Laverda SF
Hero member
Guess your running 36's - If you love your Air Filters ;o)
Loose rear end?
- Thread starter Canuck750
- Start date
Dellortoman
Hero member
- Location
- Tasmania, Australia
Piranha Brother 2 said:but if it swallows a load of kitty litter at redline ... fun fun fun!!
Yes, that was the other worry that a couple of people pointed out to me. It doesn't have a dead-man switch. Probably a good idea to fit one of them too.
Laverda SF
Hero member
Industrial Toggle Ignition Switch.
Canuck750
Full member
- Location
- Edmonton, Alberta, Canada
sfcpiet said:All Laverda 750 GT and American Eagles, as well as the GTLs, were equipped with exactly the same VHB carbs and came with a very efficient air filter as standard... :
Much the same at Moto Guzzi, Moto Morini, Gilera, Benelli, etc, etc. I think only MV Agusta totally ignored the benefits of an air cleaner.
piet
The V7 Sport, 750S and 750S3 had a rubber boot with a perforated metal plate facing downward but no filtration of any kind. Couple the unfiltered carburation and the metal gauze screen oil filtration and its no wonder most of these early Guzzi motors suffer serious bearing failure.
The 850 Le Mans MK I was no better, just bell mouth carbs.
The Guzzi 850 T3, Convert and newer bikes did get a proper air box and air filter plus a cartridge oil filter.
Canuck750
Full member
- Location
- Edmonton, Alberta, Canada
sfcpiet said:
That's good information, the 1973 Benelli 650 Tornado that I am starting to rebuild has VHB 30 carbs that don't have the accelerator pump, the bike came with the LH carb but is missing a RH one, I have a good pair of Guzzi VHB 30's but I think I should find a matching RH VHB 30 for this build.
Time to call Wolfgang.
Canuck750 said:
Seriously doubt the lack of air filtration could cause bearing failures of any kind. Any grit being sucked into the combustion chamber will wear and eventually ruin the bores and the pistons/rings. It generally gets spat out the exhaust after going through the combustion cycle. Don't think generations of competition motorcycle designers would have risked bearing failures while running open carbs. Even GP 2-strokes ran open carbs, almost to the end of their era.
Reckon the early Guzzis failed due to lack of maintenance, just like Laverdas... plain bearing engines need really clean oil to last, stretching oil change intervals beyond recommendation is simply asking for trouble. At least Lavs aren't so fickle in that department. They might wear prematurely, but they won't blow up!
piet
Canuck750
Full member
- Location
- Edmonton, Alberta, Canada
sfcpiet said:Seriously doubt the lack of air filtration could cause bearing failures of any kind. Any grit being sucked into the combustion chamber will wear and eventually ruin the bores and the pistons/rings. It generally gets spat out the exhaust after going through the combustion cycle. Don't think generations of competition motorcycle designers would have risked bearing failures while running open carbs. Even GP 2-strokes ran open carbs, almost to the end of their era.
Reckon the early Guzzis failed due to lack of maintenance, just like Laverdas... plain bearing engines need really clean oil to last, stretching oil change intervals beyond recommendation is simply asking for trouble. At least Lavs aren't so fickle in that department. They might wear prematurely, but they won't blow up!
piet
Makes sense on the intake side,
most early Guzzi bearing failures can be attributed to the chrome plated cylinder bores, the poor quality chrome flakes off and lodges in the soft bearings. Add that there was no proper oil filtration and few owners followed Guzzi's maximum 1000 mile oil change frequency. By 1976 Guzzi went to iron liners on the Le Mans MKI and then to a better plating process. I find the chrome bore motors with an oil filter (T3 onwards) tend to not have damaged crank shafts and the main bearings are typically in spec. The no air filter bikes that had chrome bores are the worst for engine wear, I think the dirty air flow hastened the chrome bore failure and then its a rapid descent to bearing failure.
AndyW
Hero member
I think you've just described how/why the big end went on my '75 T3 Cali last year. Have been scratching my head on that one for a long time. I thought it might have been oil pump failure, however, I do run an external oil filter and K&N style air filters. I changed a cylinder out (piston and barrel) a few years ago due to a seizure and noticed a lack of chrome plating across much of the bore. Never occurred to me that might have caused wear in the plain big end..
Dellortoman
Hero member
- Location
- Tasmania, Australia
Canuck750 said:
Interesting. I have a 1976 Mk1 LeMans. I've never had the engine apart and I just assumed it had the chromed bores. I'd certainly be happier if it has plain iron bores, considering the difficulties of the chrome bores described here.
Canuck750
Full member
- Location
- Edmonton, Alberta, Canada
Dellortoman said:
Your Le Mans will have iron bores.
If the oil and filter have been changed regularly the engine is probably in good shape. The common wear item on most filter engine bikes are the valve guides. Guides are cheap and easy to replace and I just fit new valves as there isn't much to machine and new ones are cheap, same with the valve springs. The original rubber foot cam chain tensioner usually turn to mush, fitting a new style sprung tensioner is the way to go. The old rubber foot style breaks down and can clog an oil pump.
Chrome bore cylinders must be replaced, regardless of mileage the chrome is breaking down and will lead to a costly engine rebuild.
Laverda SF
Hero member
Iron bores and Molly Rings forget the rest. Heavy Forged Pistons, Rods and Cranks over Light Cast is optional approaching Hi-Revs.
Light weight cast internal components rev faster but tend to brake at extreme revs.
Light weight cast internal components rev faster but tend to brake at extreme revs.
Canuck750
Full member
- Location
- Edmonton, Alberta, Canada
AndyW said:
The original round fin big block Guzzi engine cylinders where chrome plated not Nigasil or Nikasil.
Nigasil plating did not come into play on Guzzi engines until the late 70's. The chrome plating technology was not the best and the plating fails on all of these cylinders.
If you have chrome cylinders; all V700, V750 Ambassador, V850 Eldorado, V7 Sport, 750S, 750S3, 850T and T3, the best solution and the cheapest is to go for new Giladorni kits, around $350 USD a piece, comes with new cylinder, piston, pin, circlips and rings. Giladorni also makes big bore (950cc) kits to fit the 850cc engines, these have the smaller diameter spigot to fit the 850cc blocks. If you choose the big bore kits the crank should be rebalanced, no real gain in hp but an increase in torque.
When I rebuilt my 750S3 the Giladorni kits were not in stock so I sent the cylinders to Milenium Industries in the USA along with NOS pistons, rings and pins. Milenium matches the plated cylinders to the NOS pistons. It cost a little more than the Giladorni kits but I kept the stock cylinders on this rare bike.
http://www.mgcycle.com/index.php?main_page=index&cPath=68_129
Jotaman
Hero member
- Location
- Verrierdale, Qld
Canuck750 said:
I can vouch for the Giladori sets, just nice.
My chrome sloughed off the bore during a test run on the original pistons and bores with fresh rings - fortunately it occurred in front of one of Queenslands 'finest', who was most generous with his time and use of technology, he also helped me to locate the forklift number plate that i had inadvertently 'stored' on the Ambassador.
Peter
Dellortoman
Hero member
- Location
- Tasmania, Australia
If the LM1 has iron cylinder liners, I suppose they can be bored for oversize pistons. Now I'm wondering how big it's possible to go with over-boring.
Canuck750
Full member
- Location
- Edmonton, Alberta, Canada
Dellortoman said:
Rather than boring out the iron cylinders I would opt for the Giladorni big bore kit specifically made for the MKI Le Mans, 950 cc, matched set of cylinder, piston, pin and rings.
I spoke to several long time retailers , Harpers and MG Cycle and never got a strong enough recommendation to go for the big bore kits on any of the Guzzi's I have rebuilt. Swapping to a B10 cam is a better bang for the buck and if you are willing to give up the low end torque of the heavy flywheel a lightened flywheel is a good option. I have experimented with the B10 cam and lighter flywheels and like it on my V7 Sport for around town pick up but preferred the stock set up on my 850 Eldorado.
The Le Mans MK I came stock with a lighter flywheel but an even lighter flywheel is possible. Personally I like the heavy fly wheel and the torque, Guzzi big twins are not designed for off the line acceleration, they accumulate speed and hold it all day long, same as my BMW R1150RT.
Dellortoman
Hero member
- Location
- Tasmania, Australia
Thanks Canuck. I appreciate you sharing your knowledge of Guzzis on a Laverda forum. I'm not really looking to increase the performance if my LM1. Just wondering about the possibilities. The engine is sweet and runs pretty well as it is so there's no compelling reason to start messing with it. My mate has an identical bike which does have the 950 kit, and yes it has more torque, which is nice, but I can't really justify swapping out a perfectly good set of barrels and pistons for a small gain in torque.
PS: Canuck, I just noticed your web address in your profile. I see where your Guzzi knowledge comes from.
PS: Canuck, I just noticed your web address in your profile. I see where your Guzzi knowledge comes from.
helicopterjim
Hero member
- Location
- near Lone Butte, BC, Canada
Dellortoman said:
Now he's hiding it .......
helicopterjim
Hero member
- Location
- near Lone Butte, BC, Canada
AndyW said:
But our spiders aren't dangerous.