Honda-SOHC
SOHC.co.uk Forums => Other Bikes => Topic started by: Lobo on April 07, 2020, 04:08:11 AM
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Hi all, possibly one for Mick / Green1 - but welcome all thoughts.
Have a 2011 Griso 1200SE, which has only got about 3500 dry miles on it. Never seen a dealer whilst in my possession, and probably not since it’s 1st service.
Anyways, it’s a momentary-press starter button, which then cranks the motor as much as necessary. Previously this’d be a couple of seconds.... now it’s a full crank cycle of about 5 secs ... after which it aborts. 2nd attempt sometimes catches, 3 attempts and it’ll catch and keep running... for now. After this it’ll run a bit lumpy for the first mile.
I’ve tightened all the manifold and exhaust clamps, which has cured a pop on the overrun. I’ve put injector cleaner through the tank, and only ever use the highest octane / quality fuel avail.
It’s had new plugs recently; and the tappets adjusted iaw the manual.
MotoGuzzi dealers very thin on the ground here in Bris; by and large I’m not a fan of dealerships / garages unless personally recommended.
Anyhoos folks; thoughts please?
Ta,
Simon
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I used to have a 1200 Sport which did exactly the same thing. The big block Guzzis always struggled to meet emissions regs so the factory sent them out running very lean. In the end they couldn't meet the likes of Euro4 at all hence they got dropped from the line up, or that engine did anyway.You can get a unit made by Finebau Forge in the UK which will smooth out the lumpy running at low rpm. Have a look here : http://www.guzziriders.org/finebau-forge-tuning-unit_topic5867.html
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If not checked recently, make sure plug gap is set to the minimum of given tolerance for your bike.
When it has started, feel for temperature in the main battery cables, earth and pos. Plus the lead from solenoid to stater motor if they are remote from each other. Most factory fit leads aren't that generous in capacity and raise current draw noticeably.
Starting mixture should be ok as efi systems modulate this based on temp sensor and it's not usually part of emmisions testing, so should be no barrier to initial firing. Saying that, you'd normally check the sensor itself by measurement of its resistance changing in response to input temp if you think it's suspect. It just reports a gradient of resistance to the ecu which is used to alter mapping away from normal temp running while it needs richer starting.
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...thanks gents, just to be clear the bike used to start ‘on the button’.... K2 this would not support the increasing starter motor draw as the issue - as I see it.
Interesting forum page Cooler... will investigate this avenue later.
I’ll pull the temp sensor and check whether it’s resistance changes with temperature.
My gut feeling is dirty / gummed injectors... tho tbh I’ve little experience is such areas.
Are these easy to service / clean?
Keep the thoughts coming all.
Ta,
Simon
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Last Guzzi I owned was a LeMans 850 MkIII .... but I did a lot of research on these as I intended to buy a Griso.... until I read about the issues with the 4 valve heads and the tappet blocks self destructing. Aprilia never took responsibility for the problem, and it can manifest at low mileage.
Have you had any issues?
Guzzi only cured it by fitting roller tappets...and that was late in 2012
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Hi Simon
My Guzzi has been great since I stripped every single connection I could find on it. Almost everything had gone green ::)
Its now covered about 11000 miles but looks more like 50000 miles :o. You need to get some more miles on it Simon mine now runs lovely so much smoother as its just starting to think about running in
Mine did the same thing about 5000miles ago. On the Sport I pulled the yellow wire from the starter relay plug under the seat. The starter relay is the smaller one. Run a fresh feed from the battery with a 15amp inline fuse to the now free pin in the plug.
Tape the now redundunt yellow wire up and tuck it out of the way.
I have also run a larger wire from the battery to alternator.
I think the slightest voltage drop and they abort there start up procedure so a perfect battery and clean electrical contacts are a must.
I have been told If it repeateadly blows the new 15amp fuse its normally caused by the starter selanoid sticking as there filled with grease by the manufacturer and it goes hard over time.
Almost forgot the Tappet mod is a must on the 4 valver
Mick
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Thanks Mick, Sump Magnet.
Yea, I too have read about the issues with tappets (a long while since), but recall being happy / convinced that the problem had been sorted < my engine # and not applicable. So far, no probs here... and not expecting any!
Within a short while of ownership it started blowing starter fuses, and yep Mick, have now modded the start Circuit wiring - though not run any new alternator wires. Specifically why did you do this??
Today I re-affirmed no ECU Fault Codes, and had the tank off / all electrical plugs apart and cleaned. (none dirty - it’s a coddled machine!). I checked the resistances of the Engine Air Temp Sensor AND the Intake Air Sensor... both spot on iaw the book. I also checked / set the plug gaps (to min) as suggested by K2-K6.
The battery is indeed old, but a LiFe from which I expect at least 2x conventional battery life. It cranks strongly, and leaves me in little doubt it’s ok. This said, I’ve a new car battery lying around, and outta interest may just hook it up tomorrow as most avenues now exhausted.
Cooler on the Coast suggested some mod to improve low rpm lumpiness.... it’s the starting issue I really want sorting; defo not bad, but nothing like the quick-fire up I enjoyed when it was new(ish).
To recap: from cold it cranks quickly and strongly for approx 5 secs, with possibly a fire. 2nd attempt... longish strong crank... catches, runs for 2 secs and then suffers something like a lean cut. 3rd attemp... strong crank... catches and runs lumpy for 10 secs before settling. If you touch the throttle in this time it’ll stall.
Thanks chaps,
Simon
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Does sound more fuel than ignition related from that last post.....
The LeMans I had was a fussy starter when things were not 'just so' but that was cured by replacing most of the wiring and switchgear....and of course...it had hte old sticking starter motort brush thing. I had my strip and replace time down to 15 minutes.....but the modern Guzzis are a lot better in that regard. Only bike I know where the kill switch being 'off' still allowed the starter motor to crank.
The swapped lead from alternator to battery would potentially lower resistance and give a better charging voltage....larger wire gives less resistance...so for a given current, lower resistance gives more voltage. If the stock wire is marginal...it might make quite a difference, especially under heavy loads.
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When mine was having starting issues the on board volt meter was reading 11.2v and it would crank over fast but refuse to start first and second attempt. Sometimes it wouldn't crank at all the first time and just click.
I replaced all the fuses in the fuse box even though they looked OK and I gained 0.1v after cleaning every conection I gained a bit more and it was starting a bit better but still very temperamental I was reluctant to change the battery as I was convinced it was good. It drove me mad in the end so changed the battery out of desperation and then got 11.6v before firing it up.
Before all the Mods I was getting 11.2v before starting and 12.5v when running.
After adding the larger alternator wire I now get 11.6v before starting and 13.3v when running.
I found the low rpm lumpiness has now disappeared. I assume the fresh battery and alternator mod combined with more miles on the clock has contributed.
My Guzzi used too shake the handle bars at tick over and blur the mirrors but it has now lost that.
Mick
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Forgot to add the bike has now stood for just over 2 months now and I have just been out to the garage and it fired up faster then I could take my thumb of the starter. :)
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... put a healthy car battery (on jump leads) in parallel to the bike’s battery today - no improvement in the starting woes. On board battery (alone) at 13.1v on either multimeter or bike display. Drops to abouts 10.5v during cranking. I also tried a voltmeter across (1) battery -ve and frame ... & (2) across battery +ve and starter motor +ve; the voltage difference on both tests about 0.2v during cranking ... which seems pretty ok. (0.5 and more might point to high resistance leads?)
A BIG downside to this thread was Sumpmagnet’s input 😂😂😂 - as I now believe my bike indeed has potentially bad tappets... which, whilst not a big job (3 hrs?) is big money... £800 or so. Bloody ouch. Info very hazy out there... my engine number leads me to believe all’s well, though the build year doesn’t. I therefore lifted the tappet covers and compared photos.... you’ve guessed it. Never a dull moment eh?
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Out of curiosity just checked mine when cranking and I get 8.5v very briefly then straight up to 13.4v so I should think yours is getting plenty of juice.
Just a thought simon does your bike have the origanal plastic fuel filter inside the tank.
Its a well known issue as the body expands and the filter disintegrates causing fuel starvation.
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Hi Mick,
Interesting thought... and dunno. That said, once we’re beyond first start of the day it behaves beautifully and will redline iaw with my underwear. Ie I cannot imaging fuel starvation as the issue....
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You could try a routine of turning it on, but not cranking it, leaving it on for five seconds, then off again.
Do this three of four times as it should be priming the injector circuit ready to start. There's a pressure relief valve that dumps excessive fuel pressure back to the tank to give on aim psi at the injectors, this is controlled (usually) by manifold vacuum to fine tune demand against engine load. Anything "lazy" in that loop could result in lowered or raised psi which may affect the start.
You're trying to see if it then fires straight away on the "fifth" cycle to see if it changes anything.
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Sorry Lobo .... me and my big mouth ... :o
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... really enjoy the lateral thinkings - thanks all so far.
Nigel; bingo! 5 cycles of On & Off and she started 1st time, albeit a little hesitantly. What I do with this info though is the new mystery; as mentioned there are no ECU fault codes and the Engine Temp sensor resistance is spot on. I’ll now look in the parts book for any vacuum sensors and see if anything obvious there...
SumpMagnet, I’m now in touch with my solicitor wrt the unnecessary hurt and distress you’re causing me & my wallet 😂. Roller tappets Kit B on back order at £700+ plus postage to Brisbane. Holy moley. Grateful tbh that my bike is low mileage (3300) and so hopefully no damage as yet. From what I read colder climes are worse in that the issue is exacerbated by the oil not reaching temp (ie also short trips) ... and is less likely to occur where higher OATs and longer rides are the norm. (eg Oz). Anyways... er, thanks!
I bought this bike outta nowt but lust; obviously thinking with my nether regions. And true to form, it’s taking me for a ride in ways I hadn’t anticipated! Ho hum; still bloody love swinging a leg over it.
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I remember a guy being asked what it was like owning a Guzzi. His response was “It was like having an Italian mistress, temperamental and expensive however when it goes it goes like the clappers”.
I still lust after a Le Mans in black and gold.
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Had a V7 in the shop once, took 6 months to get a starter, same size as some car or other but it turned backwards so was a "special"
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At least that tells us something Simon.
May be worth a walk through to see if we can find the cause. The fuel pump can over pressure and over supply the peak injector demand on all systems like this, it's usually modulated by a pressure relief valve that dumps fuel back to the tank, but that's not a fixed pressure.
What they do is have a spring backed control valve that (static) achieves the designed pressure of the system and keeps it at that irrespective of injector demand. Then the spring preload can be altered with a vacuum diaphragm that reduces the spring pressure as vacuum builds in the signal tube going to the diaphragm. That vac tube is taken off from the engine side of the throttle plates, so that when you shut the throttle on overrun the vacuum peaks and results in a drop to the delivered fuel pressure.
It effectively runs as a little mechanical / analogue control loop as a parallel but autonomous system to the ecu mapping. But the ecu still has to take account of and be programmed to work with that which happens in this part of the system.
During start sequence with throttle closed, the ecu will give richer mixture based on temp report from engine (effectively using choke) but it should also get reduced injector pressure as the cylinders start to suck vacuum.
The total fuel delivered should be (ecu+enrichment register amount-the drop it would get from lowered fuel pressure) so if the pressure didn't drop it would effectively give double enrichment, and risk wetting the plugs.
It looks like the fuel regulator valve (sitting with continuos spring pressure closed) may be initially just a bit reluctant to release and so the the planned for fuel pressure drop doesn't happen.
Those four ignition applications may just have given it a bit of a kick ( the normal regulator pressure should prompt it to open as the fuel pump is cycled from turning it on a few times) then when you go to start it the vacuum from cranking can operate it easily.
No fuel will pass into the engine just from fuel pressure as the injectors will easily hold it. But just as the cranking starts to draw vacuum then the exercised regulator immediately drops fuel pressure to give correct start aim mixture.
The ecu won't "see" a fault code as normally exhaust Lambda sensors are ignored during initial start, plus they mostly don't monitor fuel pressure and so won't have any idea it's wrong.
Looking at Guzzi schematic, it seems that the order is tank, fuel pump, regulator assembly, then on to injectors. The regulator assembly has also a return to the tank to relieve pressure and vacuum operation from two pipes coming up from each intake tract to enact it's operation.
Because it starts and runs well when you've initially got it going, that seems to confirm nothing is significantly wrong, just that initial reluctance to modulate fuel pressure. It is, I suppose, the equivalent of the carburettor float needle valve sticking and causing the mixture to be temporarily out of range.
Turning it on and off is broadly speaking the "tap" with a screwdriver handle on an old carb to free the valve :)
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Just a thought Simon has the bike been overfilled with oil at some point. It has to be bang in the middle of the dipstick or it has been known to fill the airbox and overtime gums up the idle control valve.
When cold does it have a slightly higher then normal idle when it is running?
Brian thats the worst thing about Italian bikes it once took me 8 months to get an oil pressure switch for my Aprillia.
fortunately when the starter motor packed up on it that was easy to find as it was the same as a Fiat Panda
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K2K6, I need a lie down after reading all that!
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K2K6, I need a lie down after reading all that!
Yep you'd probably not want to invite me to a party ;D
Had to put my head in a fridge after that :)
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K2K6, I need a lie down after reading all that!
Yep you'd probably not want to invite me to a party ;D
Had to put my head in a fridge after that :)
😂😂
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Hey Nigel,
SINCERE apologies for not replying sooner to that amazing post of yours - really appreciate you taking the time out. (I took my iPad up to the daughter’s Friday to do DIY / eBay stuff... and left it there. Dang - have been lost this weekend).
Due the loss of the iPad I also lost my Guzzi schematics, and so am shooting from the hip here when I say there’s no return to the tank to relieve pressure. ..... unless, of course, it’s all incorporated within the fuel pump unit / tank itself. (ie there is just one hose from the tank... and 3 wires to the pump unit)
Furthermore, on the Griso at least, there don’t appear to be any vacuum type sensors.
Anyways, in a hurry to reply lest you figure me rude... but will double check all you say tomorrow . Thank you.
Mick - again ta for the thoughts... I’ve serviced the bike since 1500 miles iaw the book and specs. I filled it to the FULL mark on the 3 changes I’ve done; but never seen any hint of oil in the airbox. Again though, I need to double check your suggestion with the actual machine... as for the idle I’ve never really noticed any difference between hot and cold idles.
Thanks gents... truly appreciated.
Simon
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Gents... of no SOHC value... but closure at last!
So, I’m a dinosaur, and have been bought into this new century kicking and screaming.
Since last posting I’ve joined a MG forum, and learned an awful lot.
(1) MG manuals are pretty crap (2) my other forum ain’t a patch on this one - thanks Steve.
Anyways... this big lump of a machine has been ultimately cured by ‘remapping the ECU’. Nope, don’t ask me what this means, other than an incredibly frustrating afternoon with a Windows 10 Laptop (I’m Apple) and an umbilical to the ‘Guzzi uploading ECU software. Then a TPS reset (ditto - don’t ask me why)... and bingo, we’re back to starting on the button.
As I write this we’re in a BMW Dealership because my wife’s Elect i3 sunroof is refusing to close. No technical reason... it simply needs a re-initialisation ... something I can’t do at home. Apparently a battery spike can cause this, and cause (eg) the door locks to malfunction too. Roadside assist (obviously) dislike EVs I’m told. Well duh..
... so, I understandably remain a fan of the pre-computer days ...
Sumpmagnet - many thanks for your notification of Rollerised tappets - now incorporated.
Simon.
(btw, in case wondering I’m actually blown away by the EV - bloody amazing truth be told)
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Glad you got it all sorted and running :)
Throttle Position Sensor ( TPS) is basically just telling the bikes brain where the throttle was. It had obviously forgotten. It's Italian..... and they are known the world over for their high quality electrical work...
ECU remap is again telling it how much fuel to squirt in for the revs and throttle opening you have. Unlike my old LEMans where is just dumped as much raw fuel into the inlet as it could and then decided if it would burn it or waste it. It should knoiw how much...but again...it may have forgotten.
So...basically...your bike had amnesia......
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... ah, thanks Sump Magnet. I can relate to amnesia 🙄.
Fingers crossed Moto Guzzi don’t start building aeroplanes, rockets or submarines. What could go wrong eh?