The Engine

I had 2 engines to work with, a 1966 250 SCR and a 1966 250 GT and I had no idea as to who was going to do my engine.  I was out doing errands when I saw a beautifully restored 250 SCR in the window of the local Ducati dealer.  I went in and discovered that the owner, Paul Germain,  had restored the SCR and that he races a 250 and a 350 Ducati in the AHRMA.  After much discussion over a period of months, he agreed to build my engine.  I was extremely fortunate as he was very busy with his own racing bikes.  In fact in 2004 he won the championship in the 250 Grand Prix class!  In 2005, 2nd in 350GP and 3rd in 250GP.

Tearing down the scrambler motor showed why the piston had seized.  The oil finger screen wasn't screwed in properly so it never connected to the other side of the crank case, there was a bunch of gravel (!) in the sump and a small round stone had lodged itself into the intake of the oil pump.

I am using the GT engine as it is in much better shape than the SCR engine. It also has the stronger kickstarter mechanism and the stronger alternator, the scrambler is 40 watts and the GT is 60 watts.  When the output is so small to begin with, every watt counts!  At Phil's recommendation I am also replacing the Ducati regulator/rectifier with a new one from a Honda CT110.  This cost more than a little but the CT110 reg/rect is about the size of a wooden match box and weighs nothing and is easy to hide.   Nobody builds electricals like the Japanese so I will have a reliable charging system that works and as Phil says will light up the road rather than your fender! 

The GT and SCR engines were split and everything was labeled and bagged.  The GT cases were sandblasted and cleaned and new bearings, new kickstarter bushing and that sneaky o ring was installed.  The clutch pushrod seal was also replaced.  The crank ended up being half SCR and half GT.  The GT flywheel had spun on the crank wrecking the taper.  The rod and the crank bearings from the GT and the rest from the SCR.  I had read a lot about the mystical "crank sludge trap" and seeing it get cleaned out and finding all kinds of shiny stuff in there was sobering.  Change your oil, now !  I also saw how to rebuild and straighten a n/c crank.  The crank and rod was polished to a mirror finish before assembly.

The crank and gear clusters were installed and shimmed and a new flywheel was installed as the original was damaged from spinning on the crank.  The clutch was bead blasted, new bearings and the spring supports in the clutch hub were welded.  Heavy duty clutch plates and new springs from Phil and the clutch side was buttoned up.  The oil pump was overhauled and new gears were installed, line up all the dots and that side of the engine was buttoned up.  The advance and points plate were overhauled and installed.

All the engine screws were replaced with Syd's super handy stainless allen screw set.

The cylinder was cleaned and sandblasted, the liner cleaned up at 74.4.  Henry Hogben supplied a new 74.4 mm, 3 ring forged piston.  The GT head is being used as it is in excellent shape.  The head was cut for the new unleaded valve seats and for the new 40 mm intake and 36 mm exhaust valves.  The valve guides measured new and looked great so they were left alone.  The head was ported and a new manifold was made up for the carb.  New valve seals and new cam bearings were installed.  I was convinced to dump the hair springs and convert to RD springs.  I was also convinced to get rid of the shim type rocker arms and went with the screw type valve adjusters.  The rocker arms were resurfaced at Megacycle and Phil's hot street cam was installed.  The exhaust threads were perfect and I have a new exhaust pipe retainer from DomiRacer.  The exhaust pipe is stainless and the muffler is a race megaphone with Conti core from Road and Race.  I found a real Mach 1 megaphone that I am going to refinish and try out.

I restored a Dellorto SS1 29D and was contemplating using it but was again convinced that if I want power and reliability, I should go with a Mikuni.  The SS1 helped pay for the restoration.

I have the good tach drive, the one that doesn't leak and I got a Veglia (see Dellorto SS1)

The engine cases were polished by Jose at Paramount polishing.  This guy is a master.  If I had known I would have taken my hubs there as well as they are much cheaper and do a better job.  The cases are magnificent!!

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