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Posted

Do not see how changing to timing gears can help smooth running, unless of course the timing was way off before.

 

These occasional coughs seem to affect fuel injection more than carb bikes. I feel it is likely to be due to running at the edge of a fuel map cell. A light change in rpm, throttle etc may make it jump one way or the other, rich or lean, and so be momentarily wrong at that instance. Our ECU's don't have many cells so the 'jump' is more noticeable than on modern bikes.

 

A carburetter is an analogue device so the fuel metering has an infinite solution to supply fuel at the correct mixture. Fuel injection is digital of course and so moves in a series of steps, the cheaper the system the larger the steps.

 

Just my opinion of course.

I agree and as I said was very skeptical. The only reason I can think of is the timing chain drives the ignition pickup wheel on the back of the cam gear which obviously is used by the ignition pickup to time the ignition event. Does cam chain slack affect the position slightly of the wheel and its triggering cutout to mess with the ignition timing occasionally? I still think its unlikely thats why I was wondering if a bike like doccs with quite a lot of miles up has the hiccup.

I emailed Joe to let him know how satisfied I was with the gear conversion and he did mention without me translating to him of my running experiences that people that have converted to gear drive report the engine is sharper in response with the gears so my feelings were confirmed.

So carbed bikes also suffer from the hiccup as well? If so then thats definitely an ignition issue.

 

Ciao   

Posted

It’s super rare for the Sport to pop or hiccup anymore. If it does, it is typically in high ambient temperatures at low rpm (stuck in summer traffic.)

 

How did your tensioner and chain look upon removal?

Posted

I remember my mate's Guzzi Mille GT used to blow its carbs off, mainly when sitting at idle.

Posted

Mille probably used the Motoplat ignition which had electronic advance of a very unsophisticated type. It retarded the spark for starting but as soon as the engine fired it went to a quite high idle advance. Problem always was if it stalled you had to turn the ignition off to re-set it. Failing to do so and trying to start it would result in fireworks and carbs exiting stage right!

As for the spark 'Wandering' due to a slack chain? Yes, it can definitely be a problem. Commonly known as 'Scatter' you can mark the flywheel and then watch the mark with a strobe. While at higher speeds and loads there may be negligible scatter, at lower speeds and light loads (especially with the horrid 'Flappy Foot' tensioner) you'll see the mark jump about like a monkey with St. Vitus Dance! More than enough to make the ECU have a brain fart.

Pete

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  • Haha 1
Posted

It’s super rare for the Sport to pop or hiccup anymore. If it does, it is typically in high ambient temperatures at low rpm (stuck in summer traffic.)

 

How did your tensioner and chain look upon removal?

They looked fine to me @ 42,000 klm docc but more Guzzi experienced people might want to comment, Pete?

Tensioner wear between .98 and 1.44mm, drive teeth looked perfect.

 

Ciao 

 

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Posted

It’s super rare for the Sport to pop or hiccup anymore. If it does, it is typically in high ambient temperatures at low rpm (stuck in summer traffic.)

 

How did your tensioner and chain look upon removal?

Hmmmm, I remember an issue with the Mighty Scura that required several people to fix at the spine raid.. :grin:

42783216500_f632e78311_k.jpg2018-09-10_08-34-08 by Charles Stottlemyer, on Flickr

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Posted

I recall putting a "timing mark" on my flywheel and using a strobe to see if it danced around. It did not at that time, but I wonder if this is a valid indication of timing chain/ tensioner condition? :huh2:

Posted

I recall putting a "timing mark" on my flywheel and using a strobe to see if it danced around. It did not at that time, but I wonder if this is a valid indication of timing chain/ tensioner condition? :huh2:

I would think so, Docc.

Posted

Mille probably used the Motoplat ignition which had electronic advance of a very unsophisticated type. It retarded the spark for starting but as soon as the engine fired it went to a quite high idle advance. Problem always was if it stalled you had to turn the ignition off to re-set it. Failing to do so and trying to start it would result in fireworks and carbs exiting stage right!

 

As for the spark 'Wandering' due to a slack chain? Yes, it can definitely be a problem. Commonly known as 'Scatter' you can mark the flywheel and then watch the mark with a strobe. While at higher speeds and loads there may be negligible scatter, at lower speeds and light loads (especially with the horrid 'Flappy Foot' tensioner) you'll see the mark jump about like a monkey with St. Vitus Dance! More than enough to make the ECU have a brain fart.

 

Pete

 

 

 

I recall putting a "timing mark" on my flywheel and using a strobe to see if it danced around. It did not at that time, but I wonder if this is a valid indication of timing chain/ tensioner condition? :huh2:

I would think so, Docc.

 

Thanks, Chuck. My apologies I missed Pete's earlier post. :blush:

 

Someday, I'm prolly gonna hafta do something to my V11 donk. Maybe even change the original ( :o ) valve cover gaskets . . . :grin:

Posted

Dang unreliable Guzzis.. :rasta:

Heh, so, one of the two-and-a-half-million things I've learned from the fine contributors to this forum is that the US-centric, age-old "100,000 mile" rolling lifespan does not apply to my Guzzi. It's all about topping 200.000 kilometers. :sun:

 

(176.877 km and counting! Probably puts me three or four years out to *make the grade*. :oldgit: 

Look for a full tear-down with "balance-and-blueprint" at the Twentieth South'n Spine Raid  . . . :luigi::rolleyes::whistle:)

 

At which point, I simply must install these gears!! :thumbsup:

 

Thanks,  :notworthy: Lucky Phil for the great tutorial!

Posted

 

It’s super rare for the Sport to pop or hiccup anymore. If it does, it is typically in high ambient temperatures at low rpm (stuck in summer traffic.)

 

How did your tensioner and chain look upon removal?

Hmmmm, I remember an issue with the Mighty Scura that required several people to fix at the spine raid.. :grin:

42783216500_f632e78311_k.jpg2018-09-10_08-34-08 by Charles Stottlemyer, on Flickr

 

No shortage of,ahem, experience there:)

If thats your accommodation at a rally these days I must start getting to a few.

 

Ciao

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Posted

 

 

It’s super rare for the Sport to pop or hiccup anymore. If it does, it is typically in high ambient temperatures at low rpm (stuck in summer traffic.)

 

How did your tensioner and chain look upon removal?

Hmmmm, I remember an issue with the Mighty Scura that required several people to fix at the spine raid.. :grin:

42783216500_f632e78311_k.jpg2018-09-10_08-34-08 by Charles Stottlemyer, on Flickr

 

No shortage of,ahem, experience there:)

If thats your accommodation at a rally these days I must start getting to a few.

 

Ciao

 

Fifteenth South'n Spine Raid, and our tenth at those accommodations, The Lodge at Tellico (Tellico Plains, Tennessee). The weekend after (US) Labor Day (September).  Y'all come now, ya hear?  :grin::luigi::drink:

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Posted

Well he was having problems because the bloke who sold him that shitbox Scura was a complete bastard. Now feeling guilty, (Smirk!) He will gladly offer to buy it back from him for half what he paid for it simply because he's turned over a new leaf and is nice like that.....

 

:P

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