Postby DewCatTea-Bob » Mon Nov 02, 2009 4:36 am
"Is the cam difficult to change? Can I do it with the engine still in the frame? Do I have to reshim the bevel gears?"
____ IT'S EASIER TO DO THAN ON MOST ANY OTHER CYCLE-MOTOR! ...
WHILE IT'S EASIER TO DO THE JOB WITH THE HEAD REMOVED, IT CAN STILL BE DONE WITH THE BIKE LEFT IN RUNNING-CONDITION... IN THAT CASE,
YA FIRST REMOVE THE TACH-DRIVE COVER, AND THE 4 SCREWS IN THE LEFT-SIDE ('350') CAM-BEARING SUPPORT/COVER.
SEE TO IT THAT THE TIMING-MARKS ON THE TWO BEVEL-GEARS ARE MATCHED-UP, (by slowly turning-over the engine), BEFORE PROCEEDING.
_ THEN LOOSEN & UNSCREW THE CAM-NUT OUTWARD UNTIL FLUSH WITH THE END OF THE CAMSHAFT, (NOTE: that nut is Left-Hand threaded!!).
_ THEN TAP/KNOCK ON THE END OF THE SHAFT, (the nut is protecting the shaft-threads), UNTIL THE NUT HAS MOVED BACK AGAINST THE CAM-GEAR (again as it was).
YOU SHOULD THEN SEE THAT THE LEFT-END CAMSHAFT ('350') BEARING-SUPPORT/COVER HAS BEEN PUSHED FROM IT'S PLACE ON/IN THE HEAD.
AT THIS POINT, YOU MAY NOW TWIST & PULL IT OUT & OFF.
THEN AFTER YA COMPLETELY REMOVE THE CAM-NUT, YOU SHOULD EASILY SEE HOW YA CAN PULL-OUT THE CAMSHAFT, AND PUT ANOTHER IN PLACE.
__ BUT BEFORE YA PUT ANOTHER CAMSHAFT IN, YOU SHOULD REMOVE THE INTAKE & EXHAUST VALVE-COVERS AND REMOVE THE VALVE-SHIMS OFF THE VALVE-STEM HEADS.
_ THEN AFTER YOU PUT YOUR REPLACEMENT CAM IN THE HEAD AND PUT THE ('350') CAM-BEARING SUPPORT BACK IN PLACE (all the way back in!), YOU CAN THEN RESET THE VALVE-CLEARANCES, (likely with different shims).
__ THEN PUT EVERYTHING BACK TOGETHER AS IT WAS, BEING SURE TO PLACE ANY SHIMS THAT WERE BETWEEN THE CAM-GEAR & THE RIGHT-END CAMSHAFT-BEARING, BACK AS THEY WERE.
NOTE THAT THERE'S NO RE-SHIMMING (of the bevel-gearing) NEEDED! _ (UNLESS PERHAPS YOU'VE CHANGED THE RIGHT-END CAMSHAFT-BEARING (to one that's not exactly the same width).
____ IF RUNNING WITH MOST ANY MUFFLER,, NO MATTER WHICH DUKE-CAM YOU REPLACE THE STOCK (350-widecase) CAM WITH, YOU WILL GET AN OVERALL-PERFORMANCE GAIN!
__ IF YOU RUN INTO SOME DUKE-NUT WHO TELLS YOU THAT THE STOCK Green&White-CAM, (otherwise known as the 250F1-cam), HAS GOT TO BE YOUR BEST CHOICE FOR BEST PERFORMANCE... THEN THAT PERSON REALLY DOESN'T HAVE MY VERY EXTENSIVE KNOWLEDGE & EXPERIENCE WITH INSTALLING & RACING MOST EVERY STD.PRODUCTION DUKE-CAM THAT DUCATI HAD MADE, WITHIN EVERY 250, 350, & 450 DUKE-MOTOR!
(I HAVE A COLLECTION OF ALL STD.PRODUCTION DUKE-CAMS, EXCEPT THE EARLY 250GT-CAM !)
__ IF YOU INSTALL A STOCK-CAM FROM ANY OF THE THREE DIFFERENT 250Mk3 MODELS, YOU WILL THEN GET BETTER PERFORMANCE THROUGHOUT THE ENTIRE RPM-RANGE! - (NOT JUST BETTER 'OVERALL-PERFORMANCE'.)
BUT EVEN IF YOU INSTALL THE MILDEST DUKE-CAM (the 'Violet' cam, which is not really 'mild' by non-Ducati standards), FROM A 250-Monza OR A 350-Sebring,, YOUR OTHERWISE STOCK 350-Road MODEL WILL STILL OUT-ACCELERATE (from low rpm), ANY OTHER STOCK WIDE-CASE 350 DUKE! - (BUT NOT A N-C Sebring.)
AND TOP-SPEED SHOULD STILL BE WITHIN ABOUT 5MPH (against the fastest stock std.production 350 MODEL).
____ JUST AS Ducati MADE A FAIRLY BAD CHOICE WITH THEIR PICK OF CAMS FOR ALL THEIR STD.PRODUCTION 350 MODELS, THEY ALSO SCREWED-UP JUST ABOUT AS BADLY WITH THEIR 450-Scrambler/Jupiter ('Springer') MODELS!!
THAT PARTICULAR 'Springer' 450 MOTOR REALLY COMES TO LIFE WITH THE WIDECASE-350 G&W-CAM!
SO IF YOU CAN FIND A FELLOW Duker WITH A 450 (non-DESMO), TRY TO SWAP CAMS WITH HIM! , AND THEN BOTH OF YOUR DUKEs WILL MUCH BENEFIT (overall-performance wise)!!
__ IT WOULD'VE BEEN BETTER (although not the best), FOR Ducati TO HAVE MADE THAT CHOICE OF CAMS FOR THOSE TWO MODELS TO BEGIN WITH! ...
THE CAM IN THE MUCH LARGER CAPACITY (435cc), 450-Jupiter/SCR. MODELS IS ACTUALLY THE VERY SAME CAM WHICH WAS MADE FOR THE 1968 WIDE-CASE 250-Scrambler!
(Ducati DID DESIGN & PRODUCE A CAM ESPECIALLY FOR THE SPRINGER 450-Mark3 (non-'D') BUT, IT SEEMS THAT THEY NEVER INSTALLED IT INTO THEIR STD.PRODUCTION SPRINGER-450s.)
__ I'D REALLY LIKE TO KNOW THE ACTUAL STORY OF WHY Ducati DID WHAT THEY DID CONCERNING THOSE ISSUES... IT'S BEEN FIGURED THAT THE Italian-GOV. (who didn't really give a $#!+), WAS IN SOME WAY INVOLVED WITH THE POOR CHOICE OF CAMS IN THESE CASES.
CUZ BEFORE 1967, Ducati WAS REALLY QUITE GOOD AT MATCHING CAM DESIGNS TO EVERY ONE OF THEIR MANY VARIOUS MODELS!!
DUCATIly,
-Bob
PLEASE NOTE... If this-post is not-yet signed-off with '-Bob', then I'm still in the process of completing it,, and if not also included with 'DCT' near bottom as well, then I may edit this post's wording at a later time. - Dct.Bob