1967 Monza 250 restoration

[MC916]

Hi,
I am new to the form and I hope you guys can give tips and advice as I start to restore my 1967 Monza 250. I plan to get it mechanically sound before I take it apart for sand blasting and paint. I hope to keep it as stock as posable but with a few changes to make it safer to ride.

[Nick]

Congratulations on a great find! That's a really nice bike you got there. I rode a 250 that looked just like yours for daily transportation for years, and loved it!

Looks like it would clean up very nicely without going to the trouble and expense of a full restoration. Just strip and paint the fenders and side cover, The rims you could simply powdercoat black or, if you have your own paint gear, paint them with a chip-resistant black. New spokes would be nice, of course, but those could also be painted or cad plated. (The spokes are probably rusted to the nipples. However, if you put a few drops of Liquid Wrench or other lubricant into each nipple and let it sit for a few days you may be able to unscrew them. Also, if you plan to ride the bike regularly, take off that stock carb, and replace it with a more modern carb (Mikuni, Amal, etc.).
Put the stock carb in a plastic bag and stash it somewhere — you'll want it when your reach that stage in life when tinkering with your bike brings you more enjoyment than riding it.

Change the oil right away, then do so again after the first few miles, then at 1,500mi intervals.

And remember, patina is where it's at! It's the one thing you can't buy and that gives you and your bike street cred!

[MC916]

Thanks,
I have been working on cleaning up the engine. I have also been getting NOS parts when I find them on eBay. I have already bought new aluminum rims and plan to buy stainless steel spokes. One issue I have is with the front brake drum. When I ride the bike and look down at the front drum I can see it wobble. I jacked the front of the bike up and spun the tire and the rim itself runs true. The front brakes seem to work very well so I think it's just a poor casting or machining job. I would like to find a better front drum to use for my new rims and tires. If anyone has one they would like to sell please let me know. I would also like to get a rear drum that way I can leave the original tires set up until I have the new ones ready.
The bike runs great. I have put 200 miles on it and no problems. I thought I had a shifting problem but after reading about it on this forum I found some good information on shifting technique that makes it work perfect. When I down shift the shifter dose not alway come back and reset itself for the next down shift. Up shifting is alway good. I have read about the adjustment for the shifter and I understand how it works. I would like to know if anyone has tried this, making the opining of selector fork larger (maybe .020) to make it easer for it to reset?
The only big issue I have is the Lighting. I have also read a lot on here about it. I have taken the regulator completely apart and repaired or cleaned all the connections. It is better now than before but not that good. My problem is I have never had a Ducati single before and do not know anyone who has one so I have no frame of reference. The best I can describe the lighting is if you were to use a flashlight to ride at night. Should I accept more form this old system?

I was able to run the bike this morning and take some voltage readings.

I unhooked the both the yellow wires from the regulator.
low rpm 15v ac high rpm 25v ac

I put the yellow wires back on the voltage regulator
low rpm 10v ac high rpm 15v ac

I then checked the voltage at the red and gray wires coming out of the regulator
low rpm 6.1v dc high rpm 6.3v dc



It looks pretty bad.

One of the screws is missing on the rectifier.

Cleaned it up

Fixed a broken connector

I will paint it when I take the bike apart over the winter. I do not have a fuse cover.

[LaceyDucati]

Hi,

Yes it is possible to open the gap between the claws, but best done on a tool or surface grinder. The gap between the claws on a Narrowcase bike and early widecases is generally 24mm. The gap in between the claws on the later widecase hinged mechanisms is 25mm. Ducati folklore says the later mechanisms are better because of the hinged mechanism, which I can categorically say is not true. I've had many early mechanisms work perfectly with the gap opened up to 25mm, I've also worked on many poor later mechanisms. The later hinged mechanisms most of the time just add to the slack in the mechanism due to poorly toleranced parts. About 90% of the time slack in the mechanism is what makes these boxes play up. Having all new bits doesn't always solve the problems either as some parts were toleranced badly. A problem best solved with welding and some careful fettling.

The other main problem is the ident and pin drum is generally machined all over the place. Mismatches between the ident dimples and positioning of the pins causes variation of the pin positions between the claws. If you assemble the mechanism with the back off and click through the gears you will see the pins don't always stop in the same place relative to the claws, hence why opening the gap helps. I guess the factory figured the problem which is why the gap increased. Pity they didn't fix the problem properly by making the drum correctly!!!

I am convinced the mechanism got worse when they modified to 5 speed as it is that pin which is so far out. Bizarrely early Spanish Narrowcase 5 speed engines didn't suffer this poor machining and the pins are equi distance, different tooling? Then when the Italian factory obviously gave the Widecase tooling to the Spanish, the Spanish were then able to also make crappy poorly toleranced ident drums for there Widecase bikes!

In short opening the gap to 25mm will improve things. But if there is excessive slack best eliminate that too.

Best Wishes Nigel

[Jordan]

Interesting insights on the shortcomings of the selectors, thanks Nigel.
I've been lucky in that all my Ducatis had tolerable shifting after doing the adjustment.
Is there enough depth of hardening on the fork to permit grinding back by half a millimetre?

Jordan

[LaceyDucati]

Hello Jordan

Surprisingly there does seem to be, which probably explains why the claws chip like they do. Opening up to 25mm has never proved a problem for me and I have seen quite a few after many years of race use. I've not seen one unusually worn after this mod or had any complaints after nearly 20 years of doing it, so as sure as I can be it's okay to do so.

Regards Nigel

[MC916]

Dose anyone have any thoughts on the output of my charging system? I am wondering if I have it working to its original output. I was thinking that my bike would have the four coil alternator based on its year and model (1967 Monza 250 ser. 97772) but the ac volts are only 25 at high rpm. I do not want to take it apart just yet I am hoping to ride it a few more times before the snow comes here in buffalo, NY. It only has two Yellow wire coming out. I would try the modifying it to a 3 wire system but I wonder if I have the two coil alternator. Any thoughts?

[amartina75]

there are tons of old posts on here about the different Ducati charging systems and how they work, also how to modify them to gain more light output.
try searching for the info you need i'm sure it's there. As far as riding at night being like "holding a flashlight while riding" i'd say thats how my bikes are
did you look at the tech section on here? there is some info about electrics there http://motoscrubs.com/Electrical_system_service_bulletin_1.htm
i dont have a bike that uses your type of charging system so i don't know much about it. DewCatTea-Bob could tell you but he is concentrating on another post
thats now 20 pages deep of alternator talk, so perhaps when thats finished he will have time to help you out.
are you sure you have a good battery? I believe your type of charging system is prone to draw the battery down faster then it charges it, if the lights are on.
what you have is a Alternator-Battery System so any fault with the battery will affect the lighting and ignition.
good luck!
Aaron

[MC916]

I have been reading the posts on here about different modifications. They are all vary informative. I am just hoping to get some input on a completely stock system and what to expect form it. I have never had one of these bikes before and I do not know anyone who has one so just looking for an opinion. I think you are right about the battery. I have ordered a new battery and the proper size, I am hoping it makes it better. I like to ride my bike to work and I usually leave home before sunrise. I have a Honda CB175 and it has a 12v system and the lights on it are just ok. Thanks for you comments I really appreciate it.

[DanM]

I have never had one of these bikes before and I do not know anyone who has one ............

Where are you located? Maybe there is someone on the forum in your area.