1984 Moto Guzzi V65

[Mandello Cafe]

A few months ago, I purchased a 1984 Moto Guzzi V65 SP. The poor thing had been sitting for at least a decade and must have spend some of that time outside. Outside in this case meant different places in Texas. While the bike was largely complete a restauration to original condition seems unreasonable. Instead the plan is to largely repair, service and rebuild with a basic “Naked” bike focus. I purposefully avoiding the term “Café” as I am trying to steer away from LED headlights, exhaust wrap, cute leather pouches (in replacement of side covers), headlight grills and skinny jeans.

This is how things looked like when the Guzzi arrived:











After I hauled the Guzzi home, I performed the following tasks:
•   Replaces lubricants in engine, transmission and final drive;
•   Rebuild the both PHB 30 carbs;
•   Rebuild the centrifugal advance function on the ignition, replaced points and capacitors;
•   Set static timing;
•   Rewired a new ignition switch (bike came without keys);
•   Set valve gap (only minimal adjustments needed);
•   Reactivated the rear brake caliper and disabled the linked front caliper (was disconnected by a previous owner to move the bike).
•   Rigged a makeshift fuel tank out of the oil can that held the transmission oil (the Guzzi tanks has some corrosion that needs to be addressed)
At this point I was able to start the engine and ride the bike at low speed. I was able to shift through all five gears and get a basic carb setting. No nasty noises. No neighborhood pets were killed while riding with only the rear caliper and the brake performance of a 10 speed bicycle on a rainy day. The fun ended when I ran out of the less than a liter of gas my Valvoline transmission oil makeshift gas tank would hold.

Yeah! (so far)

[Mandello Cafe]

To address the corrosion inside the Guzzi's gas tank I initially built a rig to tumble the tank. I had read many opinions and strategies on the web concerning the topic of rust removal and decided against the chemical route. Here is a video of the contraption I came up with.

https://www.youtube.com/watch?v=Mhxyo6r2TTA




The stuff that is tumbling inside my tank is sandblasting sand and a chain. A laundry dryer will do a better job if you want to tumble the tank over its major axis rather than side to side. The tank is clean - as far as I can tell/see (it is really difficult to see much of anything inside a V65 SP tank). The sand and dust blown out / washed out and the tank is installed and filled.

So much better than a 1L Valvoline transmission oil can moonlighting as a gas tank. 

[Mandello Cafe]

So with the tank tumbled, some mild dents removed and back on the bike, I took another test ride. Things went well and a real tank is so much more enjoyable than a 1l Valvoline oil can moonlighting as a makeshift tank. I should have left things at that, but … 
The compression test showed the following:
•   Right side 0- 120 PSI
•   Left side – 165 PSI

That was last weekend, yesterday I decided that I would pull the right-side cylinder and look any potential evil square in the eye. Said and done – removing cylinder head and cylinder from a small block Guzzi is super easy. I could do this by the side of the road (not sure what this would help...).

This picture shows the first look in the bore and there was some initial rejoicing.




Some damage here on the very top of the cylinder bore – past the point where a piston ring would have to move.




Some damage to the piston in the top land ring area matching the location of the damage in the cylinder bore.




My experience with diagnosing the extent of engine damage is limited. I only own one other Nikasil coated cylinder that was cast in the fires of Mt. Giladorni (2-stork cylinder for a Vespa). It seems that the location of the damage above any area that is reached by the piston rings would not contribute to a loss of 45 PSI. I do not see any obvious damage to the cylinder head – no cracking between valve seats or seat and spark plug hole. I think I see some traces that may support that the cylinder head gasket was not sealing perfectly in the lower quadrant.
I would like to see some assessments of seasoned Guzzi folks that have inspected other cylinders. Let me know if you need other shots, angels or better quality pictures.

Thanks, Patrick

[Frenchfrog]

Great to have a small block thread in this section ! With regards to the low compression have you checked the valves ...sound obvious doesn't it 

[Antietam Classic Cycle]

I would probably pre-emptively replace the valves - they aren't expensive and it can be quite costly when the head pops off of one and destroys the head and piston. Been there, seen that...

[Mandello Cafe]

Frenchfrog, I have tested the valves/head by filling exhaust port and intake port with a cup of water. The exhaust side is pretty tight - maybe a drop of seepage every few minutes. The intake side does not seal as well - about a drop every 10 seconds. I will have to come up with a way to compress the valve springs and take the valves out to inspect valve and seat better.

Charlie, From reading stuff it sounded like the Lario's were the ones that had more issues with valves shearing off. I read something about the 2 valve heads having occasionally issues with exhaust valve shafts lengthening and eventually failing. That did not sound like a very spontaneous event on the 2 valve heads. Did I misunderstand things? Also the parts support on those 80's small blocks seems poor (did not realize this when I got the bike). I do not want to replace the stock valve with an aftermarket part that may have even less of a lifespan / track record. Did you swap out both (intake and exhaust) valves? What product did you use?

[Devildog]

Just curious, what is the mileage on the bike?

[Mandello Cafe]

[Antietam Classic Cycle]

Charlie, From reading stuff it sounded like the Lario's were the ones that had more issues with valves shearing off. I read something about the 2 valve heads having occasionally issues with exhaust valve shafts lengthening and eventually failing. That did not sound like a very spontaneous event on the 2 valve heads. Did I misunderstand things? Also the parts support on those 80's small blocks seems poor (did not realize this when I got the bike). I do not want to replace the stock valve with an aftermarket part that may have even less of a lifespan / track record. Did you swap out both (intake and exhaust) valves? What product did you use?

Here's a few photos. This was on a V65SP with 24k miles. I had just replaced a failed Dyna coil and was checking for spark with the new/used one. Thought I might as well check compression too - left cylinder: 130 psi, right cylinder: 0! Pulled the head off and this is what I found:

The head of the exhaust valve is folded in half and stuffed into the exhaust port.

Piston took a beating.


The left side exhaust valve was getting ready to fail as well - it's bulged where the stem and head are welded together. Good valve on the left, ready to fail on the right.


I bought a good used head, piston and cylinder from Ed Milich. Heads rebuilt with new valves, guides, seals, Nevada 750 springs, seats and retainers.



I used these parts:
http://www.mgcycle.com/index.php?main_page=product_info&cPath=68_127&products_id=2583
http://www.mgcycle.com/index.php?main_page=product_info&cPath=68_127&products_id=4401
http://www.mgcycle.com/index.php?main_page=product_info&cPath=68_127&products_id=2572
http://www.mgcycle.com/index.php?main_page=product_info&cPath=68_127&products_id=2687
http://www.harpermoto.com/lower-cup-31037015.html
http://www.harpermoto.com/upper-cup-31038015.html
http://www.harpermoto.com/outer-valve-spring-27037521.html

[Mayor_of_BBQ]

A really great and fun bike to ride, and a super base for a restomod!

[huub]

if you have the heads off , the minimum is to replace the exhaust valves , and the valve springs.
in 1990 the smallblocks got upgraded valve springs, to stop the occasional dropped valves
these progressive wound springs are a easy swap into older engines
i used to run a hotted up 650 off roader,  i changed the exhaust valves at regular intervals as a precaution,
with the upraded (actually 30% softer) springs the valve train is ok.

[Mandello Cafe]

There had been good riding weather during the last couple of weeks, so not much happened on the Guzzi. I did nevertheless remove the intake and the exhaust valve from the cylinder head. Seats looked good and there were no other surprises. The exhaust valve did not show any signs of bulging on the shaft. I will replace it preventively anyways. Which is where things get difficult. MGcycle is out of stock on most of the stuff I would need.
In my desperation I have checked the local Moto Guzzi dealer's website. The V65 is calling for an exhaust valve with part number GU19036183 (30.5mm). A Nevada (or Breva or V7II for that matter) calls for a exhaust valve that goes by part number GU20036120. The website shows it to be 30.5 mm as well. The halve cones holding the valve in place are interchangeable between Nevada and v65 (identical  part number). Can I use GU20036120 (Nevada valve)?
Also, the Nevada valve spring I have found is GU27037521. Is that the spring everyone is using in replacement of the V65 big and small combo spring arrangement?


Thanks, Patrick

[Antietam Classic Cycle]

There had been good riding weather during the last couple of weeks, so not much happened on the Guzzi. I did nevertheless remove the intake and the exhaust valve from the cylinder head. Seats looked good and there were no other surprises. The exhaust valve did not show any signs of bulging on the shaft. I will replace it preventively anyways. Which is where things get difficult. MGcycle is out of stock on most of the stuff I would need.
In my desperation I have checked the local Moto Guzzi dealer's website. The V65 is calling for an exhaust valve with part number GU19036183 (30.5mm). A Nevada (or Breva or V7II for that matter) calls for a exhaust valve that goes by part number GU20036120. The website shows it to be 30.5 mm as well. The halve cones holding the valve in place are interchangeable between Nevada and v65 (identical  part number). Can I use GU20036120 (Nevada valve)?
Also, the Nevada valve spring I have found is GU27037521. Is that the spring everyone is using in replacement of the V65 big and small combo spring arrangement?


Thanks, Patrick

Both valves are in stock at Stein-Dinse:
https://www.stein-dinse.biz/product_info.php?products_id=464630
https://www.stein-dinse.biz/product_info.php?products_id=464631

Yes, 27037521/GU27037521 is the spring I used and linked to above.

[Skiwi39]

Hi All - I'm new to bikes and bike ownership having just acquired a 1984 V65SP.

I've read the topic from top to bottom, and was aware that valves in these small blocks could be a bit iffy, but wanted to clarify the following:

There are 2 ways of upgrading the valve train 1) replacing both springs for inlets and exhausts with the post 90's set up
                                                                   2) using a single spring system from the 750 Nevada

Thanks!

[Antietam Classic Cycle]

There are 2 ways of upgrading the valve train 1) replacing both springs for inlets and exhausts with the post 90's set up
                                                                   2) using a single spring system from the 750 Nevada

Thanks!

Are those both the same thing- single springs?

[Kthomas]

What ever happened ? Did you rebuild the heads ?
I picked up a 84 v65 sp and love it. From what I was reading I probably also need to change the valves. It is a low miles bike. My local Guzzi guy said he thought the valve problem occurred in just the four valve heads. From what I’m reading I’m not sure I believe that.

[Antietam Classic Cycle]

Definitely not just a four valve head issue.

[Kthomas]

My bike has 13,000 miles and after checking it still has double valve springs.
I suppose if I’m going to keep it I should be looking at new valves in the future.

[Antietam Classic Cycle]

My bike has 13,000 miles and after checking it still has double valve springs.
I suppose if I’m going to keep it I should be looking at new valves in the future.

Or just change the springs, seats and retainers to the Nevada/Breva parts. The original valves will likely last a lot longer that way.