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Timing Gear set


Ray Sandoz

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On 7/3/2021 at 4:29 AM, Pressureangle said:

First, I cannot overstate how much more cleanly this thing drives at low rpm and low throttle. The 'city manners' are incredibly improved. The idle is steady, stable, and never missed a single beat, even though it's 100rpm lower than I had it set previously. The 'driveline snatch' at slow speed/low throttle have *disappeared*. I have to attribute this to idle/low rpm spark timing being precise, which leads to the conclusion that the stock chain tensioner is not tight enough to control the cam/crank relationship at low rpms. Significantly, the whole reason I put these gears in was because I 'thought' I heard the cam chain slapping around, and didn't know whether the bike had a spring tensioner or manual and figured if I'm in there I may as well go all the way. Supporting that suspicion is that during today's ride I had the fairing on and everything final assembled, and the reflected engine noise from the front is *immensely* lower. There was enough noise with the chain to be a constant source of discontent; not only are the gears quiet, they are comparatively silent.

This is very interesting for me. I know my timing chain is sloppy; when I point a timing light into the little inspection hole to see the flywheel mark, I can see the mark jiggling up and down. Since I have to fix this sometime, I have to ask whether you think a new chain and tensioner would achieve the same improvement as a gear set? I expect that it would be a lot cheaper. 

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1 hour ago, MartyNZ said:

This is very interesting for me. I know my timing chain is sloppy; when I point a timing light into the little inspection hole to see the flywheel mark, I can see the mark jiggling up and down. Since I have to fix this sometime, I have to ask whether you think a new chain and tensioner would achieve the same improvement as a gear set? I expect that it would be a lot cheaper. 

No, it won't. Nowhere near, but....

if you are seeing significant scatter on the spark and can't justify the cost of a gear set there is now, apparently, a Valtek type blade tensioner available that fits the V11 donk.

 

I can't remember exactly what the issue was with the earlier tensioner. Probably something to do with its mounting. The thing is though that a properly tensioned chain is probably as good as most people need.

 

That isn't to suggest that Joe's gears aren't the 'Duck's Guts' and the gold standard. Quite simply they are! But they aren't the only option and it depends on how obsessed you are with chasing 'Mechanical Nirvana'.

 

 

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5 hours ago, MartyNZ said:

This is very interesting for me. I know my timing chain is sloppy; when I point a timing light into the little inspection hole to see the flywheel mark, I can see the mark jiggling up and down. Since I have to fix this sometime, I have to ask whether you think a new chain and tensioner would achieve the same improvement as a gear set? I expect that it would be a lot cheaper. 

I built a '85 LM1000 a few years ago, using a Web 86b cam and conical beehive valve springs with about 110# seat pressure and ~280# (?) over the nose of the cam. I used a Valtec tensioner in that, and it clocks over at 1000 rpm just fine, in fact the timing shows no fluctuation and I have to say I have no inclination to change it to gears. Just yesterday I started and timed my '89 Mille GT after having replaced the stock manual tensioner with a Valtec, again although with all stock valve gear and cam the timing is extremely steady. By appearances, the good tensioner does everything you need to cure the idle glitches. 
That said;
This Mille GT appears to have been a fairly well-loved and well-kept bike most of it's life, if not perfectly maintained. The cam chain had about 3/8" slack on the manual adjuster, and contributed to crap idle and valve noise to the point I looked for a broken piston skirt. Now it ticks at 700rpm if I want it to. Here's the rub-the distributor bolts were stiff enough to make me think it's not been moved since the factory timed it, and after installing the tensioner I moved the timing somewhere  between 5º and 10º to bring it up. That's a huge amount, and assuming it was ever where it belonged means these chains stretch a lot more than I would expect. Even if you bring the ignition timing back, the cam timing remains retarded to whatever extent the chain is stretched. On an engine with a 'big' cam (any of these Guzzi 'sporting' models) the idle quality and low-speed drivability hangs precariously on that timing to the extent that 4º is a very significant change. So you see there are two primary issues to consider, spark scatter and spark/cam timing. With a tonewheel and sensor, scatter apparently becomes a much larger problem, possibly due to simple ECU confusion. 

D'oh. I do love a succinct answer, which this is not.

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1 minute ago, Lucky Phil said:

Here's an interesting image of a 1 year old blade style tensioner failure. Nasty collateral.

Z35.jpg

Ciao

 

 

I sort of wish I hadn't seen that. 
I know you're a huge fan of gears, and so am I. Now even moreso.
How did that bit get past the screen into the pump?

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8 minutes ago, Pressureangle said:

 With a tonewheel and sensor, scatter apparently becomes a much larger problem, possibly due to simple ECU confusion. 
 

...and I entirely missed the part about the ignition sensing cam position, you cannot bring the ignition timing back where it belongs in any case. Ignition retards with the cam and the chain stretch. So now I am 100% pro-gear on injected motors.

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Yesterday, i rode about 200 miles with my nephew, who agreed to leave his beloved MV F4 at home so we could go out on my Scura and my 89 LeMans 1000. I wanted to ride them back to back on the same roads, so we swapped bike after burgers and chocolate malts at Frosty Freeze in Pine Valley.

The Scura has the blade tensioner, and the LeMans has Caruso's gears. I had not heard about a blade tensioner failure until today, so it makes me feel better about converting some hard earned $$$$ into £££ (USD to GBP is about 4:3 currently) for Joe's gears.

As for the running of the bikes:

BLADE: when I put the blade tensioner in the Scura it idled better and just seemed overall smoother. The difference was noticeable even on what was still basically a new motor at the time (only has 14,000 on it now). The blade makes some cool whining noises, but as we know noise=wear. The original tensioner seems a bit too relaxed and weak to make much of a difference when a heavy chain is slinging past it.

GEARS: The gears do not make any noise on the LeMans. This is a carbureted bike, but it starts super easy, and the idle does not fluctuate. The PO said the gears made a huge improvement, especially in starting. This bike has several other mods, and I have never ridden a stock version, so that's about as much insight as I can offer.

And as for other comparison notes on the ride, basically, they are both cool, but in different ways.

One more thing, in case it hasn't been mentioned... if you take the timing cover off, be sure the use one of the metai gaskets (not paper) when you reinstall it. I think you can get them from MG Cycle. Not a bad idea to pop a new rotor seal in at the same time, just in the interest of preventative maintenance.

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4 hours ago, Lucky Phil said:

Here's an interesting image of a 1 year old blade style tensioner failure. Nasty collateral.

Z35.jpg

Ciao

 

 

It's hard to tell from the photos (scarey), but if that failure was in the area of the little metal rod anchoring the spring to the plastic body, it's definitely the weak link of the design. My first one broke right there, on installation.

I'm surmising that tensioner was probably cracked during installation, then failed during use? idk

When I replaced the timing chain on my CX100, I had read about how trying to get the blade tensioner into place could be a bit of a biatch; many posters talked of how "just use a little more force to manhandle it into position, it's well made and strong, it won't break"

I took their posted advice to heart, and managed to prove them wrong, as I used just enough force to watch my new ValTek tensioner break, while trying to get it installed. I used much more finesse the second go round,lol.

It's only plastic, obviously not as bullet proof as I'd like, fwiw.

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The blade type goes in easily if you use a small clamp to compress it against the side of the case while you install everything else. Then you release the clamp and it puts the tension back on the chain. I imagine there is a picture of that somewhere on this site... The blades have been around a long time, and seem mostly reliable, so I am not going to worry about riding mine.

But I am now looking forward to installing the gears. Possible a good project for the this holiday season (assuming gears get produced by then).

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Hey Scud, I heard of the clamp trick later on;

At the time I'd read of a few people recommending, disassembling the tensioner and mounting the support plate, then reassembling the tensioner in place; that's what worked for me on the second attempt.

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12 minutes ago, 80CX100 said:

Hey Scud, I heard of the clamp trick later on;

At the time I'd read of a few people recommending, disassembling the tensioner and mounting the support plate, then reassembling the tensioner in place; that's what worked for me on the second attempt.

That's right... I learned about that AFTER installing my own. I think that could be a better method than the clamp.

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9 hours ago, Pressureangle said:

I sort of wish I hadn't seen that. 
I know you're a huge fan of gears, and so am I. Now even moreso.
How did that bit get past the screen into the pump?

It didn't. I'd say the failed tensioner resulted in total loss of cam chain control which then caused the oil pump and drive gear failure.

Ciao 

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7 hours ago, Scud said:

Yesterday, i rode about 200 miles with my nephew, who agreed to leave his beloved MV F4 at home so we could go out on my Scura and my 89 LeMans 1000. I wanted to ride them back to back on the same roads, so we swapped bike after burgers and chocolate malts at Frosty Freeze in Pine Valley.

The Scura has the blade tensioner, and the LeMans has Caruso's gears. I had not heard about a blade tensioner failure until today, so it makes me feel better about converting some hard earned $$$$ into £££ (USD to GBP is about 4:3 currently) for Joe's gears.

As for the running of the bikes:

BLADE: when I put the blade tensioner in the Scura it idled better and just seemed overall smoother. The difference was noticeable even on what was still basically a new motor at the time (only has 14,000 on it now). The blade makes some cool whining noises, but as we know noise=wear. The original tensioner seems a bit too relaxed and weak to make much of a difference when a heavy chain is slinging past it.

GEARS: The gears do not make any noise on the LeMans. This is a carbureted bike, but it starts super easy, and the idle does not fluctuate. The PO said the gears made a huge improvement, especially in starting. This bike has several other mods, and I have never ridden a stock version, so that's about as much insight as I can offer.

And as for other comparison notes on the ride, basically, they are both cool, but in different ways.

One more thing, in case it hasn't been mentioned... if you take the timing cover off, be sure the use one of the metai gaskets (not paper) when you reinstall it. I think you can get them from MG Cycle. Not a bad idea to pop a new rotor seal in at the same time, just in the interest of preventative maintenance.

If you look at my how to post on installing the gears I used the metal gasket and did the front seal while I was there as you suggested. The most noticeable thing initially after installing the gears was the need to reduce the idle by 200 rpm as after the gear install it was idling high. Less friction and drag? maybe.

Ciao  

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