On Mon, 5 Jan 2009 18:57:28 -0600, "Terry Coombs"
wrote:

Gunner Asch wrote:
On Mon, 5 Jan 2009 05:33:22 -0600, "Terry Coombs"
wrote:

Gunner Asch wrote:
Ive been trying to get that '74 Honda XL 350 to run properly...with
no luck.

Pulled the carby tonight checked everything, Replaced idle jet
seals, made sure float was at proper height.

Timed it, adjusted valves, point gap..the whole encilada.

Will idle just fine Coughs and runs ragged and will stall if adding
throtle. The idle screw seems to do very lttle if anything. Bike
seems to not care if choke is on or off.

All passages were cleaned, all seals replaced...still doesnt run
right.

I also found while settiig the points, that the camshaft where it
comes out the side of the engine, with the points cam on it, has
about .05-.08 of wobble in it. That explains some of the popping
and inconsistant idle..the damned thing is wobbling around, the
point gap can be .015 one moment, the next .125

Ive not gotten the manuals that I purchased on Ebay, so done know if
there is a bearing, a bushing or what not in there. Ill have to
pull the head and check...sigh..I hope the camshaft is not blown
out.

Anyone know what is used to keep the camshaft lined up? Bearings on
both ends or ???

Sigh...

Gunner


If it's like the CB750's , that cam runs in bare aluminum in the
head . Not sure how they recondition them .


Plain aluminum bearings...with that much slop....Crom sob....

I guess Im going to have to pull the valve cover tommorow and see what
kind of damage is in there. Ive been searching the net for any
info..and not turning up much other than hip slick and cool new
racing camshafts with needle bearings, which apparently need a $150
line boring job to install The bike isnt worth putting $300 in
camshaft stuff....****.

That much play means the journal is likely to be egg shaped. I just
found a picture of the exposed guts of a head on Ebay...and yup..no
bearings in there.

Now the big question is how to repair the existing head, reweld the
egg shape and clamp the head an angle plate and rebore it on the
mill? Mill the hole round and make up a steel split bearing to go in
the larger hole and hone it to size? Pin the split bearing in place
in the cover and head? With the appropriate oiler hole? ****..this
is getting more complicated as time goes on.

Maybe Ill try to find a used head..though its gonna be tough unless
the '74-75 heads were used on later bikes

Still dont know if thats connected to the running problem. Maybe try
to find a 38mm Mikuni carb like the racers use, or a used carby

Labor (mine) I can afford...buying stuff...thats not in the budget.

Maybe its time to change over to the BMW and get her on the road....

Sigh

Gunner

Split aluminum bronze bushings (I like ampco18 , got a set of swingarm
bushings in my '90 FLHTCU made from it ...) . Cut the OD a thou or two tight
in the reamed-round cam bearing so they won't spin - or tab 'em like conrod
big end bearings . Might have to bolt the caps up with split shells in place
and do a light line-ream , just to make sure they're round and reasonably
lined up . Your off-idle miss/breaking up may be due to the cam bushings -
when it spools up , the loading on the lobes changes , maybe holding an
intake valve open ? For that matter ,the change in loading might throw
timing and dwell off enough to do that too .
Have fun ! I'm still not finished with the taper attachment , which I need
so I can make the mandrel and the laps , so that I can recondition the
roller bearing races on the crankshaft and the tranny main shaft . So much
fun to have , so little time to have it in !


Looking at the photos of the head, I think I can simply make a round
bearing to fit a fresh line bore, with a pin to keep them from spinning
and oil galleys drilled in the right place. Slip the round bearing over
the camshaft, line the bearings up with the pins, and clamp everything
down I dont think I need to split them at all.

I didnt pull the head yet, still doing honey do's. Thought Id get called
to work today, but the phone still hasnt rung yet. Maybe tommorow

There is indeed enough play to keep valves from opening, particularly
with .003 tapet clearences


Gunner

"Upon Roosevelt's death in 1945, H. L. Mencken predicted in his diary
that Roosevelt would be remembered as a great president, "maybe even
alongside Washington and Lincoln," opining that Roosevelt "had every
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