How To: Remove the Camshaft Rocker Arms

[XSiveAl]

Thanks for the insight..Dondlhmn, very helpful.. a lot of good sense.

Specifically, what I've found adjusting valve clearance (head torqued to spec, camchain adjusted properly) is that when i grab the adjuster end of the rocker arm i can wiggle the rocker arm side to side. (ex valves) Ill see if i can measure this somehow.. its far enough to very slightly misalign with valve stem. i wonder is if this is ok. Or how much is too much? I imagine the relationship between rocker arm hole and shaft is out of tolerance but, i think the shafts themselves are well secured.

I have a small collection of used motors. By examining the topcaps I've found one that has rockers that do not wiggle side to side on the shaft at all. Cam followers look great no bluing, no scratches, no dulling. I don't know if i can tell anymore which cam goes with which cap. Am i ok to pull shafts and rockers to install in the matching cap I'm using. Won't hurt the cam lobes or followers if i assemble with lube and back off the adjusters right?

I'm hoping the cap I'm running isn't warped, i honestly didn't check when i put it together. No leaks, no binding, oodles of power for four years now.. Riding it all the time, including today.. When i disassemble i will check for warpage and defect of cap itself.. That factor had not occurred to me.

Of course what you say about disassembly and inspection is true. The only way to know for sure what's worn and why... I know people often use salvaged hopefully less abused parts with a certain risk. Could be better or worse i suppose, i just have this thing about reusing stuff whenever possible. i will measure both sets meticulously when i am ready to do the swap and I'll take really close look at cam lobes, i have a few spare cams as well.

I've got new cam bearings and cam chain on hand, gaskets etc. I've been planning, But i thought i should get a second opinion before i tear it down unnecessarily.

Thanks again,

 

[XSiveAl]

For technical reference the Yamaha service manual 1980 edition says the standard size rocker shaft hole is 15.01mm and the shaft measures 14.98mm
Stndrd clearance 0.05mm max tolerance of 0.10mm.

 

[dondlhmn]

Now, I'm just guessing here, but I'd say that there is always going to be some play noticeable when you try to push the rocker arms from side to side as there HAS TO BE some clearance between the rocker arm and the rocker cover in which they are mounted or they would bind. Just how much, I don't know and I have not looked in the manual to see if that clearance is given there. Most rocker arms can be pushed from side to side to some degree, but none of them should be able to be pushed so far that very much (if ANY) of the end of the valve becomes visible. If that happens, something IS wrong somewhere.

When I said that you should put the rockers back in the same positions if possible, that is considered to be standard practice and is due to the surfaces of the two parts having "broken in" or worn in to accommodate each others' slight imperfections. If you have lost track of which goes where, then you can re-install them sort of just where ever, but be really picky about not putting any parts back in that look like they may have any unusual or overly worn areas on them. Sometimes a piece of VERY fine emery cloth or wet-or-dry abrasive can be used to dress the lobes and/or the rocker arm surfaces that contact the lobes, but that has to be done as minimally as possible and be very careful to leave a nice, clean, smooth surface. I believe that those surfaces are hardened, but that the hardening is NOT very deep, so be careful to NOT go through the hardening into the unhardened, softer base material. You can NOT grind through the hardened portion of the part to take out deep wear patterns or gouges without getting into the softer, unhardened base material below it and ruining the part. Ideally, you can use assembly lube, but mostly just be sure that all parts are lubed very well with oil (at least) as you assemble them. When I can, I like to turn an engine over for a while using a start roller setup after having re-assembled it to ensure that lube is reaching all parts before the engine is actually started. The best clue as to whether or not lube is reaching all areas is when you see lube being pumped back into the tank, but that is REALLY hard to do with a wet sump system such as the XS650. If you have an oil pressure gauge installed, you can watch to see that pressure is present at the gauge for a while before you actually start the engine. If you can't get your hands on a start roller, you can stick the bike in high gear and push it around for a while (but stop before you have a heart attack!), turning the engine over with the plugs out and the key off to get the oil moving around. The last choice (but sometimes the most practical) is to take the plugs out, put the tranny in neutral and kick (or use the electric starter if you still have one) over for a bit before replacing the plugs and actually starting it.

Most of the Japanese produced engines in most all brands are very robust, but you CAN NOT put worn out, out of tolerance parts back into any of them and expect good results.

Oh..yeah..."backing off of the adjsusters" is not a good idea. The clearances should be set as described in the book as too loose will allow rocker arms, cams and valves to sort of "whack" each other more than they should and setting them too tight could close the clearances up to the point that the valves will be held off of the seats a little when the engine (the valve train) is very warm, which will likely result in burned seats. Set the valves TO SPEC!!

 

[XSiveAl]

Thanks again D, you are wise in the ways of the rockers

I think you're right.. the wiggle (side play) allowed by the clearance .05mm - .010mm is normal... this makes sense.

The adjuster tip not being aligned properly with valve stem center.. not normal... this also makes very good sense

so.. i likely have excessive wear at rocker arm hole/shaft, the rocker arm has bent, the top cap has warped, or the valve/guide is out. the only thing i had had done by professional machinist was the guide install so it'd better not be out cocentricity-wise.

I've ridden well over 15000km since put together in 2009 with no engine troubles. I wouldn't have suspected anything was wrong were it not visually obvious.

As soon as i get my new tires on the 77D (next week) I'll pull this other beast apart and
mic the bits to see if we can't figure out what exactly has happened. I'll post some pics before and during to help demonstrate the issue a little better.

for clarification, I have tried various intake valve clearances per varying manuals... (ex. specs seem to vary less so i stayed with .015mm) now running .08mm in .015mm ex. The bike starts reliably first or second kick and pulls evenly through to the redline. no stumble no clanking. some chatter.. but of course, if it didn't make some valve train noise i'd be reallly worried about it

and about "backing off" the adjusters. I meant ONLY for the assembly to avoid undue stress from valve spring load on cap and valve train while torquing... to avoid possible damage.

 

[Airwolfie]

Errm,I don't have the guides for the alignment rods in there, anyone know where I can find some??

 

[dondlhmn]

Errm,I don't have the guides for the alignment rods in there, anyone know where I can find some??

I'm curious as to what you are referring to. Would those possibly be the parts that Yamaha calls cylinder head cover sleeves? There are 4 of them and they all get O rings.....

Are you SURE they aren't there or maybe in the parts boxes somewhere if you didn't take the engine apart yourself?

If you don't have them, they are available here and there....I found this site after 6 seconds of searching:

http://www.boats.net/parts/detail/yamaha/Y-256-11199-00-00.html

after 8 more seconds:

http://www.ebay.com/itm/1970-84-Yam...Parts_Accessories&hash=item257d304013&vxp=mtr



and I'm not sure that they have them, but somebody does, I'll bet. Those parts are listed in most places as "OBSOLETE", but that does NOT mean that they are unobtainable. A place to try would be your local motorcycle used parts sellers...XS650s were VERY common and it would surprise me if you coudn't find some used one from an engine that has been torn down for parts....it is NOT like they wear out or anything. Just remember to put the O rings in when you replace them!!

If you can't find the parts you need, let me know. I don't personally have any, but I'll bte I know 2 or 3 people that do have them....

 

[Airwolfie]

Thanks for that dondhmn! I think that's what I need, mine are definately missing.

Now that I know what they are called, I'll have a look see if I can get any, otherwise I'll take you up on your offer!

Thanks again!

 

[abyssmaltailgate]

I know since this bike is Japanese, y'all probably have metric sockets to work on it. But if you're like me and bought the metric tools after acquiring the bike, SAE 11/32" fits perfectly as a punch too hahaha

 

[Bushyeyed1]

So I just got a used replacement top end and I am trying to remove the cylinder head cover sleeves from the used head cover. I have it soaking in penetrate right now. My old head cover; cylinder head cover sleeves, just slid out when I took off the head cover. My question is when using the 8mm or 11/32 socket to punch it out how hard are we hitting it? Are we using a rubber mallet or a hammer? This top end looks like it was dug up from the grave so I am taking my time, but don't want to be too weak if I don't have to.

 

[Superjet]

Let them soak. I had to use a socket on mine too but once it broke its hold on it just slid out.

 

[5twins]

There's not much to hit against, the sleeves are very thin. They may be gasket sealed in on the bottom too. Still, you shouldn't have to hit them too hard. I don't think you can really, what with them being so thin. You'd probably end up driving the socket inside of them or deforming (bending) the end if you hit too hard. I would use a smaller hammer. One of my new favorite tools is a 4 oz. ball peen. It's great for smaller hammering jobs on stuff like carbs and instrument repair, and I'm using it all the time it seems. Wish I would have bought one years ago .....

https://www.amazon.com/Vaughan-TC50...7766750&sr=1-1&keywords=4+oz+ball+peen+hammer

 

[nighthog]

Applying a good dose of heat then a firm tap with a dead-blow hammer worked for me.

But now a different problem - what's the thread pitch for the rocker spindle? Everything I read says 'M6' but none of my 1mm pitch 'normal' M6 bolts will screw in. Did this change with late model ones? The one I'm dealing with seems to be SJ/SK. Could it be 0.75?

 

[5twins]

Maybe it did? I know my '78 took a standard M6 x 1 bolt.

 

[gggGary]

Applying a good dose of heat then a firm tap with a dead-blow hammer worked for me.

But now a different problem - what's the thread pitch for the rocker spindle? Everything I read says 'M6' but none of my 1mm pitch 'normal' M6 bolts will screw in. Did this change with late model ones? The one I'm dealing with seems to be SJ/SK. Could it be 0.75?

Buggered threads? Chase with a tap, think the MikesXS replacement screws are one size fits all years.

 

[5twins]

I'm pretty sure he is referring to the size of the bolt/screw needed to withdraw the rocker arm shaft (what the rocker arm pivots on) from the head, not the valve adjusting screw?

 

[gggGary]

I'm pretty sure he is referring to the size of the bolt/screw needed to withdraw the rocker arm shaft (what the rocker arm pivots on) from the head, not the valve adjusting screw?

My bad, I was thinking the cap screws threaded into those holes.

 

[nighthog]

Yes, the rocker arm shaft which we call the rocker spindle here in the UK.
Guess I'll have to buy some M6 x 0.75 bolts and try my luck - the spindle end is so far recessed I can't get a thread gauge in there. Just as well I'm in no rush for this job!

 

[Signal]

M6 x 1 and a stack of washers as you wind the spindle out add more washers. When you reinstall thread out the shaft has a cross on the other end for oil circulation. As already suggested possibly some damage from a prior careless assembly. Maybe use an intermediate tap to get it started.

 

[nighthog]

Thanks, but for all four an M6 x 1 bolt doesn't even begin to start. I've been reluctant to apply any force as I really don't want to bugger things up. I have some M6 x 0.75 x 50mm bolts coming from China (naturally ...) and if they won't work either, then I'll do as you suggest and apply a tap. If I can find one long enough!

 

[Signal]

Sounds like something strange has gone on. Perhaps someone has made their own replacements with an imperial thread (since you are in the UK). While you are waiting for the 0.75 bolts to turn up perhaps you could try some imperial bolts if you have some in the workshop.