Will a 250 picton and cylinder for on a 200?

[datsunscott]

I have a 200 Elite I am collecting parts for.
the pistin/cyl is siezed and I don't know if i can save it.

So I am going to need to figure out how to get it apart and am wondering if the 250 pistob/cyl setup will work.

It has been sitting along time-
Is the crank rebuildable?
Can the rod be rebuilt?

[DewCatTea-Bob]

" So I am going to need to figure out how to get it apart and am wondering if the 250 pistob/cyl setup will work. "

____ No, a 250's cyl.bolt pattern is wider ! _ Plus the 250-piston is too large to fit a 200 cyl.jug, (due to the 74 vs. 67mm bore-size difference).
__ With the piston/cyl.jug-sleeve soaked with penetrating-oil while those stuck parts go through a few heat-up & cool-down periods, the two parts should then be able to be pounded apart.
__ Are they still on the motor?


" Is the crank rebuildable?
Can the rod be rebuilt? "

____ Yes.


Hopeful-Cheers,
-Bob

[Jon Pegler]

The largest oversize bore that you could easily achieve with the motor you have is 222cc.\
There are standard 69mm or 1mm oversize Spanish 250 Horas pistons available for purchase from Itelket, which could be used in the 200 cylinder,
although the 70mm size would leave the cylinder sleeve somewhat thin.

[datsunscott]

Thanks- the motor is sti;ll together-
and i paln to work on this slow and with patience so as to not damage anything.

Will the Horas piston have the right compression ratio and valve clearance?
i think the 200 elite had a very high top piston.

[Jon Pegler]

My last post seems to have been slightly edited, so I will explain .
Pistons for 200 Elites are available in 67.5mm and 68mm. Both Nigel Lacey and Barry Jones at Classic Ducati have them.
24 Horas pistons are produced by italkit competicion in 69.5 and 70mm sizes (Not italjet as my previous post was edited to )
I know that Jesus Llorente in Spain has them in stock.
All these pistons are cast rather than forged.
The Horas piston was originally 10 : 1 compression ratio, so a bit more than the Elites 8.5 : 1.
What the compression ratio and valve to piston clearance is would have to checked on assembly.
It may involve a bit of machining of the piston to get the required clearance, but I doubt it.
The Mototrans Elite head is almost identical to the 24 Horas head, and the cylinder barrel/sleeve is the same, just overbored.

Jon

[DewCatTea-Bob]

" My last post seems to have been slightly edited,"

____ Jon, I'm so very sorry! ... I had unintentionally lost your original exact wording (when I had attempted to add my own comment-response concerning your post).
Right after I realized my oversight-blunder which I had mistakenly done, I then sent you a PM, with sincere apology for my accident and asking if you'd please 'Edit' your perfectly useful post so as to once again state your very-own wording (to say exactly what you meant to).
I also included (in the PM) that if you did not get back to completing the requested edit/repair before very long, that I would then/soon-later try my best to replace your missing wording which I had (read and) lost,, with continued hopes that you would eventually still fix-edit anything that I had gotten wrong (with my attempt to replace your original-wording which you had posted).
__ I now gather that either you did not get & read my PM, or you were okay with me being stung* for my foolish error/mistake, (*as I now really feel the stress/heat for that regretful screw-up!), which I certainly do not feel I don't deserve !
Once again Jon, I'm quite very-sorry for messing-up your posting, and really hope that you can forgive me for my quite unintentional editing-error !!


Hopeful-Cheers,
-Bob

[DewCatTea-Bob]

" the pistin/cyl is siezed and I don't know if i can save it.
So I am going to need to figure out how to get it apart
the motor is sti;ll together- "

____ After you've removed the cyl.head, pull the cyl.jug up off from the motor-case (as high as the stuck piston will let it go), and then place a couple of (equal sized) wood*blocks in-between -(into the created space under the finned-cyl.jug's base and above the motor-casing's cyl.platform), so as to evenly hold the cyl.jug up-&-off away from the case.
(* The thickness of your wood-blocks ought-to be between 40 ~ 90% of the maximum-height of the space-gap raised between the cyl.jug-base & motor-case.)
Then while the motor is already as cold as you can get it, poor a few ounces of boiling oil -(like a thin penetrating-oil) into the cyl.jug, and then right-away (using a lead-hammer), pound the upper tip-end of a wooden baseball-bat (or the like), that's been laid on & pressed against the crown-top of the (stuck) piston,, so as to knock the piston loose from the cyl.sleeve.
If your first attempt does not budge-loose the piston before the oil cools-off completely, then let the thin oil sit over-night, and try the same process again another day (after the oil has had more time to penetrate between the stuck/frozen-parts).
If you do budge them loose during your first-try, then add more wood-shim spacing and continue-forth, pounding more & more lightly as you get closer & closer to separation of the frozen-parts.


" The Horas piston was originally 10 : 1 compression ratio, so a bit more than the Elites 8.5 : 1. "

____ Quite true, cuz if the std.Horas comp.ratio was 10:1, then it's piston installed within a 200 should provide a comp.ratio of 8.75:1 (calculated, [due to the stroke difference being over 8mm] ).
__ Also, the long-stroke 250's std.69mm-piston would only add 12.4cc to the 200's original -(203.6cc) displacement. _ So might as well just stick with a std.200-piston (if they're the same or less in price), and save on any expensive bore-job work.


Dukaddy-DUKEs,
-Bob

[datsunscott]

Thanks for all the infprmation.
I really appreciate it.

[DewCatTea-Bob]

____ Anyone who's interested in the topic of the title of this thread, ought to look-up & read-through the thread titled: "MAKING CHANGES in a 250 HORAS" *... As that tells of a fellow-Duker who has claimed to have actually completed the work-mods which would be needed done to fit the (short-stroke)- 250's cyl.jug & 74mm-piston onto a 200-motor. - (A mod.job which I myself had never considered doing.)
(*Currently found near the midsection of page-5 [of these topic-listings].)

Fun-Cheers,
-Bob