Author Topic: CB 750 K2 oilmpan debris mystery  (Read 5517 times)

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Offline Hastenbrucke

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Re: CB 750 K2 oilmpan debris mystery
« Reply #25 on: September 22, 2013, 11:04:33 PM »
 :-\ Thanks Scottly ...I will buy you one Heineken LOL ....well the decision is clear ....pull the engine out and start at the top and go down to bottom and rebuild.Hopefully we can get all we need to complete the job..crankshaft if required might be interesting. Thankfully ACE is in the picture with this ..he is the one with the knowledge, I just assist where I can.
At least I will know its all as it should be in the end and that's what I wanted. Better now that after a catastrophic event!!!!!
My bike picture attached...

Offline 754

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Re: CB 750 K2 oilmpan debris mystery
« Reply #26 on: September 22, 2013, 11:12:12 PM »
Wow..nice bike..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline lucky

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Re: CB 750 K2 oilmpan debris mystery
« Reply #27 on: September 22, 2013, 11:19:07 PM »
One other idea.
The photo made it look like very large pieces except that then I realized the largest piece of debris is only half the diameter of that beer bottle cap.
So that piece is not that big really.
Now I want to ask. IS the drain plug in the oil pan stock or does it have a helicoil?

The pieces look like chips from a drilling operation.

Offline Hastenbrucke

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Re: CB 750 K2 oilmpan debris mystery
« Reply #28 on: September 23, 2013, 02:57:25 AM »
Hey Lucky...no it's stock. Agree ..shavings???

Offline Ace

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Re: CB 750 K2 oilmpan debris mystery
« Reply #29 on: September 27, 2013, 09:25:15 PM »
Who said rod bearing material?!

Pulled the cases apart and #2 rod in the past had let go and someone repaired it.  Marks in the case lucky it didn't punch a hole in it. Whoever did it didn't clean the cases out very well and broke a few bearing retainer clips, didn't tighten all the bolts, stripped cam tower holder threads.  Cam is darker on #3/#4 end than #1/#2. Rubber oring under the cam tower on the #4 side didn't seat properly so over tighten the cam holder bolts to try to get it to sit square. I'll pull the rods off and have a look and check bearing shells to ensure they are all good. Another post about the oil pump, blackish/blue cam and now #2 rod area case marks, seems like not enough oil and bang IMO. The crank bearings on the outside (not where the crank runs on the bearings) look blue as well from heat, so I'm guessing they looked good enough to reuse so to save some cash that's what happened.

Everything else in the engine is in very good condition.

Thanks for you input!!
1971 CB750 K1 - Sold
1978 CB750 F2 Supersport - Sold
1981 CB900 Bol d'or - Sold
2006 CBR1100 XX Super Blackbird - Sold

Offline Pecantree

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Re: CB 750 K2 oilmpan debris mystery
« Reply #30 on: September 27, 2013, 09:44:07 PM »
Pictures?
Pretty please!
http://www.harvestclassic.org/

"The suspect had experienced a ballistic interlude earlier in the evening" Miss Pao said, "Regrettably not filmed, and relived himself of excess velocity by means of an ablative technique."         ......    ?    ........         "She say you have road rash."

Offline Ace

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Re: CB 750 K2 oilmpan debris mystery
« Reply #31 on: September 28, 2013, 04:07:52 AM »
Pictures?
Pretty please!

Ask and you shall receive.

So what's toast..cam, rocker arms?
1971 CB750 K1 - Sold
1978 CB750 F2 Supersport - Sold
1981 CB900 Bol d'or - Sold
2006 CBR1100 XX Super Blackbird - Sold

Offline Hastenbrucke

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Re: CB 750 K2 oilmpan debris mystery
« Reply #32 on: September 28, 2013, 04:09:19 AM »
All I can say is I am very LUCKY to have found ACE, and that we all agreed to go ahead and drop the engine ...we found some VERY interesting issues caused I think by an oil pump problem at some stage and some dodgey repair work.
This forum is brilliant and I can tell you I have learnt so much in a short period of time.
Back in day I just gassed up and rode with no cares, now it's whole different story.
This is why I started the journey ...
Thanks again for all the help and advice

Offline Ace

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Re: CB 750 K2 oilmpan debris mystery
« Reply #33 on: September 28, 2013, 04:14:11 AM »
In the first picture you can see the marks on the case edge, look below and you can see a big piece broken off.
1971 CB750 K1 - Sold
1978 CB750 F2 Supersport - Sold
1981 CB900 Bol d'or - Sold
2006 CBR1100 XX Super Blackbird - Sold

Offline 754

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Re: CB 750 K2 oilmpan debris mystery
« Reply #34 on: September 28, 2013, 07:54:48 AM »
That is what you call minimal damage, after breaking a rod...usually much worse..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way