Idle Stumble/relay

[motoguzznix]

Hey Dawg -- does it seem to be dropping an occasional single beat at idle or trailing throttle ONLY -- not under load? If so, it may be due to a little chain whip on the cam chain. It's not serious. I've had this since Day 1, and so've many others. Being in a good state of tune overall, set to idle at ~1100 RPM, and well broken in will all help to keep it from stalling when it does this.

Ratchet

 

Since I replaced the cam chain tensioner by the stucchi part during my engine disassembly, the idle is absolutely perfect on my V11.

 

I did the TB balance after plugs valve adjust etc. The only thing I have never done since new is TPS.

 

I have Pod filters,Stucchi crossover, Mistrals, Powercomander usb with his map for my setup. I thought about increasing the mix manually in the low range on the PC if it is maybe to lean.

Nose

 

The adjustment of the TP to 150 mV at closed throttle has to be very accurate, the 500 to 525 mV at idle is less importent as the range in voltage indicates.

 

Set the valves to the 20/25 spec. Every Guzzi Engine runs better at that spec, especially at idle speed.

 

The idle CO can be adjusted via the axone tester by your dealer, 3 to 3,5 % is ok, no more. This is a better way than by the power comander as the ECU allows it. CO adjustment is the last step in the proceidure after TP, valves, throttle balance.

[Guest ratchethack]

Ratchet

 

Since I replaced the cam chain tensioner by the stucchi part during my engine disassembly, the idle is absolutely perfect on my V11.

Ernst, 3 Q's please:

 

Why did you replace the stock tensioner?

 

Am I assuming correctly that since you replaced it with the Stucchi that there's no way to adjust the stock tensioner?

 

Was the cam chain noticeably tighter by feel after you installed the Stucchi?

 

TIA

[badmotogoozer]

I was reading on the TB balance and seem to find a difference of opinion.

 

One said to set the air screws to 3/4 - 1 turn out and leave them alone that they are for co setting only.

It states how to use the set stop screws for balance only.

 

The other uses the stop screws and goes back to the air screws for a final adjustments

 

Any advice on which is better?

 

Thanks

 

Hey Nose,

 

I'm doing this same thing now for the first time. After getting everything else sorted on the "problem child" I've found my TPS totally out of whack.

 

In my readings of how to set it and balance, the consensus of "people who know" is that nobody really knows what the hell to do with the bleed screws. One says to close them and leave them there, another says 1/2 turn out, another says 3/4 and one more says 1 full turn exactly. All I would consider reliable sources. All claim result is a perfect running bike.

 

I've also got a question re: setting the 150mV. If it's way off, how is it adjusted? I'm assuming one loosens the TPS unit itself and rotates it to get 150mV, as there is nothing else connected. Hopefully there is an actual consensus on this...

 

Even among respected dealers there is no consensus on how one balances the TB's. Seems everybody and their dog has written proceedures that differ greatly. Even here advice from various members differs greatly (from pages long instructions to "fiddle with the white knob while riding until it feels right"). Best as I can figure, do it a few times and figure out for yourself what works...

 

cheers,

 

Rj

[docc]

Indeed the TPS is rotated to adjust it. Ever so slightly. And tightening it back down tends to change it. So, it takes a few tries to get it right on. The spec is 150 mV +/- 15. I find my Sport runs the best at 165 mV.

 

True the procedures vary considerably and most are compilations of one another. With 47,000 miles on the Sport I've done this several ways totalling about eight or nine times. Best results from Jeff in Ohio's method.

 

I've tried numerous times to turn my air bypass in where they 'belong.' I always end up back at a full turn to get the most stable idle especiallyin the hot, hot deep south summers.

[bento]

Argh, I have been chasing this demon since I got my bike. Would you include the hard turnover as this same problem? The bike will be idling fine, then turns once or twice like it hates to spin, then goes fine again. And the stalling out thing, both the same problem?

 

Oh yeah, bearings back in, windage/slopage plate confirmed, pc3 in place, I am looking foreward to a hot summer of riding!

 

...after I get my tach fixed

[badmotogoozer]

Thanks Docc! That's the bit of info I needed wrt rotating the TPS for the 150mV. After reading everything I could find on the subject JeffinOhio's method makes the most sense. It also seems that it will get the most repeatable results - which is what I'm after since I want a known and repeatable baseline before I drop $500 on a dynotune for my PC.

 

cheers,

 

Rj

[windchill]

Sometimes mine won't start, other times it "dies" when running along the road. Both symptoms appear to tie in with the relay which "powers" the fuel pump - if I either stop and wiggle it round, or sometimes just turn the ignition off/on again the problem is resolved for a bit!!

 

I have taken to unlocking the seat base at fuel stations these days so that if I don't hear the "whirr" of the pump pressurinsing the system (is that what the noise is?) I can get at and wiggler the relevant relay.

 

As far as i can see, all other connections are OK.

[motoguzznix]

Ernst, 3 Q's please:

 

Why did you replace the stock tensioner?

 

Am I assuming correctly that since you replaced it with the Stucchi that there's no way to adjust the stock tensioner?

 

Was the cam chain noticeably tighter by feel after you installed the Stucchi?

 

TIA

I replaced it because I do not trust it. The low tension force of the stock part is not sufficient according to my experiance. The stucchi tensioner is much tighter, some call it too strong.

 

But I have used the stucchi part for 70000km in my LM2 without any bad effects. After that mileage, the plastic material of the tensioner showed only minimal wear. That encouraged me to install it in an other engine which had to be rebuilt on a very small budget. This engine (a Quota) ran a further 25000 km since then and still works perfect.

So there was no question for me to istall the stucchi part after my engine disassembly.

 

Whether the stock tensioner nor the stucchi can be adjusted.

The stock tensioner is by design not able to give enough tension to the timing chain. When you pull the timing cover off you can feel how weak this little spring is that presses the tensioning rail against the chain. This works with most stock camshafts, but when used with a good old P3 cam in a Cali2 engine, valve train acceleration cannot be controlled by this tensioner. In a certain rpm range, there was a metallic noise from the valve train that went away with the use of a stucchi tensioner.

 

I know that some people disagree and call the stucchi tensioner too strong. But my experiance shows good results and longevity with this very simple and cheap part.

[Guest ratchethack]

I replaced it because I do not trust it. The low tension force of the stock part is not sufficient according to my experiance. The stucchi tensioner is much tighter, some call it too strong. . . . But my experiance shows good results and longevity with this very simple and cheap part.

Thanks, Ernst.

 

This confirms my suspicions that the very occasional "dropped signal miss" that my Guzzi and many other V11's I'm aware of has ONLY at idle and trailing throttle is due to a little camchain whip.

 

NOTE TO SELF: Put a Stucchi tensioner on the "future parts" list with next order o' stuff.

[docc]

How hard is it to access this part and change it?

[dlaing]

when replacing the tensioner, should one also replace the chain and sprockets?

[Guest ratchethack]

when replacing the tensioner, should one also replace the chain and sprockets?

No. They are mutually exclusive WRT service life, not tied to each other like sprockets and chain. If sprockets are worn, this means the chain is also stretched, and vice versa, so sprockets and chain typically need to be changed out at the same time. From wot I've read, I believe this may be expected not before well over 100K - 200K miles, or unless something very unusual happens.

 

It's hard for me to imagine that IF the stock tensioner simply isn't tight enough, that a simple "stacking up" or shim block wouldn't be the preferred fix, and obviate replacement of the device itself, but I've never seen one on a Guzzi, so I'm at the mercy of wot others have to say on this.

 

I think I've asked the question 3 times, 3 different ways, and no response yet that would be conclusive to my way of thinking -- Is there NOT a simple way to make the stock tensioner operate more effectively? If the tension is dependent on a weak spring and not simply a "hard" setting, it would seem that a stronger spring, or increasing the "preload" on the existing spring might be worthwhile? How about getting rid of the spring altogether and anchoring the tensioner to a "hard" clearance setting?

 

OTOH, if the Stucchi tensioner (or others -- Valtek?) are really inexpensive, maybe this trumps re-engineering the stock tensioner as Ernst seems to've concluded above?

[dlaing]

Thanks Ratchet.

Here are some prices on tensioners

http://www.harpermotoguzzi.com/timing.htm

Valtech $48.78 US

Guzzi $76.41 US

About the Valtech they say, "and cost about half as much as the new spring loaded tensioner from Moto Guzzi."

Exaggerated sales claims?!? But they are not trying to be dishonest as the price is posted there. Just bad math I guess Or maybe the joys of website maintainance as the prices may have been further apart when they first made that quote, and then they modified the price...clearly to the penny.

Half of 76.41 is roughly 38.20 and twice 48.78 is 97.56.

I suppose when you use the word "about" you get alot of leeway. I am about guilty of that myself.

[luhbo]

The Stucchi tensioner is dammed strong, maybe stronger than the oil pump bearings are. Time will tell whether this does them good.

 

Hubert

[Guest ratchethack]

The Stucchi tensioner is dammed strong, maybe stronger than the oil pump bearings are. Time will tell whether this does them good.

 

Hubert

I can't imagine that a significantly more powerful tensioner spring would put more of a load on oil pump bearings than the sudden jarring effects of a jumping, whipping chain at idle and off-throttle, (slight as the slack may be) -- not to mention the relative load on 'em from accelerating the cam and valve train up to max RPM in either case -- but that's just me.