Moto Guzzi Rebuild How to and other BS


Alright so I'm gonna dump a ton of pictures and try to do my best at somewhat of a step by step how-to rebuild a robin/benelli g2 engine. These are cool engines and are pretty simple to rebuild. I was a noob when I did mine and yall can too (had to do it twice, overheated bearings during install first time). Now these pictures are from 3 different periods of time that I messed with this bike so don't get confused as photo quality and backgrounds change. Hopefully this'll get some of you to crack them cases and do a rebuild.


This is where everything is gonna go. Those long lines with the c ends are the large circlips.

You're gonna want to take all the extras off before you remove the engine from the frame. DO NOT use a piston stop because of the angled plug hole. Either use the rope trick or a holder. Remove your intake (2 nuts) and exhaust (2 nuts and one mounting bolt). Next yer flywheel...


Re: Moto Guzzi Rebuild How to and other BS

This a dansi 101441 flywheel and uses a 19x1 puller


Remove the three flat head screws that hold that big ol' ring/cover surrounding the stator. Besides protecting the stator that ring holds the stator wires in place.


Then remove the 2-3 screws that hold the stator itself in place and remove.

Disconnect the stator wires from the wires coming from the frame. Set electronics aside.


Re: Moto Guzzi Rebuild How to and other BS

Drain your oil if you didn't already and remove all the bolts holding the transmission cover on. It helps to drive them through a piece of cardboard in the order you took them out.


As mentioned 100 times before these use the same surflex clutches that e50's use. Use the rope trick to remove the nut holding the clutch on. Use a clutch puller to pop that fucker off there.


Don't forget the little woodruff key. If you lose it, it's not a big deal.


Re: Moto Guzzi Rebuild How to and other BS

Remove the Circlip


Remove the shim and clutch bell


Remove the brass bushing the clutch bell rides on


Re: Moto Guzzi Rebuild How to and other BS

Now not all this has to be done in this exact order. But I switch over and pull the sprocket off. Using a holder to get the nut off is how the manual says to do it.


I have also used the drive gear nut to remove the sprocket nut


Either way once the nut is off, use a 2 jaw puller to pull the sprocket off


Re: Moto Guzzi Rebuild How to and other BS

The biggest part I struggled with on this engine is the nut holding the drive gear on. My best advice is don't fuck around with other methods like heat and pb blaster. Go straight for the air gun. Yeah, I hate saying that but we had this thing in a vice, heated up with map gas, breaker bar, and two dudes holding and pulling with full strength; it wouldn't even budge. It zipped right off with the air gun. Once the nut is off, put the air gun away and don't touch it again.


Next lets remove the top end. Remove the four nuts holding the head on and remove the head. Don't forget the washers.


Remove the cylinder. Hopefully it isn't a crusty, stuck mess.


Re: Moto Guzzi Rebuild How to and other BS

Remove the wrist pin clips from the piston. In this case they are circlips.


Remove the wrist pin. No picture but usually I use small socket extension and push it out. Put the wrist pin and needle bearing in a bag with some oil and put it in a safe spot.

At this point everything should be removed from the engine and it's ready to come off the frame. Remove the nuts and the three bolts that hold the engine on and gently guide the engine down.


Re: Moto Guzzi Rebuild How to and other BS

Remove the 7 bolts that hold the two case halves together. Remove that the armed springy thing with that brass bushing in the middle. Keep together and safe.


Split yer cases. I held one part of the engine and lightly tapped all around with a rubber hammer. That way it split little by little. Another more aggressive method is to heat up the stator side of the cases where the bearings sit for the drive and crank shaft; and then hit back and for with a rubber hammer. Second method only takes a few whacks but is only recommended if you understand why this method works better.


Time to remove more things.

Start on the stator side and remove the circlip holding the crankshaft seal in.


Re: Moto Guzzi Rebuild How to and other BS

Remove the seal behind it


Use a socket or something like it and bop the bearing out. Use a little heat on the case if you need it. Make sure you have the case half on something soft/forgiving so you don't mess the sealing surface up.


Re: Moto Guzzi Rebuild How to and other BS

If you haven't already, tap the drive shaft out. Remove the large circlip and remove the bearing. Heat and a couple taps should do it.


Remove the seal from the other side of the drive shaft. Then remove the bearing with a 2 or 3 jaw puller


Now here is where I start to run out of pictures. I lost 1 set of pictures from the time I had this bike and engine.

But remove all the other circlips, bearings, and seals that may be left using either 2-3 jaw pullers and/or heating the cases and taping the bearing out. You should be left with 2 case halves, trans cover, crank, and drive shaft.


Re: Moto Guzzi Rebuild How to and other BS

Clean everything reallllly well and prepare for a rebuild! I like to lay everything out so you know where its all gonna go in the end.


Freeze your bearings, crank, and drive shaft overnight.

Lets start with the transmission side. Install the outer most circlips. The bearings will butt up against these circlips.


Heat the cases up with either a small oven (not your home one) or a torch. If an oven I usually do 250-300F. In this case I used a torch. Take your frozen bearings, one 6202 for the crank and a 6003 for the drive shaft, and hopefully they should just drop right in. If they don't, take a pipe or something the same diameter as the OUTER race of the bearing and give it some taps till it goes into place. You shouldn't have to bash them in with brute force, the temperature difference should work wonders.


Re: Moto Guzzi Rebuild How to and other BS

Do the same for the other side. Install the circlips the bearings will sit against. Heat cases. Install cold-ass bearings, both 6202's.


Install the frozen crank into the clutch side. Then install the larger side of the drive shaft. Oil your case gasket up and put it on the stator side case. Put the clutch side case (with crank, shaft, bearings) on and install the bolts. SLOWLY in a CRISS-CROSS pattern tighten them down to bring the two case halves together.


Re: Moto Guzzi Rebuild How to and other BS

Just some extras.

I replaced the headset bearings on my robin with these

I used a wire wheel to make them silver again. Also had to shim the bottom race but it all came together beautifully.


I opened up the transfers a little bit and case matched them. Not a lot, nothing crazy. I left the exhaust alone because I was using the stock pan. I opened the intake just enough to match the carb. I didn't touch the port timing one bit.


On the cases there is some rough edges around the transfers. Clean all that up so it doesn't disrupt the flow of things. Again nothing crazy here; just cleaning up some jagged edges.

Re: Moto Guzzi Rebuild How to and other BS

Just got my Moto Guzzi Robin running, thanks a ton for the guide! It'll be super useful when I inevitably have to tear into the thing!

Re: Moto Guzzi Rebuild How to and other BS

Probably Fred /

Ya keep saying use the rope trick,

To anybody who cares about their stuff do not use the rope trick ever! On anything ever! whoever does is an amateur and they must have to redo their work, (yeah he did say he had to redo his bearing work so I guess ya oh well)

Way better is to use a impact zip zip for no stress on the piston at the pin, rod or anything, no stress on any of the crank/reciprocating parts,

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