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Offline ron.cieri.313

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #100 on: November 13, 2009, 08:50:17 AM »
woohoo...new used tranny arrived in the mail and it looks great (what, no broken teeth???)...all the dogs are on their leash and look well-behaved.

I cleaned all the old crap of the edges of the upper and lower cases...took alot of scrubbing with a scotchbrite pad and seafoam....much work to do this weekend...will post pics soon...l8r.
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Offline MCRider

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #101 on: November 13, 2009, 09:54:37 AM »
Quote from: HondaNorway on November 11, 2009, 01:39:44 PM
Quote from: mgab on October 12, 2009, 11:25:44 AM
I'm extremely glad I stumbled upon this thread. I've got a 74 750k with a hard shifting issue with the engine ready to come out of the frame. I'll be watching/posting in this thread frequently.

I am also extremely glad too see this thread! I actually got a '74  myself, which I'm going to fix up this winter. I started today, and so far i have taken out the battery basket, airbox, and some electric components.

Some of the thing's I am planning to do is;

-take out the engine and sandblast it -> paint it
-fix a gear shifting issue (some times it goes in neutral when it's not supposed to (CLUTCH RELATED??)
-repaint all black details
-new chain
-+++

I will read this thread often!

-Stian

If its in gear, and then hopps into a false neutral, its almost always a shift fork and usually never a clutch problem.

When a shift fork is bent, almost always from abuse, sometimes from a fall, it can't slide the gear to the left or right enough to get a full engagement and when power is applied or reduced, the gear hopps out of its engagement into the never land of the false neutral.

Between which gears is this happening? usually its the 1-2 upshift that won't stick and it jumps out of 2nd.
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Offline ron.cieri.313

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #102 on: November 14, 2009, 03:41:54 PM »
Just a quick update...sorry no pics (digital cameral is not cooperating today)...I have put in the new main shaft with new gears (i mean, the new used i just got in the mail).  In order to do this...i.e., put the old clutch on the new shaft, I seperated the clutch and sprocket assembly from the old shaft by disassembling the clutch as MC suggested...so the upper case is good.

The lower case...I also received a new shift drum with new shift forks (all bought used of course on ebay), and took out the old shift drum by removing the neutral switch...and then re-installed new shift drum...also, took the opportunity to clean metal shaving out from behind where the shift drum was.

The engine had been painted black by p.o. so I'm prepping the lower case for some cosmetic work (will prime and paint visible lower case portions with engine paint), and then will reassembly the countershaft and gears per the manual.

I have a long way home back its seems like I'm on the road back...little worried about all the shift mechanisms parts and the actually reassmebly of the halves...but first things first...will take pics before halves are put together.
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Offline nobody

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #103 on: November 14, 2009, 06:08:52 PM »
I officially hate my bike...

I bought a torch since all my penetrating blaster didn't even phase those bearing spanner bolts. So after finally breaking three of them loose, hitting my hand with a hammer several times in the process, the fourth one decided not to cooperate and the head completely stripped out after only a few hits with the impact driver.

Wish me luck with an extractor bit, I'll need it. Last time I tried I broke the bit.
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Quote from: KB02 on October 28, 2009, 02:58:26 PM
If life hands you lemons, make lemonade. If life hands you tomatoes, make tomato soup. If life hands you a box of hand grenades... well, now... THAT'S a message!!

Offline nobody

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #104 on: November 14, 2009, 06:49:11 PM »
Okay, good news and bad news...

Good: I didn't break the extractor bit.
Bad: I wasn't as fortunate as Ron to see such obvious damage after splitting the cases.

There appears to be some slight wear on the middle shift fork but it doesn't look like much. I don't see any noticeable bend either. I rotated the gears and couldn't see any chips or missing chunks. What should I be investigating further at this point?

Refresher: I ground gears going from first to second, plunk!, into gear but very rough shifting and no more neutral light.



« Last Edit: November 14, 2009, 06:55:19 PM by mgab »
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Quote from: KB02 on October 28, 2009, 02:58:26 PM
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Offline ron.cieri.313

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #105 on: November 14, 2009, 07:28:10 PM »
Hmmm, your crankcase looks alot cleaner inside than mine did.  Maybe you should pull the main gear shaft and counter shaft out and then you can examine the gears better...but wait for others to chime in...your shift fork does look good too like u said.
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Offline ron.cieri.313

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #106 on: November 17, 2009, 07:10:01 AM »
Hi everyone...some nice developments and some questions for the garage of ron.

Here's where we stand...on the upper half, primary shaft is in place:


On the bottom half, countershaft with gears, shift drum, neutral switch, shift forks and final driven shaft all in place and ready to rock.  I can even move the shift drum by hand and watch the gears and forks go through all their gyrations...pretty cool



Also, painted the lower case black


...so all is good, right?...well, aren't I missing a part in this photo below?  It is referred to in the manual as the final shaft oil drive...which makes sense cuz right now that bearing is just sitting in it groove...I don't know if it fell out at some point or it hasn't been there in the last how many years...it would makes sense the it was missing as my freakin kick start has always been a #$%* to use...not that I have much but...

and what the freak is this?...it is a small metal rubber ban like thing...if found it while playing with the final driven sprocket assembly...could be just trash but don't know...have not located it on the fiche...help identifying or putting my fears to rest appreciated

« Last Edit: December 22, 2009, 08:36:40 AM by ron.cieri.313 »
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Offline mystic_1

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #107 on: November 17, 2009, 07:25:51 AM »
That spring loop is part of an oil seal.  Check your final drive seal.  It goes on the inside, behind the lip that seals to the shaft.

The "final shaft oil drive" is a little tray thing with a funnel on the side, about an inch and a half square maybe, that diverts splashed from the tranny oil into the final drive shaft, to feed the automatic oil leak (aka automatic chain oiler) which was discontinued on later 750's.

Edit:  #10, below, part number 15621-300-000:





mystic_1
« Last Edit: November 17, 2009, 07:31:11 AM by mystic_1 »
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Offline ron.cieri.313

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #108 on: November 17, 2009, 08:03:22 AM »
Excellent...thanks Mystic...so the rubber band thingy goes on the inside diameter of the rubber seal/around the inner lip...correct?

And thanks for findings the part number for the final shaft oil drive...could not find it on the fiche...even the correct one u found makes it look like its on the outside of the case or something.

I will probably order a replacement...just too squeamish about leaving a part out no matter how potentially useless at this point.

But one more question...is it natural to get some clatter as the final drive gear rides of the countershaft gear on the end?  It is metal on metal (I did oil a bit) but everything else works so quietly.  I'm wondering  if this final shaft oil drive thingy gives some support to the bearing which lessens clatter?...what do you think?
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Offline MCRider

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #109 on: November 17, 2009, 08:21:16 AM »
Quote from: ron.cieri.313 on November 17, 2009, 08:03:22 AM
Excellent...thanks Mystic...so the rubber band thingy goes on the inside diameter of the rubber seal/around the inner lip...correct?

And thanks for findings the part number for the final shaft oil drive...could not find it on the fiche...even the correct one u found makes it look like its on the outside of the case or something.

I will probably order a replacement...just too squeamish about leaving a part out no matter how potentially useless at this point.

But one more question...is it natural to get some clatter as the final drive gear rides of the countershaft gear on the end?  It is metal on metal (I did oil a bit) but everything else works so quietly.  I'm wondering  if this final shaft oil drive thingy gives some support to the bearing which lessens clatter?...what do you think?

The final shaft oil drive thingy is completely worthless. Throw it away. Or don't get a new one which ever. It is a little tray that catches splash oil and feeds it down the center of the output shaft to oil your chain and otherwise make a god-awful mess of your rear wheel. Mystic already said so, I'm just confirming.

Absolutely fine and in my case preferable to leave it out. To your question, it doesn't support the bearing or anything else other than the makers of the degreaser you'll use to clean your wheel.

As far as the noise, shold just be a gear on gear noise. Not much help from me there.
« Last Edit: November 17, 2009, 08:24:09 AM by MCRider »
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Offline ron.cieri.313

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #110 on: November 17, 2009, 08:26:36 AM »
Lol...yes, I've been degreasing quite abit behind the sprocket cover...and thanks for the direct feeback or I'd be waiting another week or so for one to arrive in the mail.

...so I can expect some clatter then?
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Offline mystic_1

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #111 on: November 17, 2009, 08:29:34 AM »
Yeah I don't see the mount post in his motor either.  What year motor is this, Ron?

OK hold the phone, just spotted something in this pic:



The 'uppermost' gear on the left side of the photo has the line ground into the center of the teeth.  This is the hallmark of later transmissions (K7-K8 I think?) whose gears were slightly different than the earlier transmissions.  Count the teeth and compare it to your original gear.  This is probably why you're not getting smooth engagement.

Someone jump in here if I'm way off base.

mystic_1
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Offline MCRider

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #112 on: November 17, 2009, 08:32:26 AM »
Quote from: ron.cieri.313 on November 17, 2009, 08:26:36 AM
Lol...yes, I've been degreasing quite abit behind the sprocket cover...and thanks for the direct feeback or I'd be waiting another week or so for one to arrive in the mail.

...so I can expect some clatter then?
If you leave it out, you'll need to lube your chain manually. But that's what most of us do anyway, as we plug off the oiler from the outside.   and modern Oring chains require very little lube.

They are fairly large gears and should make some noise, I just can't say if yours is normal without being there. Sorry. The bearings are spinning and quiet?
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Offline MCRider

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #113 on: November 17, 2009, 08:33:20 AM »
Mystic, I removed the coomment about the mounting post as it is in the upper case, not the lower.

Nice catch on the gear, i wouldn't have known that, hope its his problem.
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Offline ron.cieri.313

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #114 on: November 17, 2009, 08:43:35 AM »
Yep, bearing are very smooth...my bike is a '76 K, the transmission was suppose to be of the same year.  I have the old transmission still and when I get home, will count the teeth and compare markings. 
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Offline ron.cieri.313

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #115 on: November 17, 2009, 10:29:01 AM »
Well only had time to compare markings during lunch, the gear i replaced did NOT have center markings on the teeth.

I will have to count teeth and/or replace this end gear with the one I took...can see if chatter changes.
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Offline HondaNorway

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #116 on: November 17, 2009, 03:13:40 PM »
Quote
If its in gear, and then hopps into a false neutral, its almost always a shift fork and usually never a clutch problem.

When a shift fork is bent, almost always from abuse, sometimes from a fall, it can't slide the gear to the left or right enough to get a full engagement and when power is applied or reduced, the gear hopps out of its engagement into the never land of the false neutral.

Between which gears is this happening? usually its the 1-2 upshift that won't stick and it jumps out of 2nd.

I think it is the 2nd gear which jump's out!
Is it a major operation to change a shift fork? Consider I don't have a lot of experience. But I will try to fix it anyway, I am just wondering.  ::)

Thank's for the reply!  :) :)
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Offline mystic_1

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #117 on: November 17, 2009, 04:09:47 PM »
Changing a shift fork is a big job.  Pull the engine, split the cases, basically everything that Ron is having to do in this thread.

mystic_1
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Offline ron.cieri.313

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #118 on: November 17, 2009, 05:58:38 PM »
Okay, Mystic, your catch should make ESPN"s web gems of the year...the teeth counts do NOT match..WTF!...I only counted two gears...the troubled C5 gear and the one at the opposite end which we've been discussing.  For the C5 gear, the original tranny broken gear had 31 teeth, tranny just received, 32 teeth...argh...the countershaft gear at the other end, original 44 teeth (or thereabouts) and the tranny just received 48 teeth

sigh, now what?...get a final driver gear from K7 or K8 or try and return the freaky tranny...damn it...I can only take solace in the fact that I didn't put this thing back together as is...here's the description from the ad below...will contact the seller see what he says.

Item:TRANSMISSION GEARS HONDA CB750 1976 CB 750 76 75
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Offline MCRider

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #119 on: November 17, 2009, 06:00:08 PM »
Yes that is what this thread is all about.  If its your first step into an engine, well its a big one.

But a human can do this (as oposed to a super-human) So if you can add, know right from left, top from bottom, and can follow directions, you can do it.
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Offline ron.cieri.313

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #120 on: November 17, 2009, 06:01:17 PM »
...more info from the description...of course his ad says he "accepts no returns"


FRAME # NA


MOTOR # CB750E-2602417


BUILD DATE: 1976


NA ORIGINAL MILES

PARTS IN THIS LISTING ARE FROM:  HONDA CB750





YOU ARE BIDDING ON: TRANSMISSION









CONDITION: GEARS AND DOGS ARE GOOD. TRANSMISSION HAS NO DAMAGE.

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Offline ron.cieri.313

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #121 on: November 17, 2009, 06:27:20 PM »
Okay, Kelley says I can exchange for another one he has in stock...he thinks its a 74 or 75...he thinks the 76 may have been from an F model.

I suggested that I could give him a tooth count and to look for no center line...is there a better way???

...thanks all.
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Offline mystic_1

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #122 on: November 17, 2009, 06:40:47 PM »
That makes sense, the F models and the K7/K8 have a lot of similarities.

Tooth count and lack of center line should be sufficient.  Best of luck!

mystic_1
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Offline 754

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #123 on: November 17, 2009, 07:08:40 PM »
I am not saying that the 76 or earlier did not have the line.. I am not sure.

 If you got the whole trans it will work, just dont run one shaft without the other... would I send it back if it fits.. not a chance...
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Offline ron.cieri.313

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Re: Splitting the cases on my CB750...first of many ?'s
« Reply #124 on: November 17, 2009, 07:42:30 PM »
K..thanks Mystic...the seller also says send him a tooth count.

7...I'm reluctant to keep it cuz of the problem with the final driven gear...I would have to positively identify the replacement tranny and buy a new driven gear assembly...and hope that's all the complications I'll run into...which I'm confident if you and everyone says that would be it then I might go for it...but boy, I just would like to stay with stock.  I guess it wouldn't effect the shift forks or shift drum?

still I'll only be out $14 to send it back...its not too hard to take it back out (he tells himself) and pack it up, and wait for another one...smh...sure hope this ass rape fairy would leave michigan.
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