03 California Stone Touring- throttle opening

[ian-jowsey]

Hi all, I m trying to get my head around why this bikes throttle linkage is limiting the opening of the butterflies in the throttle bodies. There's at least 30degrees of rotation left before the butterfly reaches the positive stop cast into the throttle body. The linkage is the limiting factor and specifically, the fast idle cam and adjuster both contact the link arms and prevent any further rotation. The TPS is set to trigger the full throttle signal at the same point at which the linkage binds on itself. It appears to have been set at the factory to significantly limit full throttle.
Has anyone set one of these up so they get full throttle opening and if so can the TPS be reset to true full throttle opening and still achieve the recommended voltage at idle?
My bike is a standard 03 hydro with the only modification being to the exhaust H-pipe which has been replace with an after market one with provision for the original LAMDA sensor to be retained.
It has been suggested that this is simply the factory way of limiting the power output on this model.
I'm not satisfied with the set up and will be experimenting with removing the fast idle cam on the throttle linkage to clear the obstruction and adjusting the TPS so full throttle is at least achieving 70-80 degrees from fully closed.
I'd like to hear from anyone else who has figured out what happens when you actually achieve full throttle opening and tuned their fuel system/TPS to match.
Regards Ian
Hobsonville, Auckland, NZ

 

[john zibell]

I think you will find the engine in all practice cannot take any more air than is provided in the stock setup. The Stone isn't a rocket ship by any stretch of the imagination. Trying to make it one would be an exercise in futility. With the exception of some intake and fueling mods that Todd can provide, trying to get more air into the system just isn't practical. The heads can only flow so much air and opening the butterflies further won't make any difference. If open too far, air velocity will drop and with the velocity drop, fuel mixing won't be optimum.

 

[GTM®]

Thanks John. Ian, welcome to the Forum.
You're going to have to dig pretty deep in order to make that all work, as there is layers of complexity to do it correctly. I'm all ears if you do it though. More power can be found in flow and fueling, see; https://www.guzzitech.com/tech/perform ... cali-power

Post again soon.

 

[ian-jowsey]

Thanks, I understand that.
I fully appreciate what you are saying but in that case why did the factory not use smaller throttle bodies and open them. The bike certainly feels like it would like a little extra breath even within the limitations of the cylinder head/camshaft architecture (the air box appears to be way too small too but that's seems to be easily relieved).
I haven't had this old girl long and I initially became aware of it when trying to figure out why twisting the throttle hard makes it go better but feels like something is going to break in the cable/linkage area, sure enough, the plastic link rods try to wrap themselves around the fast idle adjuster and cam and there is no positive stop other than on the throttle bodies.
I purchased this bike for lugging a reasonable load. It's a good slogger but it still feels like it wants to breath a bit more yet too (my other bikes include a K1200S for speed thrills, I'm not looking to make the Stone a racer, I just want it to do what it does to the best of its capability)
I'll work through the service items and clean up and reset the throttle bodies to standard factory spec and go from there.
In terms of insufficient air speed with too much throttle opening, has anyone actually tried it, these throttle bodies are smaller than the V11 Sport and Le Mans, are they really so large as to have such a detrimental effect especially at 3500-5000rpm? I'm not looking for full throttle performance straight off idle rpm.
I worked on these fuel systems on Fiat and Alfa Romeo product for many years and it was common for the factory to send them out achieving no where near full throttle, resetting them was the first place to look for a little extra performance but this set up is the most restrictive I've come across. Thanks for confirming that this is the way they're supposed to be. I'll let the group know if I can gain an improvement from my experimenting or if things work best the way they were delivered.
Regards Ian

 

[ian-jowsey]

Thanks Todd
I'll be talking to you about the Power Commander once Ive got the mechanical components how I want them. I bought this bike a s a project to play about with. The suspension is tired and the riding position doesnt suit me so i'll be making plenty of changes there too and I'm keen on seeing any old posts or talking with anyone who has experience with them.

The devil (as always), is in the detail!

Cheers Ian. :ugeek:

 

[ian-jowsey]

Hi

I knew there was a problem here! The central pivot for the throttle linkage carries the fast idle actuator. When the fast idle part seizes on the throttle linkage part the throttle works fine until the fast idle actuator tries to break the plastic links to the throttle bodies.
Once this obstruction was cleared the throttles opened to the stops. The loss of motion at the throttle butterfly is more than 50%. In my case it appears to have been seized solid for a long time meaning this bike possibly hasn't seen full throttle for years.
I'll let you know what happens when it's back together.

I'll bet there's more than just my bike out there that this has occurred on.

Regards Ian

 

[ian-jowsey]

Hi All
I've run the bike without the air box and it goes like I always suspected it could.
It now feels like a 74hp bike instead of a 45hp bike and it revs crisp and clean.
For anyone wondering we're all the power has gone on their California, check the throttle linkage. The previous owner had this bike dealer serviced but they didn't pick up on the problem. It isn't the easiest thing to work out but if you open the throttle and look down on the right hand side to where there is an adjuster screw for the fast idle (on the central pivot where the throttle cables connect) , if that screw makes contact with the plastic link arm to the throttle body your not getting full throttle because the centre pivot has seized. When restored to working order a light spring keeps the fast idle actuator out of the way of the linkages.

I'm going to use my hole saw to relieve the air box lid to let more air in but I'm not going to eliminate the lid as this is a wet country and I quite like riding in a decent downpour so I need some weather protection for the paper element filter.
With this done and the straight through H pipe fitted this bike will be about right and my focus can now switch to improving the handling and riding position.
Replacing the 30mm diameter handle bars with the flatter MX style I want to use is proving to be a problem as it seem only Moto Guzzi use 30mm bars. Has anyone else dealt with this issue? :ugeek:
Cheers Ian