Piston parts

[single-junk]

____ Seems that you must've overlooked MY previous post (above) !?
__ I also have a selection of NOS.ASSO-pistons left as well.

Apologies, didn't realize you sold parts.. I'd definitely be interested in rings/clips for my good piston once I determine whether or not it belongs to my good engine,,

____ Chances are that your other piston is made by the Borgo-brand.
__ Are both your 250-engines Monza or Scrambler models ?

So far I can't find any numbers stamped on the other piston.. that's how badly some previous owner beat it with a hammer

One engine is Monza, the other Scrambler.. as far as I can tell at least. When I got these bikes, I basically got a crate of parts; as both bikes had been pretty much stripped down. So whether or not the engines are original to the bikes is beyond me, though I don't really believe it would be otherwise. I've looked at serial number pages online through links here, and they seem to be somewhat random as to which engine serial went to which model.

[DewCatTea-Bob]

[quote= single-junk ...
" So far I can't find any numbers stamped on the other piston.. "

____ If it's a Scrambler-piston, then if you hold it next-to a Monza-piston (with piston-pin holes aligned), you should then obviously see that the Scrambler-piston's crown-top is significantly taller ! _ As their comp.ratios are 8:1 -(250-Monza) and 9.2:1 -(250-Scr).



" that's how badly some previous owner beat it with a hammer "

____ Too-bad that he wasn't smart enough to use a piece of wood in-between ! ...
__ For knocking-loose a frozen-up piston, I always used a baseball-bat placed against the piston-crown to take the hammer-blows with. _ The piston was then always salvageable !



" One engine is Monza, the other Scrambler..
I basically got a crate of parts; as both bikes had been pretty much stripped down. So whether or not the engines are original to the bikes is beyond me, "

____ The Monza-motor should have a alt.cable with a pair of yellow wire-leads within, while the Scrambler-motor should have it's alt.cable filled with 1-yellow; 1-white; & 1-red wire-leads !
__ So does that help you confirm that you have one of each model of those motors ?


Hopeful-Cheers,
-Bob

[LaceyDucati]

[quote= Jordan ...
" Don't chuck 'em out. "

____ I-myself have never thrown-away a used-piston that wasn't obviously damaged too much to be possibly used again. _ Thus I've accumulated a couple of dozen 250/350 examples, (mostly Borgo).

My comments on ring grooves was intended for inspection and judgment of piston condition. I appreciate with the machinery and the necessary skill, it is sometimes possible to skim the grooves and fit "imperial" size rings from something else. I have in the past done so myself when the funds were tight and been surprised how many more miles you can squeeze from components. I also appreciate it can be very rewarding to keep these bikes going with ingenuity and very little money.

On the other hand, not everyone has the facilities or ability to do this and unless they know someone "who can" for a reasonable price, then it's a none starter. Repairing of parts is dependant on many criteria: how you are going to use the bike, your funds, your time , your ability, risk etc etc. In racing and on the road I have heard and seen many a tail of woe of broken up pistons and snapped rods etc, causing near terminal damage to engines. So you need to be sure judgement is good! I have also had many a long conversation about replacement rings with customers, ending up in being sent the piston and cylinder just to be sure . Parcel arrives and is unpacked "WTF" ! 10 thou bore clearance, distorted/worn piston...................

Whatever, do not fear I also do not throw components away unless they are really scrap! Any stuff that is beyond my use but still servicable either gets, given away, sold or stuck on Ebay with an honest description.

However, beware secret horders of "that may be useful one day"

A) You only live so long!
B) Best use it while you can still remember what it is, where it is and remember that you had it in the first place!
C) It will all probably be skipped when you depart!

I'm as bad as most and remembering the above helps me make better decisions

Best Regards Nigel

[Jordan]

I agree with Nigel that new parts are the best option, for most people in most cases.
It makes life easier for hardworking mechanics too, avoids risks for more customer satisfaction.
It's one sensible way to go about things.

[single-junk]

[quote= single-junk ...
" So far I can't find any numbers stamped on the other piston.. "

____ If it's a Scrambler-piston, then if you hold it next-to a Monza-piston (with piston-pin holes aligned), you should then obviously see that the Scrambler-piston's crown-top is significantly taller ! _ As their comp.ratios are 8:1 -(250-Monza) and 9.2:1 -(250-Scr).

Set both pistons on a flat surface beside each other, both seem to be level, only difference seems to be slightly larger cut-outs on the top of the asso piston (those half-moon shapes.. no idea what they're called..)

" One engine is Monza, the other Scrambler..
I basically got a crate of parts; as both bikes had been pretty much stripped down. So whether or not the engines are original to the bikes is beyond me, "

____ The Monza-motor should have a alt.cable with a pair of yellow wire-leads within, while the Scrambler-motor should have it's alt.cable filled with 1-yellow; 1-white; & 1-red wire-leads !
__ So does that help you confirm that you have one of each model of those motors ?

Hopeful-Cheers,
-Bob

Well, looks like both engines only have 2 wires coming from their alternators.. I guess they must both have started life as Monza engines, and someone swapped one onto the SCR at some point. Either that, or I'm totally off about the one bike being a scambler.. pretty easy for someone to swap parts onto a frame to make it look like one maybe..?

[DewCatTea-Bob]

[quote= single-junk ...
" only difference seems to be slightly larger cut-outs on the top of the asso piston "

____ Those relief-pockets for the valve-heads are larger on the Asso-pistons so that THEIR pistons can thus-then be fitted within either small OR large valve engine-models.
__ I had meat to mention before that ASSO made two types of piston-lines for 250-Ducati engines... Their-own line-up with the oversize-increments stepping every .25mm (with a 5th-oversize of 75.25mm), as well as an identical copy of (at-least) the Borgo-line for the 250, (with oversize-increments of +.4; +.6; +.8 & +1mm).



" I guess they must both have started life as Monza engines, and someone swapped one onto the SCR at some point. Either that, or I'm totally off about the one bike being a scambler.. "

____ A n-c.type Scr.motor also has a 6mm bolt-hole (for an internal chain-guard), through the chain-inlet cowling (above/behind the drive-sprocket).
While a n-c.Scrambler-frame's most obvious difference is an extra piece of frame-tubing bridging over the rear-fender near the shock-mounts, for supporting the rear-side of a Scr.type seat.
__ So do you now still think both of your 250s are Monza-models ?


Duke-Cheers,
-Bob

[Rocla]

Hello,

You can find all dimensions of pistons from "Amicci dello Scrambler" in Italy, that not only got the genuine parts stock from Ducati, but generally displays the lower prices.

I've compared many suppliers in France, UK, Italy, Spain, Netherland (Back to Classics) and USA, and "Amicci dello Scrambler" is very often the cheaper, especially for engine parts (but except for body parts like cloks or front light, I don't know why)...

[LaceyDucati]

Rocla

For your information the parts from "Amicci dello Scrambler" are mostly if not all, NOT genuine parts stock from Ducati. Ducati has not made parts for singles since the early 80's, some 30 plus years ago.

As a specialist in engine parts, there is a good reason why we have most of our parts manufactured in the UK by manufactures we have good comunication and relationships with. We do source some parts from Italy, mostly direct from the manufactures we know and trust. Cheapest is not always best and I have real suspicions and evidence that a lot of parts sold "cheap" in Italy are manufactured in Asia and the far east with little control over specification and tracability. Don't get me wrong this is not a knock at the origin, but if the driving force is "cheap" with no quality control then you will get what you pay for.

Many of the parts "Back to Classics" have are Genuine NOS original parts and are therefore priced accordingly as rare components.

We have bought some cheap parts from Italy to check them out as sometimes we can't even get the parts made for those sort of prices. I'm more than willing to give the benifit of the doubt, but in my personal experience the parts I bought and inspected were of very poor qaulity and quite often worse than most "worn out parts"! Many engine components need to be very tightly toleranced for correct fitment, life and performance. This is not a plug for my business, but more a warning to others when making choices with certain components.

Regards Nigel

[Rocla]

Hello Lacey,

You're probably right, and I've already ordered parts to UK suppliers (front light), maybe it was to Lacey if I remember well, and it was a very high quality product.

But I've ordered lot of parts (you can see here below the result on my Scrambler) to Amicci dello Scrambler, body and engine parts, and I've never had problems. Moreover, the piston we sent to me was absolutely gorgeous, as refined and sophisticated as a competition piston, with 2 different colors parts and impressive finishing.

I saw the piston 1300 kilometers after, when I put the engine a part for renewing the distribution (you can see the related topic), and it was perfectly OK.

http://strv.pagesperso-orange.fr/motode ... Ducati.htm

[single-junk]

So I went ahead and pulled the head and the jug off of the good engine I plan to use (looks in nice shape anyhow..) and found 2 things that concern me.

I'm no expert, but it looks like the jug has (maybe?) been somewhat freshly sleeved.. as in, never yet been run. (could have been years ago, it irritates me how little I know of the history of these bikes I've gotten) And the good Asso piston I have seems pretty sloppy in it. Of course, it has no rings on it yet, so I'm wondering how much play it's supposed to have?

Same kind of story on the connecting rod from the crank.. has a fair amount of side to side play. Is that normal? or do I have a completely kifed engine on my hands?