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Rough idle at start, Popping on decel in 1st gear, Poor(er) than usual low RPM throttle control

kdirtrider

Tuned and Synch'ed
GT Contributor
Joined
Mar 27, 2014
Messages
61
Location
Grand Ledge, MI
I have a '14 custom with 17500 miles on it. Bought new in '14 with 0 miles. The motor is all stock except for the moaning whale mod and alternator tech bulletin fix. I ride 50 miles round trip commute everyday for work rain or shine. So about 6 weeks ago I started having issues when it first started. The motor would start and then idle so low it would almost stall. After 20-30 seconds it was idling fine. Then I noticed a couple of weeks ago that it seemed down on power depending on the weather that day and the throttle control was terrible at low RPM's (more so than normal). I was also experiencing popping during decel while in first gear.

I spent a couple of hours looking thru the service manual for anything (simple) that might be causing it. I figured it might be a pinched emissions hose or something. Turns out there was a reference to the correct ignition timing during start up that is related to the intake pressure sensor that is mounted to the intake manifold. The service manual recommends making sure the sensor hole is not clogged and that the sensor is not loose.

I pulled the tank. I pulled the Bosch intake pressure sensor off the manifold and sprayed it off with MAF (mass air flow) sensor cleaner that I picked up at AUTOZONE. Guess what?? Problem seems to have been solved. The idle is normal on every start. No more popping when decelerating in first gear. And the low RPM throttle control is back to a usable (subjective) state.

These motors recirculate so much oily engine case air back into the intake manifold that it clogged up the sensor. I'm adding this to my winter storage annual maintenance list for this bike!!
 
I have a '14 custom with 17500 miles on it. Bought new in '14 with 0 miles. The motor is all stock except for the moaning whale mod and alternator tech bulletin fix. I ride 50 miles round trip commute everyday for work rain or shine. So about 6 weeks ago I started having issues when it first started. The motor would start and then idle so low it would almost stall. After 20-30 seconds it was idling fine. Then I noticed a couple of weeks ago that it seemed down on power depending on the weather that day and the throttle control was terrible at low RPM's (more so than normal). I was also experiencing popping during decel while in first gear.

I spent a couple of hours looking thru the service manual for anything (simple) that might be causing it. I figured it might be a pinched emissions hose or something. Turns out there was a reference to the correct ignition timing during start up that is related to the intake pressure sensor that is mounted to the intake manifold. The service manual recommends making sure the sensor hole is not clogged and that the sensor is not loose.

I pulled the tank. I pulled the Bosch intake pressure sensor off the manifold and sprayed it off with MAF (mass air flow) sensor cleaner that I picked up at AUTOZONE. Guess what?? Problem seems to have been solved. The idle is normal on every start. No more popping when decelerating in first gear. And the low RPM throttle control is back to a usable (subjective) state.

These motors recirculate so much oily engine case air back into the intake manifold that it clogged up the sensor. I'm adding this to my winter storage annual maintenance list for this bike!!
Almost forgot... Removing that Bosch pressure sensor is a bit unnerving when not knowing what the underside looks like. Make sure you pull straight up. There is a sealing grommet around a post protruding down into the intake manifold and it could break if pried off at an angle. I twisted the sensor back and forth slightly while pulling straight up and that seemed to work good for me.

Next time I have the tank off I'll post a picture.
 
Great post, thank you. Strength in the Forum here.
Similarly, the V7 throttle body is specific about air only, no cleaners can be used at all, yet they pump oil into the air box, and on the V7 even worse because of the recommended overfill.
 
Can something be put together that simply sends the oil back into the engine? I am not familiar with the oil circulation on this bike so I don't know if that even makes sense. But, it seems that oil that now goes into the air box would probably be better off going back to where it came from.
 
Can something be put together that simply sends the oil back into the engine?
Yes. Not sure if it's engineered for the intake pressure of the engine to help scavenge crankcase, but history of this engine would say no. Easy enough to do. Just need a breather box, and divert the drain line to the oil pan using a PCV valve found on other models.
 
Almost like an oil catch can used on cars Todd that goes in the vacuum line between the crankcase and the intake mani?? I've got one on my Mustang and it catches the oily vapour before it cakes itself on the intake tract somewhere. I'd get a kit if you made one.
 
I think I would be in the market too. I am getting tired of the need to drain ~4 ounces of oil from the air box drain tube after a ride on a warm day.

This amount of oil in your airbox is not normal. As a comparison, over the 50000km that my bike has done, I have drained at most a tablespoonful of oil from the drain pipes.

Be sure that you have not overfilled the crankcase. Cold engine, bike upright, dipstick resting on threads should be in the middle of low and full level. Any more and the engine will puke it out.

About 3400cc will achieve this level after drain and filter change. The 4010cc mentioned in the manual is for a dry engine with a dry oil cooler. The oil cooler has both inlet and outlet tubes on top and thus will not drain when you drain the crankcase.
 
This amount of oil in your airbox is not normal. As a comparison, over the 50000km that my bike has done, I have drained at most a tablespoonful of oil from the drain pipes.

Be sure that you have not overfilled the crankcase. Cold engine, bike upright, dipstick resting on threads should be in the middle of low and full level. Any more and the engine will puke it out.

About 3400cc will achieve this level after drain and filter change. The 4010cc mentioned in the manual is for a dry engine with a dry oil cooler. The oil cooler has both inlet and outlet tubes on top and thus will not drain when you drain the crankcase.

I appreciate the advise, however, at my first oil at 6000 miles I drained out 2.1 litres. I then added 2 litres (and following the almost impossible method of checking oil level) I saw that the level showed full. It also showed full after a twenty mile ride to verify.

Later at about 8000 miles I discovered a 12" puddle under the oil overflow drain hose. I then drained an additional 4 ounces out of the hose. After filling with 10W40 I went to the nearest MG dealer. The was 160 miles away. Upon arrival at the dealer I explained the situation and THE DEALER DRAINED THE OIL, CHANGED THE FILTER AND REFILLED WITH CORRECT 10W60 OIL. The dealer tells me they can find no problems with my bike. I then rode another 150 miles and upon arrival at my destination, with the bike parked for about ten minutes I come out to find another large puddle of oil under the bike and the oil overflow hose full, again.

So, considering that I did not overfill the oil and the dealer did not overfill the oil, why am I seeing so much oil in the overfill tube? I have not found anyone who can come up with a reasonable answer besides "overfill" when overfill is not occurring.

I am really trying my best to love my MG, but I am disheartened by breaking exhaust systems, fasteners with the hardness of cold butter and oil leaking from overflow hoses.
 
So, considering that I did not overfill the oil and the dealer did not overfill the oil, why am I seeing so much oil in the overfill tube?
Simple, because you both overfilled it. Run it no higher than the middle. I run mine just above the low mark. Drain down to that mark, drain the overflow and wipe out the airbox (a bear to get to), and I suspect your problems will go away. My C14C rental had zero issues with this formula.
As to the fasteners and cracking parts... it's part of the "charm." Replace them with something better, twist the grip and enjoy. Or sell it I guess.
 
Simple, because you both overfilled it. Run it no higher than the middle. I run mine just above the low mark. Drain down to that mark, drain the overflow and wipe out the airbox (a bear to get to), and I suspect your problems will go away. My C14C rental had zero issues with this formula.
As to the fasteners and cracking parts... it's part of the "charm." Replace them with something better, twist the grip and enjoy. Or sell it I guess.

Todd,

I am trying my best. I get it. Moto Guzzi is a small volume producer, but that does not excuse substandard product.

As I think I stated, the oil level when I changed the oil did show the correct level on the dipstick. Like you I have been at this a long time, but this is my first Moro Guzzi. Probably longer than you and that does not make me an expert, but it can show that I understand the basics. Add on top of that thirty years of designing machines and I can show that I have an awareness of when something isn't right. Placing a dipstick on the side of the engine that is most difficult for the rider to access is just poor design. Covering a rear drive so that it can only be accessed when the rear wheel is removed is poor design. I could go on and Moto Guzzi is certainly not alone. So don't let me give you the idea that Moto Guzzi is the problem.

Like I said, I am trying my best to love and appreciate my California. IT would be nice for Moto Guzzi to respond to a customer when he asks for help. (I have and they have not) I don't buy into the "charm".

Now onto a question for you... Why is it that after running for about ten miles and then draining the engine oil would I only get 2.1 litres out of the drain hole? Any ideas?
 
I have over 500,000 miles on Guzzis in 17 years to date. Pre-Aprilia ownership, now Piaggio, production was when the bikes were still built by mechanics. Those were the good times. The bikes have now taken on typical difficulty as with other brands. So yes, you have many valid points, however evolution of the big block is it's strength. I've never measured a drain unless it looked very low, so can't say. All I can say is that for decades, 3 qts with filter is all the big block has ever taken. As to customer support, Piaggio Group just about gives me the finger everytime I inquire about anything, and I have to be one of their best new bike customers, and they don't seem to care at all to be of any help in any way. This seems to be the Italian way these days, which is completely opposite the culture as I know it.
I wish I could see your bike. Things like this are nearly impossibly tough to diagnose via the net. I can only tell you my experience with my rental units and all the bikes I work on. That said, I've had several V7's that have been hugely problematic.
Who is your dealer? Most if them aren't at all knowledgeable enough to trust sorry to say. The most experienced and passionate about the brand, have been pushed aside for the 'kick them out the door' boutique and/or multi-brand warehouse dealers.
 
I appreciate the advise, however, at my first oil at 6000 miles I drained out 2.1 litres. I then added 2 litres (and following the almost impossible method of checking oil level) I saw that the level showed full. It also showed full after a twenty mile ride to verify.

Later at about 8000 miles I discovered a 12" puddle under the oil overflow drain hose. I then drained an additional 4 ounces out of the hose. After filling with 10W40 I went to the nearest MG dealer. The was 160 miles away. Upon arrival at the dealer I explained the situation and THE DEALER DRAINED THE OIL, CHANGED THE FILTER AND REFILLED WITH CORRECT 10W60 OIL. The dealer tells me they can find no problems with my bike. I then rode another 150 miles and upon arrival at my destination, with the bike parked for about ten minutes I come out to find another large puddle of oil under the bike and the oil overflow hose full, again.

So, considering that I did not overfill the oil and the dealer did not overfill the oil, why am I seeing so much oil in the overfill tube? I have not found anyone who can come up with a reasonable answer besides "overfill" when overfill is not occurring.

I am really trying my best to love my MG, but I am disheartened by breaking exhaust systems, fasteners with the hardness of cold butter and oil leaking from overflow hoses.


Hi Dave

I fully appreciate your frustration. Lets take a few steps back.

Was the bike puking oil before the 6000m oil change? If so then there probably is a mechanical issue. One or both breather valves may be faulty. They are on the cylinder head next to the intake port. They contain an oil separator which should condense any oil in the blow by gasses and allow only oil free gasses to pass through the hose and back into the airbox. Also there could be oil accumulating in the rocker area and not draining back to the sump. These would be issues the dealer must fix.

If the puking started after the first oil change I would re-examine precisely what was done at this service. Your first oil change drain of 2.1l seems rather little. The bike should be upright when draining rather than on the side stand. Regardless, it would seem that if you put back the same amount that came out it would be unusual to suddenly now have oil puking issue. It is also important to use 10w60 oil, particularly in hot weather. Using thinner oil has been known to cause low oil pressure issues especially at idle. This may or may not contribute to increased oil vapour in the blow by gasses, I really cant say one way or the other.

The fact that the dealer performed the next oil change means, quite frankly, nothing. Most dealers that I have had dealings with simply pour in the amount in the manual and call it a day. In fact dealers overfilling is extremely common, justified by the explanation " the owner never check the oil so we put in a bit more so he doesn't run out"

So.. humour me a bit now and check your oil level the easy way:
Cold engine
Remove dipstick and clean it.
Sit on bike holding it upright.
Reach down to insert (do not screw it in) and remove dipstick.
The oil level must be NO MORE than halfway between the two marks.

You can do the same with a hot engine and you will then find the level has risen to the top mark. I prefer cold simply because I dont burn myself!

If you still have oil puking then you may want to refer this to a dealer.

PS.
The service manual is part number B043157. You will find it in pdf format to download.
 
Hi Dave

I fully appreciate your frustration. Lets take a few steps back.

Was the bike puking oil before the 6000m oil change? If so then there probably is a mechanical issue. One or both breather valves may be faulty. They are on the cylinder head next to the intake port. They contain an oil separator which should condense any oil in the blow by gasses and allow only oil free gasses to pass through the hose and back into the airbox. Also there could be oil accumulating in the rocker area and not draining back to the sump. These would be issues the dealer must fix.

If the puking started after the first oil change I would re-examine precisely what was done at this service. Your first oil change drain of 2.1l seems rather little. The bike should be upright when draining rather than on the side stand. Regardless, it would seem that if you put back the same amount that came out it would be unusual to suddenly now have oil puking issue. It is also important to use 10w60 oil, particularly in hot weather. Using thinner oil has been known to cause low oil pressure issues especially at idle. This may or may not contribute to increased oil vapour in the blow by gasses, I really cant say one way or the other.

The fact that the dealer performed the next oil change means, quite frankly, nothing. Most dealers that I have had dealings with simply pour in the amount in the manual and call it a day. In fact dealers overfilling is extremely common, justified by the explanation " the owner never check the oil so we put in a bit more so he doesn't run out"

So.. humour me a bit now and check your oil level the easy way:
Cold engine
Remove dipstick and clean it.
Sit on bike holding it upright.
Reach down to insert (do not screw it in) and remove dipstick.
The oil level must be NO MORE than halfway between the two marks.

You can do the same with a hot engine and you will then find the level has risen to the top mark. I prefer cold simply because I dont burn myself!

If you still have oil puking then you may want to refer this to a dealer.

PS.
The service manual is part number B043157. You will find it in pdf format to download.

Well stated omega1...I would only add this minor change..."the bike MUST be vertical and NOT on the side stand" while changing the oil. The plug is in the middle rear of the pan, NOT on the low side. Oil WILL remain on the low side of the pan and NOT drain out, causing a highly likely overfill and eventual puke of oil. Resting on the side stand will also NOT allow all of the oil to drain from the left cylinder jug back to the sump. Again, the bike MUST be vertical (or very close) to get a proper drain of your old oil and to be able to properly check the fill.
I have NEVER gotten more than 3.4 litres back into the engine with the filter change and that always shows a middle of the dipstick fill. Now 3 oil changes and half way to number 4 and I have never had a "puke" incident.
VERTICAL folks....if you are doing it on the stand, you are doing it wrong!! Period.
 
Everybody has pretty well covered the issue but I have to add 2 cents worth.
I've been on Guzzi's for over 40 years now.
If the oil level on the dipstick is at the full mark it is over filled. period.
EVERY Guzzi I have owned (look at my signature line) would spit oil if filled to the full mark.
EVERY Guzzi I own now if the oil level is at half or a bit lower on the dip stick it does not spit oil & will stay at that mark until the next oil change.
In other words this is normal for a Guzzi & has been for over 40 years.
We can debate all day & say "it shouldn't be" or "Why is that" or "poor quality" but in the end it doesn't matter it is what it is.
 
Well gang,today,I "FINALLY" got to take out a brandy new 2017 California 1400 Tourer for a test ride "WITH THE INTENT" of buying one.It had 8 miles showin on the clock and now has 28 miles showing on the clock,meaning,I gave it a reasonably fair test yet did NOT abuse it in any way,shape,or form.Everything about it was excellent,infact,I'll even say superb "EXCEPT" for the most important thing,the way the motor performed at idle and low speed.It was deplorable.

The salesman was very polite and prepared to do what ever was necessary to accommodate me.However, due to how poorly it idled and especially how poorly it performed under 2500-3000 rpm in any gear,I'm afraid I'll have to pass.The salesman claimed the poor performance was caused from a flywheel that was too small and too light,plus increased emmission standards which have been set here in the States.However,if that was the case,all the new motorcycles would run equally as bad,yet they do NOT!! So I'm afraid it's over.And I am disappointed ,to say the least, cause I was,infact, ready to make the jump.But not now!!

So thank you again gentlemen for responding to my questions in the past as I'll now be moving on.And I wish everyone good luck and many happy miles with their Guzzi's!! Dave!!!
 
Sad you had an un-informed dealer (flywheel?!!?) & they missed the sale because of it & you have missed an opportunity to own a great bike.
(Big Sigh)

For any one else who may read the above post & not be familiar with Guzzi's the low end fueling is not an issue and easily fixed.
Guzzi is not alone with new bike issues especially fueling. Victories, Triumphs, Harleys, Ducati's & the Jap bikes all run lean from the factory & have other issues as well.

One other comment: A 20 mile test ride is not enough to properly evaluate a bike especially a Guzzi.
Dang boys these things take about 50 miles just to get warmed up!
Put a couple hundred miles on any Guzzi & when you get off you will catch yourself turning around & looking & longing for the next ride.
 
I thought the same thing Trout! Davetac1 wrote the whole marque off because of an idiot bullshitter salesman and an incompetent Dealer Prep mechanic.

How unfortunate...
 
The salesfolk probably put in a half gallon of 87 octane in it, that would cause any motor designed to run on 93 octane a rough idle.
The first time I test rode a '13 C1400 I had the same misgivings, so I stopped at a gas station and put in a few gallons of Super. Much much better.
Too bad you wrote off the C1400 so quickly.

Well gang,today,I "FINALLY" got to take out a brandy new 2017 California 1400 Tourer for a test ride "WITH THE INTENT" of buying one.It had 8 miles showin on the clock and now has 28 miles showing on the clock,meaning,I gave it a reasonably fair test yet did NOT abuse it in any way,shape,or form.Everything about it was excellent,infact,I'll even say superb "EXCEPT" for the most important thing,the way the motor performed at idle and low speed.It was deplorable.

The salesman was very polite and prepared to do what ever was necessary to accommodate me.However, due to how poorly it idled and especially how poorly it performed under 2500-3000 rpm in any gear,I'm afraid I'll have to pass.The salesman claimed the poor performance was caused from a flywheel that was too small and too light,plus increased emmission standards which have been set here in the States.However,if that was the case,all the new motorcycles would run equally as bad,yet they do NOT!! So I'm afraid it's over.And I am disappointed ,to say the least, cause I was,infact, ready to make the jump.But not now!!

So thank you again gentlemen for responding to my questions in the past as I'll now be moving on.And I wish everyone good luck and many happy miles with their Guzzi's!! Dave!!!
 
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