Throttle body replacement - are you kidding?

[turo]

Howdy eveyone!

 

I have a question.

I adjusted the valves to .1 for intake 1.5 for exhaust,

adjusted the tps to 170mv, its as close to 150 as I could get.

and the low and high speed idles on my bike, a 2003 Rosso Corsa.

When I adjusted the throttle bodies using mercury sticks, I was told to CLOSE the air bypass screws. I adjusted the bike at 3000 rpms using the white adjustment knob until they seemed even.

The biker ran great, nice snap when I twisted the throttle, till I took it for a ride.

When I took my hand off the throttle at speed, the bike had nasty hesitation, hiccupping, etc.

when below 3000 rpms the bike ran plain ruff, felt like it would stall and lunged with hesitation, so I always kept it in a lower gear to keep the rpms up.

Anyway, took it to the dealer to try to fix it, they did, fairly well.

The tech told me that the throttle bodies are set at the factory and are not to be messed with.

He could tell from the “paint marks no longer on the adjustment screws” - that they were adjusted.

He said that they MIGHT have to be replaced as the work shop manual said so, he showed it to me, it said – do not adjust, replaced if messed with.

I couldn’t believe it yet I saw it in black and white.

Did I do something terribly wrong. $1900 is the replacement cost.

That’s crazy.

Any advice is greatly appreciated!

 

Thanks

[Guest ratchethack]

Turo, I really hate to disparage any dealer, but this sounds pretty wild. One of the first things I did on my bike after taking delivery and an oil change, heli-coiling the drain plug, suspension sags and preload adjustment, and a few other things was to remove all the yellow factory marking paint on the entire bike with lacquer thinner.

 

It sounds a lot like they're feeding you the kinda line that'd have me making fast tracks on a 180 course, but I'm not assuming I've got the whole story here, either.

 

As far as wot's in the Service Manual, I've been finding walloping whoppers in mine for years. No telling what's lost in translation -- before legal got ahold of it for final revisions, that is. . .

 

The only adjustments of any kind I can think of that carry anything like a risk of permanent damage to the TBs is the air bypass idle screws. Theoretically, if you screw these in too hard, they will permanently lunch their seats. And in this case you really do have a problem... But I reckon most guys would have to be daft to crank 'em in that hard?

 

Sorry, that's all I got on this one.

[Greg Field]

Sounds like you were talking to the self-important young kid of the shop. Those adjustments were put there for a reason . . .

[docc]

I thought the yellow paint was to help us find all the points of adjustment.

 

Check out the TPS thread. You can probably do this yourself . . .

[Guest Phil_P]

Hi, did you try to achieve the 150 mV setting with the link rod between the throttle bodies disconnected (as it needs to be)? If not, pop off the plastic ball link where the rod reaches the body and re-adjust.

 

Your posting doesn't mention any subsequent re-opening of the air bypass screws to set idle, has this been done? They want to be open by at least half a turn.

 

As for boogering your throttle bodies just because you adjusted them, what a load of BS! Perhaps the tech can explain to you how HE is going to get the required setting without adjusting the throttle bodies, and if he IS going to adjust them, just what is so magic about the way HE does it that wrecking them isn't the result.

[pete roper]

I thought the yellow paint was to help us find all the points of adjustment.

 

Check out the TPS thread. You can probably do this yourself . . .

 

I think that the person in question *may* of recently read the Guzzi tech site update on the Griso/Norge/Breva with the stepper motor control et-al. It has recently been announced that Guzzi will not warranty any work, especially replacement of TB's and linkages, if the paint has been disturbed, especially on the 'No Touchy' stop screw.

 

This is of course bullshit as there is a very GOOD description of how you can, (admittedly crudely!) fix the detonation problems some Brevas and Norges experience by [playing with the settings on Guzzitech. It's not a *sollution* but it IS probably a way of dealing with the stupidness imposed by mass production!

 

The problem, the REAL problem as I see it is that the people who are working on bikes in your 'average' dealerships, while qualified, actually have no real idea about an awful lot. They get taught theory in college but in the shop they simply change oils, filters, tyres, brake pads etc. When it comes to diagnostics or, worse still, addressing inherent faults, they simply 'Read the Book' and any sort of annalysis is in the realms of 'Black Magic' and 'White Mans' Ju-Ju'. Factories pander to this by treating Mechanics as cretins so its a self fullfilling prophesy!

 

If you own something like a Guzzi you have to learn to do the leg-work yourself or put up with second best. Probably true of other marques as well, it's just that they so far out-perform their average owner that they can run like a hairy goat and their owners still think they're Stoner!!!!!

 

Pete

[Paul Minnaert]

to add to petes story, they tell in the letter, that the tb's are syced at marrelli on a flow bench, and no way you can do it better. And because you have no flow bench, and guzzi either, if they are adjusted, there is nothing that can be done to repair. And so they will not replace them as warranty item. But it's only for the new range.

My idea it that adjusting has not only to do with flow is a body on the bench, but also with the engine sucking on it. Try to misadjust valves and see how the balance is. Or the other way arround: the tb's are ok, so adjust the valves until you have a balance on the intake.

[turo]

Thanks everyone for all of your feedback.

For some more information.

The dealer mechanic did do a decent job of adjusting the bike so it ran smooth again.

He just told me what he read and was going of the info in the manual.

When I did the work,

I did try to set the tps to 150 with the linkage disconected, ignition on and run switch on.

170 was as close as I got - sensitive bugger:) It was 375 when I tested BEFORE adjustment with the linkage disconnected - way to high!!!

The reading should be 375 with the linkage reconnected?

I also set the throttle bodies with the bleeder screws fully closed.

Were they supposed to be open a full turn as suggested in Ian's tutorial?

Could that be where I messed up?

I did reopen the bleeder screws to 1/2 turn open on both sides when I finished!

My goal here is to learn to adjust the bike myself to run really, really good.

I'm trying to avoid putting in a PCIII, in my juvenile opinion, I should be able to get the bike great with out it!

I am going to post on the 24/7 Forum for a "Guzzi Mentor" maybe I can find someone local to help me learn proper maintenance and drink beer:)

Thanks again!

[Paul Minnaert]

In the pictures all scews are marked, even the idle screws.

 

the official text:

TECHNICAL NOTE No. 007-2007 22-06-2007

MODEL: Breva 850/1100 Griso 850/1100 Norge 850/1200, 1200 Sport

SUBJECT: Throttle body seals

Dear Dealer,

we hereby would like to inform you that, from today onwards, the warranty claims relating to the replacement of throttle body on the a.m. models will no longer be valid in case an alteration of adjuster screws (sealed with yellow paint - see attached picture) is found. We would like to point out that any alteration of the throttle body does not entail any advantage to bike dynamics.

Throttle body correct balancing can be made only by Magneti Marelli, namely the Manufacturer of this part. Air flow is adjusted by a special tool called flow-meter, which is used to set air flow per time unit.

This is the reason why, if the screws used to maintain this balance are tampered with, it is no longer possible to restore throttle body correct setting, and throttle bodies have thus to be compulsorily replaced.

Best regards.

Moto Guzzi S.p.A.

Technical Service

[profWacko]

>>This is the reason why, if the screws used to maintain this balance are tampered with, it is no longer possible to restore throttle body correct setting, and throttle bodies have thus to be compulsorily replaced.

 

Does this imply that I can NEVER EVER adjust the throttle body balance on my Griso?

 

It sure makes a big difference on my Jackal and Le Mans(s) when I adjust the throttle body balance after a valve adjust.

 

Sheesh - two steps forward and three steps back.

 

-Jack

[docc]

With a vacuum meter ( mercury sticks or such), doesn't the running motor become a flow meter?

 

I can't imagine not balancing the throttle bodies.

[Dan M]

With a vacuum meter ( mercury sticks or such), doesn't the running motor become a flow meter?

 

I can't imagine not balancing the throttle bodies.

 

 

Well put Docc. The whole idea of adjustability is to make up for differences from cylinder to cylinder. In a perfect world every machined surface, valve, port and t-body would be identical, wear at the same rate and no adjustment would be needed. Until then, they will require adjustment.