Topic: HELP - how the $#%^@# do I remove a CB750K 1977 Valve Cover?

[Tim.]

I'm here with Chundy (don't ask) and we're trying to take the cylinder head off the bike - broken exhaust mounting boss.  I thought the valve cover would come off like my CB550's, but it doesn't.

What's the secret to removing the valve cover and then the cylinder head?

Thanks!  Light's fading so a quick answer would be welcomed!

[Lumbee]

...engine def has to come out of a CB750 before the valve cover will come off.  I've heard of people removing the engine bolts and letting the engine sit a little lower and removing it that way, but can't confirm...

[chundy]

Oh, tintin, we were one freakin bolt away from doing the engine drop and we backed out thinking this is rediculous.  Well is could have been a productive afternoon.  I will drop the engine tomorow, but I will need help putting it back in.  Aluminum welder here I come.

[Bobby]

Yep, that there motor gotta get out of the frame prior to removing any of the top end components.  Silly isn't it?  The CB750 is the ONLY bike I have owned that you have to pull the whole dang motor out just to replace a head gasket.

-Bobby

[chundy]

Is it possible to just loosen all bolts except the one pivot at the rear, and drop the engine forward a inch.  Or are we talking about a complete yank, for the love of God, please tell me I don't have to yank the entire engine.  If so that is just a reallt stupid design. 

[Bobby]

You can try that technique (I never had) but I still don't believe dropping an inch will much matter.  According to my Shop Manual, if you want to yank the head, the engine needs to be removed.  It's actually not that awful of a job and it gives you an opportunity to gussy up that old inline 4.

Sorry for the bad news.

-Bobby

[Tim.]

I keep telling Chundy all we need to do is cut off the top 1/3rd of the engine and make it what it should have been - a 500.

[frostypuck]

or...cut the frame pieces off, under the backbone, just below the coils. I saw one like that 6-7 years ago, but never found out why he did that. Obviously it was to facilitate removing the head, but anyone that has to remove/replace the head that much doesn't need to be modifying frames.
Chris in Boston

[Tim.]

Well, wouldn't it be fun if we got the valve cover off only to find we couldn't get the cylinder head off without removing the engine.

I'd imagine there's enough room above the studs to allow for this - can anyone confirm 100% on these different ideas?

So far we're at:

1) remove enough engine mounts (and don't forget the airbox mount to the frame) to allow engine to tilt forward and down allowing valve cover to clear valves and cam chain

2) hopefully there's enough room once the cover is removed to remove the cylinder head as well

Perhaps chum Chundy could take a pic of the reason we're doing all this in the first place .  If repairs could be made without removing the cylinder head, we'd avoid all this hassle, as compression and valves all seem good.

[frostypuck]

Remove the motor. It's easier than the other suggestions. Really. Especially since there's 2 of you. Just remember, drain the oil, after all the bolts are out, turn the whole bike over onto it's side, and lift the frame et al off the motor. Then just sit it somewhere with a block of wood under the oil filter cover to keep it from being too tippy.
Later,
Chris
Oh yeah, and in the words of the immortal Mr. Clymer..."installation is the reverse of removal" That slays me every time I read it. I needed a $22 book to tell me THAT!?!?!?

[cben750f0]

sorry to rain on the parade, but engine has to come out.... even when you want to retension the head after a 100km .. you have to take the motor out of the frame!!... its a pain , but one tht cant be avoided, i figured if by now noone can tell me that it can be done... it cant... sorry peace(pleace make me wrong )

[Terry in Australia]

 Yeah, all of the above Tim, rip the engine out. I've never re-torqued the head after 100 km though Ben, I just torque it down to 20 ft lbs, then leave it overnight and re-torque it in the morning, and I've never had a leaking head gasket. Cheers, Terry.

[chundy]

Thanks, a tonne.  As always this site, and it's members are very helpful, as well as humorous.  I will be draining her, dropping her (softly), and getting her apart.  I truly needed an excuse to clean the motor, replace some gaskets and oil seals.  Just as a side note, and funny one, the picture I am using came from an article that I found while googling my predictiment.  A guy racing a 750 lost a piece of his tach cable in the head and it basically shredded the inside of the entire valve train before the bike stopped.  So an oldimer came to hie rescue with this old bike that had been sitting in a field for 8 years with stuff growing in it.  They to needed to found themselves in my situation, however rather then taking the motor out, the just hacked the frame to bits.  Good times.  I'll be sure to take some pics and post em up.  If nothing else it should be funny, me with my back blown out from wrestling this bad boy onto 4X4's.  TinTin, leave your mobile on in case I fall and can't get up.
thanks again all.
PS here is the link to the mentioned article
 http://www.motorcyclistonline.com/flashback/122_9704_cardiac/

[carsholduptraffic]

all i can add is that the motor is 80kg. and getting it back in is as much of a bastard as getting it out. watch your fingers. about a 3 beer job.

[cben750f0]

rap some rags round the frame, protect you and the frame...peace

[mrbreeze]

Well you know what Larry (the Cable Guy) says....GITTTERRR DONE!!!!! ........But Hey Now..... Lets not go whackin' into a perfectly good frame to change a gasket.What are you going to do? Go get a new a frame every time you need to work on the top end? Like The other posters said....When your top end is off...do as much as possible.Mine runs good now but if I had to have it off....It sure would make it easier to polish the aluminum valve cover! Hope you do it right and get it back on the road though!......MRBREEZE ....ps(GITTTERRRR DONE)

[Lumbee]

...yep the 750 mill is about 2 bills.  I heard a guy say he has removed and put the motor back in by himself.  I call BS...what do you guys think?

[kghost]

Well that guy I would not want to meet in a dark alley.

Hey, I'm 6'3'' and about 230lb. Been lifting heavy thinks all my life. Not a light weight. I can lift one but stick it in the frame? No way I could do that without mangling the paint or worse.

[Gordon]

...yep the 750 mill is about 2 bills.  I heard a guy say he has removed and put the motor back in by himself.  I call BS...what do you guys think?

Well, I'm 5' 7" and about 140lbs soaking wet, and I did it by myself.  It required a complicated system involving a floor jack, a scissors jack, an empty milk crate and a block of wood, plus several shop rags to protect the frame.  So, in conclusion, it is possible, but not fun. 

[Geeto67]

A good trick taught to me by the hondachopper guys for when you are by yourself and need to pull the engine is to put the bike down on it's side (on top of some heavy duty blankets) then undoing the engine bolts and sliding the frame off the other side of the engine (it will still be heavy but not as much as the motor). I have tried this trick and it works, only I tilted the engine on to a rolling cart (on its right side) which got it up a few feet off the floor so I didn't have to tilt it as much. Just go slow and you'll get everything sorted out. To put the engine back in the frame you do the same thing in reverse, put it back on its side and slip the frame over it, bolt it in place and stand the bike up.

[kghost]

Yeah, I've done that trick with bare frames. Just can't pick up the engine and stick it in without block and tackle

[Terry in Australia]

Ahh you're such a bunch of girls! To remove the engine I just pick the bike up and shake that sucker right out, (I've found it pretty easy if you first remove the tank and exhaust and loosen all the engine mounting bolts, but don't tell my bro's, or they'll all laff at me) and to reinstall the engine I need to be extra careful, so as not to scratch the paint I use BOTH hands to lift it, ha ha! Cheers, Terry.

[Tim.]

Take the bolts out, find a tall hill, and you're done.

[smithrelo]

Terry in Australia!!!   I take offense - GIRLS would never do this.  

We buy 550's so we don't have to do all this macho "take the motor out" stuff...hahaha.

Anyway, I think this post cured me of ever wanting a 750, as I am the handy, dandy mechanical person in this marriage and I don't think I want to pull engines...ever!

Linda

[Terry in Australia]

Terry in Australia!!!   I take offense - GIRLS would never do this.  
Linda

Linda, my apologies again, I know, girls are too smart to be pulling engines out, me on the other hand, at 6'4" and 260 pounds am big enough, ugly enough, and dumb enough to do it on my own. My wife, at 120 pounds and 5'2", would rather "supervise", ha ha! Cheers, Terry.

[smithrelo]

Your forgiven!

Can't wait to see what else happens with this project! (I need photos, as I've not had the pleasure of "supervising" engine pulls!

Linda

[cben750f0]

smithi, i think you would need a decent set of ear muffs if you going to watch some engine pulling, ieither that or get a lesson in the old mother english!!! ... cos i can tell you i watch my mech and his partner with the 750 one day... was funny yes... educational.. yes.... but bloody 'ell i havent heard that sort of word play since i left school ....peace

[bryanj]

Oh the memories! It was always fun in the shop i worked watching those in the know take time of "sick" when certain bikes came in the door!( I was in front if a Hardly Abletoo got within 5 miles) take a small bit of advice and change EVERYTHING that might be worn whilst its out--ESPECIALLY the cam chain and ANY tensioners that look in the slightest bit worn-- Never re-torqued a Honda in my life, just done it to book and never had a gasket failure until at least 2 years after, that includes with "pattern " gaskets make sure all the nuts/bolts run free and you have all the correct washers CLEAN in the right places

[kghost]

I'd rather do an ebgine pull on a 750 than a really shot set of early Goldwing carbs. If they show up I run screaming from the room.

[chundy]

Ok boys, and apparently some girls.  The F'n engine is out.  I'm 6'2 I weigh 320 pounds and can lift the bike off the ground myself.  However getting that piss ant engine from the frame was the hardest thing I've done in a while.  I am off the the Aluminum welders this weekend, turns out my issue was with the headers.  The thread that holds the flange bolts in place is broken clear off, son of a.  So I am off to get it built back up by a welder, re-tapped and I should be golden.  Oh yeah TinTin sheared a bolt off on me as well when we were yanking the headers off, so I'll get that drilled.  Now what can anyone suggest is the bolt off choice for holding the flanges onto the head?  Steel, Aluminum? 

 As a side note it took me and 2 buddies to convince that engine to get out of the frame.  By the By, I have been polishing my aluminum for 24hrs now and the pieces look like mirrors, sweet.

[Lumbee]

...yep lots of work to get it out..but its a heck of lot easier to clean the bastard that way!   

[Terry in Australia]

Mild steel or stainless will be fine, just make sure you use some anti-sieze compound (copper grease) to stop electrolysis (nothing to do with unwanted hair removal Linda from setting in and welding steel bolts into aluminum castings.

Ask anyone who's tried to rebuild an old Suzuki GT750 "Water Buffalo" engine or remove the exhaust bolts on a Suzuki GS750/1000 what I'm talking about. Cheers, Terry.

[Tim.]

Ok boys, and apparently some girls.  The F'n engine is out.  I'm 6'2 I weigh 320 pounds and can lift the bike off the ground myself.  However getting that piss ant engine from the frame was the hardest thing I've done in a while.  I am off the the Aluminum welders this weekend, turns out my issue was with the headers.  The thread that holds the flange bolts in place is broken clear off, son of a.  So I am off to get it built back up by a welder, re-tapped and I should be golden.  Oh yeah TinTin sheared a bolt off on me as well when we were yanking the headers off, so I'll get that drilled.  Now what can anyone suggest is the bolt off choice for holding the flanges onto the head?  Steel, Aluminum? 

 As a side note it took me and 2 buddies to convince that engine to get out of the frame.  By the By, I have been polishing my aluminum for 24hrs now and the pieces look like mirrors, sweet.

Just to clear something up - yes, I sheared a bolt head off.  But it's not like I was using a breaker bar to take the bolt out 

And, to make sure my reputation is well solidified among the rank and file here, I didn't get suckered into helping extract the engine.  I'm far too intelligent for that.  I'll stick to pointing my finger in the direction the engine should go.

[Tim.]

Glad the engines out! it was great reading the saga, I would choose a stainless steel bolt above an aluminium one. I have no idea what the bolt is your talking about but I would still use SS, my 400 exhaust is clamped on studs the stick out from the block but the 750 must bolt on, sounds a much better method. thanks for the smiles I owe you a pint!

Along with Honda's brilliant design that encourages total engine rebuilds whenever a gasket needs to be replaced  , they also did a bang-up job on the exhaust header / cylinder head mounting design.  I hope the guy who designed all this stuff is dead.

On the 750 (and considering this is a 1977 model we're talking about, in 8 years they never sorted this out) there is an intermediary piece of hardward between the header pipe and the engine.  See the attached diagram.  These 'Exhaust Flanges' as referenced in the parts manual bolt onto the engine with two bolts that thread into the cylinder head.  No factory mounted studs.  Then, the headers clamp down onto these iron flanges.  No finicky little shims etc. to push the header into the cylinder head like on the smaller bikes.

I can appreciate the idea behind this design.  Theoretically these flanges should never come off the bike, and you should never have to replace the copper gaskets between the flanges and the cylinder head.  I suppose it isn't soooo bad but when chunks of your cylinder head go missing, this sure seems dumb.

[MRieck]

...yep the 750 mill is about 2 bills.  I heard a guy say he has removed and put the motor back in by himself.  I call BS...what do you guys think?

I removed one solo  once. Putting it back in requires 2 people. Just for the record my wife has helped me install engines in an FJ1200, a 900RR and several CBR-600's. I wrap the frame rails with linoleum as it is thin but tough. Remove cam cover breather cap and ,more importantly,the exhaust studs!!!- it makes the installation a 100% easier.