CB750 K0/K1 Hybrid

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CYBORG
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Re: CB750 K-Whatever

#256

Post by CYBORG »

looks like you have that paint thing figured out :lol: :lol: :lol:
1978 custom GL1000
1977 custom with 1200 engine
1985 gl1200
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Lucien Harpress
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Re: CB750 K-Whatever

#257

Post by Lucien Harpress »

I've gotten decently good at a skill I never wanted to have to need. :) That said:

Image

Primer, paint and clear are on. I'm going to take a day or two to let it cure up decently well, then I can start loading it up with all the internal spinny bits. I'd be nice to do that this weekend, but we'll see if the paint cooperates.

Ah well. I got a lot of winter left.
1997 Valkyrie- Light Cutomization, but Too Busy Riding
1980 KZ1300- Bike's Haunted
1976 GL1000 (Yellow)- It Runs (Poorly) and Doesn't Leak (Mostly)
1974 Velosolex 3800- Better Than Walking
1972 CB750- Broke the Chain And Ate the Motor
1969 CT90- The Most Fun You Can Have on 90ccs.
1965 CA77 Dream- Needs a Full Teardown, but Complete

All advice I give is only valid until an expert corrects me.
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Lucien Harpress
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Re: CB750 K-Whatever

#258

Post by Lucien Harpress »

I cranked up the ol' heater and figured I'd get all the internals swapped over to their new home.

Image

Image

Overall things went fairly smoothly. The kickstart mechanism was a bit iffy, just because springs are always a joy to play with. Everything else went in just fine, though, although it is a bit odd to be using engine assembly lube for it's intended purpose.

The only thing I had questions on came when I (temporarily) placed the final drive shaft in. The larger bearing (the one closest to the shaft seal) has just the slightest bit of play when I rock it back and forth. At first I thought it was worn out, but I checked my other final drive, and that bearing has the same amount of play. I'm going to do some research before I close everything up, but that might be normal.
Last edited by Lucien Harpress on Sat Nov 19, 2022 6:30 pm, edited 1 time in total.
1997 Valkyrie- Light Cutomization, but Too Busy Riding
1980 KZ1300- Bike's Haunted
1976 GL1000 (Yellow)- It Runs (Poorly) and Doesn't Leak (Mostly)
1974 Velosolex 3800- Better Than Walking
1972 CB750- Broke the Chain And Ate the Motor
1969 CT90- The Most Fun You Can Have on 90ccs.
1965 CA77 Dream- Needs a Full Teardown, but Complete

All advice I give is only valid until an expert corrects me.
cfairweather
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Re: CB750 K-Whatever

#259

Post by cfairweather »

Here is a picture of my kick starter spring. You have to push down hard to get it in the right place.
DSCN4248.JPG
DSCN4248.JPG (187.84 KiB) Viewed 920 times
Also, it looks like you are choosing to load the bottom case and then place the upper case over it. Although this is not how the manual says to do it, I think it is the best way and I have done it both ways. Doing it this way allows you to test the transmission (shifting forks) before closing the cases and you don't have to fight getting the shifting fork in place. I think I put the final drive in the upper case before putting them together so you may want to explore that idea. Use a big rubber band to keep the final shaft in place. The other challenge you will run in to is keeping the rods centered while you place the upper case over the lower case. I used packing peanuts to keep them in place. Maybe these pictures will help you. You mentioned a little play in the final drive and if I understand you correctly, it is normal.
DSCN4252.JPG
DSCN4252.JPG (212.8 KiB) Viewed 920 times
DSCN4253.JPG
DSCN4253.JPG (148.86 KiB) Viewed 920 times
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Lucien Harpress
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Re: CB750 K-Whatever

#260

Post by Lucien Harpress »

Yeah, loading the top case first seemed a bit odd to me. I've had a KZ1300 bottom end opened up, and that makes sense to load the top first. The 750 just works so much better the other way though.

Thanks for the advice on the final dive output shaft. I'd figured I'd have to do something like that due to the chain oiler pan thingy. The output shaft bearing was my biggest concern. Essentially, if you look at is as it sits on the bike, I could tilt the outer bearing ring left and right just the tiniest bit. Thing is, once the shaft is in the cases, the other bearing prevents the shaft from moving this way at all. It's great to hear this is normal.

I'll probably be a second or two before I close the cases up. I still need to set the o-ring up front and a couple of the locating dowels. Plus I'd like to zinc plate the case bolts as well. I'll probably just do the tops, though. I've seen enough about "hydrogen embrittlement" to not want to risk the entirety of bolts that ACTUALLY matter. But I still want them to at least look nice. This way I get the best of both worlds- good looking bolts that I won't have to worry about not functioning.

Thanks!
1997 Valkyrie- Light Cutomization, but Too Busy Riding
1980 KZ1300- Bike's Haunted
1976 GL1000 (Yellow)- It Runs (Poorly) and Doesn't Leak (Mostly)
1974 Velosolex 3800- Better Than Walking
1972 CB750- Broke the Chain And Ate the Motor
1969 CT90- The Most Fun You Can Have on 90ccs.
1965 CA77 Dream- Needs a Full Teardown, but Complete

All advice I give is only valid until an expert corrects me.
cfairweather
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Re: CB750 K-Whatever

#261

Post by cfairweather »

Did you inspect the dogs on the gears? If these are out of round or worn you will eventually have issues. Usually the first ones to wear out are the 1st to 2nd dogs. The bike will pop out of gear if these get worn. Take a close look at them and replace if needed. On one of my CB750s, I bought a reconditioned undercut transmission from Cycle-X which is a solution. They undercut the dogs to force the gears to stay in the right place. They do good work.
cfairweather
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Re: CB750 K-Whatever

#262

Post by cfairweather »

Also, can you take a picture of the cam holders for me. I will give you a tip that Hondaman suggests based on the type you have.
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Lucien Harpress
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Re: CB750 K-Whatever

#263

Post by Lucien Harpress »

Can do. I took a quick glance at the gear dogs and nothing jumped out at me, but I'll give it a closer check. Before I broke my engine the only real transmission issue I had was it was VERY hard to shift into neutral when the bike was warm, but would slip right in once I shut the engine off. Regardless, we'll see.

Ditto on the cam holders. If I don't have a good pic already, I'll dig 'em out.
1997 Valkyrie- Light Cutomization, but Too Busy Riding
1980 KZ1300- Bike's Haunted
1976 GL1000 (Yellow)- It Runs (Poorly) and Doesn't Leak (Mostly)
1974 Velosolex 3800- Better Than Walking
1972 CB750- Broke the Chain And Ate the Motor
1969 CT90- The Most Fun You Can Have on 90ccs.
1965 CA77 Dream- Needs a Full Teardown, but Complete

All advice I give is only valid until an expert corrects me.
cfairweather
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Location: Cheyenne, Wyoming

Re: CB750 K-Whatever

#264

Post by cfairweather »

Sounds like you might have a shifting fork that is slightly bent. These are a weak point of the CB750 and I had to replace one on the engine I just rebuilt. Check the end of the forks to make sure they are not worn out. Also, K2 drums and earlier were harder to shift due to the grooves being narrow and not as deep as the later models. I know Cycle-X always changes the drum when they build a K0/K1/K2 engine. Use a K3 or later shifting drum and you will be happy. I have the internals from two F engines if you need parts. HondaMan has a book and it has several suggestions to improve the cam shaft and rocker holders. You will notice little circles on the cam shaft holders where the rocker shafts are located. I drilled a small hole in the middle of each of these circles to improve lubrication to the rocker shafs. You have to be careful and cleanup the bearing surface after you drill the holes, but I like this modification. I think I used a 1/16" bit. Also, on one of my CB750s, I replaced all the internals with parts from a 1976 F0/F1 CB750, so I had cam holders with the 5mm bolts that prevent the rocker shafts from turning. The early shafts (K0/K1), just spin and according to HondaMan, these lasted much longer. The later ones wear badly because they are locked in one place. I left these 5mm bolts out when I put the engine together and just let them rotate like the early ones. I have not had any problems after about 900 miles. Honda added these in an effort to make the engine quieter. Consider leaving these 5mm bolts out. Hondaman's book has a lot of information in it and I cannot put it in this message but if you are interested, get the book or you can get details about these mods from him on the SOHC web site.
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Lucien Harpress
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Re: CB750 K-Whatever

#265

Post by Lucien Harpress »

All good stuff. I've got an account over on the SOHC site, and while I don't post as much, Hondaman's stuff has come up from time to time and it's all good things. I do have the earlier rocker shafts, so that's good. I took a look at my shift forks as well, and while there's a bit of wear they still seem to look fine. I compared them to the forks I pulled out of my donor engine, and the ones I'm running are noticeably better.

I got my neutral switch in (to stop the shift drum from sliding out), and shifting seems nice and smooth. I'm happy with it, at least.

Apart from plating bolt heads, I hit a minor roadblock with the locating dowels. It seems like I can't remove any of them without destroying them, so I ordered a handful of the sizes I need new, just to have them. I'll work on plating my bolt heads in the meantime, and (depending on how the holidays and shipping go) I might be able to close up the cases by next weekend.
1997 Valkyrie- Light Cutomization, but Too Busy Riding
1980 KZ1300- Bike's Haunted
1976 GL1000 (Yellow)- It Runs (Poorly) and Doesn't Leak (Mostly)
1974 Velosolex 3800- Better Than Walking
1972 CB750- Broke the Chain And Ate the Motor
1969 CT90- The Most Fun You Can Have on 90ccs.
1965 CA77 Dream- Needs a Full Teardown, but Complete

All advice I give is only valid until an expert corrects me.
cfairweather
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Location: Cheyenne, Wyoming

Re: CB750 K-Whatever

#266

Post by cfairweather »

If you have the early drum I would replace it even if it operates smoothly because you mentioned when the engine gets hot it is hard to put in neutral if I recall correctly. As the drum expands due to heat, I think the shifting might get harder because the shallow depth of the grooves. Does that make sense?

Also, read this thread on the clutch: http://forums.sohc4.net/index.php?topic=139091.0
I always add more holes to the clutch hub so it gets plenty of lubrication.
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Lucien Harpress
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Re: CB750 K-Whatever

#267

Post by Lucien Harpress »

After getting tired of waiting on two dowels and an o-ring that have been stuck in Ohio for a week, I bit the bullet, drove an hour to my closest bike dealer, and bought the parts myself. With that out of the way, the block is officially back together.

Image

Image

Image

Everything fit together, everything spins correctly, and I didn't have any bolts left over. So I'd call that a win.

I can't really start on the top end until I get my cooling fin welded back on. That said, I've got plenty to do in the meantime. Clutch, stator, studs, etc. The shift linkage is a nightmare, so that may take me a few tries to get right. Still, I'm happy to be on the "putting things back together" stage of things.
1997 Valkyrie- Light Cutomization, but Too Busy Riding
1980 KZ1300- Bike's Haunted
1976 GL1000 (Yellow)- It Runs (Poorly) and Doesn't Leak (Mostly)
1974 Velosolex 3800- Better Than Walking
1972 CB750- Broke the Chain And Ate the Motor
1969 CT90- The Most Fun You Can Have on 90ccs.
1965 CA77 Dream- Needs a Full Teardown, but Complete

All advice I give is only valid until an expert corrects me.
Shadowjack
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Re: CB750 K-Whatever

#268

Post by Shadowjack »

"Drove an hour to my closest bike dealer" kinda makes me laugh. Mine is 30 minutes away and it's just on the other side of the city. Gone are the days of dealers in your neighborhood. :)
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CYBORG
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Re: CB750 K-Whatever

#269

Post by CYBORG »

I have a dealer 15 min. away. But he alwaays has to order any thing for these older bikes. And if I order online, and pick it up at the store. it's cheaper then if I order it at the store. I just don't get this new math. :lol: :lol:
1978 custom GL1000
1977 custom with 1200 engine
1985 gl1200
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Rednaxs60
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Re: CB750 K-Whatever

#270

Post by Rednaxs60 »

:2thumbs :popcornx2
"When writing the Story of your life, don't let anyone else hold the pen."

Ernest

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2014 Can-Am Spyder RT LE
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1995 GL1500 SE CDN Edition (sold)
2012 Suzuki DL1000 VStrom (sold)
Ontario 1985 GL1200 Limited Edition (sold)
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