Author Topic: CB750 K5 Build - Project "We don't need no steenkin' name!"  (Read 16740 times)

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Offline srbakker

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CB750 K5 Build - Project "We don't need no steenkin' name!"
« on: October 24, 2011, 09:01:19 PM »
So this is my very optimistic build thread.  I say optimistic because I fully expect this to take me 2-3 years all told - time is not necessarily on my side.  Also, this is my first full project of any kind and I'm accumulating tools and mechanical skills as I go.  You'll have to forgive me if I don't always display the sort of mechanical ingenuity I've come to expect in the other build threads I read about on this site.

That said, I can't thank all of you enough for all of the incredible information and access to your individual skills and photos.

On to the bike.  This is my 1975 CB750K5 as I first got her - chopperized!  No damage or cutting on the frame - everything was done with long fork tubes and lowering blocks on the rear, plus that seat, which speaks for itself.

The bike was running when I started, but in need of a clutch and a serious tune up.  However, it was not leaking any oil.



I bought myself a Clymer manual, a Honda shop manual and Hondaman's book is on the way.  Then, I proceeded to start the strip down.





...and that's kind of where I am today.

My vision is to a) get her running smoothly and b) clean her up immaculately.  It will not be going back to stock, nor will it be chopperized - I'm aiming at a sort of retro mod, ie: updated electrics, updated suspension (to a point), but enough of the original look to be immediately identified as a CB750.  I'm planning to tear down the engine to the cases, and thinking about an 836 kit and maybe some head work as well. It won't be cafe or flat tracker, but might have some elements of both.  I've followed a lot of threads, but especially Free Booter's and Spiider's builds - sorry guys, I promise it won't be too much of a clone!

The most immediate task at hand is to pick a good name for her.   :P
I was initially thinking Whiskey Runner because of my inclination toward a good bottle of Scotch, but so far the bike doesn't really fit the name.

I'll try to post some progress pics tomorrow, but it's a bit slim at the moment.  I fully intend to do this over a couple of years - I have small kids who need me, a very demanding career, and a wife I'm lucky loves me enough to monopolize her own chunk of my time.  Cheers!
« Last Edit: February 23, 2012, 10:02:29 AM by srbakker »
1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)

Offline Retro Rocket

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Re: CB750 K5 Build - As Yet Unnamed
« Reply #1 on: October 25, 2011, 01:32:18 AM »
Quote
The most immediate task at hand is to pick a good name for her.   :P
I was initially thinking Whiskey Runner because of my inclination toward a good bottle of Scotch, but so far the bike doesn't really fit the name.

How about Brat Wurst......   Sorry, couldn't help myself...... ;D ;)
750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
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Offline lucky

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Re: CB750 K5 Build - As Yet Unnamed
« Reply #2 on: October 25, 2011, 11:27:55 AM »
Think about a name later. Not necessary. You do not need that distraction right now.
I would get it clear in your head what you are building.

Offline srbakker

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Re: CB750 K5 Build - As Yet Unnamed
« Reply #3 on: October 25, 2011, 12:26:31 PM »
Think about a name later. Not necessary. You do not need that distraction right now.
I would get it clear in your head what you are building.

That was sort of tongue in cheek.  I'm not really that worried about a name.  However - I am open to suggestions.  At this rate, it's going to end up being something like "Sausage Party," and I'll have to have someone laser etch little Germans in lederhosen all over the side cover or something.
1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)

Offline srbakker

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Re: CB750 K5 Build - As Yet Unnamed
« Reply #4 on: October 25, 2011, 01:27:10 PM »
As promised, I snapped a few pictures today. 

I've now got the frame stripped - the engine is still sitting on it until I'm ready to start that rebuild, hopefully early in the new year.



I'm developing a growing hoard of things I don't intend to reuse - either tossed completely or replaced with something newer and lighter.  That said, I don't really want to get rid of any of it yet - you know, just in case!



My first try at polishing.  It looks a lot better in person.  To me, anyway.  Honest.



The sprocket cover, drilled out and painted up.



Anubis Cycles work on my rotor.  I could not be happier - it's as good as he claims.



Battery box, stripped, primed and painted, now sitting where it will in all likelihood live for the next 2 years.  At least it's a decent AGM battery.



My seat - salvaged from a pan that was in good shape, completely refoamed and covered in marine vinyl by a local place, and not too expensive either.  It's quite comfy.



A side cover Andrew (Little_Horse from this site) is working on for me - I plan to run a polished stock oil tank on the other side.

1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)

Offline srbakker

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Re: CB750 K5 Build - As Yet Unnamed
« Reply #5 on: October 25, 2011, 03:28:55 PM »
Hmm.  Got a bit of a surprise today - I brought my wheels to my usual shop to have the tires removed.  After picking them up and humping them into the garage, I noticed that the rear rim and tire are 16", as shown below.





What have I got here?  An HD rim mounted to a stock hub?

I was intending to run stock hubs and rims.  Is there any advantage to keeping the 16" rear, other then the 130 width tire it seems to accomodate pretty easily?  Or, for what is intended to be a sporty build, should I fish up a stock 18" rim?  Or maybe there's another option, like a slightly wider then stock 18"?

Thanks!
Scott
1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)

Offline harisuluv

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Re: CB750 K5 Build - As Yet Unnamed
« Reply #6 on: October 25, 2011, 08:23:44 PM »
Hey srbakker!  That indeed looks like a classic harley rim on a stock hub.  Those harley 16" rims have a much more pronounced ridge where the spokes connect to the rim.  If it were me I would just get my hands on a 18" rim.  In my experience it can be hard finding one that isn't tweaked too bad, your best bet maybe is to buy a new one.  They aren't as incredibly expensive as you might think, they run about $110 brand new OEM.  Of course you would need some new spokes, as those harley ones won't accomodate.

By the way I think you bought a set of my rebuilt carbs from ebay!  Didn't know you were a member here.  I hope they are on your bike and running well! 
« Last Edit: October 25, 2011, 08:25:38 PM by harisuluv »

Offline srbakker

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CB750 K5 Build - As Yet Unnamed
« Reply #7 on: October 25, 2011, 08:31:31 PM »
Ha - thought I recognized that name! Yep, I bought your carbs, but as you can see the bike isn't precisely in running shape.  Made for good eBay feedback though.
1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)

Offline bluesmoke69

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Re: CB750 K5 Build - As Yet Unnamed
« Reply #8 on: October 25, 2011, 09:48:24 PM »
Looking good so far. I like how the seat turned out.

Offline harisuluv

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Re: CB750 K5 Build - As Yet Unnamed
« Reply #9 on: October 26, 2011, 01:51:41 AM »
Ohhh yeah all I noticed was that the carbs were off!  I was rifling through the pictures to find a pic of them :(

Offline srbakker

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Re: CB750 K5 Build - As Yet Unnamed
« Reply #10 on: November 27, 2011, 06:52:31 AM »
Not too much to add because I've been insanely busy with work (however, did get a week off to go to Montreal and drink too much, so I can't really complain).

I finished up my master cylinder:







I worked with Little Horse (ok, HE worked and I sent him some sketches and measurements - I am going to have to learn to machine things if this project is going to progress much more) to redevelop my left side cover, and this is what I currently have - fits nicely too!





I found an excellent condition 18" rear rim for cheap, so now I need to clean it up and prep it for PC like the front.

I thought long and hard about my suspension set up and found these, which my very forgiving wife has yet to kick me out of bed for:



I have F forks, and I think I'll pair them up to Racetech emulators and non progressive springs when I get around to rebuilding them.
I'm also planning to add a steering damper - I'm concerned I may need it with the increased height of the rear shocks.
However - the F forks are also an inch longer - so now I'm at 14.5" in the rear and 1" longer the my K5 came with in the front.  Given that I'm 6'5" and a heavy bugger, the handling my still come out fairly neutral and any center of gravity issues will still be more my fault than the bikes.

Currently I'm rebuilding the front brakes so, the MC is done, the caliper is apart on my work desk for polishing and painting and new pads etc.  Stainless lines from Slingshot are also en route to my door as we speak - thanks pampodoro!

Now for today's big question:

My next big project is the engine.  I could greatly use some community advice here as I plan my build - I'm about a month or two from ordering my parts.  I don't want the cost to be stratospheric (my initial plan had me around $3000 with parts and machining), I want a great daily runner that still pulls hard.  If I had to guess, I'd say I want to pull around 55-60 hp at the rear wheel, reliably.

I do understand the importance of tuning, I do have Hondaman's book (and he's sent me some great PMs so far to help me out, so thanks for that!) and I am planning to have this dyno tuned by a local Honda guru when it's all said and done (I'll dial in the carbs to where I think it's butt-cheek acceptable, then get it down the road to the dyno guy).

Thing is - this will be my first engine build (of any kind) so I could use any advice you guys are willing to throw at me.  I have about 6 pages of handwritten notes from that thread where two other rookies rebuild from the ground up with the help of the community, so I'll be relying a lot on that and HMs book to steer me.

Here's what I'm currently thinking for the engine - flame away:  8)

I'm starting with a previously nicely running K5 engine with 19,000 original miles on it.  This plan also assumes that nothing is broken that will need fixing and that I don't break anything myself.

I have a nicely rebuild and cleaned up stock set of carbs I'll be using, with Tintops antiPod (on order for the next batch).  They are currently stock jetted - will worry about that later.

I was hoping to send the head off to MRieck to do some porting/polishing and valve matching, since the consensus I get is that cleaning up airflow into and through the head is probably one of the more effective things to do.  I assume I have a stock, and therefore, probably rough cast K5 head.

I will of course replace all the seals and rubber bits, if for no other reason then to lay hands on them and see what they all do and where they go (remember, my first time into this engine).

I was thinking of using the Cycle X spring kit with the hard anodized alloy retainers to help out the cleaned up head somewhat, and mating that to a slightly higher lift cam like the WebCam 41, 41A or maybe Cycle X's mild-mid grinds.  I was also planning to have new valve guides pushed in.

I will replace the cam chain tensioner assembly and guide, and use heavy duty cam chains.  I was also going to replace the primary chain and primary chain tensioner - is this likely to be useful or necessary?

I am planning to use heavy duty cylinder studs from APE or similar.

I was planning to switch the connecting rods nuts and bolts out for F2 nuts and bolts and I'm thinking of having the rods polished and shot peened (for peace of mind, and I can have it done fairly inexpensively).

While I'm in there, I'm going to rebuild the clutch pack with new friction disks and springs.

Of course, the pistons will get new rings - but this is where I can't make up my mind.  I had originally thought to get a Wiseco 836 kit put in and get the boring out done as well.  From reading around, it's seems like I'll have to worry more about my clearances with that kit and it maybe won't give me the extra 10 or so hp I was hoping for anyway.  Is this something I'm better off deciding once I actually get into it so I can see what the current tolerances are?  I mean, if I have to overbore, it probably is worth going for it, if I don't, maybe it isn't.  Any thoughts on bigger displacement?

All this will then be vented into some sort of 4-1 exhaust - likely a Kerker or one of Carpy's Yoshi knockoffs.

So that's where I am at present.  Cheers until next time.
1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)

Offline Flick

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Re: CB750 K5 Build - As Yet Unnamed
« Reply #11 on: November 27, 2011, 01:59:05 PM »
Wow that master cylinder looks great!! nice work
1971 CB750 - Cafe project

Offline srbakker

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Re: CB750 K5 Build - As Yet Unnamed
« Reply #12 on: November 29, 2011, 07:45:30 AM »
Thank you!

So... nobody has any thoughts/criticisms/advice on what I'm planning for my motor?  Do I have to bribe you with a healthy splash of fine single malt Scotch should you ever find yourself in my neck of the woods?  ;D
1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)

Offline Really?

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Re: CB750 K5 Build - As Yet Unnamed
« Reply #13 on: November 29, 2011, 08:00:22 AM »
That looks like a 16x3 drop center Harley rim laced to that hub.  I think it was old school but still popular today.  You can go either way you want on the size  16 or 18.  I am not sure but a 120 might be max on an 18" rim.  I think the 16" allowed the 130 because it is not as tall because it leaves a little more room at the swing arm.  I could be wrong but I could be right too, lol.  There are ways to to go wider but there is additional cost and some members that will only stay with the stock sizes and some members that are fine not staying with the stock sizes and they all have their opinions why.  I went for looks and to drop the bike a bit more.  I achieved my goal.

I am running a rim like that on the 750.  Pics in the sig.
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 srbakker

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CB750 K5 Build - As Yet Unnamed
« Reply #14 on: December 14, 2011, 05:23:08 AM »
Looks good, Really!

Finished up the front caliper and got my lines from Slingshot - really nicely made stuff.  Here's a few pics of the caliper - the bolts are titanium.  Found them on eBay for cheaper then I could find replacements.





Also making some progress on my engine plans.  Here's my list so far:

- Mike's Stage II port and polish w/ bronze valve guides
-bore, probably just first or second oversize, and new pistons/rings
-new cam - not quite sure what just yet
-new CycleX polished valves
-CycleX spring and hard anodized retainer set
-adjustable cam sprocket
-polish and shot peen rods, update to F2 rod nuts n bolts
-new HD studs (APE)
-new HD cam chain
-new cam chain roller/slider etc.
-of course, new gaskets and rubber bits
-clutch plates

I'm aiming at 70-75 hp.  Do those of you who do this frequently usually change the primary chains and primary tensioner as well?  Motor has only 19k miles on it.

Anything I'm missing?
« Last Edit: December 14, 2011, 05:32:23 AM by srbakker »
1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)

Offline K5owner

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Re: CB750 K5 Build - As Yet Unnamed
« Reply #15 on: December 14, 2011, 05:42:32 AM »
Not sure of a name for your bike, but I like what you're doing. Nice work! Look forward to your progress.  Thanks
-Ray
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Remembering the past...   Livn' the dream

1975 Honda CB750 K5, Restored Aug/2011
1971 Honda CB175 K5, next project
1977 Honda CT70, swap meet scooter
2004 Honda NRX1800 (Rune), Cruiser
1977 Honda GL1000, daily driver

Offline srbakker

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Re: CB750 K5 Build - Project "We don't need no steenkin' name!"
« Reply #16 on: February 23, 2012, 05:10:48 PM »
I am, in fact, alive!  Although with work being what it is, sometime it's hard to tell.

I've changed my plans a bit - I'm focusing now on having a roller by the end of the year, and then building/inserting the engine likely next year, and then hopefully finishing by 2014 (aw crap, that's a loooong way off).

Nothing to exciting to add - I polished up the oil tank as I'll be reusing the stock one, and I'm about halfway through dissembling my wheels so I can rebuild them.  Would anyone be so good as to snap some pics and details of how a stock rear wheel is laced?  I only have that old 16" to work from and I'm going back to a stock 18". 

I'll try to get some new pics up soon.

Cheers,
Scott
1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)

Offline srbakker

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Re: CB750 K5 Build - Project "We don't need no steenkin' name!"
« Reply #17 on: February 23, 2012, 05:20:58 PM »
Few things I apparently forgot about that I found pictures for:

An EBay score - Aprilia RSV4R stock Sach's steering damper for $25.  I hope it's long enough - stroke length is about 105mm.


My polished up oil tank.  I polished the front and painted the backing with VHT caliper paint.  It's a Joker Machine oil cap and a nice aluminum drain screw from Kevin at TTR400.


My side cover at present (I say at present because I keep changing my mind on this) - made for me by Little Horse from this site.  Paint (which is not great, I admit) is more VHT caliper paint.  Might polish the whole thing.


I might also have Raef make me a set of aluminum side covers to polish - not sure where I want to go with that yet.

Cheers,
Scott
1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)

Offline UYD4L

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Re: CB750 K5 Build - Project "We don't need no steenkin' name!"
« Reply #18 on: February 26, 2012, 12:21:40 PM »
Any updates on this. This noob needs some help/motivation.

Offline srbakker

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Re: CB750 K5 Build - Project "We don't need no steenkin' name!"
« Reply #19 on: February 26, 2012, 02:59:42 PM »
Ha, slowly but surely.  Currently I'm tearing down the wheels to their bare hubs in preparation for sending a whole bucket full of stuff and the frame off for powder coating.  It's all going to be gold, a la Carpy!
















(No, seriously, it will be gloss black.  ;) )
1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)

Offline srbakker

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Re: CB750 K5 Build - Project "We don't need no steenkin' name!"
« Reply #20 on: March 05, 2012, 04:42:39 PM »
A nice surprise on my doorstep at the end of the work day:



Frame and engine separated easily.  Quick mockup with the seat and shorty fender:



The butt end is a bit more bulbous then I anticipated, but I sort of like it.  Looks kinda plush - we'll see as the build progresses.

And finally - not my tank, but almost exactly what I had in mind with an offset stripe running along the fenders and tank.  I will be using different colors - something a bit more in keeping with the '70s heritage of the bike.

1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)

Offline crysis

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Re: CB750 K5 Build - Project "We don't need no steenkin' name!"
« Reply #21 on: March 05, 2012, 09:01:37 PM »
Hey! that's my tank.... Cool I sort of did it on a whim since it seemed to be needing something else when it was all silver. Are you the guy that emailed me?
What doesn't kill you makes you wish you were dead.

Offline srbakker

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Re: CB750 K5 Build - Project "We don't need no steenkin' name!"
« Reply #22 on: March 05, 2012, 09:30:19 PM »
Hey! that's my tank.... Cool I sort of did it on a whim since it seemed to be needing something else when it was all silver. Are you the guy that emailed me?

Hah, yup, that was me.  Hope you don't mind me using your tank pic?  It really it exactly what I have in mind, albeit different colors.
1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)

Offline Really?

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Re: CB750 K5 Build - Project "We don't need no steenkin' name!"
« Reply #23 on: March 06, 2012, 03:41:56 PM »
I bet that hump on the back of that seat tends to look smaller when the tank and wheel is on.
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 srbakker

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Re: CB750 K5 Build - Project "We don't need no steenkin' name!"
« Reply #24 on: May 02, 2012, 01:23:32 PM »
Dropped a bunch of stuff off for powder coating today.  Pics to follow.  The guy quoted me $400 for sandblasting and coating the frame, the rims, the hubs, the triple tree and a few other odds and ends.  Sounded pretty reasonable to me!
1975 CB750 K5
2007 Triumph Tiger
2007 Triumph Speed Triple
1971 Kawasaki F7 175 Enduro
2000 Honda VFR800 (gone but not forgotten)