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Timing Gear Set - Replacing timing chain

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I am wondering if anyone actually ever done this replacement. I saw this on Gutsibits. "Fits Moto Guzzi V11 Sport - Timing Gear Set Steel Ergal Spur Cut"

 

http://www.gutsibits.co.uk/pr/TheShop/index.php?f=e&Shnew=1&Model=1&ModelName=1100%20Sport,%20V11&Cat=ENA&CatName=Engines&spPage=15#topbar

 

I am wondering what benefit will this offer and would it really improve and upgrade anything

 

Any thoughts and knowledge about this subject would be appreciated

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Beats me, from their linked article:

 

Owners of 850/1000 engines have a choice: either stick in another chain with an updated chain tensioner or go with timing gears from Agostini. Owners of 1100's (and I suspect all fuel injected models) are stuck with installing another timing chain, as the gears will bind on castings inside the crankcase. I should mention that I don't know at which point the spring loaded Guzzi tensioner loses its effectiveness, so perhaps 1100 owners have nothing to worry about, but eventually the part will lose its effectiveness, either through wear on the rubbing block or through spring fatigue.

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I have a set of gears for the wifes V11, butI have not installed them yet.

The set I got is a steel set as I recall (they are still in the box) and I think I got them through this site from a member.

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I don't see how it could improve anything, chains are so reliable.

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Chains may be reliable, but the chain tensioner is not always. And the chain can be less accurate as the tensioner wears. Gear cam timing is typically regarded as more accurate, and people who have switched the Guzzi to gear cam timing have reported smoother, steadier, running especially at and near idle where some Guzzi's have a "sneeze".

I am not saying everyone needs to change, just hinting at some of the reasons people might consider changing. There are a number of kits, so the market seems to be there. But most of the kits use aluminum gears and that scares me a little. The sets I got (one for the wifes V11, one for my Daytona) use steel gears.

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The OEM chain tensioner was a piece of junk, the little coil spring had no hope of keeping the chain in tension. I changed it along with the chain hoping to cure the sneeze, didn't do a thing, it still spits back and stalls if idling too slow, very annoying.

 

My Eldorado project has steel gears, I guess it was standard in 72

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I am definitely adding this to my to-do list, and MG Cycle can order them:

 

http://www.mgcycle.com/index.php?main_page=product_info&cPath=68_126&products_id=2568

 

The crank gear is steel, the following gears are Al. 

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I understand that some of the 1100 Sport rideability issues were due to stretched timing chains and/or tensioner after all the carb and EFI fixes were tried and failed.  I think Carl mentioned it to me after I had ridden a Sport that was serviced but still had a really bad rideability that couldn't be solved.

 

I also know a fellow with an SP3 who tried to start his bike after riding it all day only to have no compression- both exhaust valves were bent.  He assumes it was done by a timing chain slip.

 

So here are a couple of suspected timing chain issues.  

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Timing chains lack engineering "elegance".

Much better for using in the drive line though.

Ciao

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HI

 

I cannnot see a big advantage in replacing the timig chain by a gear set. In many respects the chain is the best solution:

 

1st: It is in the engine - replacement is cheap and life cycle very long.

 

2nd: The gears must take into account that the distances between crank, cam and especially the oil pump are less accurate since Guzzi changed to the timing chain as this is less sensitive in that respect. So the play of the gears is big and they are noisy. When the engine runs uneven at low rpms, the gears can rattle. This distroys the aluminium gears fast, especially the straight cut ones. They last much shorter than the chain.

 

3rd: The main reason why the chain is better is due to the nature of a 90deg V-twin: take a look at the camshaft - all 4 cam lobes are positioned on one side of the shaft, which causes irregularíties in cam rotation. When the cam runs up the ramp, the shaft decelerates, when it runs down the other side it is accelerated by the valve springs. A chain with good tension is a big mass that dampens these oscillations and makes the rotation smoother and the timing more accurate.

 

4th: I recommend the Stucchi/Valtech tensioner - it is tighter than the Guzzi tensioner and cheaper too. The timing is more accurate also at idle speed and idle gets smoother.

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Sorry, but 

 

HI

 

I cannnot see a big advantage in replacing the timig chain by a gear set. In many respects the chain is the best solution:

 

1st: It is in the engine - replacement is cheap and life cycle very long.

 

2nd: The gears must take into account that the distances between crank, cam and especially the oil pump are less accurate since Guzzi changed to the timing chain as this is less sensitive in that respect. So the play of the gears is big and they are noisy. When the engine runs uneven at low rpms, the gears can rattle. This distroys the aluminium gears fast, especially the straight cut ones. They last much shorter than the chain.

 

3rd: The main reason why the chain is better is due to the nature of a 90deg V-twin: take a look at the camshaft - all 4 cam lobes are positioned on one side of the shaft, which causes irregularíties in cam rotation. When the cam runs up the ramp, the shaft decelerates, when it runs down the other side it is accelerated by the valve springs. A chain with good tension is a big mass that dampens these oscillations and makes the rotation smoother and the timing more accurate.

 

4th: I recommend the Stucchi/Valtech tensioner - it is tighter than the Guzzi tensioner and cheaper too. The timing is more accurate also at idle speed and idle gets smoother.

Sorry, but I have to disagree.

To your first point, a properly designed and made set of gears will last the life of the motor. The chain and tensioner set up will not.

Second point, The distances between the various shafts are not something that is random. They are pretty much fixed.Gears are by nature are noisey and make their own sound, but chains are not much quieter. Belts are quieter, but that is not part of this question. If a set of gears does not fit right it was not designed/built right.

Third, That is exactly the reason why gears are better. With a cam chain and tensioner, the cam timing can vary as the cam goes through its rotation. The tensioner allows the timing to vary as tension and slack is applied. Gears give a much more accurate cam timing.

Fourth, the Stucchi tensioner is a good idea if you are keeping the chain. It seems to work better then the stock tensioner. The stock tensioner is a weak link. But if you are looking for the results you can achieve with gears the Stucchi tensioner is not going to give you them. 

 

Most people probably do not need timing gears. many people will use the stock tensioner and be happy. Some will switch to the Stucchi tensioner and be happy. Others may end up with gears, and a properly designed and built set of gears is the top of the cam timing pile.

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Interesting discussion. As for my situation: I have a low-mileage bike, but I am all for replacing known weak links before they become problems. I have a very slow leak in the timing cover - so I'll be in there pretty soon anyway to replace the gasket. I don't think I need the precision of gears for my riding style - but If I ever wear out a chain, I'd consider replacing it with gears at that time.

 

MG cycle has an aftermarket tensioner for less than $40.00, but their website does not identify the manufacturer.

 

http://www.mgcycle.com/index.php?main_page=product_info&cPath=68_126&products_id=347

 

Is this the Stucchi unit (or similar)?

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I have some friends who build and race Guzzi engines and they have said that one of the very first things one should do for the most reliable running is to switch to gears.

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Hmmm... after some more investigation on the above links, I'm getting tempted. Lighter, more reliable, smoother idle... Straight cut gears are more efficient and noisier than spur-cut. All for US$350 two months from now - about when I'll be due for service.

 

But for $40 I just get some peace of mind - no bonus gear-head noises.

 

I would also be interested to know if there is a source for the all steel gears - or if the steel crank gear with aluminum following gear setup is OK.

 

Here's an article on the "back-story" and how to install the gears (was a sub-link from Gutsibits).

 

 

Edit: The article at the link above contains this sentence:

 

"Owners of 1100's (and I suspect all fuel injected models) are stuck with installing another timing chain, as the gears will bind on castings inside the crankcase."

 

The MGCycle part does not include V11 Sports in the list of appropriate bikes.

The Gutsibits site says it will fit V11 Sports.

Edited by Scud

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