Ninja 250 engine rebuild: how do I rotate crankshaft?

I've been tasked with the project of rebuilding the top end on my daughter's
'91 EL250, which I understand uses the same engine as the Ninja 250. In
order to get the cams out I need to rotate the crankshaft so the valves are
closed, but it's not obvious how to go about rotating the crank. Is anyone
familiar with this engine?

I assume I'm going to put a wrench on either the left or right end of the
crankshaft, but I'd like to know what I'm aiming for before I start tearing
open side cases unnecessarily. It's been 25 yrs since I've rebuilt a
motorcycle engine, and these engines today have so much junk that has to be
removed just to get at anything.

Yes, I did buy the factory service manuals (set of two required)--no Clymers
or Haynes for this bike, so I had to spend the $75 for the factory manuals.
Sadly, they're nowhere near the quality of manuals of old. It just says
stuff like, "turn the crankshaft counterclockwise until the valves...", and
"turn the crankshaft clockwise 90 degrees...", but no clue as to HOW one
would turn the crankshaft. It doesn't even give me a clue which side of the
bike I'm supposed to be on, so who knows which direction "clockwise" and
"counterclockwise" is!

 

If you really can't find the nut to turn the engine over, and are
stumped by such a simple task, then I'd suggest that rebuilding the top
end is way beyond you.

However, you could always stick the bike in gear and turn the rear
wheel.

 

Not sure about your bike, but most 4-strokes have a plug in the
ignition cover that will let you access the end of the crank, where
you can put a wrench on the flywheel nut to rotate the crank with a
standard 1/2 drive ratchet handle and socket.

Jim Cook

 

Same procedure for the EX250, Jim described it accurately above...

In the Service Manual (99924-1066-01), look at photo (right-middle)
showing the alternator cover on page 8-16 and the photo (right-lower) on
page 3-7. The plug is in the center of that cover, with the slotted groove.

The photo (right-top) on page 4-9 shows the timing marks to look for as
you turn the crankshaft. That inspection 'window' is located between
the 10 and 11 o'clock position on the alternator cover shown on page
3-7. It's under a smaller plug with a slotted groove too.

 

AM EDT:

[...snipped...]

The manual specifically states 'counterclockwise' under the Valve
Clearance Inspection procedure on page 4-15 of the Service Manual. Like
Mark said earlier, one does need to read through the manual
cover-to-cover to fully understand the procedures...

 

if i recall, the left side has a removable cover.

timing is not particularly tricky.

make note of bolt lengths on the cam bearing bolts.
some jerk mixed up these and stripped out a couple of threads
on the one i fixed up.

as to when the valves are closed, just look at the cams when you turn
the crank and observe the cam lobes.
good luck, sam

 

Yeah, well my x-ray vision isn't working as well as it used to. You
conveniently snipped the part of my post where I said, "I assume I'm going
to put a wrench on either the left or right end of the crankshaft, but I'd
like to know what I'm aiming for before I start tearing open side cases
unnecessarily."

 

Thanks, NA, Wudsracer, and SAMMM.

I do see the plug, but didn't see a description of what it was for. None of
the old CB750, CL360, KZ400, KZ900, GS750, or GS1000 engines I've rebuild in
the past had a plug like that.

 

The task I was working on was camshaft removal. On page 4-8, under
"Camshaft, Rocker Arm Removal", the manual specifically states, "Turn the
crankshaft clockwise about 90 degrees."

 

I rest my case.

 

Then it's a good thing you didn't become an attorney!

 

What did you do after the Comedy Store fired you for being unfunny?