New member & narrow case questions

[narrow_monza]

Hello,

I have a 250 narrow case project bike that I have put on hold for the last 15 years or so. I'm now getting the itch to dive back into it.

Since I don't remember much (other than the engine was supposedly "rebuilt" by someone 15 years ago), I am seeking some basic info that would help me get going again. Here are some of my questions:

1) Is there a way to determine what type of 250 narrow case engine I have (Monza, Diana, etc.) from the engine number?

2) I am hoping I don't have to split the case, so what kind of damage could the engine have from sitting in my garage for over a decade. I don't even remember if I drained the oil from it. Either way, is there anything I can do to avoid damaging the engine if I try to turn it over to check for compression or for a spark?

3) What is the easiest way to determine if I have a magneto or an alternator? I tried to remove the left engine cover but it won't budge.

4) What happened to Domiracer? I used to buy parts from them but I think they've been liquidated. Anyone know what became of their parts inventory?

Thanks in advance!

-Adrian

[Nick]

Pull the valve covers, right-side cam cover and spark plug and squirt oil on the guides, on the cam gears/bearings and down the plug hole. Have a plug hooked to the high tension lead and rest the plug on the head so it's grounded. Kick the engine over a few times to get things oiled up and while doing so, see if there's spark. If there is, you're good to go. Pull the float bowl off the carb, if everything inside is clean, it's probably okay. If there's gunk in there pull it to bits and clean it. No need to take off the left side cover. (You need to use a claw hammer, carefully, after removing the clutch inspection cover to do so.)

If no spark, run a points file or some wet/dry paper between the points to remove oxidization.

If it was running when parked it will run again.

[Bevel bob]

If you dip the oil its likely to look clean, however that may just mean all the sludge/gunk has settled out and is waiting to be drawn into the strainer thats right at the bottom!,I would drain it off and use an old toothbrush or boiler cleaning brush to loosen up whats in there, tipping the bike over and leaving it to drain, be VERY carefull that the strainer nose locates with its socket with hand tightening only to feel its way in.I would also use some Parafin/kerosene to clean out the sump repeating the process till happy and refill with some heated (carefull!) oil after doing what Nick says. If it runs you could check the oil flow with the top bevel cover off.I would also pump oil into the cam end to oil the rockers ,this will also pressure the system backwards to the big end.If the oil was dirty be prepared to change it again after the engine has run.Its possible that rust has formed in bearings and rings stuck so good luck!.

[narrow_monza]

Thanks for the tips guys.
I suspect that I have the 40W magneto which I'm told suffers from a weak spark.
Is it worth the trouble to upgrade to a higher output system?

[DewCatTea-Bob]

____ WELCOME as our newest registered-member !



[quote= narrow_monza ...
" Is there a way to determine what type of 250 narrow case engine I have
from the engine number? "

____ What's the motor-number ?
__ Does your Duke-model appear to have any use for a battery ?
How about posting a picture of it !?



" What is the easiest way to determine if I have a magneto or an alternator? "

____ How many wires (and what color are they) within the black/rubber-cable coming-out of the upper/rear motor-case (near to the kick-start foot-lever) ?



" What happened to Domiracer? "

____ Have you tried doing a 'search' here yet ? ...
As there's already been a thread started on that topic, back in May.
I've done the search myself now, and here's a link to it... viewtopic.php?f=3&t=1430&p=10038&hilit=Domiracer#p10038
If you wish to inquire any further about that topic, then you ought-to do-so from THAT thread.



" Is it worth the trouble to upgrade to a higher output system? "

____ That depends on exactly what you-yourself require of your load-system. _ Generally, if you don't demand a powerful headlight, then the stock-system ought-to suffice for you.


Duke-Cheers,
-Bob

[JimF]

I've never heard of the 40-watt system having a weak spark.

My 40-watt AAU-less (auto-advance unit) ignition system has given me no issues, while it has proven to be the easiest to start Ducati single of the three I have owned. One other one was a widecase desmo with a 12-volt system and RITA ignition and the other is a narrowcase Mach 1 with the battery system. The Mach 1 with the DC 60-watt system wins the prize for hardest to start, although that could have a lot to do with the kick-start lever design (another topic perhaps.)

As Bob said, if bright lighting is not required, the 40-watt system is fine. I don't like the way the brake lamp is lit by placing it in series with the ignition coil as it can disable your ignition system if and when the brake lamp fails, but I have come to understand why it was necessary to implement back in the 1960s.

The lighting can be improved but we'll save that for another topic after you get the bike operational.


Jim

[DewCatTea-Bob]

[quote= JimF ...
" I've never heard of the 40-watt system having a weak spark.

____ In original/stock condition, it never was weak ! _ But due-to various alterations, (such as flywheel-rotor timing), the ign.spark can possibly become rather sparse.



" the 40-watt system is fine. I don't like the way the brake lamp is lit by placing it in series with the ignition coil as it can disable your ignition system if and when the brake lamp fails, but I have come to understand why it was necessary to implement back in the 1960s. "

____ The original so-named "40 watt" system was originally devised for the 250Motocross-model, and as a strictly off-road model, it had NO brake-light !
And before any brake-light setup got concocted for that minimized electrical-system, it got copied-over onto the earliest Mark-III road-racer model, as well.
So when everyone wonders why THAT electrical-system's brake-light circuit-setup seems so very-strange & oddly-idiotic, it's because it was hastily CONCOCTED to work with the preexisting power-production parts so as to help easily make the established 40w.models soon-become street-legal with the most minimal expenditures, (by sometime in 1963).


Duke-Cheers,
-Bob

[narrow_monza]

____ WELCOME as our newest registered-member !

[b]--> Thanks for the prompt replies. Regarding Bob's questions, here's what I have gathered so far:
[/b]
[quote= narrow_monza ...
" Is there a way to determine what type of 250 narrow case engine I have
from the engine number? "

____ What's the motor-number ?

--> DM250.91966

__ Does your Duke-model appear to have any use for a battery ?

--> It was never wired for a battery, when it ran, the headlight gave a warm glow

How about posting a picture of it !?

--> I will have pictures soon.

" What is the easiest way to determine if I have a magneto or an alternator? "

____ How many wires (and what color are they) within the black/rubber-cable coming-out of the upper/rear motor-case (near to the kick-start foot-lever) ?

---> Inside the rubber cable sleeve, there seems to be 2 wires coming out. One Grey and one white.

" What happened to Domiracer? "

____ Have you tried doing a 'search' here yet ? ...
As there's already been a thread started on that topic, back in May.
I've done the search myself now, and here's a link to it... viewtopic.php?f=3&t=1430&p=10038&hilit=Domiracer#p10038
If you wish to inquire any further about that topic, then you ought-to do-so from THAT thread.

---> thanks for the link!

" Is it worth the trouble to upgrade to a higher output system? "

____ That depends on exactly what you-yourself require of your load-system. _ Generally, if you don't demand a powerful headlight, then the stock-system ought-to suffice for you.

--> I don't need a powerful light, I'm just concerned about the strength of the spark it can produce.

Duke-Cheers,
-Bob

[DewCatTea-Bob]

[quote= narrow_monza ...
" --> DM250.91966 "

____ It's a later 1965-model, probably a 'Scrambler'.



" --> It was never wired for a battery, when it ran, the headlight gave a warm glow "

____ Okay then, it seems that you were correct to suspect that your Duke-model has the "40 watt" electrical-system.
__ If the headlight doesn't well brighten-up as engine-revs climb past 3500-RPM, then I'm afraid to tell you that your ign.spark is possibly weak due-to weakened rotor-magnets.



" ---> Inside the rubber cable sleeve, there seems to be 2 wires coming out. One Grey and one white. "

____ Well that's VERY-odd ! _ As no Duke-model ever had a grey-colored alt.wire-lead, and also, all the battery-less models had THREE alt.wire-leads !
What does the white-wire connect to, the headlight or ign.coil ?
__ Can you post a picture that well-shows the tip-end of that alt.cable with it's two wire-lead's colors visibly-shown ?
If those wire-leads seem to be in fairly-good condition, then that would help confirm that the originals have been replaced (by someone not much caring to retain the stock-colors).



" --> I don't need a powerful light, I'm just concerned about the strength of the spark it can produce. "

____ Since it's seeming that someone/somebody has replaced the original alt.wire-leads, it's then fairly quite probable that they had failed to first mark the flywheel-rotor before removing it,, and-so in such case, it's then quite likely that they had lost-track of the original factory-setting and inadvertently reinstalled the rotor with it not properly 'timed' to the crankshaft (as the factory had originally done). _ And such possible rotor-MIStiming would most-likely leave the rotor producing a weaker section of a power-pulse at the very time when the ignition most needs the peak-section of the power-pulse.


Hopeful-Cheers,
-Bob

[narrow_monza]

[quote= narrow_monza ...
" --> DM250.91966 "

____ It's a later 1965-model, probably a 'Scrambler'.

Is there a way to find out from the engine (other than the number) whether it's a Scrambler/Monza/Diana?

" --> It was never wired for a battery, when it ran, the headlight gave a warm glow "

____ Okay then, it seems that you were correct to suspect that your Duke-model has the "40 watt" electrical-system.

" ---> Inside the rubber cable sleeve, there seems to be 2 wires coming out. One Grey and one white. "

____ Well that's VERY-odd ! _ As no Duke-model ever had a grey-colored alt.wire-lead, and also, all the battery-less models had THREE alt.wire-leads !
Can you post a picture that well-shows the end of that alt.cable with it's two wire-lead's colors visibly-shown ?

Perhaps that cable was replaced by the previous owner. I'm going to attempt to take a photo and check if there's a third wire cut and buried in the rubber sleeve.

New question: The last time I attempted to use the kick starter, it was failing to engage. I ended up removing the kick starter and bump-starting it.
Is it worth fixing the kick starter or should I just stick with bump-starting it.





--> I don't need a powerful light, I'm just concerned about the strength of the spark it can produce.