Misfiring GRiSO 8v 1200 (2009)

Hi All,
I am enquiring as to potential reasons causing an engine misfire under load. Some will know that last week I replaced the plug caps for NGK items, plus leads and plugs (iridium) as suggested by Moto International in their tech note. This is what I thought the problem was. Since then I have travelled about 600kms over the weekend to the RFR and back. On day one after the plug cap change the misfiring was gone and all seemed well. It came back Saturday afternoon and has been intermittent and getting worse since then. My traveling companions also noted that my rear tailight was flicking on and off at higher speeds over the course of the weekend (dodgy earth or is it related?) So it seems the problem is more involved than first thought.
For the record on Friday when changing over the caps I checked the leads and caps with a multi meter. The left was showing 5K ohms as normal, but the right was at zero and dead. Is it possible for a new set of caps and leads to shag out that quickly? I'll check my work tonight as far as the leads and caps go to ensure I didn't screw something up.

I remember your mate telling me about your flickering brake light.
He asked if mine did the same.
My answer was “buggered if I know, I can’t see it”!

Obviously something is shorting, or you have 2 issues, but you’ll probably have to investigate deeper to find out what.
Have you got a copy of the wiring diagram for reference? It’s here on the forum if you don’t.

As a follow up on this item I have now checked the following;
Injector wiring / connectors
Lambda sensor wiring
Clutch cut out switch
Sidestand cut out switch
ECU earth
ECU connectors
Earth on starter battery
various main loom plugs and connectors
Checked for ECU and dash service codes (negative)
I have also replaced the plug caps and hi tension leads again.
and guess what, it is still missing!
So I am thinking maybe it is fuel and not electrics, but, I am scratching at the limits of my knowledge and ability.
I also pulled the valve covers off while I was there to see if I was actually rollerised, and it appears I am.
If anyone has any further thoughts or ideas I am all ears.[You must be registered and logged in to see this image.]

I'd like to have a look at it Darrel.

Darrell, just a thought!

Can you get it to miss while stationary, or the taillight flickers? If so, if you have one of them olde time mutimeters, with a needle (or knows someone who does), hook it up to the battery and see if there is a:
a) flicker on your taillight; and
b) a resultant flicker on the meter at the same time.

If both of these are seen, then you can wriggle the wiring at every point you can get to and try and isolate it from there. If your taillight is flickering there is "something" intermittent - perhaps a connector, perhaps a partial earth. Worth a try.

Modern, LCD multimeters are way too slow to react to an impulse (down/up) so hence the choice for something like a PEAK multimeter - it doesn't have to be calibrated. Alternatively a 24V globe connected across your battery - this will glow dim, and you "might" see it happening. If you are into electronics, a LED indicator (24V or 12V with a series resistor) can also do this. I might be able to lay my hands on a 24V LED...

Thanks Tony, I'll see what i can track down I thought my final option might be to swap out the coils with another bike. There is a parts 1100 Breva I know of that has very similar looking coils so I'll try and get one or both to see if that's the problem. Beyond that I reckon I'll fling it onto a truck for you Pete. It's my daily drive so I just have to sort out those logistics first. Pushbike here I come for a while perhaps. I'll pm you Pete if it goes this way, Iwasn't really sure if you were taking on work atm given the circumstances.

I'm not really but it's not exactly like wer're strangers.

Oh, you have checked and cleaned the other end of the earth strap where it bolts to the gearbox under the starter cover?

Yes did that also Pete. I'm now convinced it is a fuel issue. The injectors are getting cleaned tomorrow ($33 a side) and I'll replace the filter as well. For the record for those in Aust. there are equivalent fuel filters made by other companies, the part numbers are; Donaldson P55012 and Fleetguard FF149. They both cost less than $8 here in Newcastle. The reason I have to go down this path is because there are no Guzzi dealers here worth talking to and I dont want to have to overnight freight a stinking fuel filter from the big smoke or China or somewhere else wherever it might be.
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An update after several weeks of f&*)îng about with things. To date I have;
replaced leads and plug caps (twice)
replaced fuel filter
replaced fuel lines as they were leaking ($287 from MG italy). I tried doing a cheap fix (see pic) but that didn't work either [You must be registered and logged in to see this image.]

had injectors cleaned (one is new)................
and today I can report the misfire is still there wallowing away at 3000rpm in 2nd and 3rd gear on a steady throttle.
I have been unable to track down the rear brake light flicker, but I will check the switches and see if I can see anything weird there. This of course is unrelated to the misfire I think.
The only thing I can think of now is the engine map might be a contributor, but really I am FIIK. I have purchased the cables but have not downloaded Guzzi diag or anything yet.
Its more useful now I think to schedule a trip to Bungendore Pete. I'll contact you offline and see what we might be able to organise, but, it'll likely be the end of the month or early Nov before I can get my act together.

In the latest news of the day...........
The "new" MG fuel line has kinked on the section coming from the tank, thus restricting fuel flow. This is what happened to the line I just pulled out! I was quite careful rerouting this line when refitting to ensure the paths did not cause this problem again. It appears the length of hose from the tank down to the t piece is too long and once the tank is screwed down in place it heats up and then kinks itself in a 45"deg bend.
You'd reckon for $300 the f_)(*&ing line would be the right length. I am now going to make my own as I now see others have done on this forum. Should have read it before buying the factory bit of kit I suppose. Major PIA and I am not enjoying this GRiSO at all.

Try turning the pump around 360 degrees. The spigot should be towards the left of the tank.

Have you sorted the brake light yet?

Same thing happened to mine, the lever return spring lost tension.  Whilst stationary it was fine but moving and bumping would cause it to flicker.  No other affect on electrics.

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Tank is out and this is it from bottom upside down. If flipped it would be on the left of the bike, or do you mean left when it is on the bench like this? [You must be registered and logged in to see this image.]
Good tip about the brake pedal return. That's next on the list!

Well fixing the 'Misfire' was easy. it just needed a map and a tune.

The unfortunate thing is it wasn't rollerised in time. the bottom end is fucked.

Pete

Damn...

Arse!

ginormous arse

Not happy

The crankpin is unmarked, shells are toast. I'll flip a new set of shells into it and pray to Carlo. We may get lucky. If it still knocks I'll pull the rods and get them re-sized. If that doesn't fix it.........

I bet there are a few more of these late-rollerised victims out there, yet to be discovered. Arses!

Any redress Darrell?

Doubt it. Bloody thing is stinking up the workshop! Oil that can't wedge burns quickly, it smells like a bear's arse!

Pete

No redress at all. Private sale etc etc. Makes you wonder though if the previous owner knew ........... or its just an unfortunate circumstance. Does anyone have a GRiSO motor laying around collecting dust
?

I've got a motor Darrel, I'd just prefer to fix yours.

Yes, its a prick of a thing and when it was rollerised whoever did it should of realised that the bottom end was sick. Fuck me! It knocks like coppers at a meth house! I know 8V's are noisy, especially early ones, but yours sounds like a rock crusher! Just like Mark Salkeld's and Ralph's and mine! There is a very distinctive noise, like someone banging a gong in the depths of hell...............

Pete

That's funny in a way. I thought it was noisy when I looked at it and mentioned it to several people. They all said, don't worry 8v's are noisy motors! I didn't have any reference never having owned one before and with very limited experience took it all at face value. To be fair the bike had a full service history and had been rollerised..................what could possibly go wrong ?