Topic: tune-up order

[brad]

so i've changed the oil and the plugs.  what next?
i planned on doing these in this order.  is this wrong? does it matter?
1) carb sync
2) valve adjustment
3) timing

[techy5025]

...do the carb sync last.

Jim

[scunny]

I'm with Techy; valves, timing then carbs

[techy5025]

With the valves...unless you are way off...you won't see much difference in
the bikes running, and unlike the carb tuning, you won't see an immediate
difference.  You will see a difference on adjusting the timing if you do it with
a timing light rather than statically. But all these adjustments...and the point
gap...will affect the carb balance, which is why you want to do it last...or do
it several times. 

Should clarify....by see a difference...I mean an immediate difference as the bike
will be running.

Jim

[TwoTired]

Carb sync makes the engine hot.  Valve clearances are adjusted cold.

Tuneup process - cold engine:
Pull spark plugs.
Set valve tappets
Adjust cam chain tension.
Compression check (cold)  Compare with previous numbers, (I know, best numbers are when engine hot)
Dress points - Set point gap, and static time.
Replace or clean/gap plugs; install with anti-sieze
Replace or clean air filter.
Clean oil breather element foam.
Start/ warm engine with fan blowing on it.
Stop engine install vacuum gauges.
restart check/adjust vacuum sync.
Tweak Idle screws as necessary.
Change oil/filter.
Grease swing arm fittings.
Check tire pressures.
Check/adjust drive chain tension.
Check for loose spokes.
Check battery fluid levels.

Test ride
TEST ride
test RIDE
TEST RIDE
When done for the day, lube drive chain

[puppytrax]

Clean oil breather element foam.

......Is that CB750-specific??? I don't recall an oil breather element on my CB500/550...   

[byidesign]

Always carbs last after all else is perfect,
    Then Enjoy
            Bruce

[jph550]

Clean oil breather element foam.

......Is that CB750-specific??? I don't recall an oil breather element on my CB500/550...   

depending which 550 you have (I don't think there's one on a 500), there is a tube running from the valve cover which circulates unburnt gasoline back through your air filter and into the carbs. It has to pass through a foam filter element at the bottom of your stock air breather box.  at least that's all I could imagine it being.  cleans with sudsy water and ATF fluid. see manual

[SteveD CB500F]

We (UK) had it from the 550K3 on. Never appeared on the 500.

[puppytrax]

depending which 550 you have (I don't think there's one on a 500), there is a tube running from the valve cover which circulates unburnt gasoline back through your air filter and into the carbs. It has to pass through a foam filter element at the bottom of your stock air breather box.  at least that's all I could imagine it being.  cleans with sudsy water and ATF fluid. see manual

...Unburnt gasoline in my valve cover??...   

OK, all kidding aside...     (I'm guessing it's a rudimentary PCV vent)...

I know what you're referring to now...my 500 hose just exits to atmosphere near the swingarm pivot; but the two 550's had AC boxes with an extra chamber on the bottom, with a spigot for the hose...there were no elements, but I know what they look like, from old Chevy air cleaners of the 60's and 70's...   

Might be something to change over to in the future, as I have the AC boxes...seems to me I  recall someone saying the 550 AC element itself was different, too...

[SteveD CB500F]

The 550 air cleaner element is different - because the box is a different shape to accommodate all the environmental gubbins.

I say ditch it all and go back to the way it was when these bikes were first designed!

[puppytrax]

The 550 air cleaner element is different - because the box is a different shape to accommodate all the environmental gubbins.

I say ditch it all and go back to the way it was when these bikes were first designed!

I would tend to agree...but...when removing one of my 550 motors from the frame, I noticed there seemed to be a sand plug in the valve cover breather spigot [no hose on it]...turned out to be a larvae for a sand wasp...   

It's bad enough that I seem to have an inexhaustible supply of field mice in my storage shed; I don't need sand wasps plugging up all my open holes...on the bikes, I mean...   

[TwoTired]

Chapter eight of the cb500 550 shop manual lists the recirculating breather as a new feature of the Cb550 models.
I believe all the Cb400s have a similar arrangement.

I'm not sure when the Cb750's got the recirculating breather, certainly by 77.

I say ditch it all and go back to the way it was when these bikes were first designed!

I hope you are joking.  The crankcase vents oil vapors and blowby gasses (Carcinogens) past the piston rings into the atmosphere and lungs of nearby mammals.  You'd really prefer to breathe these fumes rather than simply having the engine incinerate them?
The recirculating breather costs no horse power and simply adds one extra hose and a foam element water separator.  It's very hard to believe this is too complex a system to deal with.