Breathing sensitivity with an open loop map.

Very interesting indicator of just how picky the 8V motor is to changes in lift and duration in the valvetrain.

Prior to heading off to the cabal last weekend I thought that I'd better check the valve clearances on my old bus as I hadn't looked at them for ages, well over the recommended 10,000km interval. Last time I'd done them I'd changed to the later clearance specs of 6 & 8 thou inlet and exhaust and it was with these clearances that Mark had been log building the custom Hi-Pipe maps. Just for shit and giggles I decided to go back to the 4 & 6 originally specified for the A5 motor simply as an experiment to see what sort of effect it would have on the running.

To be honest I wasn't expecting much. If anything I thought it would run a tiny bit leaner at idle and might need to have the CO trim bumped up one or two microseconds. Boy was I wrong! That simple two thou difference which, (I haven't actually measured it exactly.) can't account for more than a few extra degrees of duration and two thou extra lift had an extraordinary effect on running! No matter what I did with the CO trim it didn't want to idle from cold and even when at operating temperature it was idling slow and the stepper was struggling.

I didn't have time to re-adjust the clearances on Friday before we left so the first day I rode with this 'Tune' and it was, quite simply, pretty horrid. Mark and Ralf both noticed it was poppy, farty, sounded 'Wrong' and with the idle trim at +5 where it felt best, (But still a long way off good!) it stank just for good measure. This was particularly vexing because prior to my little *Experiment* it had been running superbly!

Now I'm sure that with a stock map, be it the 68S or the '03 and the lamda on it probably would of been able to at least make an attempt to trim itself into some semblance of normality but because the custom map is open loop it can't and won't trim.

Needless to say the problems were less pronounced at wider throttle openings but it was still painfully obvious that it was unhappy and I'm sure the situation was exacerbated by the very high temperatures we were riding in. Quite simply it was downright nasty! No way was I going to put up with more than a day of it! So, come Saturday morning in the car park of the motel it was off with its lids and re-set the valves back to 6 & 8. Result? Instant return to perfect running! Idle spot on between 1200-1250, (I left the CO at +5 and it actually felt better than *Before* when it was at zero. The plugs were on the lean side of ideal on zero. I haven't looked at them yet at +5 but my 'Butt AFR meter' says it's closer than it was before. That may be wishful thinking though! ) and a return to seamless performance and liquid torque from 2,000rpm to redline.

I have to say I was surprised by what a huge difference it made. Really, it was extraordinary. The one thing it did tell me though was that it must be very hard for people to not notice when their flat tappets are going tits-up! I've learnt that you can tell when they are going very, very early in the piece as the engine will start to sneeze back through the throttle bodies just when you open the throttle barely perceptibly and the idle will be slow and erratic. On engines displaying those symptoms I've pulled the camboxes and found just the very earliest stages of failure of the DLC on the foot of the tappet. The effect on lift and duration must be miniscule, but it's noticeable! Once the wear becomes more extreme the noise starts and the engine will barely run at idle but by that time it should be obvious to blind freddy's cat that something is seriously amiss! How anyone could ride one to death I have no idea!

Anyway, that's something to think about for today.

Pete

Pete
Does Mark use 6 & 8 for all his map building? If so I run the old A5 settings of 4 & 6 the bike runs great but do you think it would be worth trying 6 & 8 going by your experience. I am running Griso24S-FU2-FCE6.2014.08.18

I would definitely try 6 & 8. If it runs better at 4 & 6 you can always go back. The difference is huge in terms of rideability.

Ok I will give it a go soon and report back on my findings.

The FCE6 map is ancient! Did I not send you an update?

Pete, I am going to start a thread on mapping issues and this is one topic that needs to be mentioned.

I wasn't sure of the designation but the build date sure looked old so I'm not surprised it has been superceeded.

As you mention in the other thread people HAVE to realise that the bike MUST be properly tuned. It's no good expecting a re-map to work like a magic wand or fairy dust that with the press of a button will cure what ails the bike. The tune must be correct and the bike HAS to be un-mollested in terms of major modifications, especially modifications to the airbox which, apart from upsetting the tune will achieve exactly 100% of fuck-all in terms of performance improvements but will accelerate wear in the engine.

If you honestly believe that you are going to be able to turn your GRiSO into a fire-breathing 130hp monster by arseing about with a load of tacky aftermarket add-ons dreamt up by people who don't actually have much of a clue how an engine works? Well, good on ya! Go fer yer life Tiger! But Mark's maps won't work and I can't advise you on how to make a bucket of shit into a three course meal!

You want clean, liquid, 'Real World' performance and a fine running motorbike? We can help.

Screechers needn't apply!

Pete

That is the last map I got and was very impressed with it less vibes good fuel economy and goes like shit of a shovel.
My bike is box std except for the Guzzi Termignoni.

PM your emIl address and I'll flick you the latest map.

Ok after last night I checked my thumb drive where I keep my GRiSO stuff and found I quoted the wrong map the one I have is actually the latest one Mark has confirmed this.
Any way got a chance to do the valves today the bike now idles from cold it has never done this for a while so looking good so far. I was going to give it a run this afternoon and then balance the throttle bodies but rain interrupted play so maybe tomorrow. Will update tomorrow.

Well, if yours was running like mine did with the smaller clearances, (And the poor cold idle symptom was immediately apparent on mine.) I think you're going to be astonished after you give it a proper tune up!

I'd suggest balance the TB's and re-set the TPS and since you're there just re-set the self learners just 'cos you can. I think you'll be very happy!

What pipe are you running?

Pete

Guzzi Termignoni with DB killer.

Good-O! That works well with the dBk installed. Mark reckons its vibratory, I never had an issue with mine when it was on my bike.

Pete

Well it’s a bit latter than tomorrow but got it done eventually.
Right here goes.
Gave it a run to warm it up very poppy of gas.
Did the throttle body balance at 3750, set tps and reset learning all good.
Went for a run around 150 miles fuck did it vibrate at around 3000 and hot idle was lumpy,no popping on over run, when I got home I redid the throttle body balance at 3100 reseting tps and auto learning.
Went for a test today said before I left said if it was ok I might be a while 151 miles later and all is good. Vibes back to normal goes maybe a bit better hard to say, smooth idle, more mpg + more spm (smiles per mile) main + is cold idle.
Now I don’t know if the previous owner has messed with the link rod or not paint is still on sacred screw.
Maybe it’s my manometer nothing much can go wrong with it

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don’t know but now I am happy as is the bike.
After setting the throttle body’s at 3100, checked at 3750 and 25mm difference, just as a test gave the throttle a big handful and the manometer never moved so I don’t think it is to far away.

Pete Roper wrote:

Very interesting indicator of just how picky the 8V motor is to changes in lift and duration in the valvetrain.

Prior to heading off to the cabal last weekend I thought that I'd better check the valve clearances on my old bus as I hadn't looked at them for ages, well over the recommended 10,000km interval. Last time I'd done them I'd changed to the later clearance specs of 6 & 8 thou inlet and exhaust and it was with these clearances that Mark had been log building the custom Hi-Pipe maps. Just for shit and giggles I decided to go back to the 4 & 6 originally specified for the A5 motor simply as an experiment to see what sort of effect it would have on the running.

To be honest I wasn't expecting much. If anything I thought it would run a tiny bit leaner at idle and might need to have the CO trim bumped up one or two microseconds. Boy was I wrong! That simple two thou difference which, (I haven't actually measured it exactly.) can't account for more than a few extra degrees of duration and two thou extra lift had an extraordinary effect on running! No matter what I did with the CO trim it didn't want to idle from cold and even when at operating temperature it was idling slow and the stepper was struggling.

I didn't have time to re-adjust the clearances on Friday before we left so the first day I rode with this 'Tune' and it was, quite simply, pretty horrid. Mark and Ralf both noticed it was poppy, farty, sounded 'Wrong' and with the idle trim at +5 where it felt best, (But still a long way off good!) it stank just for good measure. This was particularly vexing because prior to my little *Experiment* it had been running superbly!

Now I'm sure that with a stock map, be it the 68S or the '03 and the lamda on it probably would of been able to at least make an attempt to trim itself into some semblance of normality but because the custom map is open loop it can't and won't trim.

Needless to say the problems were less pronounced at wider throttle openings but it was still painfully obvious that it was unhappy and I'm sure the situation was exacerbated by the very high temperatures we were riding in. Quite simply it was downright nasty! No way was I going to put up with more than a day of it! So, come Saturday morning in the car park of the motel it was off with its lids and re-set the valves back to 6 & 8. Result? Instant return to perfect running! Idle spot on between 1200-1250, (I left the CO at +5 and it actually felt better than *Before* when it was at zero. The plugs were on the lean side of ideal on zero. I haven't looked at them yet at +5 but my 'Butt AFR meter' says it's closer than it was before. That may be wishful thinking though! ) and a return to seamless performance and liquid torque from 2,000rpm to redline.

I have to say I was surprised by what a huge difference it made. Really, it was extraordinary. The one thing it did tell me though was that it must be very hard for people to not notice when their flat tappets are going tits-up! I've learnt that you can tell when they are going very, very early in the piece as the engine will start to sneeze back through the throttle bodies just when you open the throttle barely perceptibly and the idle will be slow and erratic. On engines displaying those symptoms I've pulled the camboxes and found just the very earliest stages of failure of the DLC on the foot of the tappet. The effect on lift and duration must be miniscule, but it's noticeable! Once the wear becomes more extreme the noise starts and the engine will barely run at idle but by that time it should be obvious to blind freddy's cat that something is seriously amiss! How anyone could ride one to death I have no idea!

Anyway, that's something to think about for today.

Pete

Hey Pete or Mark -

I've done a ton of reading on this site and much appreciate the help both of you (and others) provide to those of us new to the GRiSO. Forgive the curiosity... I haven't yet found why the recommendation went from .004 & .006 to .006 & .008 for clearance. Was this a factory update or found by the experts in tuning and services GRiSOs.

My brother recently completed his first service (took it to the dealer) and they would only do .004 & .006 as that is the factory recommendation. So that sparked the question above.

Hi AOAM,
4am here in Aussie land.
I'm sure marks maps for the 8V engine were set up using the .006 and .008 settings.
Pretty sure the factory changed to these settings when they went to the roller tappets.

No, the change predated the change to rollers. My guess is that one of the early stabs at finding a cause for the failures was a guess that when the engine got really hot the gaps were closing up and the tappets were riding the cam. If there is no clearance then the tappet is always under pressure on the cam from the valve springs and this makes it very difficult for a film of oil to be maintained to wedge between the two components and boundary lubrication will occur with subsequent failure. It was a reasonable assumption and worth a try but at the end of the day was fruitless because it wasn't the problem.

The shop's refusal to use anything other than book specs is not unusual in an unthinking 'Monkey see, Monkey do' world. It is widely assumed that when the engine changed designation from A5 to A8 and the part number for the cam shafts changed it was because the cam profiles had changed and this had required the difference in setting clearances. Problem is that this was exactly that. An assumption. Nobody, apart from me apparently, ever bothered to actually graph the cams! If you do so you'll find that the profiles are identical. The part # change was due to the fact that at that point they started shimming the cams for end float and the journal length changed to accomodate the shims!

Look, it's no big deal. If you're running one of Mark's maps just re-set the valves to six and eight. It is annoying because doing so will have a minor effect on things like TB balance but as long as it is done reasonably accurately it shouldn't impact too radically on the balance factor.

Pete

Pete, much appreciate the reply. I agree with the comments on the monkey shop. Hence, my desire to be educated.

I haven't yet touched my bike as it only has 200 miles on her... but I have cables, maps, exhaust, manometer, tools, liquid, filter, etc. all newly purchased to do correctly after break in.

The do it "correctly" is what directs my research.

Unfortunately, my brother is several states away otherwise I'd just do the work for him - as he is less savvy or at least less interested.