75 850t Cylinder

[850brian]

I'll add two more points-  one is obvious, I hope.  Label your Left/Right, Intake/Exhaust parts.  Don't mix and match.  And- when you do take out the sludge trap, use an impact driver.  It is less likely to strip out.  I suggest just buying a new plug- they are very cheap.

Great thank you!

[850brian]

Update: just got off work and am in the process of removing the cylinders. I was able to get one of the spindles out but the other one isnt budging. Any tips?

[John A]

If it’s not on top dead center on the compression stroke there may be spring pressure on it. Will the pushrod spin with your fingers? It’s an exhaust valve so it could be on the exhaust stroke with the pushrod pressing on it, even with the adjuster backed off. Otherwise it could have the spring on the rocker shaft caught on a wear mark on the shaft in which case I would take a screwdriver and rotate the shaft back and forth a little while pushing on the shaft .

[850brian]

If it’s not on top dead center on the compression stroke there may be spring pressure on it. Will the pushrod spin with your fingers? It’s an exhaust valve so it could be on the exhaust stroke with the pushrod pressing on it, even with the adjuster backed off. Otherwise it could have the spring on the rocker shaft caught on a wear mark on the shaft in which case I would take a screwdriver and rotate the shaft back and forth a little while pushing on the shaft .

It will not spin in my fingers, easiest way to verify TDC?

[guzzisteve]

Easy way would be rotate back wheel forward till you see intake valve go down & come up then you are on compression stroke, when piston gets to top is TDC.

[850brian]

Easy way would be rotate back wheel forward till you see intake valve go down & come up then you are on compression stroke, when it get to top is TDC.

Maybe I'm just really dumb but nothing seems to be moving when I spin the wheel.

[John A]

Rotate the engine and watch the pushrod actuate the valve. Depending on the state of disassembly you have to be careful the pushrod doesn’t come out of its socket  and get bent. I would just rotate the engine until the pushrod goes down relieving the pressure. Always put it at tdc compression stroke before disassembling to make it easier but it’s not necessary now. Generally I pull the plugs and valve covers,rotate the engine clockwise viewed from the front and watch as the valves operate. After the intake starts to close put your finger over the spark plug hole and you will feel air pressure. That’s the compression stroke. The exhaust will be closed at that time. If you put a straw down the hole you can feel the piston come up and when it stops you are near tdc. There is dwell at the top and the crank can be turned slightly back and forth without the piston moving. In the middle of that movement is tdc which should correspond with timing marks on the flywheel through the hole in the bellhousing.  Be careful of jamming and bending a pushrod as you rotate the engine in a partially disassembled engine.

[John A]

Maybe I'm just really dumb but nothing seems to be moving when I spin the wheel.

A higher gear will make it easier to turn the engine but it will turn faster

[850brian]

Easy way would be rotate back wheel forward till you see intake valve go down & come up then you are on compression stroke, when piston gets to top is TDC.

False alarm. I got it and I'm really dumb

[guzzisteve]

Un-Experienced , not dumb

[850brian]

Update: right cylinder

[850brian]

Looks like I only have o rings on 3 of the 5. Should I remove these as well?

[850brian]

Additionally is there any tricks on getting these buggers out?

[850brian]

Realizing #14 and #16 were not on the short stud and the short stud on the right cylinder came off with the sleeve nut. Should I purchase 2 new washers?

[Antietam Classic Cycle]

Additionally is there any tricks on getting these buggers out?

No tang to grab hold of on the piston pin clips? Not factory - installed by a previous owner. If you can find the end, you may be able to wedge a pick under it and remove the clip.

Realizing #14 and #16 were not on the short stud and the short stud on the right cylinder came off with the sleeve nut. Should I purchase 2 new washers?

14 is an o-ring and is likely still stuck in it's groove on the underside of the plug. 16 is a washer, most often stuck on the cylinder head. Fish a magnet down the hole - if it grabs hold of something, the washer is stuck in there.

 

[850brian]

No tang to grab hold of on the piston pin clips? Not factory - installed by a previous owner. If you can find the end, you may be able to wedge a pick under it and remove the clip.

14 is an o-ring and is likely still stuck in it's groove on the underside of the plug. 16 is a washer, most often stuck on the cylinder head. Fish a magnet down the hole - if it grabs hold of something, the washer is stuck in there.

I got the circlips out. I believe the part is called the gudgeon pin

[850brian]

I got the circlips out. I believe the part is called the gudgeon pin

Also you were correct on the washer and o ring thank you.

[850brian]

It looks like I have to press them out but I'm not exactly sure how to do that while they are still connected to the rest of the engine

[John A]

I use a rubber coated pliers handle to cradle the piston against two studs so I don’t put any side load on the piston. It’s curve holds the piston in place so it’s not flopping around like a fish.Then heat piston so it’s hot to the touch. I use an oak dowel to push and tap on the pin. It should come right out without much drama.

[850brian]

I use a rubber coated pliers handle to cradle the piston against two studs so I don’t put any side load on the piston. It’s curve holds the piston in place so it’s not flopping around like a fish.Then heat piston so it’s hot to the touch. I use an oak dowel to push and tap on the pin. It should come right out without much drama.

Thanks for the reply John I will attempt  this in the morning. I am assuming you have to use a blowtorch to heat the piston? Also if I bought an aftermarket kit that comes with new pins is there any harm in using a socket to tap out the original pin?

[Tom H]

What John A said. All you need is a heat gun, maybe even a hairdrier will work.

Charlie: The upper cylinder stud, the one covered by the sealing plug. Have you seen a washer on that stud? I normally see the lower and the 4 inners with washers but never that one, just the allen head nut.  Enquiringly minds need to know

Brian, the 2 O rings at the base go on top of the base gasket. Put gasket on, then the top and bottom stud get an O ring. Then the cylinder goes on, then the head. Put O rings on the center 4 studs, then the rocker blocks. Oh..and don't forget the piston

Tom

[Tom H]

A socket is what I use. IIRR a 14mm, maybe 15mm, pick one that fits inside the pin hole in the piston.

Tom

[850brian]

A socket is what I use. IIRR a 14mm, maybe 15mm, pick one that fits inside the pin hole in the piston.

Tom

Great! Thank you tom!

[Pescatore]

Quote from: 850brian on Today at 06:22:53 PM

It looks like I have to press them out but I'm not exactly sure how to do that while they are still connected to the rest of the engine

I use a C clamp, without forcing, to avoid the side banging.
But as people already said,  heat is required. It might even slide out by pushing with your finger.

[Antietam Classic Cycle]

Charlie: The upper cylinder stud, the one covered by the sealing plug. Have you seen a washer on that stud? I normally see the lower and the 4 inners with washers but never that one, just the allen head nut.  Enquiringly minds need to know

Yes, I find a washer on that stud more often than not. But as in my previous post, they usually stuck to the head very well and only come during cleaning and media blasting. The only way I know if they're in the hole is a magnet sticks (or not). 

[BigDen]

See the various DIY tools for pulling piston pins (wrist pins, gudgeon pins) in this article from Greg Benders This Old Tractor Site.

https://www.thisoldtractor.com/moto_guzzi_loopframe_wrist_pin_puller_tool.html

[850brian]

See the various DIY tools for pulling piston pins (wrist pins, gudgeon pins) in this article from Greg Benders This Old Tractor Site.

https://www.thisoldtractor.com/moto_guzzi_loopframe_wrist_pin_puller_tool.html

Thank you for the article, I will give this a try after work tomorrow. Fingers crossed!

[Tom H]

I have never had a washer in that hole as far as I could tell. Always thought there should be one. Never had one fall out like the lower hole washer does. I shall check for it more closely in the future!! So that I can be sure to install it!!

Thank you!!!!!!
Tom

[n3303j]

Never had to fight a piston pin out of a Guzzi. Maybe a touch with a heat gun but no more than that. Then carefully slide the pin out with finger pressure.

It is most important that there are no burrs caused during circlip removal. A burr will hang the pin. The pin is a gage fit. The whole path for extraction must be undamaged.

[John A]

I have never had a washer in that hole as far as I could tell. Always thought there should be one. Never had one fall out like the lower hole washer does. I shall check for it more closely in the future!! So that I can be sure to install it!!

Thank you!!!!!!
Tom

Like Charlie, I make sure one is there and often a magnet is the way .