# 4-5500528
The 528th 400 made.
Have'nt inspected behind LH side case yet but...
Cylinder bore and piston look very good
on 71.25mm
spins free, no rust on crank halves, mains feel notchy.
Cylinder fins good, no cracks or big scratches on side cases.
Head has dual sparkplugs (trick), one nicked fin and one slightly bent fin.
Splines on kick start good
Splines on shift shaft goofed up a little but not gone.
There are some numbers etched by hand in the back of the LH center case, like the works factory mechanics do for I.D.
With correct Bing carb, intake and exhaust manifold.
$280.00
Thanks
Bob
Hi Bob,
It sounds interesting. That should fit in a MC5 frame, shouldn't it? What about that twin sparkplug, couldn't you run one and plug the other?
Thom Green,I own and ride a 76 250 MC5 MX which I bought new.
I would be very interested in your engine. You can e-mail me at
[email protected].
Just a sidenote. If the bore is printed correctly and is 71.25 that is a 250 and not a 400. Perhaps it was mistyped and was meant to be written 81.25. That would be a half over early 400.
You're right Larry, thanks for noticing, it is 81.25 mm.
I use to have a bultaco that came with 2 sparkplugs and 2 sparkplug wires. I never thought that it made much of a difference. If there was ever any problem with timing between the two sparkplugs, I could imagine that causeing a problem.
Thom Green,I own and ride a 76 250 MC5 MX which I bought new.
The second plug hole was often used for a compression release which was a fairly efficient braking tool more often used by flattrackers than MX'ers and enduro riders.The intent of the second plug was one heat range for starting and another for after warmed up as well as a spare plug in case of fouling.If they are not firing they don't foul in the insulator area as readily as when the are running.The Bultaco system was Femstronic of which I have several.You actually run a hotter plug in the rear.Bultaco felt because of the trough type design of the combustion chamber that a centered plug would not give uniform fire.It actually works pretty well.Unfortunately most Bul heads you find have been drilled and tapped for a third hole for the aforementioned compression release and they crack between the three holes.
I would like to buy your engine. I have two frames needing a prime mover.
I have a ten dollar reward for anyone who can trick rob w into responding to one of my many attempts to purchase his motor. Is there a secret POG handshake they forgot to tell me about when I joined...or maybe they didn't forget hmmm....