Monza 250 (NC) restoration.

[Blaine.Hale]

Got my wiring ordered. Had to find a US resource. I forgot to mention that I'm located in the US

Everything is coming together nicely. The top end is just temporarily on until I can source some piston rings. Is it worth moving to a modern piston instead of trying to hunt down the correct rings for the Borgo piston?
Everything is rebuilt/restored with the exception of the bodywork. Haven't found a paint guy in Atlanta, yet. I honestly don't mind the crusty paint, though. Gives it some interesting character. If I do end up getting it painted, I'll go with the 67' red and silver paint scheme. I really like that over the all silver Monzas.



By the way, I have a Mark 3 350 Desmo up next, after I finish this one.

[themoudie]

Aye Blaine,

I would still give Nigel a call/email re: your piston rings.

As for the paint, it's your bike!

The 350 appears that it will keep you out of mischief and pocket for a wee while!

Good health, Bill

[Blaine.Hale]

Nigel at Lacey has been very helpful but, unfortunately, it looks like piston rings just aren't available for the old Borgo pistons. I can go one over bore (74.25mm) with the rings and gap them down to the 74mm standard bore and it may work, but I'm not a fan of that solution.
Looks like a new, modern piston is the way to go.
Sticking with Lacey, it looks like the piston they offer would result in a lower compression ration with my Monza engine. Would this mean any significant power loss or adverse effects? https://laceyducati.com/ducati-parts/25 ... p-540.html

Is there another piston I should be looking at that would make the most of the Monza's engine?

[Blaine.Hale]

Another option could be that I grab this piston off ebay for the oil ring...then I'd also have a backup piston.
https://www.ebay.com/itm/224093099594?c ... dDEALw_wcB

[double diamond]

Have you tried the Hastings Piston Rings website? I found a set that fit a 250 Mk3 (single oil ring). Wiseco is another possibility.

Matt

[Blaine.Hale]

Have you tried the Hastings Piston Rings website? I found a set that fit a 250 Mk3 (single oil ring). Wiseco is another possibility.

Matt

I found a 74mm bore 2.5mm thick ring on their site. Is it reasonable to expect that to just work? I've never ordered just an piston ring, usually just kits or a new piston etc.

It's the 1st Oil Ring here: https://apacatalog.com/HastingsCatalog/ ... detail/776

[double diamond]

I didn’t use individual ring part numbers. I ordered a set of 74mm rings from the Hastings racing piston ring catalog. They fit a Honda Civic. Found the correct thickness and diameter in the application chart. The oil rings are three-piece rather than the one piece scraper Borgo design. The oil ring you have found is also a three-piece design and will work in your original piston if the height dimension is the same as original and the ring grooves on your piston aren’t excessively worn.

Matt

[Blaine.Hale]

I didn’t use individual ring part numbers. I ordered a set of 74mm rings from the Hastings racing piston ring catalog. They fit a Honda Civic. Found the correct thickness and diameter in the application chart. The oil rings are three-piece rather than the one piece scraper Borgo design. The oil ring you have found is also a three-piece design and will work in your original piston if the height dimension is the same as original and the ring grooves on your piston aren’t excessively worn.

Matt

Excellent! That was way easier than hunting originals. Thank you

[Blaine.Hale]

I've put about 40 miles on it since the rebuild. It's been a seriously wonderful and fun 40 miles. Not much stress and not much wrong. Just little fine-tuning. It's a weird-looking bike with everything being fully restored to new, save for the bodywork. I ordered the proper decals and I'm thinking about getting the bodywork painted. Of course, the seat needs to be upholstered. I think the worst part of the Monza model is the seat. It's just a freaking brick, so I'm trying to design something that looks period correct but slimmer and complementary to the mid-century lines of the Monza.

[Commodore]

I agree that the seat needs some work, but it is certainly salvageable and will be more comfortable that a 'race' seat, and add an original "look", but subtly different. What I did was cut my frame down about two inches so the profile would be lower, and fit my tank better. Used all the old springs and fittings. Then I resewed the thick rubber liner with dacron sail thread, cut the sides down to match the frame, and then designed a new cover with two densities of thin foam beneath the leather, so I could get the pleating to look similar to the original. Lots of research on how to sew the pleating!!