pete roper

Look, I know I'm not an *expert* but is there any reason why you can't st the TPS to it's required voltage with the link rod connected by simply using the idle stop screw. This will get you the correct degree of opening for the map to work as it should. Then if the idle is too high of low simply set it with the air bleeds, it's what they're there for. I must say that I've found this to be perfectly satisfactory as long as nobody has been farting about and moving the TPS willy-nilly. Obviously if the idle speed can't be set correctly with the bleeds then you have to start fiddling about with the TPS but on most of the V11's and Calis I'v dealt with this seems to work OK?? Pete

Look at the avatar boneheads! Obvious innit? The very best Yak FAt is all you'll ever need in cold weather Pete

It may be the case in very highly tuned race motors but think about the the practicality of machining an *accurate* ellipse into a rod? yes, rods will stretch and deform, generally though unless they are taken beyond their design parameters the amount of deformation will of been taken into account in the design and manufacture of the rod. Remember, we are talking about 'Production' vehicles here. Not some incredibly expensive, 'Hand Tooled' perfectionists device. It has to be easily repairable by people with access to *ordinary* tooling. But I do imagine that you are correct in the fact that the clearances used in your average rod WILL take into account deformation of the eyes. Hopefully to a point where interference with the bearing's ability to wedge won't be effected. Pete

As far as I'm concerned side-spurs are fine One of the things I come across constantly is the fact that many people whoi are excellent 'Home Mechanics' have 'Blocks' of information missing. If I can insert something into these empty spaces? That's a good thing. I am definitely NOT, (As I have oft stated before . I do have a wealth of knowledge both general and Guzzi specific. To say otherwise would be bloody stupid. I'm more than happy to share it and help others if I can but as in all cases this requires people to be aware of their own limits. I know mine, (I can't weld for sh!t! Molten metal and I have an agreement. I don't f@ck with it and it doesn't f@ck with me ) I try not to exceed them! But understanding stuff like this makes it a WHOLE lot easier to understand what you're trying to achieve if you accept that anything you try and do is invariably going to be a test of cobbling together the very best set of compromises, not finding the 'Magic Bullet' that will make everything marvey! Pete

Using a heavier oil can produce its own problems. The heavier the oil the greater its internal friction. This not only means that it will get hotter before it escapes from the bearing but its viscous drag on the bearing itself will increase. This will not only use power that could otherwise bring the horizon towards you faster, (Or use more fuel.) but there is a risk, albeit slight, that the oil's friction will overcome that between the back of the bearing shell in the end of the rod and its cap and the rod itself. What governs and limits the bearing's will to spin within the big end eye is not the little tangs on the bearings, they are just locators, it's the contact between the back of the shell and the seat it sits in. This is called the bearing 'Back Clearance' and can be examined on a shell that has seen long service by looking at the differential discolouration on the back of the shell when it is removed. What actually controls the effectiveness of the back clearance is called the 'Nip' of the bearing. If the rod eye is correctly sized then when the shells are inserted and the bolts tightened, (This is without the rod on the crank.) the ends of the bearings will clamp against each other. Once both bolts are torqued correctly one of them can be loosened and the force of the shells pushing against each other will spread the cap from the rod slightly. This can then be measured with a feeler guage and the process is known as 'Measuring the nip'. If the nip is too large there is a danger of the bearing shells deforming as the bolts are tightened on the crank and grabing the journal. If the nip is too small there will be insufficient pressure to ensure a good back clearance and the shells will be prone to spinning in the eye of the rod. The good news is that Guzzi rods are generally a.) Well made and b.) strong so you can get away with a lot on a Guzzi rod that would be much riskier on some other motors. Pete

Ok, subject closed. I've pulled my response, perhaps Pierre would like to do the same. Pete

The 24 atmospheres would presumably be at maximum, or close to best, volumetric efficiency. As I said, my figures were rubbery and didn't take in things like blow-by or frictional losses and are only relevant when the angle of the rod is at, effectively, zero. Close the inlet tract, (By shutting the TB butterfly/carb slide or whatever) and add in restrictions on the expulsion of the exhaust gasses, (Exhuat/muffler design.) and you can see that everything is going to change. I was trying to explain the principle, not the exactitude. There are simply too many variables to give a definitive answer. That's why we have sh!t like flow benches. It's all experimentation! Pete

Jude and I used to have a book, long lost unfortunately, that was essentially a recipe book for cooking stuff on your car engine. Unfortunately it was American so it contained very little that was edible. (Please note, this was a J O K E and not intended to offend anyone!) It was good fun but got lost in our move. The book was called 'Manifold Destiny' I asked Jude, (Who remembered this.) Who wrote it. Her response was "Some f@cking MAN! No woman would be so stupid!" Pete

Alas I'm too stupid to pull up graphics off the net, (Honestly, I am, I know it's *easy* but I'm obviously the computer version of Piltdown Man ). So lets look at why you don't have to have vast bearing surfaces. remember this is the bonzoid, simplified version for thickies like me. If you want heaps of sums go talk to an engineer! It's actually very clever. as the jornal rotates in relation to the bearing, at the point where the greatest force is being applied to the oil film there is a phenomenon created called the 'Hydro-Dynamic Wedge'. At this point, as the journal tries to force it's way through the oil film as it spins a rolling wave-front of pressure is created within the film of oil that radically multipiles its effective pressure. The smaller the clearance, the greater the rise in the pressure wave of the wedge and the less likely it is that you will get the two surfaces rubbing together. (A phenomenon known as 'Boundary Lubrication'). "OK," you say. "But if smaller the clearance the greater protection you'll get, why not run plain bearings with microns of clearance rather than the standard amount?" which tends to be about 1 thou for every inch of journal diameter. Well the answer to that lies in the other property of the oil, (We'll ignore thermal expansion of jornal and bearing for now.). It's other property is to COOL. That is, take away heat and dump it somewhere else. Now to do that the clearance has to be great enough that you get a good throughput of oil. The oil has to do a LOT of work. The forces acting upon it, as we have seen by the 'Back of an envelope' calculations above are pretty big and they are, in the big ends, occuring many, many times a second. As the journal tries to *squash* the oil out of the Hydrodynamic Wedge between itself and the bearing it gets crushed quite effectively at the mollecular level. Liquids are, to all intents and purposes, incompressible. So to cope with this sort of force all it can do is make the mollecules rub together and as they do this they heat up. If you ain't got enough throughput of oil the oil can't transport the heat away and the bearing will overheat and change state, (Liquify!). Once the bearing has lost it's integrity and clearance the oil can no longer form the HD Wedge and the whole poxy lot goes to hell in a handbasket in about the time it takes you to utter a few 'Potty Mouthed' phrases and whip the clutch in! So, like so many things in your engine you have to look at the bearings as another example of compromise. There is no *ideal* clearance for a plain bearing. What you want for some boring old sh!tter you're going to plod through traffic on on the way to work is going to be very different to what is required in a race engine for example. If you're going to 'Blueprint', (A daft term!) a motor for a commuter you'll make the bearing clearances as tight as possible as it isn't going to work terrifically hard and you'll want it to last for ever. For a race engine you'll deliberately try and get the clearances on the looser side so as to get a higher throughput of cooling oil! The formation of the HD Wedge is also very dependent on both the journal and the bearing it rotates in being perfectly round. this is one of those things that people often overlook, especially when dealing with connecting rods. If an engine is being rebuilt properly after it has shagged it's big ends, (As V11's are particularly prone to due to the oil pick-up exposure problem.) then it is very important to check the roundness of the big end eyes. If they've been playing hop-scotch on the crankpin there is a very good chance they will no longer be round. Install the shells and they will be out of round and this will seriously compromise the engine's ability to form a wedge in the bearings and another failure will simply be waiting to happen. In any of the bearings, especially on the crank, in your Guzzi motor, the speed that the bearing material is moving in relation to the journal is quite high. Say your journal is 1 and 1/2 inches across. The circumfirence of a circle is Pi x the circle's diameter. So in that case the circumfirence of the journal is about 4.77 inches. Now if the crank, and there fore the journal, is rotating at 6,000RPM the speed relatively betwixt journal and bearing will be 4.7 x 6000 = 28200 inches per minute or 2350 feet per minute or 39 feet per second! Try getting someone to tow you up the road on your arse behind a car at 39 feet per second without smearing your bum with some lubricant and see how long it would last! Even with a bum the size of mine I can tell you it wouldn't be long! That is the reason it is VITAL to maintain both oil PRESSURE and VOLUME to plain bearings. Loose that, (As in when your oil light comes on during a hard launch.) and you're basically rubbing some soft tinny metal on some hard, nitrided steel at 39 feet per second while exerting a force of thousands of pounds per square inch on it! Any guesses as to how many times you can do this without serious damage occuring? Answers on the back of a postcard to 'Pedants Annonymous' Care of 'Who-gives-a-toss-ville!' Pete, trying not to be too Potty Mouthed.

You're quite right But kindly remember I'm an who rides like the grandfather of the oldest in the world . Pete

Given the somewhat rancorous nature of a couple of threads recently perhaps its time to examine this issue. Over a year ago I was about to try and explain something about the relationship but them my Mum set about dying and I sort of gave up. Perhaps it's time I revisited the issue. Note this is NOT going to be a discussion of the relative merits of oils. Simply a brief explanation of their purpose and function with bearing surfaces. I'll also try to keep it both simple and acurate. If people want to jump in and correct me or add adendums and caveats? Thats fine by me. Firstly oil has two basic functions. 1.) To lubricate. 2.) To cool. Lubrication essentially consists of forming a layer between two parts that are moving in relation to each other so that they don't touch. Cooling is the ability to remove waste heat to prevent various parts reaching the point where they can change state, basically melt! So how does this relate specifically to plain bearings as are used in our motors? For this purpose let us look specifically at the bearings on the crank, although the cam bearings are of the same type. Lets look at the loadings that are going to be imposed for example on the big end bearings of the connecting rods. These are a very good example because the forces imposed on them are relatively easy to calculate, at least on a simplistic level, and remember this IS simplistic. OK. So the piston is at bottom dead centre, (BDC.) on the induction stroke. Theoretically the cylinder will be full of mixture at atmospheric pressure. 14 PSI. Now the crank rotates until the piston is at top dead centre (TDC) with both valves closed and the spark about to ignite the mixture. But the same amount of mixture is now crammed into a much smaller space. With a 10 to 1 compression ratio it's pressure will of increased tenfold, (In fact it increases more than this because as the gas is compressed it heats up but we'll overlook that for our purposes.) so now you have a pressure of 140PSI in the combustion chamber. When the spark ignites the mixture it gets VERY hot, VERY quickly. The gas REALLY wants to expand, and so it does, pushing the piston down the cylinder. But during those brief moments when the mixture is burning the pressure rise in the combustion chamber is astronomical! Lets say for convenience sake that it increases the pressure by another factor of ten. So you now have a pressure of 1400PSI pushing down on the top of the piston. Calculate, (roughly.) the area of the piston. 92mm is about 3 and 1/2 inches. The area of a circle is Pi x the radius squared or about 9 and 1/2 inches. So 9 & 1/2 times 1400 = 13300 lbs pressure all bearing down on the rod and thence onto the big end bearing! But hang on???? The oil that is being delivered to that bearing is only being delivered at 50-60 PSI? Surely if the bearing was going to have to take that load it would have to be HUGE? 13300 divided by 50? You'd need 266 sq inches of bearing wouldn't you? Well, actually, No. Firstly there are a lot of other issues at play that mean that the pressures imposed on the bearing won't get to those levels but for our purposes today they explain the situation clearly and simply. The other reason you don't need VAST bearing surfaces is because of the relationship between the bearing and the journal it turns on and the way the oil behaves within the confines of that bearing and we'll go there next time. Pete

Why the difference in pressure between when accelerating and cruising I have no idea. I can't see how there could be that much resistance in the galleries to make a whole heap of difference. As you accelerate hard through the gears, at higher RPM's I'd expect there to be a slight presure drop due to demand/delivery issues. Is your guage electronic or one of the 'Pipe' types? If it's electronic perhaps it's voltage related . As for point 2.) You've got to be wrong. It's pure snake oil being sold by a crook. Actually while I know that people like pulling wheelies It's always seemed a bit pointless to me. Any energy you waste lifting the combined weight of bike and rider into the air is energy not available for making the horizon come towards you faster. S'OK if you're on a machine with ludicrous quantities of HP but on a poor, wheezy old thing like a Guzzi it seems a bit counter-productive. Pete

yeah, not a problem. Pete

Mark, I don'tr usually do credit cards, I have to use Graham's EFTPOS machine and they slug you some silly amount for the priveledge. Just send me a cheque for $165 and I'll stick one in the mail. Pete Roper POB 102 Bungendore NSW 2621. Don't forget to include an return address!!!! Pete

Dan or anyone else who's interested. I had a huge clean out of my workshop yesterday and among the assorted munt I found a couple of sloppage sheets. As I said, I've got another batch on order but if anyone wants one NOW i can supply. Pete

Definitely. Thing to remember though is that squish is set not by the dimensions of the head so much as by the height of the barrel. You can set it either by using differentially thicknessed gaskets, (As with the new 8V motor.) or machining the base of the barrel. The thing to remember is that no two engines are ever going to be the same. While generally an overly lean mixture will be the chief cause of detonation if the CR is OK and squish is close to correct an overly rich mixture will also tend to contribute for the reasons Dan listed. I'd tend to think that that the timing is one of the least likely culprits simply because the timing component of the map is shared between all bikes, those that detonate and those that don't, and I assume it would be fairly immutable? I may be wrong there of course. If your plugs are very dark try the 'Gloop up the ETS with anti seize' trick and see if it improves things. Mind you doing that will probably require another dyno-tune for the PCIII. Other than that? Use an octane booster? If 93 is the best you can get I'm not overly surprised it pings. Pete

Running with zero oil pressure bearing damage starts for all intents and purposes immediately. Guzzis have very nice, big bearing surfaces and they can take a fair bit of punishment before they develop insufficient load-carrying capacity. If you only once had this happen you'll probably be fine, yes the life of the bearings will of been diminished but by how much? Imposible to tell without inspection but they'll probably last 'Long enough' What happened though if you only noticed it once and it's happened more often? My advice would be to drop the sump and spacer and drop off the big end caps for a looksee. Standard big end shells are dirt cheap and you can slip a set in with the rods in-situ from underneath with a bit of grovelling as long as you're sure the crankpin is OK. If the pin is damaged that's a different matter but its unlikely to be if the engine is currently running sweetly. The ideal time to do this is, Ta-Da!!!!! When installing a sloppage sheet, but I would say that wouldn't I because I'm grasping, dishonest and venal....... Pete

Greg might have one left, I think Todd is out of them. I just ordered another batch of 20 today though, should be ready next week. Cost will be much the same as before, probably a small increase due to materials cost. From memory the plates were about $155AU last time and shipping was about $20AU so I think they were about $175AU shipped It'll probably cost me $10 or 15 more per plate this time so say $190 if you but from me. I've also had the design slightly modified. The clamp bolt holes for the thermostat/filter mounting munt I've had increased in size from 6.5mm to 7mm which should elliminate any of the previously reported problems with hole alignment. The outer ones were already 7mm but I think having that little bit of flexibility in the middle ones will mean that there will be enough *give* for things to line up without a struggle. Pete

Yup, the valeo starter motor is a D6RA or some such, they aren't cheap but the bolt straight on. As for a relay? Go to Halfords and buy yer standard 25 amp shitox plastic 4 pinner relay, should cost you about a quid! If you haven't done so already run a direct feed to the delivery side from the battery rather than having the jump wire that has already been up and down the bike half a dozen times delivr a few tired electrons to the solenoid Pete

Look, I'd really like to end this. At the end of the day I don't give a toss what Kevin, or anybody else thinks of me. What pissed me off was the fact he was giving out poor advice. I just hope that Foxy gets his bike fixed with the minimum of fuss and bother. FWIW KH has pulled the pin over at Wildgeezer too, all posts and profile removed so perhaps he was just trolling? Who knows? Who cares? Pete

Erm. Do yuo mean the entire bevelbox? Getting this off isn't very hard. Disconnect the torque rod, remove the wheel and pull it off. Watch out for the spacers and stuff as the wheel comes out; The thing to be most careful of is removing the crappy paint and polishing the box. The best way to do this would be bead blasting but you can't do that with the box in one piece, it'll have to be stripped. If you use some sort of paint stripper be very careful. A lot of them are highly caustic and will attack the alloy of the box and could well damage oil seals and the like. Polishing the housing with the pinion carrier still in-situ is going to be a pain, in fact well nigh impossible. Make sure that you have worked out exactly what you want to do before you start. While removing the box is easy, the rest may be more tricky. Pete

To be brutally honest I don't think most anti drain back valves are particularly effective in most oil filters. All they are really is a sort of rubber diaphragm that sits inside the filter above the holes where the oil comes in, (The oil comes into the filter through the holes around the outside of the base-plate and then exits to the bearings through the orifice that screws onto the mount.). Certainly on my Patrol which has two oil filters, both with anti drain back valves, they seem to empty themselves if the time it takes for pressure to build up and the light to go out is any guide. It has always been thus. One of the huge advantages the Guzzi motor has is that it has very short galleries. Once the pump is spinning, even at cranking speed, it takes next to no time for the galleries to fill. Even filling the filter doesn't take long. You can check this out by taking the plugs out and removing the ignition relay next time you do a filter change and put the filter on empty. Spin the motor on the starter and even at cranking speed it only takes a few seconds for the filter to prime. It's easier to see this on the older bikes that don't turn the idiot lights out while cranking but you can do it by pressing the button for a couple of seconds and releasing it, then repeating till the light doesn't come back on. Obviously it's far better to prime the filter by filling it with oil but I wouldn't die in a ditch about it. Few car filters are primed before installation due to the fact that few of them sit facing down and most workshops just change the oil and filter and then fire the engine up, there is residual lubrication in there but it's best if you can get fresh oil flowing to the bearings immediately. Certainly starting an engine with a dry filter by planting your foot to the floor and 'firing 'er up' isn't a bright idea but priming at cranking speed, even with the plugs in, shouldn't do any major damage but I'd avoid it if I can. Pete

You and me both . Lets wait for the anally retentive pedants to kick in! Pete

Good point The counter argument is that the LeMans wasn't built in 2001 I don't think I thought they came out about '03 or so? I'm quite happy to be wrong on that. Likewise I thought the long spine was a 2002 inovation. Best bet is for use to be able to see a pic of the bike so we can stroke our multiple chins and gurn sagely and offer our worthless opinions so the poor woman gets even more confused and decides we're all mad a s balloons! Pete

Well, first thing I'd do is make sure you're getting trigger current to the relay, then the solenoid. The relay is a typical cheapshit thing, just bin it and stick on a modern one. For the bendix to throw out and push the pinion into engagement the solenoid has to work. As the solenoid pulls in it pulls a yoke forward tht pushes the bendix mechanism forward and engages the pinion in the ring gear. These have been known to break but in this case I think it's probably a relay issue. Try simply getting a piece of wire and jumping from the batter + to the trigger spade on the solenoid. If it spins up nicely then the problem has to be the relay. 'Pete