Topic: How often do you adjust your valves ?

[smpls70]

Danno , I was trying to find some info on " shaft drifting" couldnt find anything. Talk to me, tell me about it.

[754]

 In the 500s and 550s the rocker shaft holes in the head or housing sometimes wear and elongate. once there is play in a hole it generally wears at an accellerated rate as it gets bigger.. ie gets worse real fast..

 Have not seen it on 750s though..

[MCRider]

Hah, I had a BAD adjuster bolt, it was pitting on the end... valve stem had a small crater, not as bad as the adjuster..

 I should check a few others..

I've been mentioning this in many threads, including #8 of this thread. Haven't heard back if this was done. I once bought a handful of adjusters from a salvage yard. Fully 1/4 of them were beyond using, and assumable these all came out of running bikes. Here's one with a pit.


I've been suggesting everyone should pull these now and then every 5-10k thereafter and check for wear, which looks like a worn path across the stellite tip, or a full blown pit.

If there is wear, it can only get worse. Even more so with a pit. And getting a good adjustment would run from frustrating to impossible.  Sorry yours includes the valve as we know what it will take to fix those. New adjusters is quick and simply.

[TwoTired]

Anyone use the "degrees of adjuster turn" method for clearance?

Take the thread pitch.  I don't recall the actual thread pitch on the CB750 Adjusters.  But, lets say it was 1.5 mm.  Divide that by 360 (degrees in one full turn). Divide that into the desired clearance, and you have the number of degrees to turn the adjuster out from making contact with the valve stem to achieve proper clearance.  If your desired tappet clearance is say, .05mm, then turn the adjuster out 12 degrees.  If your adjuster and stem are convex and concave respectively, this will give a more accurate adjustment than using a feeler gauge it the gap.  The error induced would be from loose thread engagement examples.

I've seen adjuster tools that have the degree wheel markings as part of the adjuster in a Honda shop.  It was a single tool that did the whole adjustment, unlock, screw in, screw out, and lock down.  I don't have one, though.  I'll see if an internet search can find a picture of one and post later.

Anyway, be aware that if your adjuster and stem ARE convex and concave, it will wear valve guides faster, due to the arc geometry of the rocker movement putting side loads on the valve stem to guide.

Cheers,

[754]

I am finding this;
 Usually I dont have a good fit to the slot in the adjuster.
 The adjuster tends to turn slightly while adjusting.
 The torquing tends to lift adjuster slightly.. due to thread clearances.

 So I eyeball slot orientation, and can tell if it moved a bit or not, couple tries and its done. The mre often I do them the quicker it gets..

[KingCustomCycles.com]

Yep, the angle measurement sure beats trying to feed a feeler guage down in there and I would surmised is more accurate than an inexperienced person unaccustomed to the proper friction using the thickness guage.  Also, as you mentioned the concave/convex shape of the worn parts will give a false indication of clearance when using the thickness guage.  The valves would then be set with excessive clearance equal to the wear plus the measured thickness.

[crazypj]

Anyone use the "degrees of adjuster turn" method for clearance?
Cheers,

I think pitch is 0.5 mm?
Anyway, I've done it on a couple of motors.
Suzuki don't give a clearance for SP/DR 370 (and I think 400), only how much out from touching valve tip

[754]

.75mm pitch..that should be 29 to 30 thou per turn..

[Rgconner]

.75mm pitch..that should be 29 to 30 thou per turn..

So a tenth of a turn for the exhaust, 36 degrees. and a twelfth of a turn, 30 degrees, for the intake.

I will stick with feelers.

[70CB750]

I think I will adapt the degrees of adjuster method, I dont like to work with the feeler  through the hole.

Thank you, Mr.TT.

[70CB750]

.75mm pitch..that should be 29 to 30 thou per turn..

So what's the thread on the tappet adjuster?  M6x0.75???  10mm wrench is typically M6 nut

[TwoTired]

Only SOHC4 motor I have apart right now is a CB550.  Thread pitch on the tappet adjuster is 0.75.