Author Topic: Help! What's caused this?  (Read 2731 times)

Offline Bristolbadger

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Re: Help! What's caused this?
« Reply #15 on: March 25, 2022, 07:20:24 PM »
i was told by an old honda guy to turn the engine over with the rocker cover caps off to see if oil arrives at the head. i assume that's a good idea?

F#@#####CK!! I can't think why I didn't do this with the engine in the bike not just on the bench, I assembly lubed everything as i went and was fixed on the pressure being good and having seen the oil getting up there on the bench I assumed all was well..... so moved on to the next thing. TW@T!@!!

Here's that vid:
https://youtu.be/TnXZu-yCPGA

Like you all say rockers 3&4 got starved of oil and just running dry and melting the cam and holders. I don't think, & hope - until I can investigate further - that the head itself is damaged, pray be.

Thanks muchly for the call and support Roo. These are sour times man

Offline Bristolbadger

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Re: Help! What's caused this?
« Reply #16 on: March 25, 2022, 07:36:56 PM »
I suppose in theory, even though oil is observed getting up to the cam on a newly rebuilt engine at initial start up, it could take a few miles of riding to dislodge any debris that is in the bottom end, such as the dreaded silicone sealer, blobs of glass bead etc, etc.

Julie I reckon you're spot on and this is what happened. I'd been pretty surgically clean and really tried to make sure all oil routes were clear but I guess something somewhere blocked a jet and gave me the two fingers!!

So painful to fall on the last hurdle like this after a couple of years but I guess I'd be looking at ANOTHER tear down of the head etc anyway even if I'd discovered the oil blockage before meltdown. Just this is now even more of a costly one for parts and it now not going anywhere (will cancel my insurance on it now as it's just started) and almost beyond me putting anymore into it, moan moan f@#k s@*t

Offline Oddjob

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Re: Help! What's caused this?
« Reply #17 on: March 25, 2022, 07:38:37 PM »
Any blasting media used on the engine cases etc?

I ALWAYS spin the motor over with the camshaft out and holding the camchain up on a screwdriver, plugs out of course. You can then compare oil feeds to see if one looks weaker than the others.
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Online K2-K6

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Re: Help! What's caused this?
« Reply #18 on: March 25, 2022, 07:49:24 PM »
"Like you all say rockers 3&4 got starved of oil and just running dry and melting the cam and holders. I don't think, & hope - until I can investigate further - that the head itself is damaged, pray be."

Not quite as bad as it seems.

The rockers do get hot on the cam from no oil (you can see colour gradient in the rocker web indicating the range,  through blue to staw colours) but it's not that that takes the cam bearings.
The bearings without oil quickly pick up through their own friction causing the aluminium to stick to the cam, as this continues it's more like a snowball and wrapping more aluminium onto it.

The "good" bit is that the above is usually totally contained within the cam, carriers and rockers, which obviously go on replacement list. The head usually escapes anything serious if anything at all.

For historic (other's looking in here later) this is where Graphogen assembly paste outperforms virtually anything else, in that if you do have a feed failure during initial assessment, it just lasts longer and is remarkably good at preventing metal pickup from one component to the other, even with zero oil.

Offline Oddjob

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Re: Help! What's caused this?
« Reply #19 on: March 25, 2022, 07:55:25 PM »
Honda are now recommending using Molybdenum Oil on the cams and shimbuckets etc when assembling. Evidently you can make it by mixing MolyB grease and engine oil 50/50. I've tried it and it seems to work very well.
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Re: Help! What's caused this?
« Reply #20 on: March 25, 2022, 08:20:35 PM »
Interesting comparison, graphite appears to hold sway with high heat application though http://www.molybdenum42.com/molybdenum-disulfide-grease-vs-graphite-grease/#:~:text=The%20biggest%20difference%20between%20them,than%20that%20of%20graphite%20grease.

Graphogen is very good and probably exceeds most in this arena. 

Moly based, definitely as torque load increases and standard in things like CV joints (relatively low heat but high contact pressure) probably more readily available in workshops though.

Offline Oddjob

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Re: Help! What's caused this?
« Reply #21 on: March 25, 2022, 08:27:13 PM »
Wasn't saying use it Nige just that Honda seem to have swayed in that direction lately.

I have a tube of Graphogen still so I'll carry on using that until it runs out.
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Re: Help! What's caused this?
« Reply #22 on: March 25, 2022, 08:47:17 PM »
 :D yeh Ken, I like a good lubrication comparison me  ;D

It's a shame for Nick to get stuck on something like this though, hopefully it won't be too bad to sort out.

Offline Trigger

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Re: Help! What's caused this?
« Reply #23 on: March 25, 2022, 11:31:12 PM »
I suppose in theory, even though oil is observed getting up to the cam on a newly rebuilt engine at initial start up, it could take a few miles of riding to dislodge any debris that is in the bottom end, such as the dreaded silicone sealer, blobs of glass bead etc, etc.

Julie I reckon you're spot on and this is what happened. I'd been pretty surgically clean and really tried to make sure all oil routes were clear but I guess something somewhere blocked a jet and gave me the two fingers!!

So painful to fall on the last hurdle like this after a couple of years but I guess I'd be looking at ANOTHER tear down of the head etc anyway even if I'd discovered the oil blockage before meltdown. Just this is now even more of a costly one for parts and it now not going anywhere (will cancel my insurance on it now as it's just started) and almost beyond me putting anymore into it, moan moan f@#k s@*t

If when you strip the cam towers off and the oil jet is not blocked then, you have to look at the oilways in the towers. A lot of owners forget to check the oilways in the towers. When you find out what caused the problem and rebuild, when you start the engine do so, with the tappet covers off. This way you can see if oil is feeding the cam  ;)
 
You have not said, if the engine was media blast cleaned.

Offline Lobo

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Re: Help! What's caused this?
« Reply #24 on: March 26, 2022, 11:19:41 AM »
This thread is of great interest to me as I am planning to imminently have ‘my bits’ hydro-blasted. 
I’m spending a fair few of my days with an engine builder, who cautions me of 90 degree corners within oil ways, and that when wet blasting, media sludge can remain in such areas, and if not washed out whilst wet will harden and become difficult to shift later. It is basically hidden, and can be a cause of grief such as this.

So, I’ve been advised to ensure only the finest glass media is used, and that on removal from the cabinet the component is tho thoroughly flushed whilst wet. I honestly can’t say it makes me happier…. keen to hear advices.

Awful news Nick, we’ll all be keen to hear the source of the issue.

Offline Johnny4428

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Re: Help! What's caused this?
« Reply #25 on: March 26, 2022, 11:29:28 AM »
Devastating! That’s enough to make any owner of a newly built engine check their camshaft and rockers.🥵
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Re: Help! What's caused this?
« Reply #26 on: March 26, 2022, 11:41:35 AM »
We don't know in this case yet if it's been through any type of blast process.

Certainly I'd not subject the interior of these engines to blasting of any media type. It brings too many questions that don't need to be considered. 
The gasket faces for one, any bearing surfaces, any interior paint Honda used to prevent oil seep from original material porosity etc.

Completely enclosed, assembly with all ports plugged, all bolts substituted (unless you're going to subsequently plate them ) then I could see a case before then dismantling and refinish of outer surfaces.

Offline Bristolbadger

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Re: Help! What's caused this?
« Reply #27 on: March 26, 2022, 03:15:15 PM »
I suppose in theory, even though oil is observed getting up to the cam on a newly rebuilt engine at initial start up, it could take a few miles of riding to dislodge any debris that is in the bottom end, such as the dreaded silicone sealer, blobs of glass bead etc, etc.

Julie I reckon you're spot on and this is what happened. I'd been pretty surgically clean and really tried to make sure all oil routes were clear but I guess something somewhere blocked a jet and gave me the two fingers!!

So painful to fall on the last hurdle like this after a couple of years but I guess I'd be looking at ANOTHER tear down of the head etc anyway even if I'd discovered the oil blockage before meltdown. Just this is now even more of a costly one for parts and it now not going anywhere (will cancel my insurance on it now as it's just started) and almost beyond me putting anymore into it, moan moan f@#k s@*t

If when you strip the cam towers off and the oil jet is not blocked then, you have to look at the oilways in the towers. A lot of owners forget to check the oilways in the towers. When you find out what caused the problem and rebuild, when you start the engine do so, with the tappet covers off. This way you can see if oil is feeding the cam  ;)
 
You have not said, if the engine was media blast cleaned.
No media blasting was done just careful pre cleaning of all components with cans and cans of parts cleaner on assembly. When the head and block was off initially I degreased them, washed, then steam cleaned all the hard to get to passageways before spraying out with parts cleaner before assembling

I was double careful of all the tower oil passageways, metering jets ×2.

When I got the engine the bottom end was together just the barrels and head taken off, it had been taken apart by a friend who was a careful and had covered the opening with bubble wrap. I should have probably flushed out the crankcase then somehow but for some reason didn't. I stripped the oil pump completely, there was sludge on the mesh with what looked like possibly a little of rubber hose shavings... I later had to split the cases to get to the gearbox so made sure that whole area was spotless as could be with careful cleaning of the inside cases and with all remnants of the pervious sealant got rid off.

I wished I'd maybe used a cheap light engine oil and changed it after a few initial start ups/miles to help just flush the system then used the decent 15/40... might have spared this pain but maybe wishful hindsight thinking... F*#K!!!!!

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Offline Oddjob

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Re: Help! What's caused this?
« Reply #28 on: March 26, 2022, 03:18:10 PM »
At least it's a 750 and is repairable, if it was a 500 you'd have ruined the head, cam and camcover. Count your blessings, could have seized when you were riding it.
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Offline McCabe-Thiele (Ted)

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Re: Help! What's caused this?
« Reply #29 on: March 26, 2022, 06:15:50 PM »
A very disturbing / scary post it will be informative to read what you find was the cause of the oil starvation.

If you are like me after beating yourself up you will find the cause and get it sorted best of luck with the investigation.
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