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Tech
Tech articles for all models.
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The Periodic Clutch Bath - Single Cylinder Guzzis |
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Written by Todd E
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Tuesday, 19 January 2010 23:16 |
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For anyone are currently experiencing noisy gear change action and poor clutch performance on cold starts. Time for a refresher on the clutch design and the required periodic method of bathing the parts.
The Guzzi-Single clutch is composed of a stacked sandwich of 5 steel and 5 bronze plates. The steel plates are connected in their center to the clutch fixed body hub on the primary shaft of the transmission. The bronze plates are connected at their perimeter to the gear-like outer body basket. There may be one or two friction material rings installed at the base of this stack as well. The outer body basket may run on a continuous core bushing or it may have a packet of loose rollers. All of these options depend on which model and year you have, but the multi-plate design and basic operation are all the same.
Here are pictures of a used plate stack and a fresh stack already installed into a SuperAlce:
When the clutch is bound by its spring, the stack of plates and all of the clutch components rotate as an intact, unit mass. When you pull on the clutch handle, the spring pressure is countered or relieved and the various pieces are released and allowed to move independently. In theory, the stacked sandwich parts should all slip smoothly over each otther so that the outer body remains spinning with the motor, while the inner body remains stationary. This allows you to remain in gear with the engine running.
In addition to these parts, there is a small passage at the top of the crankcase which allows for a fine mist of air and engine oil to pass from the crankcase chamber to the exterior clutch chamber:
This mist of oil lubricates all the parts in the clutch chamber, including the plates, and eventually condenses into a puddle in the clutch chamber. It is a total loss system. There is no way for this oil to get back into the engine case. Eventually, this condensed puddle grows to the level that the bottom of the clutch parts are sitting in a pool of oil and any further excess starts to leak out behind the flywheel where the crankshaft passes through the clutch chamber. There is no seal for this passage. This blue tape represents the maximum depth of oil puddle within the clutch chamber before it will simply pour out the crankshaft hole.
Guzzi didn't want to waste this oil mist, so there is also a crossing passage which goes from the clutch chamber back to the right side in the vicinity of the chain drive sprocket. Some of the oil mist works its way out over here and drips onto the chain as an automatic oiler. Clever, but messy. Many of us plug that cross passage to reduce the mess and we then relay on modern chain sprays. You can see my plug here:
Warm, thin, clean oil is a very nice substance to put onto the clutch plates. It lubricates everything for smooth action and minimizes wear. However, cold, dirty oil acts more like a glue than a lubricant and prevents free action of the plates. The various clutch pieces all bind together and fail to slip as intended. It can become very noisy to shift gears, especially down into first gear. The noise also produces damage to the tips of the gear teeth. The COMPLETE CURE is to fully disassemble the entire clutch package and clean all the parts to new condition.
The INTERMEDIATE MAINTENANCE solution is the BATHE the clutch parts to remove any oil or dirt or wear material and restore original action. Here is the procedure. It will be a VERY messy job so protect your floor and be prepared for hazardous disposals.
First, at the lower rear curve of the clutch cover plate, there will be a small, slotted screw-plug. Remove that to drain away all of the condensed puddle of oil. Here is the drain plug at the lower rear of the clutch cover.
Flipping the cover over, you may be able to see the interior tip of this drain plug at the lower left.
Second, at the top of the left side crankcase you will find an engine breather tube which returns crankcase pressure and oil mist back to the oil reservoir tank. Adjacent to that breather tube is a slotted plug which leads directly to the clutch chamber below.
Third, introduce a pint of 'paint thinner' into the clutch chamber via the upper plug. If you put too much, it will simply run out the opening behind the flywheel.
CAUTION: In America, paint thinner is also known as mineral spirits. It is a good solvent, but not particularly volatile or harsh to painted surfaces. In Europe however, the term 'paint thinner' refers to something Americans call lacquer thinner. This latter material is highly flammable and an instant paint remover and should NOT be used for this cleaning purpose. In a pinch, you can use gasoline. But please don't smoke while working.
Fourth, push the kickstarter repeatedly. While doing so, pull on the clutch handle slightly so that the engine does not turn over but the kickstarter does go through full throw. In this way, the kickstarter will be rotating the inner body and steel plates, while engine compression will be holding back the external body and bronze plates. The paint thinner will remove oil, grime, and wear contaminants from the clutch parts and drop them into the bottom of the clutch chamber cover. Do this kicking and feathering for several minutes.
Fifth, remove the plug at the rear lower corner of the clutch cover and drain away the contaminated paint thinner. Although dirty, it might be useful for other rough part washing tasks around your shop. Let it settle for a week so you can decant the liquid off of the settled sludge.
Sixth, repeat steps three through five, perhaps a total of three rinse cycles.
Seventh, clean up your mess and go for a ride. It will likely be several months or a year before you need to repeat this procedure depending on your miles driven.
As a TEMPORARY AID before you have an opportunity to perform the more involved bathing or disassembly tasks you can assist the releasing of the cold clutch plates. You will generally find that shifting from neutral into second gear is a lot easier than shifting down into first. So, on a cold started motor, shift into second. Gently rev the motor slightly, and, while holding the hand or foot brake, feather release the clutch handle a few times so that you force a slippage of the plates several times. Do this almost to the point of stalling the motor. This will quickly heat the oil film which is binding the plates and the underlying components. You may now be able to return to idle and more quietly shift into first gear.
Patrick Hayes
Fremont CA
SuperAlce and Falcone-NT
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Last Updated on Wednesday, 20 January 2010 23:11 |
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Written by Todd E
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Friday, 30 October 2009 03:53 |
Install notes for the GT-Rx Stepper Motor Kit:
NOTE: Below is install instructions for a Norge. Breva 11 & Sport 1200 should be identical. For the Griso 11 & 8V, the servo-valve will fit just in front of the stepper motor, but use your discretion on the install location.
1. Remove seat, fuel tank and air box (note rubber hose connections for re-connection) to expose the stepper motor that resides between the cylinders.
2. Cut approx. 2" out of the supply hose that feeds the stepper motor as shown below. This measurement is the equivalent to the distance between the spigots of the new valve. Yellow arrow notes the air-flow from the air box to the stepper motor. Red arrow is the cut hose section and blue arrow is the stepper motor. The valve should be noted as to flow; A.B. = Air Box, S.M. = Stepper Motor, if not, look for the screen in the inlet, and position it towards the air-box side (towards the yellow arrow below). Push the hose onto the valve on each side, be sure to position the new valve downwards at a similar angle to:
3. Connect the power supply (red) wire using the posi-tap connector to the yellow wire of the stepper motor (plug) as shown below:
4. Route the switch wires from the left grip, down along the clutch line, and zip tie as needed. The plug (yellow arrow) goes on the other prong of the valve (side is not important). Red arrow notes the angle of the valve (angle downwards for the connectors to clear the bottom of the air box, and be sure to reconnect the stepper motor plug (blue arrow):
5. The remaining ground strap can be connected to the front air box bolt (on Norge, Breva & Sport 1200) using the supplied star-washer underneath the shouldered bushing (as noted by the yellow arrow). Test with ohm/voltmeter to ensure proper earth.
6. Install switch using the supplied clutch perch assembly, or drill a 1/4" hole in the perch cover on the Norge. Dimensions provided on request.
7. Be sure that all connections/wires and valve is clear of pinch points and high heat sources.
8. To determine the switch on/off position to your liking, lightly suck air from the hose. Off/normal position will not allow air through. The 'On' position will allow air flow.
9. Reinstall airbox, fuel tank and seat.
10. On cold start, turn the switch to the 'On' position to allow airflow to the stepper motor, and turn 'Off' once warm and leave off.
---End---
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Last Updated on Friday, 06 November 2009 16:34 |
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Written by Todd E
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Wednesday, 28 October 2009 18:10 |
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Since several of us on the GuzziTech site seem to have fallen victim to the Speedo sensor gremlin, I thought I'd have a crack at finding a longer-term solution. I've not written this as a specific 'How-to', though it'd be easy enough to replicate the process.
To start with I've worked with the premiss that the Hall effect sensor electronics are basically sound, more often than not (In my experience), failures of this type are a result of a process failure (Assembly). The store I bought the bike from was kind enough to let me experiment with a couple of defective sensors they'd amassed, plus a brand new replacement for my second failed unit. So I began looking at the body of the sensor under a microscope, probing where moisture might be getting in.
Firstly the cable entry point seems (As several have said), a likely candidate and as you can see from the 2nd picture there is a gap into which water could pass through. What the shot doesn't show is there doesn't seem to be any form of protection in this area other than the glue/conformal coating around the wire sleeve exit on the inside of the sensor body. You would have thought they'd have filled the bore of the hole with something to seal it?
Secondly the rubberized epoxy the manufacturers have used to cover.
Seal the PCB into the sensor case has not bonded sufficiently to prevent moisture ingress.
As you can see from the following two shots I used a jeweller's screwdriver to test the bond between the two surfaces, could open a gap between the two materials with very little pressure applied. What I found disturbing with both test samples was that approximately a third of the overall circumference had not bonded the surfaces adequately. Viewing the gap under high magnification I found moisture droplets in-between the two surfaces, though they evaporated quickly under the warmth of the lights.
Next I gently prized out the rubber epoxy, without damaging the PCB, was surprised at how cleanly it came away from the sensor case, without any tearing. As you'll see in the following pics, note the smooth internal walls of the sensor case (PIC6). This is what I suspect is the cause of all the trouble, the fact that the walls of the sensor case have NOT been scored to enable a good bonding surface.
I debated whether to pull the PCB right out of the case, decided against it since the risk of damaging the circuit board/magnet/cable was quite high., bearing in mind the sensor is about the same size as a postage stamp. So at that point I decided to dry it out thoroughly in an environmental chamber @ 50C for 4 hours. I used a chamber rather than a conventional household oven, or a hairdryer simply to maintain a consistent temperature, to be pretty sure all of the moisture had been expelled.
Applying the fix
Since the walls of the sensor case were essentially smooth they needed a good roughing up to allow a good bond, so I broke out a needle file and scored the internal walls thoroughly, also lightly scoring around the entry point of the cable sleeve. I decided on a second application of conformal coating, since, on pulling out the rubber epoxy a small amount of the CC came away on its removal. I also wanted to make sure that there wouldn't be an air gap around the edge of the PCB and the case wall + sealed the internal end of the wire sleeve, since in theory moisture could travel (Internally), down to the sensor if the wire sleeve got damaged. Once that had been applied with a small artists brush, had let that dry I could now mix up and pour the two part epoxy I'd chosen.
As you can see from the shot (Sorry I had to use my phone camera), having mixed up the two-part epoxy and poured it carefully into a syringe I could refill the sensors and lay a bead around the cable entry point.
The only thing to make sure of when filling them up is to do it in a way that will NOT allow for any air-gaps, or spaces. Once full it was just a case of laying down a strip of double-sided sticky tape on a flat surface, pressing the sensor firmly to the tape and let the curing process begin. I could have put them in the oven again to speed the process, but according to the instructions would have invited some shrinkage in the mixture. So I let them dry out naturally for several days.
Here you can see in the final shot the overall result.
Results
I've now fitted one of the sensors to the bike, have tested it in wet weather conditions, taken to the back roads for vibration tests and given the bike a good hosing down, during cleaning sessions and I'm happy to say no hint of a failure as yet.
Note* This article is the result of some experiments by the author, will not accept any liability for faults/accidents/wrath of deities, etc incurred by anyone else attempting this fix, i.e. If you mess it up…Don't blame me! :P I only say this as this is a public forum, we seem to sadly live in an age of litigation culture.
© Steve UK 2008 (All rights reserved) Exclusively for Todd @ GuzziTech.com
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Last Updated on Thursday, 04 March 2010 02:55 |
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Brake Rotor Removal for Those Pesky Hex Head Fasteners |
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Written by Jerry Riedel
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Saturday, 10 October 2009 13:34 |
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Ed: First things first: the bolts that hold the rotors on these bikes just plain suck! They will instantly round off, and they were also installed with Loctite from the factory. Ham-fistedness with the bolt removal will necessitate extracting the stripped bolt from the wheel.
First, heat the bolt and the area of the wheel casting around the bolt hole with propane or Mapp gas. Get it good and hot to expand the hole and melt the Loctite. Whack the top of the bolt with a hammer a few times. Now use an impact driver with a Craftsman or higher quality 5mm socket (not a cheap import socket) and a hammer and impact the bolt loose. Repeat heat/impact until the bolt comes loose. Once the bolt turns ½ turn or so, remove the bolt with your ratchet.
In this case, impact (dynamic torque), and not static torque is your friend.
Ed Milich
Jerry: There may come a time when it is necessary to remove the disc brake carriers on your newer Guzzi, e.g. in order to power coat the wheel or replace a worn/damaged rotor. Since the factory uses special button-head socket-head (Allen) cap screws secured with thread lock, they can be a real bear to remove, and the Allen recesses on the bolts are easily damaged. Here is the right way to do it.
You will need: 1) replacement bolts, from the dealer. These are special made bolts that are not generally available. 2) a high-quality 3/8" drive 5mm Allen bit. Do not try to use the cheap stuff. 3) 3/8" drive impact driver. 4) a 4lb sledge hammer. 5) a reasonably thick piece of carpet, cardboard or other such padding to place in between the concrete surface and the wheel. 6) a heat gun. A hair dryer won't cut it. 7) safety glasses, just in case. 8) a 3/8" ratchet drive.
Step 1: after removing the wheel from the bike and laying it on the floor, don the safety glasses
Step 2: apply heat to the area of the bolt. While it is hot, insert just the Allen bit and whack it good a few times with the hammer. The idea is to use the heat to soften the thread sealant and the blows to break it loose. If you try to use a cheap Allen bit, you may find that the hammering will peen the drive opening such that the 3/8" drive will no longer go into the bit.
Step 3: heat some more, if necessary and then repeat the process with the impact driver. The bolt should break free and loosen. Use the ratchet to remove it while still warm.
If this is done correctly, all of the bolts should come out without the necessity of cutting/grinding. If for some reason this isn't the case, it is best to use a cutting wheel or other such to carefully cut a slot in the head of the bolt and try to turn it out with the blade screwdriver bit on the impact driver. Grinding the head off the bolt will get the carrier off, but then you have to contend with removing the rest of the bolt with vice grips.
Credit due: I learned this procedure while working as a mechanic at Moto Guzzi Classis, from the proprietor, Mark Etheridge, Guzzi Sage Extraordinaire.
Jerry Riedel
jerry.riedel@attbi. |
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Last Updated on Saturday, 10 October 2009 13:38 |
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Written by Mike Peavey
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Saturday, 26 September 2009 03:46 |
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I recently bought a Ladola and needed to prepare it for the East Coast Motogiro. The forks were sticky and the patina on the bike indicated that very little preventive maintenance had ever been done, so time to take a look.
The first hurdle in removing the fork tubes is making a tool to remove the large internal hex cap that holds the tubes in place. The internal dimensions of the hex is 29+mm, but that’s complicated by a 17mm nut and shoulder in the center. There’s a special tool, but in lieu of that, we machined a 3/4inch heavy nut which measures 31.75mm down to 29mm and then bored out the threads for a 20mm center diameter.
Next I could not for the life of me get the cap to budge with a wrench or breaker bar, so I had a 1 1/8 socket and after grinding a little additional off the upper portion of the (now) 29mm nut/special tool, I put an impact wrench to it and with one short burp, that was all it needed. After this, the whole deal is pretty anticlimactic and just plain common sense maintenance.
Discuss this in the forums
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Last Updated on Monday, 02 November 2009 19:19 |
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