Topic: Splitting the cases on my CB750...first of many ?'s

[mystic_1]

Hey Ron, glad you finally got your gearbox all sorted out.  I'm sure the smile on your face was as epic as this thread.

Regarding the neutral light staying on, make sure you've fully seated the neutral switch.  I seem to recall it's easiest to put the o-ring up into the hole and then push the switch into the o-ring.  If you put the o-ring on the switch and try to put it in like that, the o-ring can catch on the sharp edge of the hole and keep the switch from seating all the way.  This prevents the switch from opening when you're in gear.

mystic_1

[ron.cieri.313]

Thanks Mystic...that so seems to be the problem...cuz that how i reassembled unfortunately...also, thanks for all your help and support along the way.

I still have idling issues too when the bike warms up she wants to idle fast and then i have to turn down the idle setting screw which of course then makes it want to konk out when i come to the next stop...so I've been playing with the pilot air screws but it probably needs more tweaking then that...may give the slow jets a good cleaning to be sure thats not it and then maybe a plug chop at idle?

Just put new handlebars grips on her (gold trim to match the bike's trim)...she's looking good and hopefully we will getting her tuned up the way she should be...we're close!...i need to post pics soon but there are no pics of the great feeling everytime I put her into second gear!

[nobody]

Glad to hear that all is finally well, I'm sure you get a big smile every time you get on the bike again. I know I did when mine was first back on the road.

[y2kc0wb0y]

Powerful thread right there! I believe I have the 2nd gear C5/shifter fork issue too on my K3 and reading this EPIC thread was very informative regarding the suspected problem. Thank you for taking the time to share your story.

[ron.cieri.313]

Not at all...pass it forward as our most knowledgeable folks here like to say

[nobody]

WOOOOOOOOOOOOO! I saw this thread come up and my first thought was "RON?!?!?! NOT AGAIN!!!!!". Haha.

I'm relieved to see that my assumption was incorrect.

[ron.cieri.313]

Lol...yes, I can see y...the tranny has been fine but get this, I do have a small, and it is small leak from the area of the 3rd cylinder valve cover gasket...which means of course, if I want to fix properly, I have to take the engine out...probably NOT this winter job though...but still and lot better than splitting the freakin' cases!...and the bike (knock on wood) has been doing great.

[nobody]

Hahaha, what did you do to piss that machine off? Maybe you need to wax her more or something, let her know you care. Maybe give her a tire massage?

I must have tagged a pothole pretty hard or something a little while back, my rear wheel has a good bend in it and the tire wore down in one spot to make up for it. The kickstand needs replacing and the speedo doesn't work. Also, it fell over one night and I came out to find my tank trim cracked, no other damage though.

So I won't be getting saddle time until I get a wheel, a tire, a kickstand and fix my speedo. The trim can come later but I'm anal so I want that soon too.

It's always something with these bikes isn't it?

[ron.cieri.313]

Yes, always something...the trim is so expensive too (got nos replacements from Ohio Cycle). 

[nobody]

Yeah, when I saw the cracked trim I was like "crap, that's not going to be easy or cheap to get."

[scroggins5000]

I just read this whole thread, and it is great. I have a 78 CB750F that needs transmission work, and I found a good used transmission from a 77 CB750F to use. I know almost all F2 and F3 parts are the same, but I wasn't sure about the transmission. Is the trans/ gear ratios the same on these bikes?

[ron.cieri.313]

Don't know much about the F's as my is a K...hopefully one of experts will chime...glad this helped!...I finally think have fixed the minor idling problem but rebuilding the airbox which was warped a bit.

[scroggins5000]

Don't know much about the F's as my is a K...hopefully one of experts will chime...glad this helped!...I finally think have fixed the minor idling problem but rebuilding the airbox which was warped a bit.

It's tough trying to get info/parts on the F's sometimes! Sometimes I wish I had gotten a K, but the extra struggle does make me appreciate it more.
Yeah, my 2nd gear needed to be replaced because of missing teeth (unsure how that happened, because I bought it not running), but the trans. still isn't rolling completely smooth because of some minor corrosion that caused some pitting on the main shaft. After reading this, I realized that I should probably do the following also: Replace the main shaft, replace the gear across from the 2nd gear I already replaced (just in case), and also the middle shift fork because it also looks worn. I just wanted to make sure these two models were interchangeable before I made a purchase. Thanks again.

[scroggins5000]

Don't know much about the F's as my is a K...hopefully one of experts will chime...glad this helped!...I finally think have fixed the minor idling problem but rebuilding the airbox which was warped a bit.

Going by Bikebandits parts fiche the part numbers for the transmission parts match between the 77F & 78F schematics, so I guess I found the answer.

[ron.cieri.313]

Sounds good...that's the only bad thing about bikebandit is that they use their own numbers

[MCRider]

Sounds good...that's the only bad thing about bikebandit is that they use their own numbers

try motogrid.com among others, for official part numbers.

[scroggins5000]

Sounds good...that's the only bad thing about bikebandit is that they use their own numbers

True, yeah they match up on motogrid too. Awesome.

[GammaFlat]

Lol...yes, I can see y...the tranny has been fine but get this, I do have a small, and it is small leak from the area of the 3rd cylinder valve cover gasket...which means of course, if I want to fix properly, I have to take the engine out...

I thought I had heard of someone changing the valve cover gasket without removing the engine.  The biggest problem will be getting to all the screws.  Once you have them off (and the cap in the center... and screws underneath), I think you can wriggle a new gasket in place by lifting the valve cover a bit.  Heck, if you can get good access to all the screws, it's worth a try.  (did you use allen/socket heads?)

[MCRider]

Lol...yes, I can see y...the tranny has been fine but get this, I do have a small, and it is small leak from the area of the 3rd cylinder valve cover gasket...which means of course, if I want to fix properly, I have to take the engine out...

I thought I had heard of someone changing the valve cover gasket without removing the engine.  The biggest problem will be getting to all the screws.  Once you have them off (and the cap in the center... and screws underneath), I think you can wriggle a new gasket in place by lifting the valve cover a bit.  Heck, if you can get good access to all the screws, it's worth a try.  (did you use allen/socket heads?)

Yes the CB750 valve cover gasket can be changed without removing the engine. A couple of the center screws are at a bad angle. But worse than that is getting the old gasket out. Hopefully it comes out cleanly and is not stuck and rips. Cleaning a stuck gasket may call for removing the engine.