sp838 Posted January 13, 2015 Share Posted January 13, 2015 So, as one thing always seems to lead to another, looking into upgrading the pistons in the V11 has also led to investigating the con-rods. The recommendation is, when swapping out both the con-rods and pistons, to re-balance the whole package. Looking at the workshop manual, it looks like the entire engine has to be disassembled in order to get it out. At least, to do it "right". Does anyone know if there is a quick and dirty way to get it out, without removing the engine from the frame, and without breaking the transmission off the backside of the crank case? Mainly a rhetorical question, as I'm almost sure the answer is "no", but I am curious to know what, if any, workarounds to complete disassembly might exist. Link to comment Share on other sites More sharing options...
Cabernet Posted January 13, 2015 Share Posted January 13, 2015 Basically, you have to split the engine from the gearbox to get in to the clutch housing, to release the crank out the block, so "no" as you expected. Link to comment Share on other sites More sharing options...
gstallons Posted January 14, 2015 Share Posted January 14, 2015 I do think it would be more economical to leave the c/shaft where it is and do the rods/pistons and live with the results . Link to comment Share on other sites More sharing options...
Zooter Posted January 14, 2015 Share Posted January 14, 2015 How balanced can two cylinders even get? Iirc you need 4 on a 4 stroke. Wouldn't it be something to graft two motors into a V4 2 litre tire shredder with a fully balanced crank. Link to comment Share on other sites More sharing options...
Cabernet Posted January 14, 2015 Share Posted January 14, 2015 Or graft two BMW cylinders and fifty vertical one making a 5/8 radial. Link to comment Share on other sites More sharing options...
thumper Posted January 14, 2015 Share Posted January 14, 2015 And after all that you still will not have the horse power of a modern sport bike. Link to comment Share on other sites More sharing options...
GuzziMoto Posted January 14, 2015 Share Posted January 14, 2015 Standard practice is weigh the parts you took off and match the new parts weight by adding or removing metal if required. This is a little trick as you need to weigh both ends of the rods separately as well as total weight. Usually the new parts will be close enough and not require any metal added or removed. But it pays to check. Link to comment Share on other sites More sharing options...
Scud Posted January 14, 2015 Share Posted January 14, 2015 Who needs a V-2, when you could have an O-7 (radial)? Seriously - balancing the throttle and timing is one thing, balancing the weight of the reciprocating or rotating internal parts of the engine is another thing entirely - same principle as balancing wheels. IMO - if you've got the parts out, you may as well balance them, but it seems like a lot of extra work for relatively small gain if they are not already out. Could you just balance your new pistons to be sure that you don't introduce any new imbalance? Link to comment Share on other sites More sharing options...
LowRyter Posted January 14, 2015 Share Posted January 14, 2015 So if I understand this, if the replacement pistons and rods were weighed and determined to have the same weight as the old ones, you could bolt it back together and go. But to gain performance, lighter pistons and rods were installed. This means the entire rotating assembly needs to re-balanced? I am guessing it's not possible to subtract the differences from the existing counterweights with any accuracy? Link to comment Share on other sites More sharing options...
GuzziMoto Posted January 14, 2015 Share Posted January 14, 2015 That would be correct, if the new parts are substantially lighter than the ones they replace the balance of the rotating mass will be changed. That is almost always a change for the worse. To get the benefit of lighter rods and pistons you need to re-balance the crank. Besides, if you are doing that (who made these lighter parts?) you should probably be lightening the crank anyway. Most of the pistons I have seen are not lighter than stock. Carillo rods are often more about being stronger then lighter. Changing the rotating mass of the crank assembly is not an easy/simple thing to do. I would probably be working with an engine builder at that stage of things. Balancing the crank assembly requires removal from the motor. At least on a Guzzi you can do that without messing with the trans. Link to comment Share on other sites More sharing options...
sp838 Posted January 14, 2015 Author Share Posted January 14, 2015 Mike Rich pistons are lighter than stock, by about 6g each. Don't know about the Carrillo rods yet. If I do this, I'll first do it on my crank as-is, see how it works out. If it ends up being ok, all the better, if not then I will bite the bullet and pull it. I have a recommendation for a shop that can do it, that isn't the biggest concern... Link to comment Share on other sites More sharing options...
GuzziMoto Posted January 15, 2015 Share Posted January 15, 2015 Then I would ask Mike Rich what he recommends. He knows his parts and is one of the top Guzzi Builders in the USA. He certainly has done this more than I have. Link to comment Share on other sites More sharing options...
docc Posted January 15, 2015 Share Posted January 15, 2015 I had always imagined that if I had my motor down, I would want to have it balanced, "blueprinted," and polished rods simply because the original Telaio Rosso V7 was so done and it would make for interesting shop talk. I suspect it would impart a 'sweetness' to the running as well. (Seems to me the flywheel would have to be in on the balancing act as well.) 1 Link to comment Share on other sites More sharing options...
sp838 Posted January 18, 2015 Author Share Posted January 18, 2015 Gonna do it in stages. I'll balance the crank-flywheel-piston package when my clutch eventually blows up and will need to be re-done. Link to comment Share on other sites More sharing options...
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