Author Topic: Project Awesome  (Read 5449 times)

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laminarflowone

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Re: Project: CB750 Ebony
« Reply #25 on: August 02, 2010, 07:25:25 PM »
I probably could have bought one, but then I would have to bike all the way to Home Depot to get it (over 20mi round trip), and with my professor working me like a slave driver, it really wasn't going to happen till the weekend.

Plus, when you Mcgyver something and it works, its 10x more satisfying.

I'm hoping tomorrow I'll be able to take apart the engine and see the State of the Union.  Those screws worry me, but we shall see...

Offline Roach Carver

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Re: Project: CB750 Ebony
« Reply #26 on: August 03, 2010, 06:52:53 AM »
Give those screws a try with the reg screw driver but if they dont want to budge, dont bur the heads. once you do the job gets a LOT tougher. You could order a cheap impact and it will be to your door in a few days. This is one of those must have tools in my opinion. Good luck either way.

laminarflowone

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Re: Project: CB750 Ebony
« Reply #27 on: August 03, 2010, 02:16:13 PM »
The screws weren't that bad on the top case, for the most part.  The valves also came off with relative ease.  Using my cheapo corded drill and lots of pressure from leaning my entire body up against the drill, the screws ended up coming out. 



Valve cover removed:



However, at two screws, they were stuck pretty good.  One just needed a little coercing with a screw extractor because the PO stripped it pretty nicely.  The other one, was so rusted that the head snapped off when I tried to unscrew it.



Still couldn't get this one out even with the screw extractor...



So I moved up to a bigger-sized extractor...and CRACK!  You can see here, that the threads had rusted and cold-welded to the casing. 


Offline Roach Carver

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Re: Project: CB750 Ebony
« Reply #28 on: August 03, 2010, 02:18:49 PM »
when I get a steel bolt stuck in aluminum due to corrosion I have had a lot of success heating the area with a torch and then using wax on the threads. has worked for me many times.

laminarflowone

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Re: Project: CB750 Ebony
« Reply #29 on: August 03, 2010, 02:22:44 PM »
Yeah, I tried that as well as some penetrating lubricant I picked up at the hardware store to no luck.  Many of the bolts I have found on this bike have been so severely over-tightened that the metals have cold-welded to another.  The PO PO must have been a real brute or the bike must have experienced such severe changes in temperature or both for this to happen...it sucks.

laminarflowone

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Re: Project: CB750 Ebony
« Reply #30 on: August 03, 2010, 04:53:13 PM »
Yup, this sucks. My house-mate's gf is around and eating all of my food in the fridge and then complaining about it, not to mention, my engine is giving me 'tude....

I tried to take off the screw, but the extractor ended up breaking the bolt housing of the center cover of the cam housing...sucks.  It broke off at the beginning of the cam housing, which doesn't help the situation at all because the bolt is still stuck.  Turns out, it was impervious to heat and other methods because it was cross-threaded...



Still can't get it out...The hole extends down the bolt, but the bolt broke in such a fashion that it is essentially impossible to grab whats left with vice grips.....

In addition, I found some small cracks under the center cover.  Should I be concerned?  My camera phone doesn't quite capture it, so I might have to borrow someones camera.
« Last Edit: August 03, 2010, 04:55:08 PM by laminarflowone »

Offline fastbroshi

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Re: Project: CB750 Ebony
« Reply #31 on: August 03, 2010, 06:00:40 PM »
   Seems like you're going to the extractor pretty quick.  I'd use an impact before I used an extractor.  That's a last resort for me as I've always been afraid of breaking one off.  Are you using the correct screwdriver?  These screws tend to use JIS or Japanese Industrial Standard screws.  The head of your phillips should fit well will no slop. 
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laminarflowone

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Re: Project: CB750 Ebony
« Reply #32 on: August 03, 2010, 06:23:51 PM »
I hope it doesn't seem like that...I only go to the extractor after there seems like no hope at the end of the tunnel.  I legit tried everything listed in the forums, but some of these bolts are just doggone stuck.  Maybe with fresh eyes on it tomorrow, I can figure out how to take it out, but it looks like I'll need a new cover...or at least bore it out and insert a helicoil...this sucks.

Any suggestions how to remove this stubborn bolt?  Also, are the 1978 head breather covers compatible with my 1976K model?
« Last Edit: August 03, 2010, 06:43:02 PM by laminarflowone »

Offline Roach Carver

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Re: Project: CB750 Ebony
« Reply #33 on: August 04, 2010, 06:26:37 AM »
just so I am clear... You heated the bolt to red hot and tried wax. not penetrating oil. Right? penetrating oil in this situation just vaporizes on contact with the heat. wax is actually pulled by the heat down into the threads.It has worked for me every time I have tried it, but I am sure there is a situation that it wont work. If you have done that you may just have to drill it or take it to a machine shop.

laminarflowone

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Re: Project: CB750 Ebony
« Reply #34 on: August 04, 2010, 08:23:49 AM »
I used penetrating liquid/oil (not sure exactly what is in it).  What kind of wax is this and where can I pick some up?  Hopefully this will be save the cam case!!

Offline Roach Carver

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Re: Project: CB750 Ebony
« Reply #35 on: August 04, 2010, 12:18:36 PM »
I just use candle wax. you may not have enough to work with now though.

laminarflowone

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Re: Project: CB750 Ebony
« Reply #36 on: August 04, 2010, 12:53:03 PM »
I went to CVS and picked up a tub of parafin wax, which is one of the major components of candle wax, and tried to warm the bolt very gently with my mapp gas burner.  I then proceeded to turn the bolt extractor very gently, until a bolt chunk came out.  The bolt has broken into little sections and upon closer examination, nearly all the pitch rounds were cross-threaded...

THANK YOU PO!!!

So, there is a small portion of the bolt leftover inside.  The only thing left to do is to insert a helicoil.  There is a local company that makes similar products, and I will just have to stop by this weekend or the next, and bring the cam housing to Hampshire College's machine shop (which they have graciously allowed me access to...for my thesis...) and carefully bore out the hole.  I hope when I take apart the engine, there aren't any more nasty surprises...

Offline Ecosse

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Re: Project: CB750 Ebony
« Reply #37 on: August 04, 2010, 03:31:18 PM »
... and bring the cam housing to Hampshire College's machine shop (which they have graciously allowed me access to...for my thesis...)

for your thesis... riiiiight.  ;)

all i can say is when you emerge from the other end of this you'll have a sense of self the other guy on the (insert bike of choice) cannot comprehend.

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laminarflowone

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Re: Project: CB750 Ebony
« Reply #38 on: August 04, 2010, 04:19:26 PM »
Yeah, this bike is the same love-hate relationship I have with my research. 

Mostly love though...

The cam cover off:



Camshaft exposed:  Is this the right color, because I have seen in other project threads a more brownish tint?



More nekedness:



Rotated crankshaft with marking at the end parallel to the cylinder head:



Remove cam chain tensioner:



Then start removing rocker bolts, etc.



Ghettoliscious parts table:



laminarflowone

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Re: Project: CB750 Ebony
« Reply #39 on: August 05, 2010, 02:36:29 PM »
Question, how does one know its it is time to replace cam parts?

My lil' rockers:



Camshaft:



Also, I can't seem to get the cam holder off.  Anyone have any good tips?

« Last Edit: August 05, 2010, 05:21:39 PM by laminarflowone »

laminarflowone

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Re: Project: CB750 Ebony
« Reply #40 on: August 12, 2010, 06:31:55 PM »
I got the cam holders removed, and there was some visible wear on the rockers and the cam bearings especially:





I think I might spring for the polymer-coated rockers that cycle-x sells, and maybe a new camshaft or cam holder.  I'd rather not sell an arm and limb but if it will make it more reliable, it shall be done.

Good news is, I got my paint order from Eastwood lickity split.  I was genuinely surprised how fast they got the order to me, and they even threw in a free can of chassis cleaner for good measure.  Hopefully, this paint will last me for quite some time, but if I do have to order, I would definitely order from them again.



In contrast, the HVLP turbine sprayer that I ordered from Harbor Freight nearly a month ago still hasn't arrived.  They shipped me a cheap motorcycle stand instead, and then when I called them up asking for my HVLP spray system, they told me I had to ship the stand back to them at my expense....Ummmm, ok?  I tried asking for my product nicely, and that if they give me RMA postage and stuff I would send the stand back, but no, they wouldn't hear any of it.  I had to threaten them that I would dispute the charge on my AMEX until they agreed to ship the HVLP before I returned the stand...Yup, definitely not the best way to keep customers.
« Last Edit: August 12, 2010, 06:33:47 PM by laminarflowone »

laminarflowone

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Re: Project: CB750 Ebony
« Reply #41 on: August 14, 2010, 01:15:48 PM »
For a lazy Saturday afternoon, I took the cylinder head off, to find some nicely charcoaled pistons.  



A few loose crusty black particles in the cylinder second from the left.



My feeble camera-phone attempt at a detail shot...



Here is the cylinder head.  Everything has a thin coat of carbon, and if you look closely, you can see a little brown patch on the second to the left valve.  Rust?



I plan on venturing further into the case and check out the transmission because the PO did say the second gear sounded funny. 
« Last Edit: August 14, 2010, 01:47:27 PM by laminarflowone »

laminarflowone

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Re: Project: CB750 Ebony
« Reply #42 on: August 14, 2010, 02:33:44 PM »
A piece of the gasket broke off at some point, and some pieces were trapped in between the shifting paddle and such.  Not sure if that would make the 'noise.'



Taking a look at the pistons, there is some funny wear on the sides. It's mostly vertical, but there are some horizontal burrs thrown in the mix.





Not sure if these are fine or whether they should be replaced.  I still need to measure the parts to see if they are in spec.