Author Topic: So while driving to work today...transmission fun! - total engine rebuild fun!  (Read 9519 times)

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Offline nobody

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I'd be paranoid running high speed with a dodgy box that something would give out, like a tooth, and jam the box solid so all i saw was
Ground
Sky
Ground
Sky
OW!

I would definitely agree with this... At the very least, you could end up causing more damage to your transmission. At the very worst, you could end up in a box in the ground.
74 cb750k

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 TwoTired

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Nothing to add to the list? How about; New valve springs?

If the spring height meets service specs., reuse them.
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline SKTP

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My problem was a busted final gear bearing and to replace it meant splitting the cases.

Andy, how obvious was this? I worry I will get the thing apart and not see any obvious damage?

Also, engine bearings...replacing them sounds like a #$%*...is there an engine bearing kit available somewhere?

Also, Cycle-X's Gasket set....any opinions?
« Last Edit: December 03, 2009, 12:12:27 PM by SKTP »
1978k rebuild thread http://forums.sohc4.net/index.php?topic=68423.0
BIKE OF THE MONTH - OCTOBER 2017
2003 Ducati M800ie
1997 Honda CR-V
2004 Honda CR-V
1966 Honda S90

Offline mystic_1

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Andy, how obvious was this? I worry I will get the thing apart and not see any obvious damage?


Sometimes it damages your case, or at least the seal, when it lets go.  Do you see any external signs of distress?

Also, engine bearings...replacing them sounds like a #$%*...is there an engine bearing kit available somewhere?

No kits exist, because selecting the proper combination of crankshaft and connecting rod bearings is the only real hard part of the process.  It's (potentially) different with each case/crank/rod combination.


mystic_1
"A ship in harbor is safe, but that is not what ships are built for."
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My build thread:  http://forums.sohc4.net/index.php?topic=68952.0

Offline andy750

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My problem was a busted final gear bearing and to replace it meant splitting the cases.

Andy, how obvious was this? I worry I will get the thing apart and not see any obvious damage?

Also, engine bearings...replacing them sounds like a #$%*...is there an engine bearing kit available somewhere?

Before jumping to any conclusions verify the bearing is/may be the problem. This is the final gear bearing that sits in between the lower and upper cases. There is also a half-circlip that sits on top of it - this was the issue on mine (I think that may have caused some freeplay with the bearing - perhaps? - anyway -we replaced that main bearing (very easy I seem to recall - still get it from Honda BUT the circlip is discontinued!! I asked on the forum for a spare one and someone very kindly sent me one from their old engine  - on my first attempt at fixing my issue I and a friend had used a modified circlip (non-stock) and put engine back in bike and it ran fine for about 1000 miles before issue returned......I then repeated the procedure but this time used a stock circlip and another new bearing - no issues anymore!!

For me...when I moved off in first I would hear a grinding/clunky sound - not good. When checking the bearing post-splitting the cases it was pretty obivous it was grinding when turned.

Hope this helps
cheers
Andy

Current bikes
1. CB750K4: Long distance bike, 17 countries and counting...2001 - Trans-USA-Mexico, 2003 - European Tour, 2004 - SOHC Easy Rider Trip , 2008 - Adirondack Tour 2-up , 2013 - Tail of the Dragon Tour , 2017: 836 kit install and bottom end rebuild. And rebirth: http://forums.sohc4.net/index.php/topic,173213.msg2029836.html#msg2029836
2. CB750/810cc K2  - road racer with JMR worked head 71 hp
3. Yamaha Tenere T700 2022

Where did you go on your bike today? - http://forums.sohc4.net/index.php?topic=45183.2350

Offline SKTP

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Most of my grinding only seems to happen under a load...I can shift on the center stand (rear wheel in the air) with no issues...
1978k rebuild thread http://forums.sohc4.net/index.php?topic=68423.0
BIKE OF THE MONTH - OCTOBER 2017
2003 Ducati M800ie
1997 Honda CR-V
2004 Honda CR-V
1966 Honda S90

Offline mystic_1

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Andy, how obvious was this? I worry I will get the thing apart and not see any obvious damage?


Sometimes it damages your case, or at least the seal, when it lets go.  Do you see any external signs of distress?

Also, engine bearings...replacing them sounds like a #$%*...is there an engine bearing kit available somewhere?

No kits exist, because selecting the proper combination of crankshaft and connecting rod bearings is the only real hard part of the process.  It's (potentially) different with each case/crank/rod combination.


mystic_1



Oops, had it in my head that you were talking about crank/rod bearings, not transmission bearings.  Still no kits that I know of, but there's nothing to select, there, you just buy standard replacements.  Putting them in takes a bit physically if you don't have the appropriate bearing pullers/drivers.

mystic_1
"A ship in harbor is safe, but that is not what ships are built for."
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My build thread:  http://forums.sohc4.net/index.php?topic=68952.0

Offline SKTP

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Well, I killed it...Had to load it into the but of a friend's pick-up. It's now locked in second (I think, maybe first) I leaned the bike to the left while running and it basically sounded like the tranny shifted to the left then would not shift back. It was not a pleasant sound. I am currently considering pulling the engine and driving it up o http://www.valleycycles.net/index.htm and having them rebuild the transmission. They told me that the lowest they would think it could be done for would be about a grand if everything went perfectly. (I currently have a 77 and 78 trans from ebay for parts). during that time I would strip the rest of the bike. have the frame sent out to powder coat and paint a bunch of small stuff (battery box, etc...) install the new headset bearings...and then pu the engine back in. I think for my level of skill and free time this is the only viable option to get my baby back on the road in a reasonable amount of time.

I looked at another bike and figure with all the time and effort I have put into my current bike buying a second for less than 2 grand is just going back to the same place I was 2 years ago (other than the new tranny deal)...

so, am I a wuss or what? :)
« Last Edit: December 08, 2009, 03:00:35 PM by SKTP »
1978k rebuild thread http://forums.sohc4.net/index.php?topic=68423.0
BIKE OF THE MONTH - OCTOBER 2017
2003 Ducati M800ie
1997 Honda CR-V
2004 Honda CR-V
1966 Honda S90

Offline JeyLux

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Well, I killed it...Had to load it into the but of a friend's pick-up. It's now locked in second (I think, maybe first) I leaned the bike to the left while running and it basically sounded like the tranny shifted to the left then would not shift back. It was not a pleasant sound. I an currently considering pulling the engine. and driving it up o http://www.valleycycles.net/index.htm and havign them rebuild the transmission. They told me that the lowest they would think it could be done for would be about a grand if everything went perfectly. (I currently have a 77 and 78 trans from ebay for parts). during that time I would strip the rest of the bike. have the frame sent out to powder coat and paint a bunch of small stuff (battery boc, etc...) install the new headset bearings...and then pu the engine back in. I think for my level of skill and free time this is the only viable option to get my baby back on the road in a reasonable amount of time.

I looked at another bike and figure with all the time and effort I have put into my current bike buying a second for less than 2 grand if just bringing back to the same place I was 2 years ago (other than the new tranny deal)...

so, am I a wuss or what? :)

A wise man does his own work.  A wiser man knows when he should call someone to do it for him.

Sometimes it's better to have a pro do it.  maybe buy something you're not depending on like a CB350 or something small to 'dabble' with and get your mechanical wits about you, it sounds like you have the concepts but haven't split a case before to understand what you're getting yourself into.

Best of luck
1973 CB500k
1972 CL350

Offline nobody

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A wise man does his own work.  A wiser man knows when he should call someone to do it for him.

Sometimes it's better to have a pro do it.  maybe buy something you're not depending on like a CB350 or something small to 'dabble' with and get your mechanical wits about you, it sounds like you have the concepts but haven't split a case before to understand what you're getting yourself into.

Best of luck

There's always a first time for everything, you can't learn it if you don't try it.
74 cb750k

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 andy750

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The first time my tranny (gear bearing) went I did it with a friend and completed it in one long 15hr day from pulling the engine to riding off at midnight. That repair lasted 1000 miles due to a modified circlip we had used. Next time I did it myself. I reassembled lower cases and it wouldnt shift in any gear...stumped me!.... So...I took it to an ex-Honda mechanic and it cost me $800 for him to do what I couldnt do...... :-\.

It was probably something really simple as well but riding season was on (it was May)...if I were you Id try again...once more...a grand is a lot of money...

good luck
Andy
Current bikes
1. CB750K4: Long distance bike, 17 countries and counting...2001 - Trans-USA-Mexico, 2003 - European Tour, 2004 - SOHC Easy Rider Trip , 2008 - Adirondack Tour 2-up , 2013 - Tail of the Dragon Tour , 2017: 836 kit install and bottom end rebuild. And rebirth: http://forums.sohc4.net/index.php/topic,173213.msg2029836.html#msg2029836
2. CB750/810cc K2  - road racer with JMR worked head 71 hp
3. Yamaha Tenere T700 2022

Where did you go on your bike today? - http://forums.sohc4.net/index.php?topic=45183.2350

yozzie

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maybe not really relevant to a CB, but this reminds me of exactly what my yamaha xj1100 was doing.  I could only start off in 1st gear and wouldn't dare touch the throttle because it would slip out of gear and and the resulting noise was like a machine gun.  I would quickly shift into second and could full throttle through fifth gear.  On that bike I took off the oil pan, clutch, shifter assembly and had full access to all the tranny gears.  Turns out the dogs on first gear were worn a bit on an angle and the slots in fourth they fit in to were worn as well....a bit of torque applied and they would pop apart.  I found a used tranny with good gears for $75, and four hours of labor had it fixed.  But the CBs sound a little more difficult.  Hope my CB550 holds out!

Offline SKTP

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I could only start off in 1st gear and wouldn't dare touch the throttle because it would slip out of gear and and the resulting noise was like a machine gun.  I would quickly shift into second and could full throttle through fifth gear.  On that bike I took off the oil pan, clutch, shifter assembly and had full access to all the tranny gears.  Turns out the dogs on first gear were worn a bit on an angle and the slots in fourth they fit in to were worn as well....a bit of torque applied and they would pop apart

Yes, exactly and from looking at the 6 manuals I have now...it looks to my very untrained eye that this is exactly what is happening...My friend is going to help me rip it apart. but that will not happen until the new year. Way to busy right now...I will make a detailed thread about the my first engine tear-down ever...lots of pictures and I'm sure lots of questions. I figure I might try a new CAM while I have the entire thing apart (I plan on replacing as many gaskets as possible while I'm at it)...

Still very welcome to CAM recommendations and Gasket set recommendations.

Right now I am considering the Cycle X products...
1978k rebuild thread http://forums.sohc4.net/index.php?topic=68423.0
BIKE OF THE MONTH - OCTOBER 2017
2003 Ducati M800ie
1997 Honda CR-V
2004 Honda CR-V
1966 Honda S90

yozzie

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Just out of curiousity why are you looking at totally rebuilding the engine with an overbore kit and all that good jazz if it was running well like you said at the beginning of this post?
If it was me I would find the tranny problem, fix it, and keep tearing up the streets til it really needed a rebuild.  But that's just me. 

Offline SKTP

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You're right. I seriously doubt I'll do the overbore...but for me taking the engine out is a big-ass deal so while its out why not do as much to it as possible? Since I will be replacing head gaskets, why not drop in a cam?
1978k rebuild thread http://forums.sohc4.net/index.php?topic=68423.0
BIKE OF THE MONTH - OCTOBER 2017
2003 Ducati M800ie
1997 Honda CR-V
2004 Honda CR-V
1966 Honda S90

Offline ron.cieri.313

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Remember, most of the work is in deconstruction in order to get the motor out...you would have to do this to split the cases or put in an entirely new engine...so a new tranny is only about $100, half the price of putting in a new motor.
Making the world a better place, one motorcycle at a time.

Offline MCRider

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You're right. I seriously doubt I'll do the overbore...but for me taking the engine out is a big-ass deal so while its out why not do as much to it as possible? Since I will be replacing head gaskets, why not drop in a cam?
You would only want the mildest of cams, without doing springs too, which would involve pulling the head. A cam is $150- $200. And a hotter cam would also beg for head work.

 I'd vote for an ignition, (HondaMan or Dyna) front suspension and brake work first.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline TwoTired

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There is risk in everything you do.  The more you touch, the more opportunity to break more than you are fixing.

For example, if you can fix the trans without opening the top end, how will you feel when head studs pull out or snap off while mucking with top end changes,  Or, accidentally plugging up one of the oil restrictors and later having the cam snap in two?  It wouldn't be the first time reading posts about such occurrences.

Some time ago, I read the story of a guy with a good running 550.  On the basis if it being old, he thought the engine needed rebuilding.  So, without checking anything beforehand, he took the engine apart, found all wear to be well within limits and bought a new gasket kit to put it back together.  While putting the cylinder cover on, he bent several valve stems.  After that discovery he stopped posting on the forum thread.  But, the final comments after diagnosis sounded like the engine would never be repaired as the parts needed were costlier than his investment in the bike, and he was short on cash.  The end to an otherwise good engine due to unnecessary meddling.
Could also be described as being careful what you ask for, as you may just get it.
If you do the head gasket, you should also do the cylinder base gasket.  What if you break a ring/crack a piston ring land putting the cylinder block back on?  Experience teaches.  Sometimes you have to pay for it.  Experience is learning to avoid past mistakes.  Risks like these I place on the secondary or spare bike.  Not on the only one I have.  But then, I've gotten a bit more conservative in my old age.

Best of luck!
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline mystic_1

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Good post TT, I agree completely.

In addition SKTP, there's no such thing as a free lunch.  Adding a single performance component won't really gain you much without the other complimentary upgrades.  So for example, for your cam swap you'll also probably need a slotted cam gear so you can time the cam properly, you'll likely need to retune your intake system, and if your pipes are stock then they'll be a bottleneck in the system.

Don't get me wrong, I'm in the midst of a "do everything at once" build myself at the moment, and I can tell you that you'll be much happier just getting the bike on the road as a reliable runner for the moment.  Once you've done so and gained the experience and insight, THEN start collecting your performance upgrade parts and install them in a planned session NEXT winter.

cheers

mystic_1
"A ship in harbor is safe, but that is not what ships are built for."
- John Augustus Shedd

My build thread:  http://forums.sohc4.net/index.php?topic=68952.0

Offline SKTP

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OK...so I'm fianlly back from my Christmas/visit the folks "vacation"...and the engine is coming out soon

the plan is to fix all leaks and fix the transmission

I plan on buying;

- Cycle-X, gasket set
- Gssket sealer

I am considering
- new cam chain
- new 1978 piston rings (any leads on this would be amazing)

and, what are you opinions on this? I bought a 77 and 78 transmission off ebay...maybe I should send one to Ken and get a prefect one if I'm replacing it hopefully for the first and last time ever...

http://www.cyclexchange.net/Engine%20Parts%20Page.htm

Quote
Cycle X Race Transmissions.
Includes:
* Glass bead gear assemblies for inspection. ( also, makes them purdy)
* Magnaflux gears  (generally an additional cost elsewhere, not here)
* Undercut gears   (a must for Hot-rod Honda sohc's)

 Note:
Send us your transmission.  We will inspect it and send you back one of these race prepared transmissions.
If your transmission is bad, don't worry.
We have race transmissions in stock, ready to go.

                                                                       $ 289.00            # EN-0808
                                                                           CALL TO ORDER
1978k rebuild thread http://forums.sohc4.net/index.php?topic=68423.0
BIKE OF THE MONTH - OCTOBER 2017
2003 Ducati M800ie
1997 Honda CR-V
2004 Honda CR-V
1966 Honda S90

Offline mystic_1

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the plan is to fix all leaks and fix the transmission



Nice, a clear concise plan is always good.

Regarding the transmission, $289 ain't too bad for a rebuilt transmission, much less the undercutting.  If your budget can handle it, go for it.  Do they warranty their work?

mystic_1
"A ship in harbor is safe, but that is not what ships are built for."
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My build thread:  http://forums.sohc4.net/index.php?topic=68952.0

Offline dave500

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hi sktp,,do it once,do it well,,replace the cam chain and tentioners ,,at least hone and rering the bores,ide go for a rebore but the money is up to you,the head is off so, ,dont get it ported ,,but clean up factory mis castings for want of a better word,reseat the valves(grind) and valve guide seals of course,your doing the right thing in your choice of tools,,also get a telescopic magnet,so cheap,so handy!you dont want it to be a hotrod motor so if your cam is good stay with it,plan A quickly becomes plan B once you start modifying things,,although any factory improvements should be done now,,do those carbs,,and replace those jis bolts with allen key stainless ,this bike is your daily driver and not a toy like most of ours here,good luck and happy new year!!!

Offline SKTP

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Well, I'm thinking a 2005 CBR 1000 might also be in the works...

plus, a new neutral switch!
1978k rebuild thread http://forums.sohc4.net/index.php?topic=68423.0
BIKE OF THE MONTH - OCTOBER 2017
2003 Ducati M800ie
1997 Honda CR-V
2004 Honda CR-V
1966 Honda S90

Offline MCRider

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Well, I'm thinking a 2005 CBR 1000 might also be in the works...

plus, a new neutral switch!
You know... we all love our old CBs, but once you get your hands on some modern technology, you'll go WHOA!.

A CBR1000 would just stomp on any old CB no matter how built. And for me it has some soul too.

Both would be nice.   :D
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline dave500

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i rode a friends new r1,and it started raining lightly!!im thinking great,here i am on my mates brand new super bike and im scared,,too much for me,ide never get the power down,i was amazed how you could be in way to higher a gear and just accelerate like the wind!he only got 25000 ks untill all the cam and valve gear chewed up!back under warranty and hes not happy,its been back twice again but its not the same he says,,i dont think he rung its neck,hes 52 and mature but high tech can mean high problems as well.