Author Topic: Just another 71 CB750 K1 (After over a year, I finally got some 4 into 4 pipes!)  (Read 92019 times)

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Offline edhaeuser

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Great progress Ed.  ;D I love watching the engine build sections. That's the most exciting part for me.

I would agree with others that for the for cost of the part and how deep you are now you really might as well replace that cam chain!

IW

Thanks!  I installed a new heavy duty timing chain and have a new tensioner to go with it.  I guess I forgot to mention that.

Offline cheftuskey121

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nice work Ed, you've moved through it pretty quickly. youll be back to bike assembly in NO time. very excited for you :D

Offline edhaeuser

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Quick question.

Can I use regular O-rings between the cylinder and head.  It appears the kit that I have only has o-rings for the later heads.  I cannot source viton seals locally, only the regular type.  I really want to get the top end done today, and this is holding me up.




Offline HondaMan

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Quick question.

Can I use regular O-rings between the cylinder and head.  It appears the kit that I have only has o-rings for the later heads.  I cannot source viton seals locally, only the regular type.  I really want to get the top end done today, and this is holding me up.




The OEM ones were Buna N (durometer 65-75). Those are real common. Make sure the size is 2.5 x 12mm, not the undersized ones found in some gasket kits lately. I just bought some 2.5x12 in both Buna and Viton, if you can't find any there.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

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Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
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Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

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Offline edhaeuser

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Thanks Hondaman!!

The extras that I have in my o-ring kit look like they could block the hole because they are so small.  I will try to find the Buna ones locally.  As always, you have the answer!!

Offline edhaeuser

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Well, here goes another question.  Can I pull this metal cap on the cam chain tensioner to replace the seal underneath?  How would I pull it?  Or....do I need to find another cam chain tensioner.  I was hoping it was just an o-ring that I could pop out and replace, but it appears to be a small seal with a spring.  Live and learn  :-\


Offline edhaeuser

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Here is another picture heavy update.

A few highlights as to what I have done with the engine:

case hole repair

new main bearings

new timing chain

new tensioner

honed the cylinders (still within new tolerance)

new rings

new wrist pins

recut valve seats

new valves

just ordered new stainless screw set for engine covers from James Spillane, a member here...stock style, not allen screws

some new engine case bolts and some I replated myself

Basically, a stock rebuild....nothing fancy as this is my first Honda engine


new tensioner from Cycle X, the old one was pretty chewed up



new wrist pins



cyclinders on



three angle valve seats




new valves from Cycle X



valve train back together



I polished up the valve cover....did I mention how much I dislike polishing...ugh.  It is not perfect, but it will do.







I was hoping to get the engine back in the frame before I have to leave for work again early next week, but I decided to order the new cover screws, rather than re-use the old ones.  So, I need to wait for the screws before I attach the valve cover.
« Last Edit: July 13, 2013, 09:36:44 PM by edhaeuser »

Offline cheftuskey121

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Ed. wow. just wow.

Offline edhaeuser

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Ed. wow. just wow.

Thanks Justin.  I'm not altogether satisfied with the polishing, but I need to draw the line somewhere.  My finish date looks to be more like next spring....a year longer than planned.  This whole engine rebuild is going very slowly.

Offline SOHC4 Cafe Racer Fan

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It must be one of those things where the pictures hide the details/imperfections.  The polishing looks good.
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 Tews19

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Damn! Sick polishing! Seriously! I always like the bling on these engines!
1969 Honda CB750... Basket case
1970 Honda CB750 survivor.

Offline edhaeuser

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Damn! Sick polishing! Seriously! I always like the bling on these engines!

It must be one of those things where the pictures hide the details/imperfections.  The polishing looks good.

Thanks Guys!  I did walk into the garage this morning and thought.  dang, this does look alright.  I think I can live with this.  My wife says I am too much of a perfectionist sometimes....maybe I am.

Offline iron_worker

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Ed,

The problem with doing meticulous work like engine painting/detailing/polishing is you're looking at it from a few inches away, maybe a foot or so. In reality, anyone looking at your bike (including yourself *most* of the time) will be looking at it from a few feet away. All the imperfections that seem HUGE to you at the time of the work really blend in with the overall bike when it's all together.

I know exactly how you feel! I'm starting to get over it a bit now that I've started riding. Once it's on the street, it will never be as clean as it once was! lol Road grime, bugs, water spots, a bit of chain oil, some spilled gas, etc etc.

The engine is looking really nice.  8) Keep up the good work.

IW

Offline edhaeuser

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IW, you are right, of course.

I have one last small update before I head off to work for three weeks.  I turned on the Tour De France last night to watch yesterdays stage.  I figured I would get a little done on the bike while watching the race.  I decided I would do one of my favorite things. (not)   More polishing.  Except, this piece was really rough.  The stator cover had seen better days.

I started out with this scratched up, dented piece.  First, I block and hand sanded the deep scratches out with sand papaer.  I started with 80 grit because there were some reall nasty gouges.  From there I worked through 120, 400, 600, and 1000 grit.  I only used the 80 and 120 on the really bad areas.  After sanding, I used emery, tripoli, and finally white rouge buffing compounds with my bench grinder.  With each compound I went to progressively softer wheels.

The start...actually I guess that I had started a little sanding with 80 grit by this point.



I'm pretty sure this is after sanding out the scratches through 120 grit.  I did not get every scratch out, but most are gone.



It's a dirty job, but someones got to do it.



I'm pretty sure this is after wet sanding 400, 600, and 1000



First cut with emery compound...before cleaning for the next step.



after the tripoli compound.  All cleaned up and ready for the white rouge.



After white rouge....all done, except for maybe a little hand polishing if I really feel like it.



I don't know if this is the right way to polish....I think I got this technique off the Caswell site.  Once again, not perfect, but pretty good.  It seems I always have a few errant sanding scratches that I don't get out.  Of course, considering that I had to use 80 grit to get the gouges out, it looks good.  There were scratches all over this thing.

Offline SOHC4 Cafe Racer Fan

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Damn fine job.
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 Viktor.J

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Hey ed !
Great work with The polishing, your method and results are simular to mine. But do you have Any plan to preserve this newly polished finish ?
I was thinking on wax but don't know if there's any wax that can stand the heat :)
Please ! Take a look and give me feedback in my project thread, its much needed :)
http://forums.sohc4.net/index.php?topic=112745.0

Honda CB750 K2

Offline edhaeuser

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Hey ed !
Great work with The polishing, your method and results are simular to mine. But do you have Any plan to preserve this newly polished finish ?
I was thinking on wax but don't know if there's any wax that can stand the heat :)


Your guess is as good as mine on that.  I will probably wax it and see how that goes.  I polished up my Triumph covers a few years ago, and they are holding up fairly well.

Offline Viktor.J

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Hey ed !
Great work with The polishing, your method and results are simular to mine. But do you have Any plan to preserve this newly polished finish ?
I was thinking on wax but don't know if there's any wax that can stand the heat :)


Your guess is as good as mine on that.  I will probably wax it and see how that goes.  I polished up my Triumph covers a few years ago, and they are holding up fairly well.

When you do it would be great if you could provide which wax & method, that you'll use. I've been riding with my polished covers a few months now and they allready lost quite a lot glow, so Ill probably end upp hand polishing a bit beafore I wax...
Please ! Take a look and give me feedback in my project thread, its much needed :)
http://forums.sohc4.net/index.php?topic=112745.0

Honda CB750 K2

Offline Stev-o

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Hey Ed - motor looks great as well as the stator cover. I've got an old one, mind if I send it over for a polish job? Ha!
Where have you been working?
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline edhaeuser

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Hey Ed - motor looks great as well as the stator cover. I've got an old one, mind if I send it over for a polish job? Ha!
Where have you been working?

Steve, I only polish because I'm too cheap to pay someone else to do it :-)   I've been working in Europe this month.  I enjoy the work, but ready to be home.

Offline edhaeuser

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Should I remove my oil pan and pump to re-install my engine in the frame?  Thanks.

I think I will, it seems like there would be a lot more wiggle room.
« Last Edit: August 12, 2013, 02:01:50 PM by edhaeuser »

Offline 70CB750

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You dont have to remove the pan, safer for the engine actually.

Exhaust studs if you have them and greaat trick is to grind down the flange of the right front mount on the frame to make it easier to install.

Offline edhaeuser

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You dont have to remove the pan, safer for the engine actually.

Exhaust studs if you have them and greaat trick is to grind down the flange of the right front mount on the frame to make it easier to install.

Thanks for your reply.  I had already ground down the flange on the frame.   Per your suggestion I tried to remove the exhaust spiggots.  I figured I would remove the three on the left side...leaving the one on the far right.  (it didn't seem like that one would interfere with anything)  Well, I got the first two loose with an impact screwdriver....not so lucky on the third one, one of the screws twisted off in the head.  I guess I will be doing some carefull drilling to try to get that broken screw out.  Insert expletive here! My wife said "I knew you had screws loose in your head, but I didn't know any were broken"

Offline 70CB750

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Sorry! :)

I was lucky, my bolts came out just fine.


Offline edhaeuser

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Sorry! :)

I was lucky, my bolts came out just fine.



No worries, it's not your fault.  I appreciate the input!