops the ignition from working while still allowing the engine to spin?
Both the neutral and stand switches disable the igniter. The clutch switch does not disable the igniter but instead disables the starter relay (headlight cutout relay).
If the bike is not running at all you can check out the stand switch by shorting its contacts in the connector with a paper clip, which will be the equivalent of 'sidestand up'. The neutral light will tell you if that switch is working visually, if the light comes on/goes off the switch is working.
You don't say whether the bike just won't start or whether it won't crank to start. If the bike does crank over, the clutch switch can be ignored in this instance because it does not prevent the bike from running.
And as silly as it seems, there have been a few with intermittent and rough running problems on here, all with carbed bikes I notice, who have found the cause to be loose battery terminals.
If all checks out okay, given that you have a clean ignition switch, my money would be on the igniter. Also you say that the pickup coil has been replaced. Did you set the air gap correctly? It was originally 1mm but Triumph changed it to 0.8mm because of starting and running issues.
Hi Ripper, yeah the bike turns over fine but there's no spark, even when the side stand multi plug was disconnected when the fault wasn't there it still ran. The problem is strangely intermittent, one day it will run and the next day without touching a thing, it won't. I spoke to TTP who remapped the igniter and he reckons if it was that at fault it would run rough or try to fire at least.
The only thing I haven't checked is the neutral switch although it seems to function ok as the neutral light is on when it's supposed to be and then when the bike is in gear pulling in the clutch allows it to turn over, the question is although it appears to function as it should is there a secondary fault that disables the ignition while still allowing the engine to turn over? I've got an led tester light to check the igniter as per a post I found on here, I think it might have been yourself who posted it. Am working tomorrow but off tuesday so will get into it then.
I wish I could tell you that there is a secondary fault but the truth is there must be a thousand things that can inhibit the ignition whilst still allowing the bike to crank. You see, there are two circuits here, the starter and the ignition. Although there are links between the two, they work independently of each other. As I understand it, your bike fails to start or run, but always cranks. That places the fault in the ignition circuit. The stand and neutral switches are part of the ignition circuit but the clutch switch is not.
What Mike says about the igniter seems logical. I suggest that in addition to testing the igniter, get some voltage readings with a multimeter. When the bike is in a state of refusing to run, leave the ignition on and check for voltage on the Green/Red wire to pin#2 of the igniter. If you have no voltage on that wire we can then check backwards on the other components in the chain, namely the alarm connector, kill switch, ignition switch and the ignition fuse. And all the wiring connections in between. We are not so much interested in what the readings actually are, but whether there is voltage or not, and is it at or very near the battery voltage.
Other things that could cause your problem:
Pressure on the igniter connector from the seat pan
The igniter connector block (loose connection)
Faulty diode pack (inside the harness)
Dodgy connection anywhere in the ignition circuit
Bad connection on the engine ground (that's the thick cable from battery negative), but if it were that, the starter motor would display intermittent behaviour too.
Broken crimp joints inside the harness
So there's a few more things you could check out, but since the problem is intermittent I would suggest taking one step at a time.
Cheers for that Ripper, plenty to have a go at there! The Haynes manual mentions the diodes but where exactly are they located and what do they look like? Also you mention the alarm connector which I wondered about, having seen it in the wiring diagram but can't find it on the bike. Also do you know what the connector is under the seat next to the igniter that has two wires looped back into it ? They are part of the starter circuit as the engine won't turn over if it's disconnected.
Thanks again for such a comprehensive reply, am off tomorrow so will get stuck right into it!
Also do you know what the connector is under the seat next to the igniter that has two wires looped back into it ? They are part of the starter circuit as the engine won't turn over if it's disconnected.
Thanks Forchetto, I will check that out, strangely, although it could be my imagination, when I was looking at this connector the other day when the ignition was on and the engine turned over a few times it seemed to get warm. I'll check the voltage and then replace the plug-in part to see if that makes a difference.
By the way, I noticed a post of yours to another member who needed to isolate his ignition switch, but in the end didn't need to, anyway, in order to eliminate that from my checks would you mind PMing me how to do this too? Thanks.
By the way, I noticed a post of yours to another member who needed to isolate his ignition switch, but in the end didn't need to, anyway, in order to eliminate that from my checks would you mind PMing me how to do this too? Thanks.
Forchetto, I think my ignition switch is ok as I already carried out the test as per the Haynes manual, but as it's a known weak link in the system, for future reliability I'm thinking of doing away with it while I'm searching for the main problem.
Ripper, I did the LED test today but it wasn't conclusive, the light seemed to dim/flicker as the engine turned over but didn't appear to physically go out for the split second you described, maybe as the only LED I had was a red one it may not have been so noticeable.
I've got power at pin 2 on the igniter so I'm presuming that rules out the ignition switch, kill switch, alarm connector and ignition fuse as the culprits (I checked the fuse and connectors already anyway)
The continuity readings on the side stand switch are a bit puzzling though. The manual says with the stand down there should be continuity between the terminals and with the stand up, no continuity. What I'm getting is, stand up, continuity between the brown and black wires and stand down, continuity between the green and black wires! I'm presuming the green and the black are both earths and the brown according to the wiring diagram is +ve.
What makes it more puzzling is that when the engine was in a mood to start it did so even with the side stand disconnected and nothing bridging the terminals in the connector!
Tomorrow I'll check the neutral switch and the diodes. The engine refuses to start at all now but I think that's prob a good thing as it doesn't give false impression that the problem is solved by moving or tweaking any components.
That's fine. You should get continuity between the Brown and Black wires with stand in folded-up position. The other wire is for another set of contacts within the switch, not used on the Bonneville.
Ok, still at square one having borrowed a good igniter and engine still doesn't fire! Definitely no spark whatsoever.
Started at the beginning again with checking and testing in case I had missed something, still got power at pin 2 on the igniter and all connections at the plug are sound. The safety switches work as they should so I think I can rule them out.
The resistance at the primary winding terminals on the ignition coil reads 0.4 ohms, the Haynes manual says it should be 0.6 ohms.
The secondary windings however read 2.71 on the 20k setting on my meter but I don't know if thats K ohms or what. The manual says that reading should be 15 K ohms, so a discrepancy there I think, but can only be sure by substituting for a known good one.
I checked the plugs, leads and caps and the plugs and leads are ok but one of the caps shows no continuity at all, but that shouldn't prevent the other plug from sparking so I can't see that being my main problem.
Getting a new pick up coil was difficult as they're out of stock at Triumph until mid October! I found one after phoning round several dealers but when it arrived it had clearly been used. They told me that a tech had used it to check against a suspect pu coil and then put it back in stock. They assured me it was ok and gave a discount so I fitted it as the meter readings on it were fine, I didn't do the hot water check though so will whip it back out and do that tomorrow.
I feel like I'm blundering around in the dark now not finding anything conclusive but getting some iffy readings here and there. I think I will replace some of the less costly components like the HT leads and caps along with a couple of new plugs, they're all probably overdue for replacement anyway.
Your opinions on the ignition coil readings would be welcome fellas although I'm leaning towards buying a new one for comparison.
The secondary windings however read 2.71 on the 20k setting on my meter but I don't know if thats K ohms or what. The manual says that reading should be 15 K ohms, so a discrepancy there I think, but can only be sure by substituting for a known good one.
A reading of 2.71 on your 20k setting would be 2.7k/ohms which is wayyyy too low AFAIK. The figure stated in the manual of 15k/ohms - is that including the plug cap? The plug caps are resistive and should measure 5k/ohms each, so if you measured the secondary with the plug cap on you have to deduct 10k to get the true reading for the secondary. Definitely something wrong with these coil measurements. With both plug caps on, you should be reading around 30k/ohms and your meter should be set to the 200k/ohm range.
I checked the plugs, leads and caps and the plugs and leads are ok but one of the caps shows no continuity at all, but that shouldn't prevent the other plug from sparking so I can't see that being my main problem.
Oh yes it will prevent the other side from sparking! The two coil outlets are in fact both ends of the secondary winding. The circuit is completed by the cylinder head, and its a bit difficult to understand, or to explain even - but on any spark cycle the power enters one plug and jumps the gap from centre electrode to ground electrode, travels across the cylinder head and jumps the gap on the other plug from ground electrode to centre electrode, then back to the coil. Wasted spark. That's the best I can explain it.
I'm not going to start cheering yet, but you may have found your culprit. Fingers crossed.
Primary resistance 0.5ohms nominal
Primary inductance 2.5mH
Turns ratio 85 to 1
Dwell time 2.1ms max
Peak current 10.5A at max dwell
Spark energy >60mJ at max dwell
Secondary voltage 35kV max Secondary resistance 2.155 Kohms
Connections 6.35mm spade terminals. (LT polarity must be observed)
Whereas the PVL or Nology coil has a secondary of around 8K ohms, same sort of resistance on the primary.
I don't know where Haynes get that info from, even adding the resistance of two plug caps it'd come to less than 15k Ohms
To add to ripper's description of a wasted spark system here's a diagram:
Thanks again guys, your input is very much appreciated.
Haynes list the resistance values for each component individually so I took the secondary windings reading directly from the pins in the coil and removed the caps from the HT leads and checked each item separately. Reading Forchetto's specs for the coil would throw into doubt the Haynes figures, it would be interesting to know where they got them from, it wouldn't be the first time they got something wrong, they can't be spot on 100% of the time!
Anyhow that's all academic as we know that a coil can be duff and still show a good reading but in this case as the coil is new I would tend to go with both your fine explanations and diagrams of the wasted spark principle and put the blame on the dodgy plug cap.
Triumph have low to zero stocks of a lot of Bonnie ignition parts for some strange reason right now, hopefully HT leads and caps are available! I'll phone my local dealers this morning and order a pair.
Triumph have low to zero stocks of a lot of Bonnie ignition parts for some strange reason right now, hopefully HT leads and caps are available! I'll phone my local dealers this morning and order a pair.
Be sure to be sitting comfortably when you see the ludicrous amount of money they want for them, have a look at item 5, the price is for EACH cable/plug cap:
The cap can be bought separately but not from Triumph, It's cap type SD05F part number 8022 in black or number 8238 in red. A Google search using those part numbers, as in "NGK 8238" brings up lots of sources. See this one, in the UK, just £2.59 for a cap...
Forchetto, my mind boggles at the thought of how much money you must have saved the members of this community, since 2009 and in over 18,000 posts, using the information that you so dilligently collect. Without doubt, the forum's greatest asset.
What made you change your ignition coil, total and obvious failure or were the readings off the old one just a bit suspect?
I see you're in Edinburgh Callumity, would you happen to have a spare coil to try on my bike in order to rule my possibly dodgy one out? I already borrowed and returned my cousin's hubby's igniter to try but he's in Northumberland and using his bike this weekend so can't ask to borrow his ignition coil too.
No, our market is limited mainly to Spain and South America really, so we see no need yet. It has an enormous amount of stuff on it so translation would be a huge effort. If we export to English speaking countries and they request it we'd translate the product's documentation.
Sorry, just seen this. I am pretty certain it is the same coil until the efi model was introduced. Perhaps others can verify. Meanwhile I have no spare as I junked the Gill coil which read ok but misbehaved then wentbtotally open and still misbehaved but more persistently with misfire symptoms. Beacause of the balance pipe it was easy to convince myself it was one side or the other but I think it was randomly either side and worse at low rpm.
Send me a personal message with your address/phone and I will look to swing by soonish. I am actually near Biggar but that is a bit wee for www site!
Hi Forchetto. Great saving on plug caps. Thanks for that as I'm looking to renew soon. Don't suppose you can do the same for the plug leads by any chance.
Sorry to hijack this.
The HT leads are not the car sort where the conductor is a sort of textile carbon filament with an in-built resistance for radio interference purposes. On the Bonnie it's a normal copper-cored cable and all the resistance is in the cap itself.
The cap screws into the end of the cable with a kind of self-tapping screw which bites into the copper conductors.
The coil side has a metal piece that is crimped on to the cable, photos and details of the original, a suitable replacement, etc on this thread:
Ripper and Forchetto, I'd like your opinion once again regarding the ignition coil readings if you don't mind fellas, as you can see from my enquiry with Haynes they are getting a reading of 14.9 k/ohms with the leads and caps attached, with my shiny new leads and caps attached I'm getting 12.5 k/ohms. Leaving aside the possibility that the coil can be goosed and still have a good reading do you think that the 2.4 k/ohms difference is significant?
Callumity is kindly bringing his ignition coil to substitute and get a definitive answer as to the coil being the culprit, so I'll know one way or t'other tomorrow.
Forchetto is your man for the numbers and statistics, I've known them (through him) for years but can never remember them when needed. However this time I jotted the official ones down for the OEM Gill coil:
Primary resistance 0.5ohms nominal
Primary inductance 2.5mH
Turns ratio 85 to 1
Dwell time 2.1ms max
Peak current 10.5A at max dwell
Spark energy >60mJ at max dwell
Secondary voltage 35kV max Secondary resistance 2.155 Kohms
However this is far from precise, coil windings have a very wide tolerance so this figure is just a nominal one, but the 2.15k coil resistance plus the 10k combined plug cap resitance comes out at 12.15k. That makes your actual reading of 12.5k bang on the money.
Ignore the pics in the Haynes manual, in mine the pic is too faded even to see a decimal point, but I would guess that the meter is reading 14.9k, which is a bit off the nominal readings but wouldn't matter that much. The coil resistance is about +/- 10%, and the plug caps I think are worse, at +/- 20% each.
Coil windings and plug cap internal resistances have wide manufacturing tolerances, +-10-15% are not uncommon. Secondary winding resistances measured from plug cap to plug cap are as follows:
For the OEM Gill Industries coil, the reading should be 5k+5k+2.2k= 12.2 Kilo Ohms
For a Nology or PVL after-market coil 5k+5k+8k=18 Kilo Ohms
The cables are copper-cored and we can ignore their tiny resistance.
I can't explain how Haynes got that 1.490 Mega Ohms according to the photo. Maybe there was something wrong with that meter or its connections, even if the meter was in the mega-Ohm range, the reading for 12.2 Kilo Ohms should show 0.0122 Mega Ohms.
The saga continues, Callumity came round with his ignition coil and still no joy, so back to square one!
Everything seems to check out ok, although while I had the neutral light switch out today to fit a new sealing washer I checked it for continuity, so while gripped in a vice I checked it with the plunger both in and out and there was continuity both ways. I would have thought it should be an open circuit in one direction and closed in the other, what's the verdict on that one fellas?
I checked it with the plunger both in and out and there was continuity both ways. I would have thought it should be an open circuit in one direction and closed in the other, what's the verdict on that one fellas?
That's OK. The switch is only half a switch, a spring-loaded plunger contact. The other half of the switch is formed by the gearshift drum. The plunger makes contact with the gearshift drum surface and completes the circuit to ground and turns the light on.
Ronnie sorry I could not stay longer so If I may try and narrow this down......
The starter circuit appears fine. Battery healthy, ignition on, engine cranks over but no spark. Coil known good also pick up coil and igniter (all have been substituted at some stage) Continuity check from pick up to igniter all good.
Significantly, there is battery power at the coil. (Kill switch has been disassembled, cleaned and re-built, sidestand switch ok. )
So........
Logically if the coil is energised the problem is with triggering the igniter to cut power and induce a spark. Neutral light on but could this be a false indicator......Ronnie is it actually in neutral or just appears to be so? Could a faulty neutral switch earth isolate the ignition circuit but illuminate the neutral light. Ronnie, did you use the skinny washer when replacing the switch or a fat one that will affect plunger depth? Could a faulty diode pack create the apparent conflict between a lit neutral and an inoperative igniter coil signal? Ronnie have you tied clutch lever back to activate that switch too?
Any electrical Ninjas care to narrow this down to 2 or 3 possibilities?
Forchetto padding around at 4 in the morning again! I had quite forgotten by 1 o'clock when I relinquished baby sitting duties that the neutral 'switch' was merely a contact.
I am following this thread closely as I have the same condition: intermittent crank but no spark. Bike is fine one day and dead the next for no apparent reason. I have replaced the igniter w/Procom unit but problem persists. Ready to install another (used)harness. Also replaced coils, plugs, plug wires, pick-up (including revised gap).
Along the way with many hours of testing, I was able to stop the motor a half dozen times (when it would run) by manipulating the harness just outside of the igniter. I was not successful in removing the wires to the igniter from inside their plastic connector. I had planned to insert a small pin to test for voltages on the various wires there. (But got sidetracked firing-up a different project.) Anxious to get back to my America and get it fixed (hopefully, finally, successfully !) Perhaps you folks will find the answer first !! Good Luck and Godspeed.
The diode pack is located near the harness where my 'tap and wiggle' could kill the engine, but my diode pack tested 'good'.
I am following this thread closely as I have the same condition: intermittent crank but no spark. Bike is fine one day and dead the next for no apparent reason. I have replaced the igniter w/Procom unit but problem persists. Ready to install another (used)harness. Also replaced coils, plugs, plug wires, pick-up (including revised gap).
Along the way with many hours of testing, I was able to stop the motor a half dozen times (when it would run) by manipulating the harness just outside of the igniter. I was not successful in removing the wires to the igniter from inside their plastic connector. I had planned to insert a small pin to test for voltages on the various wires there. (But got sidetracked firing-up a different project.) Anxious to get back to my America and get it fixed (hopefully, finally, successfully !) Perhaps you folks will find the answer first !! Good Luck and Godspeed.
The diode pack is located near the harness where my 'tap and wiggle' could kill the engine, but my diode pack tested 'good'.
Callumity and I have just finished checking once again wires and components especially the connector block to the igniter. All checks out ok. I spoke to Mike at TTP and given the symptoms he would suspect either the pick up, ignition coil or the igniter but as these have been ruled out by substitution it would point to a broken wire in the loom or a bad connector somewhere, this would be borne out by the fact that this was an intermittent fault but is now permanent.
Although I already used a known good igniter with no joy I'm going to send mine to test on another bike..clutching at straws here, but if it starts the other bike I know for absolute certain it's not that at fault.
More in the next episode, stay tuned!
Just to lob in my tuppence and see my logic shot to bits!
All circuits and components tested. Continuity proved and impedance values to spec. So, turn on ignition and press starter. Engines turns no spark. Battery voltage both sides of coil and back to pin 8 of igniter. Conclusion: the problem is in the 'trigger' mechanism i.e. Pick up coil or internal to igniter. As stated, pick up giving about 560 ohms and continuity to igniter pins.......therefore the igniter is prime suspect.
Very interesting post, this bloke has a lot more patience than me! The distorted casing he describes is evident on mine too.
When I tried the replacement igniter a few days ago I hadn't yet found the faulty plug cap so I may have got a false negative result, which would also mean that I've had two problems going on, the igniter and the plug cap.
I've sent my igniter off to be tested on another bike so will be waiting eagerly for the result.
Isn't it odd that the 3 components that gives us most heartache happen to be made by the same maker? Gill Instruments UK. The three items being the igniter, the ignition coil and the pick-up coil. Together they're called "the GP4 Digital ignition system", although some of us have called them other less impressive names.
I could have told Callumity roughly the same about the igniter without having to open one up, but I found the thread that he linked to extremely useful. What else could you expect, when these igniter units have a single transistor output which is only rated at 80 watts / 7 amps WITH a heatsink, which Gill happen to think better of omitting? According to the data sheet for the TIP152 the device is adequate for this job, but without proper heatsinking the max wattage/current rating will fall dramatically, which makes it a weak component. I don't know why they didn't use a more robust MOSFET instead, the cost would be about the same, and an N-channel enhancement mode device has a very low on resistance in comparison to the bipolar TIP152.
Pin#8 of the igniter (the coil output) should be connected to the collector of that transistor. When the transistor switches on in response to the trigger pulse from the pickup coil, the collector voltage falls to 0v, effectively forming a ground link to whatever is connected to the collector (in this case, the ignition coil). It was this principle behind my thoughts of using a LED to test - replace the ignition coil with a 12v LED, and it should illuminate every time the transistor turns on. Ronnie reported that the LED came on but did not extinguish, which may show that the transistor has gone short circuit. Its difficult to tell with a LED, but one thing is for sure - if the igniter is damaged/faulty, the fault will almost certainly be transistor failure.
Because the igniter is such an expensive item, I have always advocated eliminating the other components before replacing it, but the price of the OEM leads and caps has made me think again. I hope you had enough left to drown your sorrows after that purchase Ronnie.
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