Guzzi 650 NTX blowup and rebuild

chris a · 07-26-2012, 11:00 AM

Torched the right hand big end on my little ol NTX a while ago ....
Mystified as to why as the other one is fine and so are the other bearings, oil pump, oil level etc.Just my bad as I was going up to a family funeral but I made that ok thanks to a hire car !

More posting after dinner !

chris a · 07-26-2012, 12:14 PM

%20march%2009%20Moto%20Guzzi%20%20NTX%20650%20by%20chrisarmstrong1,%20on%20Flickr[/IMG]

%20IMG_1116%20by%20chrisarmstrong1,%20on%20Flickr[/IMG]

%20IMG_1118%20by%20chrisarmstrong1,%20on%20Flickr[/IMG]

The accountants at Moto Guzzi did a good job : no oversize shells have ever been available for their smallblock models.
As the crank would need a regrind to be reused I obviously needed to get another unworn one....and new shells for all the bearings .The accountants have done a good job there too and the prices of everything new was staggering to me : for example a front bearing halfshell is euro 79 !
So off I go looking for a good second hand engine...finally located and arrives down here by courrier.
They've been useing the engine for drop practice

%20V65%20Damaged%20inlet%20stub%20by%20chrisarmstrong1,%20on%20Flickr[/IMG]

%20V65%20wonky%20flywheel%20by%20chrisarmstrong1,%20on%20Flickr[/IMG]
The seller of the engine was totally cool ....sent bits to replace the damaged ones and also gaskets so that I can lift one of the heads off as broken inlet manifold bits have got in there.....While I'm at it might as well replace all the seals tooas the engine has been sitting for a good while.
Hey presto next issue !!!!!!!
various alternaters have been fitted to these bikes over the years.Mine had a Saprisa so I order a Saprisa seal for the crank.The Saprisa seal is the left hand one on the photo

%20NTX%20crank%20and%20seals%20by%20chrisarmstrong1,%20on%20Flickr[/IMG]

Theres no way that's going to work unless I get the angle grinder out....
The "local" Guzzi guy is away on holidays on Sunday and wont put one in the post but i can come over and pick one up....a round trip of 3 1/2 hours in 35 degrees C but at least I've now got the right seal

chris a · 07-28-2012, 09:20 AM

Got the rear mainseal out easely even though I was anticipating having to split the cases.

%20rear%20mainseal%20removal%20by%20chrisarmstrong1,%20on%20Flickr[/IMG]

I like it when jobs go like that!
Still have to re do the gaskets on the right hand barrel but the clutch and timeing side are now done....looks like I'll be able to assemble the bike back together pretty soon

chris a · 07-31-2012, 07:50 AM

These engines are pretty simple heron head pushrod 90 degree v twins and have been updated many times over the years.
The only update I've done to this 1983 one is to add the weird rubber pushrod oil retaining caps

%20Pushrods%20and%20rubber%20cups%20by%20chrisarmstrong1,%20on%20Flickr[/IMG]

%20NTX%20650%20head%20by%20chrisarmstrong1,%20on%20Flickr[/IMG]

I had considered uprating the oil pump to the newer and larger type too but can't really afford the cash .I've also got a vented sump cooler that was on the other engine but I'm leaving that off at the moment as it didn't seem to do much .

%20NTX%20650%20drivetrain%20by%20chrisarmstrong1,%20on%20Flickr[/IMG]
These bikes are very easy to strip down as the trans ,engine and swingarm are built up into one unit to which the frame and front cycle parts bolt onto.Easely done by one person for the smallblocs, bit more tricky for the heavier bigblock twins.

%20NTX%20650%20by%20chrisarmstrong1,%20on%20Flickr[/IMG]

Soon I'll have all the rest of the bits bolted on,battery recharged and the engine re-timed and go for a test.

lrutt · 07-31-2012, 09:14 AM

wish I could see your pictures, just red x's

Tosh Togo · 07-31-2012, 12:58 PM

Until the image links are un-borked: http://www.flickr.com/photos/chrisa1/7684316620/

chris a · 08-01-2012, 01:50 AM

I can't work out why the pics don't come out but if you click on the links then you can see them.
Maybe someone can explaine how to do it better...computing has never been a strength.

Another weird annoyance and delay;
The original motor was fitted with the Saprisa Alternator whilst the replacement had a Bosch fitted.The timing casings SEEMED identical but the Saprisa fitting bolts for the stator are 5 mm whereas the Bosch ones are 6mm.On the Saprisa case they used inserts to reduce the size which I hadn't noticed until it was all together.Now I either have to get new seals and fit my old case ,put inserts into the replacement one or make up special bolts which is probably what I'm going to do.
Sometimes the goal looks so close but is so far !!!!!!

07-26-2012, 11:00 AM	#1
chris a ^OP Adventurer Joined: Oct 2011 Location: Southern France Oddometer: 40	Guzzi 650 NTX blowup and rebuild Torched the right hand big end on my little ol NTX a while ago .... Mystified as to why as the other one is fine and so are the other bearings, oil pump, oil level etc.Just my bad as I was going up to a family funeral but I made that ok thanks to a hire car ! More posting after dinner !

07-31-2012, 09:14 AM	#5
lrutt SILENCE.....i kill you Joined: Jul 2005 Location: Deltona, FL Oddometer: 812	wish I could see your pictures, just red x's __________________ 2004 Harley Sporster 1200C, 2001 Ducati M900, 2001 Honda XR650L, 1994 Harley Heritage, 1978 Honda CB750K with sidecar, 1977 Moto Guzzi 850 LeMans, 1976 Honda CB750K, 1965 Honda 305 Dream, 1973 Norton 850 Commando, 1971 Triumph Trophy 650, 1970 Honda Trail 90, 1970 Triumph Tiger 650, 1973 Honda Z50, 1984 Yamaha Virago 1000, 1981 Honda Passport 70, 1970 Suzuki T250, 1971 Yamaha RT1 360

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07-26-2012, 12:14 PM	#2
chris a ^OP Adventurer Joined: Oct 2011 Location: Southern France Oddometer: 40	%20march%2009%20Moto%20Guzzi%20%20NTX%20650%20by%20chrisarmstrong1,%20on%20Flickr[/IMG] %20IMG_1116%20by%20chrisarmstrong1,%20on%20Flickr[/IMG] %20IMG_1118%20by%20chrisarmstrong1,%20on%20Flickr[/IMG] The accountants at Moto Guzzi did a good job : no oversize shells have ever been available for their smallblock models. As the crank would need a regrind to be reused I obviously needed to get another unworn one....and new shells for all the bearings .The accountants have done a good job there too and the prices of everything new was staggering to me : for example a front bearing halfshell is euro 79 ! So off I go looking for a good second hand engine...finally located and arrives down here by courrier. They've been useing the engine for drop practice %20V65%20Damaged%20inlet%20stub%20by%20chrisarmstrong1,%20on%20Flickr[/IMG] %20V65%20wonky%20flywheel%20by%20chrisarmstrong1,%20on%20Flickr[/IMG] The seller of the engine was totally cool ....sent bits to replace the damaged ones and also gaskets so that I can lift one of the heads off as broken inlet manifold bits have got in there.....While I'm at it might as well replace all the seals tooas the engine has been sitting for a good while. Hey presto next issue !!!!!!! various alternaters have been fitted to these bikes over the years.Mine had a Saprisa so I order a Saprisa seal for the crank.The Saprisa seal is the left hand one on the photo %20NTX%20crank%20and%20seals%20by%20chrisarmstrong1,%20on%20Flickr[/IMG] Theres no way that's going to work unless I get the angle grinder out.... The "local" Guzzi guy is away on holidays on Sunday and wont put one in the post but i can come over and pick one up....a round trip of 3 1/2 hours in 35 degrees C but at least I've now got the right seal

07-28-2012, 09:20 AM	#3
chris a ^OP Adventurer Joined: Oct 2011 Location: Southern France Oddometer: 40	Got the rear mainseal out easely even though I was anticipating having to split the cases. %20rear%20mainseal%20removal%20by%20chrisarmstrong1,%20on%20Flickr[/IMG] I like it when jobs go like that! Still have to re do the gaskets on the right hand barrel but the clutch and timeing side are now done....looks like I'll be able to assemble the bike back together pretty soon

07-31-2012, 07:50 AM	#4
chris a ^OP Adventurer Joined: Oct 2011 Location: Southern France Oddometer: 40	These engines are pretty simple heron head pushrod 90 degree v twins and have been updated many times over the years. The only update I've done to this 1983 one is to add the weird rubber pushrod oil retaining caps %20Pushrods%20and%20rubber%20cups%20by%20chrisarmstrong1,%20on%20Flickr[/IMG] %20NTX%20650%20head%20by%20chrisarmstrong1,%20on%20Flickr[/IMG] I had considered uprating the oil pump to the newer and larger type too but can't really afford the cash .I've also got a vented sump cooler that was on the other engine but I'm leaving that off at the moment as it didn't seem to do much . %20NTX%20650%20drivetrain%20by%20chrisarmstrong1,%20on%20Flickr[/IMG] These bikes are very easy to strip down as the trans ,engine and swingarm are built up into one unit to which the frame and front cycle parts bolt onto.Easely done by one person for the smallblocs, bit more tricky for the heavier bigblock twins. %20NTX%20650%20by%20chrisarmstrong1,%20on%20Flickr[/IMG] Soon I'll have all the rest of the bits bolted on,battery recharged and the engine re-timed and go for a test.

07-31-2012, 12:58 PM	#6
Tosh Togo Beastly Adventurer Joined: Nov 2010 Oddometer: 1,594	Until the image links are un-borked: http://www.flickr.com/photos/chrisa1/7684316620/

08-01-2012, 01:50 AM	#7
chris a ^OP Adventurer Joined: Oct 2011 Location: Southern France Oddometer: 40	I can't work out why the pics don't come out but if you click on the links then you can see them. Maybe someone can explaine how to do it better...computing has never been a strength. Another weird annoyance and delay; The original motor was fitted with the Saprisa Alternator whilst the replacement had a Bosch fitted.The timing casings SEEMED identical but the Saprisa fitting bolts for the stator are 5 mm whereas the Bosch ones are 6mm.On the Saprisa case they used inserts to reduce the size which I hadn't noticed until it was all together.Now I either have to get new seals and fit my old case ,put inserts into the replacement one or make up special bolts which is probably what I'm going to do. Sometimes the goal looks so close but is so far !!!!!!