On cleaning and assembling this 74 GT I have come across some problems, not sure if they're typical. Oil leak from porous casting on a case bolt hole that was somewhat repaired with epoxy at a prior teardown.Crankshaft shimmed on both ends.Shims need replacing as they're split in two. Sludge traps almost full.Oil pump installed with silicone.All this done by a reputable dealer/race shop.But it did run this way 15 years.Can't wait to tackle top end.Any idea of piston clearance?
Tom
GT Reassembly Issues
Thanks GT Pete,
Glad to know the shim destruction and porosity are not unique.Back when I first picked up this bike early nineties it was a dog and when pushed hard it would destroy the forward sparkplug.Turned out the previous owner had both carbs being fed by one tap and the front cylinder bore the brunt of leaness.When I tore it apart a couple of seasons later the front piston compression ring was in 22 segments,but all held in a rather damaged land.No scoring in barrel!As the bike has come back in my possesion with new pistons I have a one standard used Mondial sport piston donkey'y for trade.Looking for a std. piston for my Monza.
Tom
Glad to know the shim destruction and porosity are not unique.Back when I first picked up this bike early nineties it was a dog and when pushed hard it would destroy the forward sparkplug.Turned out the previous owner had both carbs being fed by one tap and the front cylinder bore the brunt of leaness.When I tore it apart a couple of seasons later the front piston compression ring was in 22 segments,but all held in a rather damaged land.No scoring in barrel!As the bike has come back in my possesion with new pistons I have a one standard used Mondial sport piston donkey'y for trade.Looking for a std. piston for my Monza.
Tom
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Crashfangio
- Mariana
- Posts: 35
- Joined: Fri Aug 15, 2008 6:48 pm
- Location: Melbourne Australia
Tom,
These are typical, my '73 750GT cases have had some form of hard epoxy placed around the front bolt holes inside the cases, I suspect to address the same problem. My oil pump has also been assembled using clear silicone, both of these 'mods' from the factory. My cases had never been split up until now. I tore my motor down recently and discovered both mains shims split through the middle as well and yes, my sludge traps were full of junk.
I'm not woried about the epoxy or silicone. It beats having leaky cases. The sludge traps are doing what they are designed to do. The thing that does concern me a little is the split shims, I still haven't had any clear explanation given as to the cause.
Anyone who does know for sure feel free to weigh in.
These are typical, my '73 750GT cases have had some form of hard epoxy placed around the front bolt holes inside the cases, I suspect to address the same problem. My oil pump has also been assembled using clear silicone, both of these 'mods' from the factory. My cases had never been split up until now. I tore my motor down recently and discovered both mains shims split through the middle as well and yes, my sludge traps were full of junk.
I'm not woried about the epoxy or silicone. It beats having leaky cases. The sludge traps are doing what they are designed to do. The thing that does concern me a little is the split shims, I still haven't had any clear explanation given as to the cause.
Anyone who does know for sure feel free to weigh in.
73 750GT