Idle Stumble/relay

[motoguzznix]

I would not worry about the oil pump needle bearings as these can be replaced in case of wear.

I would worry about the camshaft bearing that is without oil pressure the first few seconds after starting the engine.

 

But my observation shows no wear within my mileages.

 

The stock tensioner would by design not benefit from a stronger spring. Tension force would not increase noticably by this measure.

 

The best way to go would be a tensioning rail with a fixed low tension (to adjust) supported by a hydraulic tension device. Hard to get under the guzzi timing cover.

[Guest ratchethack]

Ernst, in your opinion, would it be feasible to replace the spring on the stock tensioner with a hard adjustable block, shim, screw-adjuster, or some combination thereof?

[motoguzznix]

Ernst, in your opinion, would it be feasible to replace the spring on the stock tensioner with a hard adjustable block, shim, screw-adjuster, or some combination thereof?

Ratchet

 

A fixed adjustment was in every Guzzi engine until the end of the 80s.

This was the worst case solution, because the chain looses tension after very short mileage, and no one pulls the timing cover every 10 000 km to readjust the chain. At least after 30 - 50 000 km the rail was adjusted to the end of the scale and from that point the chain was always loose. A new chain is necessary to solve the problem.

So, why going back to stone age when better solutions are available?

Even the stock tensioner is better than a loose chain over most of the time.

[luhbo]

.... -- but that's just me.

 

 

Nevertheless it sounds good. Yes, you're right I think.

On older crankcases I've seen the driven oil pump gear beginning it's way into the housing, because the tension, or better the forces on the chain, had tilted the gear's axis.

 

Hubert

[motoguzznix]

Older V7 and V7 Sport (I own one) engines had the oil pump run in plain bearings in the engine cases light alloy without any bushings. These were driven by timing gears, no chain. Under these circumstances, they lasted, but they never last with a chain drive.

With the swap to chain drive the oil pump changed to the double needle bearing design as the V11 still sports these days.

[nose2wind]

Dawg, you're in pretty good shape, IMHO. I can only tell you wot I'd do, and keep in mind this is just me. My Guzzi runs so well I can't imagine how it could possibly run better (except for the very occasional miss at idle or off throttle ONLY, and I hardly notice it), and no one else has ever touched it. I've got the same bike as yourself, with just about exactly the same mods and setup, only real difference being intake. I'd get the idle up to ~1100 RPM and set the TPS the way I've always done it, which is the way Todd Eagan (Dynojet Rep) has always recommended doing it for Guzzi's with PC III installed: With TBs linked, set TPS to 500-525 mV between top and bottom pins.

 

I finally got my TB balanced (used Ohio guys method). Reset the TPS and went well from there. Went up to Missouri meet this weekend. Bike was running smoother However the stumble is still present. It seems to not be as bad or at all when the temps are cooler. I also noticed a possible stumble at 3000 very slight. Only when holding the throttle steady. Very few incidence of this. The worst is at idle and also the coming down from high rpm and stalling. I made a parking lot adjustment to see if it would be fixed. I moved the idle up by opening the air screws some. The idle seems to readjust itself downward. I left the TB screws alone. I did this sitting in parking lot engine warm at idle and opened the screws to about 1 turn and the idle moved up to 1100 or so from 1000. Next day the bike ran pretty well in the am 62 degrees. After warming up to 90 degrees the stumble returned with the occasional stall at stop from high rpm. When restarted it will first idle at 1000 and slowly start to return to the 1100 on its own. Do we still think this is a timing chain tension issue? I have a spare TPS and am thinking of changing it, just in case it is not working consistently, do you think this is a waste of time?

 

It seems odd to me that the idle once set will not stay in its preset location (seems to wander)

 

Any other advice?

[Tom M]

I finally got my TB balanced (used Ohio guys method). Reset the TPS and went well from there. Went up to Missouri meet this weekend. Bike was running smoother However the stumble is still present. It seems to not be as bad or at all when the temps are cooler. I also noticed a possible stumble at 3000 very slight. Only when holding the throttle steady. Very few incidence of this. The worst is at idle and also the coming down from high rpm and stalling. I made a parking lot adjustment to see if it would be fixed. I moved the idle up by opening the air screws some. The idle seems to readjust itself downward. I left the TB screws alone. I did this sitting in parking lot engine warm at idle and opened the screws to about 1 turn and the idle moved up to 1100 or so from 1000. Next day the bike ran pretty well in the am 62 degrees. After warming up to 90 degrees the stumble returned with the occasional stall at stop from high rpm. When restarted it will first idle at 1000 and slowly start to return to the 1100 on its own. Do we still think this is a timing chain tension issue? I have a spare TPS and am thinking of changing it, just in case it is not working consistently, do you think this is a waste of time?

 

It seems odd to me that the idle once set will not stay in its preset location (seems to wander)

 

Any other advice?

 

I'm no expert but I think the TPS swap is a real good idea if only to eliminate it from the mix. A stumble when hot could indicate a lean condition. Are your intake boots in good shape and is your bike stock or modified?

[Guest ratchethack]

Dawg, since you asked, by my experience with the TPS, the symptoms you describe would NOT point to any problem with it.

 

You may have many things contributing to the stumbling problem, but it sounds a whole lot like my own tiny (entirely too tiny to complain) symptoms, similar to many other V-11's I'm familiar with -- just magnified. Do you have your valves set to World Spec? If not, I'd make sure about this, with the expectation of realizing a noticeable improvement if not already set to .004" and .006". In hot conditions, you may find an improvement overall running them .006" and .008", my preference year-round.

 

Again -- if the only time it stumbles is at steady throttle, trailing throttle, or idle, this indicates to me that the timing chain is loose, and yours might be whipping and jumping a little more than the next. . .

[nose2wind]

I'm no expert but I think the TPS swap is a real good idea if only to eliminate it from the mix. A stumble when hot could indicate a lean condition. Are your intake boots in good shape and is your bike stock or modified?

 

The bike has mods.

 

K&N's, Stucchi x-over, Mistrals, PC III usb. I'm running a map that Todd Egan sent supposed to be for my setup.

Valves at world spec.

 

My intake boots look bad but did the propane test and no idle change. Todd (mph) great guy very helpful sent me some boots just in case. Most say him included that they look bad on the outside but usually are not cracked through. Todd also said the TPS don't usually fail altogether but has had them develope bad spots.

 

I was thinking, since I have the parts, I might just change the boots when I change the TPS since I will have to re-balance anyway.

 

Also with the PC3 it is easy to up the fuel mix manually and see if it has the desired effect. Would you increase the low setting only or the mid range too. I will pull the plugs and see how they look.

 

The bike really runs great otherwise. No pinging ever, Never stumbles above 3000rpm. The occasional stumble at idle is no big deal but the stalling at a stop is a pain. You find yourself trying to compensate with the throttle.

 

I will start with an increase to the mixture. If that doesn't work I will try the others. If that doesn't work I might try setting the TB screws up to around 1200 (seems fast) then when it drops it will only drop to around 1100, maybe!

 

After that I don't know if timing chain tensioner is worth the effort. I assume you have to pull the engine for this.

 

Thanks

[motoguzznix]

After that I don't know if timing chain tensioner is worth the effort. I assume you have to pull the engine for this.

Thanks

 

There is no need to pull the engine.

Dismount the alternator and pull the timing cover. You need a special tool to loosen the crank nut. Everything else is easy.

Reassembling the chain and sprockets with the strong stucchi tensioner is a little less easy but worth the effort.

[docc]

While the cam chain, TPS and even the temperature sensor may all be suspect, remember that the tach may be optimistic. Mine reads 300 rpm high so that idling the bike at 1100 indicated means she's trying to stay alive at 800. Does not make for a happy twin at idle. Resetting the idle to an indicated 1300 sounds high but not if the true idle speed is actually 1000. Of course resetting the idle speed means going back through the entire TPS/ TB balance procedure.

 

The crank sensor on the left top of the timing cover is known to loosen up. Usually they'll get weepy but also could affect the pick up clearance.

 

Always looking for the easy way out . . .

[Tom M]

The bike has mods.

 

K&N's, Stucchi x-over, Mistrals, PC III usb. I'm running a map that Todd Egan sent supposed to be for my setup.

Valves at world spec.

 

My intake boots look bad but did the propane test and no idle change. Todd (mph) great guy very helpful sent me some boots just in case. Most say him included that they look bad on the outside but usually are not cracked through. Todd also said the TPS don't usually fail altogether but has had them develope bad spots.

 

I was thinking, since I have the parts, I might just change the boots when I change the TPS since I will have to re-balance anyway.

 

Also with the PC3 it is easy to up the fuel mix manually and see if it has the desired effect. Would you increase the low setting only or the mid range too. I will pull the plugs and see how they look.

 

The bike really runs great otherwise. No pinging ever, Never stumbles above 3000rpm. The occasional stumble at idle is no big deal but the stalling at a stop is a pain. You find yourself trying to compensate with the throttle.

 

I will start with an increase to the mixture. If that doesn't work I will try the others. If that doesn't work I might try setting the TB screws up to around 1200 (seems fast) then when it drops it will only drop to around 1100, maybe!

 

After that I don't know if timing chain tensioner is worth the effort. I assume you have to pull the engine for this.

 

Thanks

 

I'd say go ahead and richen up your map in the area where you're getting the stumble. That's the beauty of the Power Commander. Changing values in a map or pushing buttons on the Power Commander is a lot easier than pulling carbs and changing jets, needles, slides and float heights. If you plan on keeping the bike for years without any more engine changes I think your best fix may be to get a custom map done.

 

I'm in a similar situation to you in that I changed my bike enough over the winter to require a new map so I'm using a downloaded one for now. On our first hot day here I found that I have a stumble when pulling away from a dead stop only when the bike is really hot. I noted the approximate rpm and throttle position where the stumble was occuring then edited the map in that area to richen it up a bit. I just did this last week and we haven't had hot enough weather since then to know if I fixed the problem yet. I did similar edits to my old custom map last year with good results so I expect that I'll get this problem sorted soon enough.

 

FWIW I've looked at a few maps from different sources that are supposed to be for very similarly equipped V11's and saw that the maps can vary greatly. I'm using one for an '02 with pods and aftermarket crossover + cans and it is significantly LEANER than stock at certain rpm/throttle settings compared to other maps that I've seen for the same bike without pods. It seems to me that the map for the bike with opened up intake & exhaust should be RICHER in most areas, not leaner, but what do I know? I'll just tweak it until it feels right and check the plugs to make sure I didn't get too rich or lean.

 

Hope this helps.

[nose2wind]

I will start with the easiest fixes and work my way down with timing chain as last resort.

 

It would be nice to know what actually is the cause so anyone wanting to finally resolve it can.

 

I will keep you posted on each step and the results.