15RC Cal Vintage TB balance

[lazlokovacs]

anyone got a definitive write up for balancing the tbs on the 15RC Calvin? (or the earlier 15M calis?)

The procedure in Guzziology doesnt seem that logical to me...

It's been a long time since I've done it on the Calvinand have subsequently got used to the procedure on the griso so I could do with some reminders...

cheers

[Tom H]

Here is two good ones. I prefer to use the text only version, the other is nice because the pics show what the screws are.

Text:
https://archive.guzzitech.com/EVTuneup-Jeff_B.html

With pics:
https://bradthebikeboy.blogspot.com/2012/10/throttle-position-sensor-setting_21.html

Tom

[janguzzi]

Maybe my new video might help you.
https://www.youtube.com/watch?v=zF889tECKvg

Yes, it is text intensive and you have to know what you are doing.
The text below the video might help too.

[CharlieW]

I followed Tom's links and my 02 Stone is running Great.
 The big help for me was using the TPS breakout adaptor(http://www.casperselectronics.com/cart/index.php?route=product/product&product_id=853). With this I was able to set TPS to spec, the rest I followed the the advice from the two links.
 Good luck
 CharlieW
   

[lazlokovacs]

thanks a lot guys 

[Kiwi_Roy]

TPS setting can be confusing. just remember 150 mV with the throttle idle stop backed right off.This value is so the TPS is safely away from the end of its travel, it won't bang up against a stop and get damaged, this is a procedure we used in many devices back in the day when everything was still analog.
Once set you don't move the TPS again, you might see 400 mV at idle but thats when the butterfly is jacked open by the idle screw, its not something you set by moving the TPS, if you backed off the idle screw it should go back to 150. You can actually skip measuring the 400 mV and just set the idle to 1100 you will see it works out the same.

[lazlokovacs]

well,

I set the throttle to 3.6 via guzzidiag and the left hand throttle stop screw, (it was at 2.1)

balanced the high speed running with some gauges by way of the adjuster

and then balanced the idle with the air bleed screws.

It is running better, but still missing a bit at idle and low throttle openings.

One other curious thing I noticed is that the tacho needle is always vibrating, it's been a long time since I rode this bike and I can't remember if that's normal... any thoughts? could that be symptomatic of a bad ground somewhere???

I would have gone the whole way and removed the linkage to check that the 150mv value was correct but I was too nervous of losing the throttle linkage clip on my friends garage floor...

I'm really not sure why my bike is misfiring, I guess it could be the coils, HT leads, ECU ground, partially  clogged injectors, incorrect TPS baseline setting -a lot of variables !!!

[Kiwi_Roy]

Is it this one with twin plugged heads?
https://www.thisoldtractor.com/guzzi007/schematics/2008_California_Vintage.gif
On a single plugged machine you can read all the high tension from plug cap to chassis about 8,000 Ohms but a twin plug setup you should read from one plug cap to the other plug cap for that cylinder. Hopefully it will measure the same on both sides, if you find one open its probably nasty resistor type lead, throw that and put some proper copper core wire.

[lazlokovacs]

great tip thanks

Just did the TPS properly as per Janguzzi. (Out of all the methods I've read, his seems by far the most logical FWIW)

All steps up to and including the high speed balance went great. Though I found that to set the idle balance I had to wind out the RHS air bleed screw say 1 full turn and leave the LHS air bleed where it was. I was a bit concerned about this apparent imbalance, but the thing was idling pretty nicely until all of a sudden the vacuum started dropping on the left hand side quite considerably. I could 'chase' away the imbalance by opening the air bleed on the RHS yet further, but obviously this is less than satisfactory...

I'm guessing I have a misfire, and that it's coil or HT lead related.

[guzzisteve]

Before doing anything else, like I said before , clean TB's and airscrews.  When you open or close airscrew it changes the mixture! You balance idle w/stop screws and keep airscrews closed or at a constant L&R same setting. I set them at 1/2-3/4 open and both the same if you don't want to close them cause the bike won't run with them closed.

[lazlokovacs]

thanks guzzi steve,

I have put the mixture screws in the ultrasonic bath and the butterflies look extremely clean!

I understand that the air bleed changes the mixture.

I studied 7 different methods of balancing the TBs and I opted to use Janguzzis. In his method you baseline the TPS then bring LHS throttle stop in until you get 3.6degrees on guzzi diag without the linkage being connected. Then you pop the linkage back on, having made sure that it doesn't change your 3.6 degree position. Then do the high speed via adjusting the linkage adjuster, then balance the idle by bringing out the air screws.

He gave a link to his method above.

In all 7 methods I saw, I believe there is a definite compromise going on, as any changes you make at high speed will affect your settings at idle and just off idle. JanGuzzi's seemed like the most pragmatic approach...

I will humbly suggest that it's not quite as good a system as the later bikes such as the griso...

[guzzisteve]

I don't go by 3.6, I go by how fast I want to idle. The degree is never right on the $.

[lazlokovacs]

So... the thing I don't get.... If you balance idle with the stop screws say, then surely any adjustments you make at hi speed via the adjuster arm will throw your idle adjustment out when you come back to the stops??

For example, the guzzi training vid says to baseline the TPS on the LHS then use the throttle stop on the RHS to set balance, then refit the arm (I imagine the arm must go back on in a position where it doesn't mess with the relationship between the idle stops) and then do the high speed balance by adjusting the arm.

BUT doesnt this last step mess with the position of the butterflies at idle, thus nullifying your previous work on the idle balance???

This problem seems to crop up in ALL of the methods of balancing that I've seen published on the net or guzziology...

I must be missing something, help appreciated.

 

[janguzzi]

Idle balance with air bleed screws only.