Good afternoon everyone! I would need some help... My girlfriend bought a lovely bonneville 790 from 2006 (carb model) 8 month ago. The bike had around 3000 miles on the clock. Everything was fantastic until the bike start to manifest some intermittent problems: rough idle and poor acceleration (hole in acceleration at low rpm, staling...). She went to a Triumph dealer, they check the bike and did not find anything (intermittent problem). They done carburetors synchronization. As the bike had stand without running for quite a long time, they suspected dirty carb and offer if the problem continue to clean them for a price around £500/700... The problems became permanent. The bike quite dangerous to drive and harder and harder to start. To finish to not starting at all... During Christmas holiday, I done some work myself: Cleaning the fuel tap Strip and clean the carburettors Change the sparks plug Change the air filter. Fuel is flowing but the bike still did not start. And it appear to be a different problem... I have no spark on both spark plugs. So I checked the ignition system: battery look ok (12.8V) spark plug cap ok ignition coil was dead, I replaced it. Pick up coil ok Ignition main switch, side-stand switch, clutch switch ok. I run out of idea apart a defective Ignition Control Unit... Do any member of the forum leave near or in Warwick/ Leamington Spa/ Midland/ Birmingham and would allow me to try to start their bike with my ICU to see if it is really defective? Or come try to start the bike with your ICU to see if it start? Thank you all! Adrien
Well you are right, outside of an electronic lab the igniter can really only be tested by substitution. However, the more likely culprit is the pick up coil which is also much cheaper. You should get about 570 ohms resistance measured at the connector tucked up to the RH side of the battery under the side cover. Have you also checked to see if you are getting battery voltage to the +ve side of the coil? No power would point to the igniter if is itself getting power. Equally it could an internal failure that is not cutting coil power and hence not collapsing the magnetic field to induce the spark. Your cheapest igniter replacement is https://www.triumphtwinpower.com/fire-starter-performance-igniter-unit.php
So: I re-check the pick up coil, 558 ohms: it is good... I have the battery voltage coming to the + side of the coil. Do you have any suggestion?
Ouch! Sounds like the igniter. The problem with coils is that they can appear to be ok but break down under load or heat - it is just a break in a very fine wire winding. They do not always show an open circuit in the winding. Failing a local test igniter swap.....Get cheeky. If you send your igniter to TTP (above) for a £112 remap - telling them you think it dodgy - they can test it for you and, if defective, supply a new £234 unit...... Either way, you will get a worthwhile modest performance benefit - especially starting.
Thank you for your help! I like the TTP website. Just in case I will bring the ICU tomorrow to a local Triumph dealer to see if they can cheek it. If not, I will control everything again, and see with TTP. I will update with the result! Thanks again!
So, Triumph dealer can't diagnostic directly the ICU. Triumph do not supply them with the equipment to directly plug on the Igniter. They encourage me to see on Internet for a society specialist on ICU tuning. I email TTP. Here their answer: Unfortunately, testing igniter units isn't as fool proof as we first thought. We have tested igniter units that proved good on the bench, but when in use they don't work correctly. The only real way of testing the igniter is to swap it for a known good unit, sorry. If you have replaced the ignition coil and you know that the pickup coil is good then there is only the igniter unit or the wiring loom that could be causing the problem. Your igniter unit is now 12 years old, so there's a high possibility that it is the problem. So I am going for a new one. But before a last question as I went to check the bike again: On my new ignition coil, the primary and secondary resistance are correct. But the resistance between the primary and the secondary is infinite. Do you know if it is normal as I though it should be some resistance but they should be linked? Thank you! Adrien
The coil has two entirely separate circuits. They are NOT connected so low tension to high tension will show an open circuit. Set multimeter range correctly! The 12v tabs with spade connectors should measure about .7 ohm tab to tab. And the High Tension circuit (spark lead socket to socket) should read about 18 kiloohms.
A small afterthought. Having previously proved you have 12v at the coil you have shown continuity in your wiring loom - part of the reason I asked you to check. The igniter is triggered by a pulse from the pickup coil to cut power to the ignition coil. The spark induced fires in both cylinders - one approaching top dead centre on compression, the other on exhaust (so called lost spark). The igniter reads engine speed from the signal and applies the appropriate advance from the throttle position sensor. As the igniter MUST be getting power if it is present at the coil then, by a process of elimination, you can be pretty confident that a failure to spark is caused by internal igniter failure. There is pretty much no other explanation as all the safety switch circuits inhibit the starter circuit but not the ignition circuit which is energised by the key.
Thank you for your answer! So the ignition coil is good! I went to check everything again. And, I do not know why, I had some sparks !!! Really happy, I put back the bike together! And the Bonneville start straight away !!! I went to the petrol station to refile. She almost did not restart ... She started without hesitation but after more than 10 tentatives. I rided around 15 miles before to go back home. On the ride all good: the idle was stable, perfect smooth acceleration. I stopped the engine at home. Impossible to restart. So I check again: no spark … (even after I disconnected and reconnected everything in case of false contact). I do not think there is any wiring problem (and really hope not). I will go for a new igniter. Just in case, do you have any other suggestion after what happenned today? Many thanks for your help!
Nailing down an intermittent electrical problem is the trickiest of tasks. Even when you are totally systematic it can fail to manifest itself when you check. Without placing any probability on where it lies, it could be: a dodgy connection in the harness - two multiplugs. One in headlamp shell, one under fuel tank buried in tape. If the bike turns over without sparking discount these bits of the harness - they must be ok. The pick up coil. It could pass impedance/resistance tests but still fail intermittently to generate a pulse. Result - no spark. Part no 1 https://www.worldoftriumph.com/part...g/triumphmc/modelid/3130/block/100064758-0-2/ The new ignition coil. Possible but unlikely. Is it Gill (OEM) or PVL? I have more faith in PVL! The igniter. Check it for marks and the underside of the seat. There is a known issue of pressure from the underside of the seat crushing the casing and knocking out the sparks. At the end of the day you are faced with replacing suspect parts until the problem disappears. Your guess is as good as mine between pick up (common) and igniter (less common) and you know exactly how and when the problem manifests and if is purely an ignition problem. When it runs out of sparks check that live feed to the ignition coil! Instinct says igniter or pick up coil. Pick up coil exhaustively tested in pan of hot water to replicate engine heat. Gap installed .8mm
One thing i would add is double check the charging circuit before spending out for a new igniter...it could be showing a relatively heathy 12.8v but when running and there is more current draw if there is a problem with the alternator or regulator/rectifier the voltage available may not be enough to give consistent results, so to be on the safe side i would first check.
Thank you for the answers! The bike turn over without sparking. The new ignition coil is a PVL. I will check the charging circuit tomorrow! If the bike accept to start... But, even with is a problem with the charging circuit, shouldn't there be some sparks when I try to start the engine? (as the power will come be directly from the battery before the engine start)
If the engine cranks it should certainly spark. Without spectating it can be difficult to know how much someone knows about testing the ignition circuit. You would need something like an oscilloscope to measure the pick up coil output - an ordinary multimeter would probably not register the pulse. It seems almost certain the problem is with the pick up or the igniter. The difficulty is knowing which. The pick up is cheaper........ but you might actually need the igniter. Tentative en Anglais veux dire ‘provisoire’ ou ‘timide’. Le mot juste est ‘attempt’ !
I have been spotted... Thanks Callumity for the rectification! The earth lead is good! So, the main problem is within the ignition system. I will still check the charging circuit later. Never know... I will go for a new igniter. It is more expensive, but on the test the pick up coil look good... The ignition coil was defective (and probably for a few month as I suspected a carburetor problem not an ignition problem). I think it may had damaged the igniter. Or while testing the ignition coil or the spark plug, I may have damaged the igniter... I let you know when the problem is solved! Many thanks!!!
To check the ignition coil totally disconnect the wires from the ignitor to the coil. Fit a spare spark plug into the HT lead and make sure the body is earthed Connect one side of the coil to the battery positive with a new wire. Connect a new wire to the other terminal and touch it to earth ( frame ) on and off This should produce a spark at the plug, if no spark the ignition coil is faulty.
Good evening! I received the new igniter unit from Triumph Twin Power. I installed it and the bike started straight away ! Really happy ! Thank you very much everyone for you help !!!
