Author Topic: 1972 CB750K2 (start from scratch) project. Cases back together  (Read 99259 times)

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Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #50 on: October 24, 2014, 07:54:06 AM »
So, I'm at a little standstill with my project due to some car problems that I had to fix first. (responsibility ugh!) I want to get going with it again soon, but I would like some advice/opinions before I do. My questions are concerning the crankshaft and connecting rods. My plans for the engine are ported /polished head, wiseco 836 kit, HD studs and primary chains. I checked the crankshaft bearings which were all well within spec. As I was about to check the rod bearings I stopped because I'm not sure what I should do. I don't know if I should remove rod bolts, check bearings and reuse (can't tell if they've ever been taken apart) Get new rod bolts (seem hard to find and expensive, plus read factory rods could be weak link here ) or with everything else I am doing just go with lightened and balanced crank/forged rods from cyclex. (not sure if this would be overkill) I'm not afraid to spend the money for the right parts to do this right, I just don't want to waste $$. I'm split down the middle on this one so any advice and past experience from you all wold be greatly appreciated! Thanks!

Offline edwardmorris

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #51 on: October 24, 2014, 12:20:39 PM »
Have JMR save a set of the stronger F2 connecting rod bolts and nuts when he can procure some from Honda (I'm in line ahead of you, they may be more). For the bearings, if they're in spec, I just replace with same color for peace of mind (unnecessary I know, but oh well). Standard rods *should* be fine for 836 but if I'm wrong, please any of the masters here, step in :)

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #52 on: October 24, 2014, 02:51:29 PM »
I think they should be fine, but I ride a lot and want peace of mind so I'm torn.

Offline calj737

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #53 on: October 24, 2014, 02:53:32 PM »
Well, if you're feeling sporty, you could always upgrade to a set of Carillos and dispense with the worries over the stock/possibly worn rod bolts. Or, get some ARP bolts if there's an application for your stock rods.
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"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #54 on: October 24, 2014, 08:20:25 PM »
Well, if you're feeling sporty, you could always upgrade to a set of Carillos and dispense with the worries over the stock/possibly worn rod bolts. Or, get some ARP bolts if there's an application for your stock rods.
I was looking at arp, but would be a custom order and pricy for 8 bolts/nuts. Really leaning toward cycle x rods/bolts now, getting my stock crank balanced as well.

Offline edwardmorris

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #55 on: October 26, 2014, 09:49:00 AM »
Dave,

     Found this when searching around for my own 836 build. If you haven't already, give this a read

     http://forums.sohc4.net/index.php?topic=135886.msg1529730#msg1529730

     Covers a lot of ground, should answer your stock rods question, among others ;)

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #56 on: October 26, 2014, 10:04:59 AM »
Dave,

     Found this when searching around for my own 836 build. If you haven't already, give this a read

     http://forums.sohc4.net/index.php?topic=135886.msg1529730#msg1529730

     Covers a lot of ground, should answer your stock rods question, among others ;)

Awesome thanks!

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #57 on: October 27, 2014, 07:40:12 PM »
Got my cylinder head back from Mike Rieck today. Wow! Very happy!

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #58 on: October 27, 2014, 07:48:05 PM »




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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #59 on: October 27, 2014, 07:54:34 PM »
Another satisfied MR customer.  Gotta love the personalized engraving on the head, too!   ;D
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2008 Triumph Thruxton (http://forums.sohc4.net/index.php/topic,190956.0.html)
2014 MV Agusta Brutale Dragster 800
2015 Yamaha FZ-09 (http://forums.sohc4.net/index.php/topic,186861.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html and https://magazine.cycleworld.com/article/1995/3/1/song-of-the-sausage-creature)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html) - Sold

Offline edwardmorris

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #60 on: October 27, 2014, 09:22:25 PM »
Post up some pix of those nice Stage 2 ports please, would love to get an idea how extensive Stage 2 is.

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #61 on: October 27, 2014, 10:55:21 PM »

Post up some pix of those nice Stage 2 ports please, would love to get an idea how extensive Stage 2 is.
Here ya go...




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Offline calj737

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #62 on: October 28, 2014, 05:21:09 AM »
Stock replacement springs, Dave? And stock size valves? Did you have Mike do a Serdi cut on the head?
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"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #63 on: October 28, 2014, 07:09:58 AM »
Stock replacement springs, Dave? And stock size valves? Did you have Mike do a Serdi cut on the head?

Yes, yes, and yes  :D

Offline calj737

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #64 on: October 28, 2014, 07:22:06 AM »
well that should be a nice little wake-up to the motor.
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"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline edwardmorris

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #65 on: October 28, 2014, 08:05:19 AM »
Ports look great! Any word on what cam you're going with yet?

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #66 on: October 28, 2014, 01:08:02 PM »
Ports look great! Any word on what cam you're going with yet?

I wish I knew. Definitely not my area of expertise. I'm going to use the wiseco 836 10.25/1 pistons. I want to take advantage of the extra displacement and flow through the head, but I still want a very street-able bike.  I ride pretty much daily so I want something that has a pretty broad range, nothing extreme. Very open to suggestions/experiences!!

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #67 on: October 31, 2014, 01:57:47 PM »
So, I'm at a little standstill with my project due to some car problems that I had to fix first. (responsibility ugh!) I want to get going with it again soon, but I would like some advice/opinions before I do. My questions are concerning the crankshaft and connecting rods. My plans for the engine are ported /polished head, wiseco 836 kit, HD studs and primary chains. I checked the crankshaft bearings which were all well within spec. As I was about to check the rod bearings I stopped because I'm not sure what I should do. I don't know if I should remove rod bolts, check bearings and reuse (can't tell if they've ever been taken apart) Get new rod bolts (seem hard to find and expensive, plus read factory rods could be weak link here ) or with everything else I am doing just go with lightened and balanced crank/forged rods from cyclex. (not sure if this would be overkill) I'm not afraid to spend the money for the right parts to do this right, I just don't want to waste $$. I'm split down the middle on this one so any advice and past experience from you all wold be greatly appreciated! Thanks!

I've decided to use factory rods and crank, with new F2 rod bolts and nuts (supposedly stronger?). Crank and alternator are getting balanced right now. Ordered rod bolts 1 week ago and they already showed up yesterday. They look the same as what I have already, did I get the right ones? part number is 13213-kv0-000



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« Last Edit: October 31, 2014, 02:49:24 PM by Davez134 »

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #68 on: November 13, 2014, 08:27:43 AM »
Making slow progress, mostly trying to locate parts. Some showed up today...



Got a deal on swingarm, complete triple tree from Dennis (Old Scrambler) so I can get frame mocked up, then powder coated.


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Offline edwardmorris

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #69 on: November 13, 2014, 09:20:11 AM »
I just saw Wiseco and Forged in one of the pix, here is some reading you might wanna glance over, been doing some research myself, thought I'd save you some time ;)

http://forums.sohc4.net/index.php?topic=132990.msg1489322#msg1489322

http://forums.sohc4.net/index.php?topic=75828.msg847562#msg847562

http://forums.sohc4.net/index.php?topic=85642.msg971049#msg971049

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #70 on: November 13, 2014, 10:50:37 AM »
I just saw Wiseco and Forged in one of the pix, here is some reading you might wanna glance over, been doing some research myself, thought I'd save you some time ;)

http://forums.sohc4.net/index.php?topic=132990.msg1489322#msg1489322

http://forums.sohc4.net/index.php?topic=75828.msg847562#msg847562

http://forums.sohc4.net/index.php?topic=85642.msg971049#msg971049
Thanks! Have seen the first link, just read through the other two. Same Pistons I have in my other bike, have a little over 8000 miles on em since my top end rebuild, and who knows how many before that as I just switched out the rings. Going to read a little more on the subject before taking to machine shop for peace of mind though.

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #71 on: November 13, 2014, 11:10:00 AM »
These are what the pistons look like. Same "height" as Honda pistons, but with more pronounced "u" shape cutaway on skirts as I saw mentioned in the linked posts. Also noticed no oiling holes under piston pins like stockers I have to compare to...



 Packaging states .0020 piston to bore clearance

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« Last Edit: November 13, 2014, 02:14:05 PM by Davez134 »

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #72 on: November 15, 2014, 01:40:37 PM »
One down, one to go...



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Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #73 on: December 03, 2014, 04:18:47 PM »
Been trying to get the nasty paint off cases, and finally got my cylinders bored for 836cc pistons. Almost done with cases...


Here are cylinders. Bored, surface trued, media blasted old paint off.

Must have blasted after surfacing as I noticed this rough spot in next picture. It's in front of number 4 cylinder around the hole dowell goes into. Surface is still true there using my strait edge, just feels a little rough. Is this anything I should worry about?



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« Last Edit: December 03, 2014, 04:24:39 PM by Davez134 »

Offline Davez134

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Re: 1972 CB750K2 (start from scratch) project. Small leak!!! Damn!
« Reply #74 on: December 06, 2014, 06:58:56 PM »
Welded/repaired chipped fin. Going to do final shaping tomorrow, then clean/paint.



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