Author Topic: Rocker Shaft Trouble  (Read 18670 times)

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Offline mick7504

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Re: Not Happy Hondaman
« Reply #50 on: March 02, 2012, 09:59:42 PM »
Let me know if you can't find a replacement shaft mate.
Hopefully we can get to bottom of this.


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Offline 70CB750

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Re: Not Happy Hondaman
« Reply #51 on: March 02, 2012, 11:06:03 PM »
How long did it run?
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Offline Terry in Australia

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Re: Not Happy Hondaman
« Reply #52 on: March 02, 2012, 11:18:00 PM »
Mate, this has happened before, and has nothing to do with the 5mm screws being removed. As has been said previously, the K0 and K1 (and maybe K2, but I can't remember) 750's didn't even have 5mm screws holding the shafts in place, and the shafts didn't suffer the damage shown in the pic.

The cam, rockers, etc are lubricated by means of fine jets of oil which travel from the oil jets in the head, thru fine drillings in the cam towers. Some oil goes direct to the cam bearings, and some just sprays up, hits the inside of the rocker cover, and rains back down again. The rockers have countersunk holes on top, so the oil raining down is collected in the countersunk holes and is distributed over the bearing surfaces, and along the shafts.   

My suspicion is that either the oil jet under the cam tower, or the fine drillings in the cam tower that lubricate the cam and rocker gear, has become blocked, or you didn't prime your oil pump and you've starved the top end of oil, and the heat and friction has caused the rockers to "nip up" on the shaft. You said that you shut down the engine pretty much right away, which probably saved the cam, (which I assume you would have manually lubricated as part of the rebuild?) but the "four cats fighting" noise would have been the metal on metal screeching due to no lubricant on the rockers and shafts.

I remember in 1981 when I managed to block an oilway on my first K1 (due to a Triumph mechanic in Sydney using silicon to seal everything rather than fitting new gaskets) I destroyed my cam, all rockers and rocker shafts, and seized the engine in a very short space of time. Once I "de-siliconed" my engine and replaced everything from the conrods up I rode it for another 4 years including a trip to Bathurst in 1983 with no problems at all. Back then you could buy the earlier towers new from your local Honda shop, (if you didn't mind paying 400 bucks for new cam towers, ouch!) so I used the correct K1 towers and shafts with no 5mm screws, as I didn't even know that there was an "update" available.

Make sure you check your entire lubrication system before you fire it up and ride off into the sunset. Cheers, Terry. ;D   
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Offline mycb750k6

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Re: Not Happy Hondaman
« Reply #53 on: March 03, 2012, 05:22:39 AM »
No, no no, not so fast. I still say you diss'd Hondaman and owe him a public apology.  After all your subject line clearly says " Not Happy Hondaman" and then you go on to blame his info on the bolts. Many long time experts here (not me) have posted replies and made it clear that that these bolts are not to blame but you won't accept that. Nobody with a pre-72 bike has these bolts and there were over 150,000 of them made in that time frame.  I think until you get past that, you're not going to find the cause or solve your problem.

Offline ekpent

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Re: Not Happy Hondaman
« Reply #54 on: March 03, 2012, 05:34:02 AM »
I keep this paperweight around from a parts 750 bike as a reminder of the power of silicone or a plugged oil port.One side is trashed and the cam tower bearing area was shredded.Will have to take a peek at the rockers and shaft next time at the shop.That's one way the cams can break and it makes a tremendous amount of scrap metal in the engine. First pic is good side,other 2 not so good.  Think anybody heard a Kitty in there  ;)  :)

Offline 70CB750

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Re: Not Happy Hondaman
« Reply #55 on: March 03, 2012, 06:59:12 AM »
No, no no, not so fast. I still say you diss'd Hondaman and owe him a public apology.  After all your subject line clearly says " Not Happy Hondaman" and then you go on to blame his info on the bolts. Many long time experts here (not me) have posted replies and made it clear that that these bolts are not to blame but you won't accept that. Nobody with a pre-72 bike has these bolts and there were over 150,000 of them made in that time frame.  I think until you get past that, you're not going to find the cause or solve your problem.

+1
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Offline wrenchmuch

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Not Happy Hondaman
« Reply #56 on: March 03, 2012, 07:04:00 AM »
My k1 didn't look as bad as that but it sure screeched pretty loud before it stopped. 


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Offline burmashave

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Re: Not Happy Hondaman
« Reply #57 on: March 03, 2012, 08:02:42 AM »
...As to my being abusive of Hondaman , I was not, read the original post. I was pissed off at the situation however as would any one who had to remove and disassemble their engine again....

As I am eminently unqualified to help out in areas this deeply technical in nature, I will help out in areas of politeness, consideration and respect. As suggested, I reread your original post and then reread it again.

A thread titled "Not Happy Hondaman" simply implies, although apparently not to you, that you are not happy with Hondaman. Evidence, my man. You may well note that in its short lifetime, this thread has attracted nearly 1,300 views (that's 3,016.8 in metric). Many folks have seen the title and asked themselves, "Self, why would anyone be unhappy with Hondaman? How can this be?"

Again, I'm not the technical guy; however, I might have gone for the more neutral title of, "Problem with Rocker Shaft Bolt Removal" or "Engine Rebuild: Rocker Shaft Destruction." Then again, as a less experienced hand, I tend to first consider that mebbe I did something wrong. But that's just me.

As to your second wrongness, you might read your post again. If you were merely angry at having to rebuild the engine, I am a bit confused as to why you would ask Hondaman to forgive you. We have lots of respect for Hondaman here. As awesome as he is, we do not come to him for absolution of our general sins. Well, at least I haven't yet.

Pony up an apology to Hondaman. I had held off on posting until you dodged your opportunity to apologize. Even if you are convinced that you did not slight Hondaman, consider well that one apologizes not only for a slight intended, but also for a slight reasonably perceived.

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Offline heffay

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Re: Not Happy Hondaman
« Reply #58 on: March 03, 2012, 08:27:49 AM »
Censored
« Last Edit: March 06, 2012, 06:23:57 AM by heffay »
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Offline thrutheframe

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Not Happy Hondaman
« Reply #59 on: March 03, 2012, 04:14:29 PM »
+1
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Offline mick7504

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Re: Not Happy Hondaman
« Reply #60 on: March 03, 2012, 04:15:15 PM »
Pics or it didn't happen.  ;)
A few photos for reference.





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Offline singedebile

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Re: Not Happy Hondaman
« Reply #61 on: March 03, 2012, 06:51:39 PM »
As much as I agree with what is being said in terms of politeness etc.. too many of the responses here have been inflammatory (popcorn references for a start.. as if this persons trouble/misdirection is entertainment).

These responses will only make the poster more defensive and less likely to listen to the otherwise Great advice given by a few of the other members such as "Terry in Australia"

...many of us have been there before, follow someones advice and something goes very wrong... in our rash anger we make a few irrational snap judgements,  ...common guys and girls were better then this. Lets keep this productive.
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Offline Retro Rocket

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Re: Not Happy Hondaman
« Reply #62 on: March 03, 2012, 07:31:06 PM »
Quote
These responses will only make the poster more defensive and less likely to listen to the otherwise Great advice given by a few of the other members such as "Terry in Australia"

Well said....
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Offline heffay

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Re: Not Happy Hondaman
« Reply #63 on: March 04, 2012, 07:52:14 AM »
Censored
« Last Edit: March 06, 2012, 06:24:29 AM by heffay »
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Offline 70CB750

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Re: Not Happy Hondaman
« Reply #65 on: March 04, 2012, 08:10:03 AM »
To blame a mistake on somebody else is very humane, but I am with you Heffay.

But that is not important, I want, above all, to know what caused this failure.
« Last Edit: March 04, 2012, 08:12:12 AM by 70CB750 »
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Offline ekpent

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Re: Not Happy Hondaman
« Reply #66 on: March 04, 2012, 08:11:48 AM »
Like a good mystery book,not that I read them,but it still would be nice to have a conclusion as to the cause. Quite a few threads unfortunatly end that way from the OP's and does no good for people looking for their answers to their questions and concerns.
  I think there was an oiling issue between the rocker and rocker shaft and a mini seizure that may have caused it.Thousands of early bikes have proved the setup works.  On to the next mystery-------------

Offline City Boy

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Re: Not Happy Hondaman
« Reply #67 on: March 04, 2012, 08:13:56 AM »
Human maybe,humane not!
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Offline mycb750k6

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Re: Not Happy Hondaman
« Reply #68 on: March 04, 2012, 08:19:07 AM »
I think the thread should be locked and/or deleted so we don't have to look at the Not Happy Hondaman anymore :P  But that's just me talking again.

Offline BobbyR

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Re: Not Happy Hondaman
« Reply #69 on: March 04, 2012, 08:57:25 AM »
I think the thread should be locked and/or deleted so we don't have to look at the Not Happy Hondaman anymore :P  But that's just me talking again.
You do not have to look at that title. It can be edited easily. It would be nice if some good instruction came out of this so that someone else can avoid the grief.
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Offline RSchaefer

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Re: Not Happy Hondaman (VERY HAPPY WITH HONDAMAN!!)
« Reply #70 on: March 04, 2012, 09:13:56 AM »
Well, goes to show you how much respect everyone has for Hondaman as do I.  I am rebuilding my '75F, bought Hondaman's book and am basically doing nearly everything he has suggested in his book, the low cost HP upgrades, not the high cost upgrades.

I countersunk the oil pickup holes on the towers and drilled out the additional Honda marked holes as well.  I am going to leave out the 5mm.

The most obvious issue with Groovers situation is the lack of lubrication.  The only other things that came to my mind as I thought about how this could have happened was the possibility that the cam tower pins may have gotten mixed up and not put back in the same tower they came from.  So competing wear patterns caused the friction.  Also Hondaman goes into great detail regarding the torquing process for the 6mm bolts and the possible need for lock-tight should binding of the shaft occur before the torque #'s are hit.

Anyway for me the dialog is good as it tells me how careful I need to be as I put this thing back together.  I can't image how I would feel if what happened to Groovers, happened to me after all the work it takes to get back into the engine of one of these things.
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Offline Spanner 1

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Re: Not Happy Hondaman
« Reply #71 on: March 04, 2012, 10:12:14 AM »
I'm totally with Ekpent's dowel-pin-not-seated theory!....the dowel at the end of the cam holder ( closest to the 'puck' cover) was not seated/wrong length causing one end of the cam/rocker holder to be 'bent' downwards towards the center as the 6mm bolts were tightened forcing the rocker shaft hard against the 6mm center bolt... anyone else ?
« Last Edit: March 04, 2012, 10:20:32 AM by Spanner 1 »
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Offline wrenchmuch

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Not Happy Hondaman
« Reply #72 on: March 04, 2012, 10:43:37 AM »
Op's other posts show o ring recesses in the cylinders #1/2 looks deeper than #3/4 side. This was pointed out by MReick in a previous post. This could lead to a loss of oil pressure in the head. The cylinder assembly has been decked. Who knows by how much. I've never needed to resort to deepening o ring recesses after decking. There could be many many things going on with this build. Op isn't offering any more info. Time to let this post go to sleep.
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Offline ekpent

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Re: Not Happy Hondaman
« Reply #73 on: March 04, 2012, 10:51:30 AM »
Mike - Mriek made the good observation when his build thread was posted later that he had the cylinder milled down 1mm and also because of that had to have some oil flow holes countersunk deeper. As he noticed in the pics the hole on the right is quite a bit deeper than the left. If the o-ring did not seal well that could be an oiling issue and that deep hole happens to correlate to the #1 and #2 side where the problem occurred.With the mill job the dowels may be too long also if not modified correctly.
   As Bobby mentioned also I think that original posters are able to go in and 'modify' their posts and or titles.  ;)

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« Last Edit: March 04, 2012, 10:54:02 AM by ekpent »

Offline markb

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Re: Not Happy Hondaman
« Reply #74 on: March 04, 2012, 10:53:28 AM »
I'm totally with Ekpent's dowel-pin-not-seated theory!....the dowel at the end of the cam holder ( closest to the 'puck' cover) was not seated/wrong length causing one end of the cam/rocker holder to be 'bent' downwards towards the center as the 6mm bolts were tightened forcing the rocker shaft hard against the 6mm center bolt... anyone else ?
I agree, either that and a lubrication issue.  At least I know I shouldn't have any problems if I make sure neither of those conditions exist.
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