73 Honda CB750 Custom Build Part 16 - Cylinder Head Install
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- Опубликовано: 15 сен 2024
- Installation of the cylinder head on a 1973 CB 750K3.
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Hi Dean, I've owned three CB750's back in the day, grew up on them. 1 K2 and 2 K4's. Did all sorts of things with them but never pulled one apart and put it back together. I am thoroughly enjoying watching you put this mighty machine back together. Very impressed with your patient and clear approach, I feel like i could have a go - assuming I had one. BTW what we used to do with them was to strengthen the swinging arm and the top rails from the yoke back to the vertical frame bit. The frames had a lot of flex in them. One of mine even stood up mid way through a corner when I touched the front brake. A steering damper helped a lot too. We used to run dunlop k81's - they were the best grip for dollar value back then. I imagine you're doing this in your spare time so once again a BIG THANK YOU!
Noel Cunnington Gald you're enjoying it! I owned a 76 Super Sport in 81. That was my one and only CB750 experience. I remember the thing being a little twitchy at speed. Adding the tapered roller bearing to the steering head in this one should help a lot. Thanks for watching. :)
I'm getting tons of vicarious fun watching your engine go back together. Very glad to notice your eyeballs are in proper working condition, too! Many, many thanks for all the hard work you are doing putting these videos together.
Oh, right, sir! I like your enthusiasm to fix motorcycle engines 💯💯💯👌👌👌
Thanks again!
The problem with oiling the threads is that you can overload the bolt, screw, stud etc. There is less resistance and if you torque to the same spec as dry you have now overloaded the bolt and stretched more than you would have if dry. The jury is not out, there is a dry spec and a lubed spec. Honda gives a dry spec. Lubed spec could be upwards of 40 percent less. You'd be surprised how much tensile stress is on a single 5mm (dia) bolt with even just 5 ft lbs of torque applied!
Just to add to what you already stated. About 90% of the torque is used to overcome the friction between the mating surfaces of the screwhead and the mating component and the friction between the threads of the screw and nut. Only 10% is used for pre-tensioning the screw.
Good on holding the head of the torque wrench. I have seen other tutorials doing this incorrectly. Nice video, and also the thin oil does reduce friction, but I agree that will apply more stretch on the bolts, maybe too near their max tolerance. I suggest clean and dry, if that's what the manual says.
I'm a mechanical engineer, and I agree with you about lubing the threads before torquing. What matters is not the resistance from applying torque, but the strain of the bolt or stud.
Thanks a ton for posting these videos. Doing anything with the engine can be a really daunting tasking (especially if you haven't done anything with it before). I have a DOHC 750 and although slightly different, these videos have been super helpful with understanding various components on the bike. Cheers.
Awesome video
When i get to my four cyl job
I plan to drop some oil on
Cam journals
And then let the cam set in
For a softer fit
Just my thought
One of the best videos I have seen so far showing us the process, really liked it!
You need those oil jets. They are a pecision part, and if left out you will get most likely no oil in the bottom end.
TAXI JACK I'll have to track them down. No longer available from Honda parts sources.
***** I'd hazard a guess they are oil restrictors as you say but, they are in place to squeeze a bit of extra pressure to the cam as that would be the last area of the engine that needs to see oil pressure (runs back to the sump after here under gravity).
I see the oil control orifice "available" in several place - (PN 12238-300-010)
not clear if they ACTUALLY have in stock
parts.southernhonda.com/p/Honda__/ORIFICE--OIL-CONTROL/54980698/12238-300-010.html
www.powerplantmotorcycles.com.au/find/part/M.81983
I've sent an email to Southern Honda asking if they REALLY have it. Thanks for the research.
A few more episodes to complete the cb :) so excited to view the final result
***** Ha! More like a few times 10! Still a lot to tackle. Thanks for watching!
love the vids, and did anybody else think of Bob Ross when he was painting on liquid gasket?
Appreciate the detailed honest videos! Looking forward to watching them all and seeing this fire off.
Another great vid from hackaweek, the engine build has been great and I'm really looking forward to seeing this engine going back in the bike. Great job and great vids.
I swear it looks like early in the video the short head studs are on the back in the wrong place but then when you put the head on they were correct. Am I seeing things? Nice video. Very helpful.
Great video, as always! I'm replacing my head gasket this spring so your videos are a great help! Looking forward to the next videos to finish up the top end.
Starting to come together nicely! Good work! Can't wait to get into my CB350 engine.
Outstanding resource for all of us, Sir. Thanks a ton
As usual, nice hand work.
Cheers, Mark
Thanks for taking the time to make these videos!!
cant wait to hear this baby run thanks
wow,i had no clue there was so much to this,excellent video,thank you,john
It's looking good Dean!
I'm really enjoying the work of a very talented individual! It's great! I'd like to make a comment on torque. I am an A&P, but not a Honda motorcycle mechanic. I learned early that torque specs are dry unless otherwise specified. (I don't even remember where I learned it.) Sometimes they may be specified in front of the service manual. I can't find it right now, but I used to have a machinist's manual that listed lube torque specs depending upon the lube used. I am not suggesting that you've hurt anything, but I'm offering that it's entirely possible that the torque specs have been exceeded, depending upon what the manufacturer had in mind. (dry or lube torque) Keep it coming!
clean work as always! But i think you have forgotten the dowel pins with rubber on the cylinder! They are supposed to guide the used oil safe back into the crankcase.
Thank you!
You're welcome!
My 1983 GoldWing has those oil flow restrictors on each head as well...and they had O-rings on them as well. Honda must think they are important...
cant wait to hear that beast :)
I was hoping to see a bit more about the valves. Maybe lapping them and a closer look at the valve spring assembly and whatever specifications the assembly must meet.
I bought this bike with the head already rebuilt.
Hackaweek!!! I'm absolutely loving this videos. Thank you so much. I'm rebuilding a 77 CB750, first ever engine rebuild (barring a snowblower), and in addition to the manuals and parts list, this is incredibly helpful. I am wondering, however, as I'm sorting through my poorly sorted hardware for the head, the six bolts you point out, where the hell does the really long one go? The 6 x 90? And also, those missing oil jets you mention, are there one of two? The head I have only has one resting in it. Thanks again.
Nice video! But, no assembly lube for the camshaft? I'm looking forward to the next episodes!
GREAT video!
Congrats.
Hey Hackaweek, awesome videos, I really enjoy watching them and they are very helpful for my rebuild. One thing I'm not sure about, isn't there a dowel and a seal missing on the eight studs between cylinder 1/2 and 3/4?
Cheers
GREAT videos! Love it!
In addition to my first comment, i have looked it up on CMSNL. Those dowel pins are missing in a early K0 engine, but the pins are listed for your K3 engine. best regards!
Tobbe M They got installed in the previous video and they are there to seal the oil gallery so that oil can be pumped under pressure to the camshaft and rocker arms.
HackaweekTV I think we are talking about two different things now :) On this drawing www.cmsnl.com/honda-cb750-four-k3-usa_model481/partslist/E++05.html#results i meant the numbers 2 and 3. They go over the inner stud bolts, some models have 4, later models 8 of them.
Tobbe M Interesting. I'll have to look into that. I had no dowel pins for those in my parts. This is one of the challenges of assembling something that you did not take apart AND have never built up before! :) Thanks!
Tobbe M I just checked on my two parts sources and those parts are no longer available. I guess I'll just leave it as is. I could see how this could turn into a leak at high mileage. I may do some mods to this engine at a later date and I'll address the issue then, Again, thanks for pointing that out.
***** no problem. Keep up the great work!
Hey . best CB750 build ever. Would you recommend the gasket sealer on a sandwich plate for an oil cooler fit up. Like where the sandwich plate bolts up against the case at the filter outlet?
Did you at least check the head and cylinder surfaces for flatness? did you lap the valves? Check spring tension? replace valve stem seals? check valve guide clearance?
The cylinder head was already done by a reputable CB tech. It was perfect.
@@HackaweekTV I guess I missed that part of the video.
Love the videos...getting to this phase of my CB750. How come you didn't put the cylinder stud bolt orings/gaskets on (8 pcs)? They go between the cylinder and head. Which is why you have oversized holes on your head gasket. 4 in between the cylinders 3 and 4 and 4pcs in between the cylinders 1 and 2. Can you explain?
Hi Dean, I am new to your videos on the CB750. They are fantastic. Ive learned so much. I am currently working on a 76 CB750 and these videos are awesome. Could you possibly tell me the source where you got those drawings and schematics of the engine and parts etc. much appreciated. I look forward to seeing more of your builds. Thanks Kim
In regards to oiling the threads as well as the seating surface before torqueing........My 2006 Kawasaki z1000 factory repair manual says that this should be done on the cylinder head bolts.
Also, it looks like you did put assembly oil on the camshaft but it was not included in your video but later on we could see it.
FYI - there are some excellent YT "course videos" from - WITC Motorcycle and Powersports Technology Program available.
They (instructor Shane Conley) always recommends oiling threads / fastener components before torquing.
Hi Dean, nice work on your CB. Do you remember what the deal is on the small oil jets inserts, should I keep them in my 78 cb750k or take them out to increase flow to the cam shaft journal bearings? Thanks, Nick V.
Leave them in! Super important! Without you loose pressure on the main bearings that need it more. The cam is fine with the oil metering jets in place.
Good
did you even get warm soapy water and clean out the cylinder boars after you honed them they would have metal filings in them
I am definitely no expert. Regardless, i'm pondering the torque values dry vs oiled. I get what you're saying about why you use lube to reduce friction in the measurement. But, wouldn't that leave you with oiled nuts that are more prone to loosening?
Great videos, I'll be assembling a cb750k. Engine soon myself and I've read that it's a good idea to put a little hondabond on the edges of those bolt cover pucks. They are known to leak. Also, like the others said, find those oil jets, they need to be there. Someone on forum.sohc4.net probably has an extra setm
I have a mystery question... what is the function of the unused holes in the center line of the head, #2 and 4 of what we call the the 6 “nickels” that we place the seals onto? They do not appear to have any function. Any clue?
Don't forget to LUBE it, LUUUUUBE it real good.
If you aren't supposed to use lube for bolts because it causes torque inaccuracies, then why does ARP, arguably the world's premier supplier of automotive fastener, give you specific lube to use when torquing their fasteners? The most accurate way to measure clamping load is with a bolt stretch gauge, like you do with many aftermarket rod bolts, however, kind of tough when the bolt goes into a blind hole. Food for thought.
OK then. They specified a lube to use for the torque setting. That's a lube torque spec, and when that's what you're given, that's what you use.
Regarding the oil control jets. Thinking you could replicate these with thin .012-.020 sheet punched on a punch press, then drill the needed size orifice??? Just a thought???
Nice job so far. Really like your channel. But i seem to remember you like to pre lube all turning parts. Is the cam shaft an exception or did you just forget.. Looking forward to the running bike 👍
Did it but missed it in the video edit.
***** just looking out for you 😊 good luck with the rest of the project..
Excellent fascinating,,,,,
hello sir! im restoring a 73 cb 750. and i was wondering if u have a particular gasket set brand to recommend? thank you!
Hi do u rebuild carburetors for motorcycles? I have one off of a 1985 Honda Nighthawk 650. Any help is appreciated!! Plz
9:52 Ah Nuts
What size are the dowel pins and where can I get them?
Hi Matt,
Love from Germany.
u make my weeks !! Have to say anyway that a hacker should not use creamy windows10. Especially unsponsered by Mr. Gates which I truly believe u never would accept. For your basic video cuts i suggest using kdenlive on libre software. Consider this tip as a generous donation:) cause u save all future windows licenses. Away from that you can start software hacking if that is your cup of tea. Anyway never learned so much about those mysterious motors. Keep on hacking !!
use gaskacinch it stays rubbery , that stuff your using hardens up and it a pain to remove.
you need hondas specs for oiled threads, you over torqued the nuts.
honda service manual says to torque head bolts in three strages, also to use a pivot handled torque wrench
@13:00 when you hold the manual up to the camera
it says 8 lb ft on the 6mm Cylinder head bolts.
Then @16:53 you say that you torque it to 10 lb ft.
Just letting you know.
True, I was about to say that too.
PhyXs Able I said 10 but I set them to 8. :) It gets a little strange sometimes talking to a camera with no one in the room while you're building an engine.
Is there any bearings for the cam shafts?
Ibrahim Bawi No, just the journals in the camshaft holder and the caps.
Every engine on the planet requires anti-seize to get the proper torque specs
didn't the book say 8 lb of torque , you whent to 15 lb on all of them .
I went to 15 ft. lb. on the head nuts, 8 ft. lb. on the small bolts.
Traduccion en español🙏
He polish the seal place but its already clean
But he leaves the piston dirty from the seal xd for me its dissapointing :/
What piston? Dirty? I do not understand.
from the seal that he applyed between the block and the cyl.
Sry im trying my best im from croatia :)
no no no