Author Topic: Bat out of hell Build  (Read 27407 times)

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Offline 1980cm400t

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Re: Bat out of hell Build
« Reply #75 on: August 12, 2011, 06:44:00 AM »
While waiting for what might be the correct piston I pulled the carbs apart.  They are the worst I have ever seen.  The floats were ruined and there is a measurably thick layer of varnish on everything.  I'm going to have to get a bucket of b12 the spray alone isn't going to cut it.




Offline Really?

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Re: Bat out of hell Build
« Reply #76 on: August 12, 2011, 08:11:09 AM »
The bucket of B12 would be good.  I hear that it is not as good as it used to be though.

HF also has a decent ultrasonic cleaner at a good price, better with the 20% off coupon.

I actually do both when cleaning the carbs, along with some wire for the small holes.
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline 1980cm400t

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Re: Bat out of hell Build
« Reply #77 on: August 12, 2011, 10:48:09 AM »
B12 used to be better!? The stuff i have burns through nitrile gloves instantly!  The ultrasonic cleaner is tempting but my budget is a bit tight at the moment I think I'm going to try to improvise something first.

Offline Really?

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Re: Bat out of hell Build
« Reply #78 on: August 12, 2011, 12:25:54 PM »
I read that it is not as strong as it used to be.  Like they changed up the misture in the can.  If the can is one of the older ones....
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline 1980cm400t

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Re: Bat out of hell Build
« Reply #79 on: August 15, 2011, 06:42:20 AM »
My second attempt to get the right pistons did not work out.  I bought at new 78-79 piston and the weight was 197 grams.  The piston probably would have been the right mass except for the parts that had been ground down/cast differently.  The intake portion was depressed and the oil ports to the piston rod were larger than the original pistons.  So as of now 80-81 pistons are too heavy, and 78-79 are too light and have a different intake casting.  The bike I'm working on probably had 79 pistons that they didn't bother to machine to 79 specs.  I have one more dealership to call and then I will have to use my modified 80-81 pistons and hope that overheating isn't an issue because the pistons I need probably don't exist :-\




Offline Really?

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Re: Bat out of hell Build
« Reply #80 on: August 15, 2011, 07:58:47 AM »
You make me happy knowing I never had to pull the one I had apart!  :)

Keep posting, I am watching your build.  I just wished I could be helpful.
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline 1980cm400t

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Re: Bat out of hell Build
« Reply #81 on: August 19, 2011, 06:25:27 AM »
I think I'm out of strikes on finding the right piston.  I bought another new old stock piston from a dealer in California that was listed for the 78-79 xs1100s.  It did not have the the intake cutout or enlarged piston rod oil ports that the last one did but it weighed in at 197 grams (4 grams too light).  So lesson learned: If Yamaha lists 2 different part numbers for pistons there are at least 4 different pistons within these part numbers. :-\  I'm giving up on trying to find an identical match to the original pistons instead I will use the heavy ones that I ground down to the correct mass

Offline 1980cm400t

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Re: Bat out of hell Build
« Reply #82 on: August 24, 2011, 09:14:53 AM »
It turns out the b12 chem tool in the soak can is not the same chemical as in the spray cans.  I soaked each carb for a full 24 hours and was not particularly impressed they are definitely usable but not nearly as clean and shiny as the last set I did.  The carbs had 3 stuck pilot screws and 2 stuck slow jets which came out easily enough with reversed direction drill bits and screw extractors.  I'm currently waiting on a tread chaser (one of the pilot screws left its threads in the carb body).  I have heard that running carbs through the dishwasher is effective so I will probably give that a shot. 

Offline Lostboy Steve

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Bat out of hell Build
« Reply #83 on: August 24, 2011, 09:18:37 AM »
Lacquer thinner worked well for me.


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Offline 1980cm400t

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Re: Bat out of hell Build
« Reply #84 on: August 25, 2011, 07:07:17 AM »
Ran the carbs through the dishwasher on pots and pans setting with lots of liquid cascade.  It got all the dirt and grime out of the nooks and crannys that was not removed with carb cleaner and a toothbrush.  The drawback was the cascade cause some corrosion of the aluminum carb bodies and bowls.  I'm going to soak them for another 24 hours in b12 which will hopefully remove the corrosion (it seemed to remove the corrosion well before)

Offline lucky

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Re: Bat out of hell Build
« Reply #85 on: August 25, 2011, 08:21:33 PM »
Would you  p l e a s e  spray down that right side of that engine with WD40! Thanks

Offline 1980cm400t

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Re: Bat out of hell Build
« Reply #86 on: August 26, 2011, 06:22:40 AM »
Don't worry the engine doesn't even look like that anymore I'm just waiting to get it all assembled before I post a picture

Offline 1980cm400t

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Re: Bat out of hell Build
« Reply #87 on: August 30, 2011, 06:51:30 AM »
I made good use of the hurricane and finished rebuilding the carbs.  These were easily the worst i have ever seen in terms of varnish buildup.  My cleaning procedure was the following: spray down with b12 and scrub exteriors with a toothbrush, soak for 24 hours in b12, run through dishwasher on pots and pans setting with liquid cascade, soak for another 24 hours in b12, spray down with wd40 and reassemble.  In anticipation of pod filters and straight pipes I installed 125 main jets, 42.5 slow jets and moved the needle up 2 notches (I suspect this will be a little lean but I won't know until I get the engine together).



Offline Really?

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Re: Bat out of hell Build
« Reply #88 on: August 30, 2011, 07:02:17 AM »
They look clean on the outside.  Hopefully they are just as clean on the inside.  Dya use compressed air through all the holes?

Every once in a while I look for one of these bikes.  I need redemption. :)  So, it is good for me to see what you are going through. :)
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline 1980cm400t

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Re: Bat out of hell Build
« Reply #89 on: August 30, 2011, 11:15:59 AM »
after the 1st 24 hours in the b12 the insides were good no compressed air necessary.  I did have to use reversed direction drill bits and screw extractors on 3 of the slow jets and 3 of the pilot screws.

Offline 1980cm400t

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Re: Bat out of hell Build
« Reply #90 on: September 12, 2011, 06:32:51 AM »
The engine is now finished.  Everything is cleaned, painted, and assembled ready to be dropped into the frame.  I replaced all the original hex cap bolts with stainless steel replacements.  Although it may be technically possible to used 2nd oversize rings and cut them to fit the standard size bore I found it extremely difficult to compress the rings either by hand or with hose clamps.  After hours of frustration and several cracked fingernails I ended up ordering the standard bore rings (which fortunately were now available).  The standards were much easier to install.   










Offline Really?

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Re: Bat out of hell Build
« Reply #91 on: September 12, 2011, 06:38:55 AM »
Looking good.  I am looking forward to seeing it run.
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline lucky

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Re: Bat out of hell Build
« Reply #92 on: September 12, 2011, 02:06:08 PM »
The engine is now finished.  Everything is cleaned, painted, and assembled ready to be dropped into the frame.  I replaced all the original hex cap bolts with stainless steel replacements.  Although it may be technically possible to used 2nd oversize rings and cut them to fit the standard size bore I found it extremely difficult to compress the rings either by hand or with hose clamps.  After hours of frustration and several cracked fingernails I ended up ordering the standard bore rings (which fortunately were now available).  The standards were much easier to install.   










Using 2nd oversize rings and cutting them down would be disaterous!!! Good thing you did not do it.

Offline 1980cm400t

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Re: Bat out of hell Build
« Reply #93 on: April 06, 2012, 11:49:47 AM »
It has been a while since I posted an update (a result of moving across the country).  The bike is now out of the basement i was building it in and is now more conveniently stored in a garage.  The Clymer manual says that then engine requires 3 people to install. I wish I read that before I put it back in with 2 people.  The Engine is now installed and torqued in the only engine bolts that need to be torqued are the final drive bolts.  Does anyone know where I can get a long (around 3") crowfoot 6 point 12mm wrench?  There is not enough clearance to fit a socket in there and I have to put 76 ft-lbs on it.  I got new carb insulators and installed them, the carbs and the velocity stacks that i salvaged from the airbox.  54mm pod filters are on the way.  I suspect I will have to cut the velocity stacks down to give the filters enough clearance to fit in the frame.














Offline Mcwilliams570

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Re: Bat out of hell Build
« Reply #94 on: April 06, 2012, 12:02:38 PM »
Bike is looking good glad to see you back..

Matt
My CB550 project http://forums.sohc4.net/index.php?topic=101182.0

Project UFB Cb550 http://forums.sohc4.net/index.php?topic=112143.0

Like a 10 dollar hooker on Friday night its going to be ridden.

1974 cb550
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1981 gl500i

Offline Free Booter

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Re: Bat out of hell Build
« Reply #95 on: April 10, 2012, 07:23:46 AM »
While waiting for what might be the correct piston I pulled the carbs apart.  They are the worst I have ever seen. 

No sir (and not trying to thread jack LOL) THESE are the worst carbs you've ever seen...



You are welcome! heheheh

Offline 1980cm400t

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Re: Bat out of hell Build
« Reply #96 on: April 22, 2012, 10:31:40 AM »
I tried using acetic acid (i.e. vinegar) to remove the rust from the tach and speedo covers It worked pretty well.  It does take a while the results below are from a 2 week soak.  I had to keep the lid vented as it did offgas a bit, I did not remove 2 bolts that were rusted to the cover.  The vinegar unfroze them but it also turned them from an M6 to and M5 bolt size so i'll have to replace them. After 2 weeks there still is  pitting on the inside but most of the rust is gone.  It took longer than it would to have to do it with a wire brush but i was able to do other things in the mean time.

Before




After



Offline OneWheelDrive

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Re: Bat out of hell Build
« Reply #97 on: April 22, 2012, 10:51:55 AM »
Wow!  That's an amazing result!  Any idea how to soak fenders  :o?
1975 CB550 cafe
1971 CB500 stocker
2008 Ducati Hypermotard 1100S *sold*
1973 CB350F *sold*
1975 CB550K Project "Keeper" *sold*
2010 Ducati Monster S4RS *sold*
1976 CB360T *sold*
1974 CB550K *sold*
1973 CB750K *sold*
1978 CB550K *sold*
2007 Vespa LX150 *sold*

Offline Really?

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Re: Bat out of hell Build
« Reply #98 on: April 22, 2012, 03:52:24 PM »
Ahhhh, she is back!  (the bike that is)
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline 1980cm400t

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Re: Bat out of hell Build
« Reply #99 on: May 04, 2012, 07:16:53 PM »
To soak fenders try a wheelbarrow and soak it 1/2 at a time?  I don't know where you can buy 40 gallons of vinegar though.