Topic: Frequent #1 intake tappet adjustment....

[joeyvans]

I picked up the '74 roller with an unstuck '75 motor and a stuck '76 motor (early '76 with the inferior valve cover) this past Sunday.  Pulled the cover on the '75 motor and none of the rocker shafts have any up/down play in them.  The rocker arms and camshaft look good with no uneven wear. 

So, last night I pulled the cover that came on my bike to look everything over.  As expected... A LOT of up/down play on the #1 intake rocker shaft and a LOT of uneven wear on that rocker arm and cam lobe.  In fact, there is quite a bit of uneven wear across the board on that camshaft.  I haven't put a micrometer on it, and I don't intend to.  I think it is unusable.  Just by running my finger over some of the lobes, I can feel a slight "valley" before I get to the end of the lobe.  This thing has seen better days. 

The other rocker shafts are snug, but that doesn't really matter because this cover is toast. 

My plan is to pull the cam that came off the '75 motor and pair it back up with the cover I pulled from that motor.  Things just look so much better with that combination.  Pucks, gaskets, washers, SS hardware have all been ordered for the cover install.  Hope to get this done next week.  This will be my first time swapping cams, installing the cover, etc.  So, it should be an interesting experience.

I have also had a conversation with another member about his '78 valve cover.  It needs some cleanup. So, if him and I can work out a deal for the cover, rocker shafts, and the pins.... I will clean it up over the winter and put that one on for next year's riding season.

Kyle

[alacrity]

I picked up the '74 roller with an unstuck '75 motor and a stuck '76 motor (early '76 with the inferior valve cover) this past Sunday.  Pulled the cover on the '75 motor and none of the rocker shafts have any up/down play in them.  The rocker arms and camshaft look good with no uneven wear. 

So, last night I pulled the cover that came on my bike to look everything over.  As expected... A LOT of up/down play on the #1 intake rocker shaft and a LOT of uneven wear on that rocker arm and cam lobe.  In fact, there is quite a bit of uneven wear across the board on that camshaft.  I haven't put a micrometer on it, and I don't intend to.  I think it is unusable.  Just by running my finger over some of the lobes, I can feel a slight "valley" before I get to the end of the lobe.  This thing has seen better days. 

The other rocker shafts are snug, but that doesn't really matter because this cover is toast. 

My plan is to pull the cam that came off the '75 motor and pair it back up with the cover I pulled from that motor.  Things just look so much better with that combination.  Pucks, gaskets, washers, SS hardware have all been ordered for the cover install.  Hope to get this done next week.  This will be my first time swapping cams, installing the cover, etc.  So, it should be an interesting experience.

I have also had a conversation with another member about his '78 valve cover.  It needs some cleanup. So, if him and I can work out a deal for the cover, rocker shafts, and the pins.... I will clean it up over the winter and put that one on for next year's riding season.

Kyle

All good thinking brother.  Note that one thing that can actually be the root cause of the problem you're discovering is a sticky or partially stuck valve. Imagine the extra resistance as the follower tries to push the valve down and the valve is resisting and the rocker pressure against the cam is greater than it should be by a lot,  and you get a lot of wear between those two points because oil can't get in between. So now the rocker face galls, the cam lobes press the rocker followers too hard for too long, and this much more intense angular pressure/force on the steel shaft  (which doesn't yield) is then transferred into the far softer cast aluminum material of the tunnel walls of the cylinder head cover, which does yield.  And you end up with what you have.   I don't think this is always the cause of the problem, but it sure was in an engine I had.  Fix the valve, then do the parts that contact it, or your root cause is just gonna cause the next cyl head cover and cam and rocker to go bad in the same way. 

[alacrity]

Wanted to see if anybody had a theory on my slight issue....

'76 CB550K - no known go-fast motor bits.

I have found that I need to adjust my #1 intake tappet quite frequently.  But, only the #1 intake... never the exhaust.  After every few rides.... it starts to develop a slight tick which can be cured by readjusting (specifically, tightening or turning in) the tappet screw when the engine is cold.  With the next startup, it sounds like a sewing machine again.  I have been tightening down the tappet lock nut probably tighter than I should because I was concerned that was the problem.  But, it appears this problem isn't going away.

I haven't had a chance yet, but I think I will pull the nut and screw and check the bottom for damage, excessive wear, etc. 

Does anybody have any thoughts on the cause of this issue?  Problem with the rocker?

Thanks

Kyle

This might help you determine if the valve is indeed sticking.
http://forums.sohc4.net/index.php/topic,158286.0.html

[BomberMann650]

And this for the cam swap.

[joeyvans]

All good thinking brother.  Note that one thing that can actually  even the root cause of the problem you're discovering is a sticky or partially stuck valve. Imagine the extra assistance as the follower tries to push the valve down in the valve is resisting and the rocker pressure against the camo is greater than it should be by a lot ,  and you get a lot of wear between those two points because oil can't get in between. So now the rocker face goals, the cantaloupe and "values" as you discovered, and this much more intense angular pressure/force on the steel shaft  which doesn't yield,  is then transferred into the far softer cast aluminum material of the tunnel walls of the cylinder head cover, which does yield.  And you end up with what you have.   I don't think this is always the cause of the problem, but it sure was in an engine I had.  Fix the valve, then do the parts that contact it, or your root cause is just gonna cause the next cyl head cover and cam and rocker to go bad in the same way.

Hmmmm..... interesting thought.  How would a stuck valve affect my compression readings?  Or... would a leak down test detect a stuck valve?

My compression readings after a warmup ride (cheap Actron automotive tester with long rubber hose) on 5/15/16 were pretty even...  Definitely within 10% across the board:

       Dry/Wet
#1  130/137
#2  127/136
#3  131/136
#4  129/131

Also.... if that intake valve was stuck.... would I notice some serious chatter and tappet screw damage? The thing sounded like a sewing machine at startup after the slight tappet adjustment.   Even after the tick started.... it wasn't very noticeable. 

Thank you for the pic and instructions on that process, alacrity!  Much appreciated!

[joeyvans]

And this for the cam swap.

Thanks Bomber.... I've got the Honda Service Manual and have read many posts/tips on the cam removal/install and cover install.  Can't say enough things about this forum.  Usually don't even have to post a question... it's already here.  Apparently this topic was here as well, but I wasn't searching for the right thing.

Thanks again!

[BomberMann650]

And this for the cam swap.

Thanks Bomber.... I've got the Honda Service Manual and have read many posts/tips on the cam removal/install and cover install.  Can't say enough things about this forum.  Usually don't even have to post a question... it's already here.  Apparently this topic was here as well, but I wasn't searching for the right thing.

Thanks again!

Same here, the number of posts that start with "not running smooth".  Often end with "timing chain off by one tooth".  I had those words in my head when doing my rockerbox/cam swap.

[joeyvans]

Back on the road again. Installed the cover and cam from the '75 motor I picked up last week. No, not a late model cover, but hopefully this one gets me through the summer.

New SS hardware, side cover o-rings, tappet cover o-rings, pucks, breather and valve cover gaskets.

25 mile ride, no leaks so far... valve train sounds great!

Thanks everybody for the help!


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[flatlander]

there's a trick that i read was used by shop mechanics with the older type covers: put some o-rings (same size as on those triangular rocker cover end caps) in the holes of the rocker shafts. then put that end cover on. the o-rings apparently create enough friction to keep the shafts from rotating.
as you have an older cover in good shape this might be worth trying. if it works you may not need a different cover at all.

[joeyvans]

there's a trick that i read was used by shop mechanics with the older type covers: put some o-rings (same size as on those triangular rocker cover end caps) in the holes of the rocker shafts. then put that end cover on. the o-rings apparently create enough friction to keep the shafts from rotating.
as you have an older cover in good shape this might be worth trying. if it works you may not need a different cover at all.

Brilliant!  It's certainly worth a shot.

Thanks Flatlander.... I will add some 6x3 O-rings prior to putting any more miles on this thing.

[joeyvans]

Extra o-rings installed in the end caps. They squish in nice and tight as I'm turning the end cap screw. There has got to be a fair amount of friction there now.

All ready to go, then the rain came. Damn.




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[alacrity]

All good thinking brother.  Note that one thing that can actually  even the root cause of the problem you're discovering is a sticky or partially stuck valve. Imagine the extra assistance as the follower tries to push the valve down in the valve is resisting and the rocker pressure against the camo is greater than it should be by a lot ,  and you get a lot of wear between those two points because oil can't get in between. So now the rocker face goals, the cantaloupe and "values" as you discovered, and this much more intense angular pressure/force on the steel shaft  which doesn't yield,  is then transferred into the far softer cast aluminum material of the tunnel walls of the cylinder head cover, which does yield.  And you end up with what you have.   I don't think this is always the cause of the problem, but it sure was in an engine I had.  Fix the valve, then do the parts that contact it, or your root cause is just gonna cause the next cyl head cover and cam and rocker to go bad in the same way.

Hmmmm..... interesting thought.  How would a stuck valve affect my compression readings?  Or... would a leak down test detect a stuck valve?

My compression readings after a warmup ride (cheap Actron automotive tester with long rubber hose) on 5/15/16 were pretty even...  Definitely within 10% across the board:

       Dry/Wet
#1  130/137
#2  127/136
#3  131/136
#4  129/131

Also.... if that intake valve was stuck.... would I notice some serious chatter and tappet screw damage? The thing sounded like a sewing machine at startup after the slight tappet adjustment.   Even after the tick started.... it wasn't very noticeable. 

Thank you for the pic and instructions on that process, alacrity!  Much appreciated!

There are gradations of "stuck" that include, "fused in place" to "slightly sticky" to "barely stickier than all the others..."   Even a little "stickiness" can keep the pressure on the rocker too long and cause the binding and side load on the shaft as discussed, but it might not be enough to decrease your compression in that cylinder...
I am facing this on an engine now... :-(

[flatlander]

Extra o-rings installed in the end caps. They squish in nice and tight as I'm turning the end cap screw. There has got to be a fair amount of friction there now.

great! make sure to post your long-term experience.  i can imagine many 500/550 guys will be interested to know how it works out.

[BomberMann650]

Yup, damn this weather.

[joeyvans]

great! make sure to post your long-term experience.  i can imagine many 500/550 guys will be interested to know how it works out.

I will absolutely do this, flatlander!  I hate nothing more than an incomplete thread.   

I made note of the mileage at the time of the extra o-ring install.  If I can get to that 3,000 mile threshold without any additional tappet adjustment..... I think it will be a success.

Thanks again for the tip!

[flatlander]

i hope it works. never tried this myself as i replaced my worn-out cover with one of the pinned ones.

[alacrity]

it does work. I did it on a cb500.

[joeyvans]

it does work. I did it on a cb500.

Good to know, thanks. I'd be more worried about the interior (2&3) shafts turning at this point.

Went 85 miles last night.... No further adjustment necessary so far.

Sure sucked a lot of fuel though. Was between 70 and 80 mph (6K+ RPMS) for the majority of the round trip and only got about 29/30 mpg. It was windy, but yikes.... I am usually at 35 mpg.


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[BomberMann650]

it does work. I did it on a cb500.

Good to know, thanks. I'd be more worried about the interior (2&3) shafts turning at this point.

Went 85 miles last night.... No further adjustment necessary so far.

Sure sucked a lot of fuel though. Was between 70 and 80 mph (6K+ RPMS) for the majority of the round trip and only got about 29/30 mpg. It was windy, but yikes.... I am usually at 35 mpg.

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Your average mpg is lower than bloo's 42/43mpg

Are you jetted?  Must have really been flogging that pony!

[joeyvans]

Your average mpg is lower than bloo's 42/43mpg

Are you jetted?  Must have really been flogging that pony!

Yeah, jetting is finally correct for my MotoGP Werks 4-1.

I may or may not redline every shift.

Headwinds were about 20-25 mph sustained for about half the ride. Oh yeah.... it was about 86 F and humid too. It was miserable.



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[BomberMann650]

Your average mpg is lower than bloo's 42/43mpg

Are you jetted?  Must have really been flogging that pony!

Yeah, jetting is finally correct for my MotoGP Werks 4-1.

I may or may not redline every shift.

Headwinds were about 20-25 mph sustained for about half the ride. Oh yeah.... it was about 86 F and humid too. It was miserable.

Aha!  That explains the 7mpg difference.

What size jets worked for your motogp setup?  Curious minds inquire to know!

Don't ya hate it when the air conditioning goes out on your bike?!

[joeyvans]

Stock intake. Settled on 110 mains, needle in the middle (3rd clip), 38 pilots, and a/f screw at about 1 1/3 turns out. Normally at my elevation (900 ft), 105 mains should do the trick, but they were too lean for my liking.


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[joeyvans]

With this pipe (minimal baffle).... it is VERY hard to short shift. 


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[BomberMann650]

Stock intake. Settled on 110 mains, needle in the middle (3rd clip), 38 pilots, and a/f screw at about 1 1/3 turns out. Normally at my elevation (900 ft), 105 mains should do the trick, but they were too lean for my liking.


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Where did you go shopping for keihin jets in the US?

I'm pretty sure my mac/yoshi combo is flowing a bit more than 100mains can deliver. i've got my A/F screw backed out beyond the manual spec.  Luckily that screw has a pretty wide adjustment range!

[joeyvans]

Not Keihin mains.... But have had good luck with Jets R Us repros. Others have also used Sirius Inc.


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