Author Topic: 1972 CB750 Four K2 -- Rebuilt to NEW OLD STOCK -- PIX ON PAGE 50 (Read 271866 times)

edwardmorris · « **Reply #775 on:** February 14, 2015, 09:10:19 PM »

Thanks Mark, I do have all NOS o-rings and seals for the entire engine so I won't miss it.

I'm still not a 100% clear on the orientation of the gear on the final drive. From my old pic it looks like Option A is the right way, anyone else concur?

Also the fiche shows grooved bearings but from what I can tell, the cases were never split before. So mine are both smooth, but with a retainer anyway, so I'll stick with non grooved replacements.

edwardmorris · « **Reply #776 on:** February 14, 2015, 09:12:20 PM »

Main shaft was next, followed usual inspection steps, installed new SKFs. 1" PVC diy driver worked like a charm. The left side bearing slides into position, then presses in.

edwardmorris · « **Reply #777 on:** February 14, 2015, 09:16:02 PM »

Primary was next, 1-1/2" PVC DIY driver. The needle rollers were pressed in by the machine shop for me. The basket/bell pressed on with the same 1-1/2" PVC.

edwardmorris · « **Reply #778 on:** February 14, 2015, 09:20:43 PM »

This was quite the adventure, and I'm glad its finally back together. If you read back a few pages, you'll find my story of how I got the SKFs and found a shop to widen the grooves for me without asking for my organs in exchange. Only the two smaller ones need widening, the large one already has the correct width.

All was going well, till I decided to put the counter shaft back together next. Started inspection, smoothed out rough splines, inspected worn dogs and remembered I bought NEAR NOS condition C2 and C5 gears from Bill Benton

All jolly I went to go fetch them and after five straight hours of ransacking the entire house, I still haven't found them

Infuriated beyond all recognition

Davez134 · « **Reply #779 on:** February 14, 2015, 09:38:10 PM »

Quote from: edwardmorris on February 14, 2015, 09:10:19 PM

Thanks Mark, I do have all NOS o-rings and seals for the entire engine so I won't miss it.

I'm still not a 100% clear on the orientation of the gear on the final drive. From my old pic it looks like Option A is the right way, anyone else concur?

Also the fiche shows grooved bearings but from what I can tell, the cases were never split before. So mine are both smooth, but with a retainer anyway, so I'll stick with non grooved replacements.

All I can offer is mine were grooved with retainers. Although I'm sure my cases had been split before. Reply 87 on my project shows bearings. Probably not much help but just another reference

edwardmorris · « **Reply #780 on:** February 14, 2015, 10:01:30 PM »

Thanks man, I'm wondering this is another early K2 oddity. I went back to look at the pix from the tear down, I found these two. First one shows the large retainer hangin loose when I split the cases

This is the lower case I think, and looks like all the retainer grooves are on this side. I don't see one for the inner final drive one, so mine may never have had one?

Terry in Australia · « **Reply #781 on:** February 14, 2015, 10:52:12 PM »

Here you go Rafi, this is CMSNL's schematic for a K4, but in my experience, all of the K's were pretty much the same, as were the F0/F1. There should be the "full circle" retainer outboard of the bearing on the sprocket side, and I'm pretty sure, a half circle on the other bearing, which is grooved in the pic. Cheers, Terry.

http://www.cmsnl.com/honda-cb750-four-k4-usa_model482/partslist/E++21.html#results

edwardmorris · « **Reply #782 on:** February 15, 2015, 12:04:37 PM »

Thanks Terry! I don't know what I want to write this off as, but I think I know how I'm going to proceed for now.

I found just 3 half circle retainers from when I tore down the engine, and one full one. Like Terry said, I believe the full one sits NEXT to the large bearing. The other one is definitely not grooved because there is no recess cut for a half ring in either of the cases. So either these are a terribly odd cases, or the fiche is wrong. Either way, I think it will work out fine if I put it back together using Option A above. Pix to come as soon as I'm done with it.

In the meantime, I finally found the newer C2-C5 set. Now that I've taken a closer look, they don't really look that much different when it comes to dog wear, but then again, this is my first time so what do I know. Can anyone tell if the used set is any worse? The only difference to my untrained eye is that the parkerizing has been blasted off the newer set. Its also missing an oiling hole, and the stamping is different. Thoughts? Should I reuse my old ones and save the clean set for someone else?

C2?

edwardmorris · « **Reply #783 on:** February 15, 2015, 12:05:44 PM »

MCRider · « **Reply #784 on:** February 15, 2015, 12:44:22 PM »

EM: Sorry I can't remember what your original problem was, jumping out of 2nd gear?

If so, my experience, personal and with a few otherwise, is that its not just the gear dogs that get worn. First, its the shift fork that gets worn or bent. From abusive shifting.

THEN, the dogs get worn because the fork is not moving them into full engagement. Each time they jump apart they take some metal with them, ultimately causing visual wear.

But, if you put new gears in with a worn or bent shift fork, you will soon have the same problem. How's your shift fork?

edwardmorris · « **Reply #785 on:** February 15, 2015, 12:55:34 PM »

Hey Ron, the bike only "ran when parked" so I never rode it to see how things were. When I tore it down, I posted up close up shots of the dogs and shift forks. Couple members expressed concern over the state of the dogs for the C2-C5 combo and also the shift forks. So I purchased the "like new" ones pictured above to avoid having issues, along with a set of "like new" shifter forks to go with them. But now that I have them side by side, I only see the old shift forks being a little too worn, but the dogs look damn near identical. Again, to my untrained eye. So I was pondering what to do with the old one, especially if its no better than the replacement....

edwardmorris · « **Reply #786 on:** February 15, 2015, 02:25:26 PM »

Final drive done, now on to the part that worries me, driving the last counter shaft bearing into the crankcase. Any suggestions? I was planning on using a heat gun then tapping it in since I don't have any specialty bearing tools..

edwardmorris · « **Reply #787 on:** February 15, 2015, 02:26:14 PM »

Dammit the page turned, still need input on this one

http://forums.sohc4.net/index.php?topic=126735.msg1651328#msg1651328

Restoration Fan · « **Reply #788 on:** February 15, 2015, 04:18:18 PM »

Not that the teeth are bad on the ones on the left but the ones on the right have pristine looking teeth on them (more square and no rounding on the edges).

MCRider · « **Reply #789 on:** February 15, 2015, 04:28:46 PM »

Quote from: edwardmorris on February 15, 2015, 12:55:34 PM

Hey Ron, the bike only "ran when parked" so I never rode it to see how things were. When I tore it down, I posted up close up shots of the dogs and shift forks. Couple members expressed concern over the state of the dogs for the C2-C5 combo and also the shift forks. So I purchased the "like new" ones pictured above to avoid having issues, along with a set of "like new" shifter forks to go with them. But now that I have them side by side, I only see the old shift forks being a little too worn, but the dogs look damn near identical. Again, to my untrained eye. So I was pondering what to do with the old one, especially if its no better than the replacement....

I see. All I can say is be sure to use good shift forks. A bent fork will have an arc of wear following the arc in the fork. And/or the pads at the ends of each tine will show wear.

If the gears look the same, flip a coin, assuming both are good. I'm not qualified to say.

edwardmorris · « **Reply #790 on:** February 15, 2015, 06:23:31 PM »

Thanks Ron! I'll wait for Terry or Mark to swing by and have a look as well. If I can, I want to save the clean set for my next 750.

In the mean time, these guys cleaned up well. How do they look? One concern I have is that half the rocker arm adjusting nuts are stuck, almost welded together. Will have to deal with that soon. I dropped some mineral spirits in all the oil passages to break loose the gelled up oil, then compressed air after final rinse. Some wear on the journals but doesn't look too bad does it?

edwardmorris · « **Reply #791 on:** February 15, 2015, 06:24:07 PM »

Restoration Fan · « **Reply #792 on:** February 15, 2015, 06:28:45 PM »

Dang, Rafi...very nice cleaning job! Looks brand new.

MCRider · « **Reply #793 on:** February 15, 2015, 06:34:29 PM »

YHeah looks good. Have you looked at the contact points of the tappets themselves? Often worn in a line or pitted. This will make adjusting them difficult. Cheap to replace.

Just get medieval with those nuts. They may be candidates for replacement too.

edwardmorris · « **Reply #794 on:** February 15, 2015, 07:19:04 PM »

Thanks Ron and Ron. The contact points are pretty smooth without any visible pitting from what I can tell. Feel pretty smooth too. I'll try the caveman approach on the nuts sometime this week, chances are I'll be home for another day if its too cold to work

HondaMan · « **Reply #795 on:** February 15, 2015, 07:45:18 PM »

Like Ron said...that's how it happens.
Another thing that causes it is when the bike falls over on the shifter side and it gets pulled hard UP while running: this often bends the fork, too. This is often the "parking lot accident" scenario, after which the [usually new] owner shows up at the shop with this shifting problem.

Your old gears look a little worn, but I am curious about the rusty-looking spots on their inner bearings. Is that really rust? Otherwise, they could be made perfectly serviceable again with APE's help on their dogs (and holes). Mismatched oil holes on the gears are not usually an issue of concern, but mismatched holes on the shafts definitely are. In general, if the gear has inner teeth to the shaft and the shaft has a hole, the gear (and position on the splines) must be made to match. This is general Japanese gearbox design for this era of engines, all brands: sometimes I think a "hidden" vendor in Japan made all of them for the Big Three bikes in those days?

There is a dividing line on the inner bearings, too. Along about the New Factory K3, the inner bushings on many of the gears switched from Oilite dimpled Bronze 841 to cast iron composite (by the "F" bikes only the F0 early ones had bronze at all). This lost power (and life) overall, but was about 10% as expensive, hence the switch. If you have the option in any of them to use the bronze types, go for it. It pays back in top-end power on the road.

edwardmorris · « **Reply #796 on:** February 16, 2015, 09:06:23 AM »

Drats! Oh well, I guess the old ones will be saved for a later project with a back cut trans. Thanks for reviewing Mark! I did follow the step by step in your book, found points I wouldn't even have dreamed of before assembling (flat vs rounded edges on spaces

). This trans has all bronze inner bushings that look good without any scoring or gouging. Also, those rust looking marks are rust, but not on the gear, I had accidentally set it on a rag I was using to clean up a few other pieces I'd just pulled out of my derusting tank, wiped right off. The old gears are pretty clean. I didn't go for blasting off the parkerizing after a thread I had asking about it somewhere, otherwise all of the old ones would have shined up like the new ones above. Once I put the counter shaft back together, the entire trans will be left soaking in oil till assembly.

edwardmorris · « **Reply #797 on:** February 19, 2015, 03:15:39 PM »

GrrraahhHH

!

I figured out the damn problem. I've been looking at the wrong damned gears all this time. My C5 is definitely toast (pix 1 & 2), which is why bought the replacements. Only the replacement isn't a C5

. So no wonder I kept thinking why replace it when it looks just as good.

Pic 3 shows C5, C2, C3, C4, C1 and Transfer gears as they go on (I think the order is right $:-\$ ). Time to page Bill Benton

edwardmorris · « **Reply #798 on:** February 20, 2015, 10:03:49 AM »

All sorted, correct sets should be on their way soon, thanks to Bill!

Lesson Learned: When you find really awesome stuff, CHECK IT RIGHT AWAY and don't stash it away like a crazy squirrel!

edwardmorris · « **Reply #799 on:** February 24, 2015, 10:30:46 PM »

Correct gears arrived last night, isn't Bill the best

Started putting them together and I notice that after the circlips are installed in place, the C2 rotates freely and has some side to side play (very small) while the C3 sits sung with no play and doesn't spin as freely with the circlip in place (spins freely without it, so I know its not the shaft, I smoothed the tapers on that). Is this normal?

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Author Topic: 1972 CB750 Four K2 -- Rebuilt to NEW OLD STOCK -- PIX ON PAGE 50 (Read 271866 times)