Author Topic: 1972 CB750 Four K2 -- Rebuilt to NEW OLD STOCK -- PIX ON PAGE 50 (Read 241152 times)

Kickstart · « **Reply #325 on:** February 01, 2014, 09:13:18 PM »

How bad is the electrical stuff? Was the wiring harness chopped up?

Let me know if you have any questions on bearings... I spent a lot of time researching them (and arguing with bearing shops), but I got it all worked out.

Keep up the good work!

edwardmorris · « **Reply #326 on:** February 02, 2014, 10:02:55 AM »

Nothing chopped up thankfully but slathered in 40+ years of gunk. Need to clean out the harness and apply some dielectric grease to rejuvenate it a bit. I searched a lot about new sleeves and it looks like there isn't an exact match available (either slightly light or loose) and if I do decide to change it, then I'll have to redo all the bullet connectors as well because all the wires won't just slide into a new sleeve.

I searched a ton on the bearings too and believe it or not, one of your posts is what definitively told me that modern day SKF NR suffixed bearings are not drop in replacements, and enlarging the grooves costs an insane amount of money.

I am curious however, about how to even get to the bearing between the primary drive sprockets and the clutch basket? The shaft pulls out but the rest of the assembly looks pretty tight. And for that matter, how to get the needle bearings out? The tips and trick section had a post where someone used a large socket and hammered a bad bearing out that way but not sure if that's a good idea for a bearing that isn't damaged....

edwardmorris · « **Reply #327 on:** February 02, 2014, 08:48:08 PM »

You were right Terry, looks like there's bondo paste on the tank. I'm gonna clean up the new tank and use that as is, the paint looks excellent.

Kickstart · « **Reply #328 on:** February 02, 2014, 09:35:41 PM »

Quote from: edwardmorris on February 02, 2014, 10:02:55 AM

...
I am curious however, about how to even get to the bearing between the primary drive sprockets and the clutch basket? The shaft pulls out but the rest of the assembly looks pretty tight. And for that matter, how to get the needle bearings out? The tips and trick section had a post where someone used a large socket and hammered a bad bearing out that way but not sure if that's a good idea for a bearing that isn't damaged....

There's a circlip inside the basket that holds it onto the primary sprocket. Once you remove that you can get to the bearing.
I used a cheap bearing puller tool to remove it. I figured I'd save myself some grief and just buy the tool. Came in handy for the bearings on the final drive:
http://www.harborfreight.com/bearing-separator-and-puller-set-93980.html

Oh, those needle bearings are tough to get out!
I think I spent half a day trying to get those out using a brass drift, screwdrivers, needle nose pliers, plenty of penetrating oil, heat (from a electric griddle) and I could not get them out.

I finally broke down and purchased a blind bearing puller:
http://www.harborfreight.com/blind-hole-bearing-puller-95987.html
IMO, this tool is necessary to get those bearings out. It's not cheap, but it works (actually I might have picked it up on sale now that I think about it). If you pull these bearings, make a note of how deep each one sits in the sprocket unit. I damaged a new one installing it because I thought it wasn't in there deep enough. When installing the new ones, heat the sprocket unit up on an electric griddle (I put it between the 200-250f setting) and use lots of gentle taps rather than harder ones. There's really not much case strength to those needle bearings. The bearing on the one side is recessed some, so save the old bearings so you can use one of them to help drive the recessed bearing into place.

And yeah, no matter what method you use, I'm pretty sure these needle bearings will be damaged upon removal.

You may be able to rent those tools for free from you local Pepboys/autozone/advancedauto/etc.

All that said, do you think your bearings are in bad condition? I replaced, mine, but honestly mine were ok. When I took the old ones to my machinist (as reference for the groove) he was like "what's wrong with these?" I did it because I'm trying to make my engine "like new" and I wanted the learning experience... but all this stuff starts adding up to a lot of money

edwardmorris · « **Reply #329 on:** February 02, 2014, 09:56:13 PM »

Thanks Kickstart(Chris?), will take a look tomorrow, its been bugging me because I KNOW I saw a thread with pictures here but I can't find it for the life of me.

The bearings yes, it will be an all or nothing deal. I have no way of telling how many miles are on the engine and what condition the bearings are in. I wan't to change those out with SKFs (costly but permanent and available withing a mile from my residence) and not think about them for 80-100K miles. But unless I figure out an economical option to get the standard SKF grooves widened, tranny is on the back burner.

The needle rollers, same story (pardon the "while its open" thinking), change them out with SKFs and forget about them. With these I might be in luck, my local auto shop has a great blind bearing puller similar to the one in the second link.

You are right about stuff adding up, but I'm hoping this is a good investment to make so I always have a reliable rider while go parts hunting for my next project

edwardmorris · « **Reply #330 on:** February 05, 2014, 12:36:27 PM »

Yamiya is out of K2 body sets? There goes that plan. Have they restocked these in the past? I suppose I should get my back up plan in motion, suggestions on renewing my gas tank? Visually there isn't much rust on the inside as it seems to have always had some gas in it. Don't have the set up for proper electrolysis, so what chem treatment to try?

calj737 · « **Reply #331 on:** February 05, 2014, 03:50:40 PM »

Least expensive is electrolysis. Then Apple Cider Vinegar. Then EvapoRust. Depends upon which/what you have access to. Lots of folks use ACV very successfully, though it does take a few "cycles" of soak, rinse, soak, rinse. Cheaper than EvapoRust.

edwardmorris · « **Reply #332 on:** February 05, 2014, 08:08:17 PM »

I'll have to read up on the electrolysis method again. Also, how do you get the petcock off the tank? Search didn't help much (moody piece of crap).

I made some time today to clean up some hardware. This weekend is grocery shopping weekend so I'm thinking about picking up some zinc plating ingredients. Grepper posted a great step by step, sounds easy with outstanding results, so worth trying.

calj737 · « **Reply #333 on:** February 06, 2014, 03:24:32 AM »

I can't say for sure on your tank as I have 500s, but mine are all threaded on. Should be a large nut that threads onto a neck from tank, the petcock comes free with the nut. Then further disassembly once free from tank is possible. A pic would help me confirm whether my advice is accurate on your tank.

I'm sure someone with 750 knowledge will correct me if I'm steering you wrong.

seanbarney41 · « **Reply #334 on:** February 06, 2014, 01:25:03 PM »

Quote from: calj737 on February 06, 2014, 03:24:32 AM

I can't say for sure on your tank as I have 500s, but mine are all threaded on. Should be a large nut that threads onto a neck from tank, the petcock comes free with the nut. Then further disassembly once free from tank is possible. A pic would help me confirm whether my advice is accurate on your tank.

I'm sure someone with 750 knowledge will correct me if I'm steering you wrong.

yep, you are wrong! If your tank is correct for your year, Ed, you have to unscrew the sediment bowl, pull out the sediment sceen that is held in by an o-ring...then inside the petcock are two JIS screwsthat hold the petcock body to the tank

edwardmorris · « **Reply #335 on:** February 06, 2014, 09:50:28 PM »

Quote from: seanbarney41 on February 06, 2014, 01:25:03 PM

yep, you are wrong! If your tank is correct for your year, Ed, you have to unscrew the sediment bowl, pull out the sediment sceen that is held in by an o-ring...then inside the petcock are two JIS screwsthat hold the petcock body to the tank

Thank you Sean and Calj, mine is the correct year tank. I will gather some supplies this weekend to set up the electrolysis. I assumed that the petcock needs to be removed before doing this, that's why I asked. I'll have to find a way to plug the holes well. Hopefully some progress report this Sunday.

calj737 · « **Reply #336 on:** February 07, 2014, 05:21:57 AM »

Have seen many folks use hard rubber plugs/corks in the fuel supply to stop it off.

Sean- thanks for setting Ed (and me) straight.

seanbarney41 · « **Reply #337 on:** February 07, 2014, 01:26:23 PM »

Ed, it's kinda tricky 'cuz you got two screw holes and the actual fuel outlet hole...so what I have done is make a little metal plate, drill it for the two screws and then screw it on with some rubber(I cut a piece out of a heavy duty rubber glove) or gasket material sandwiched between the plate and the tank.

edwardmorris · « **Reply #338 on:** February 07, 2014, 07:07:14 PM »

Quote from: seanbarney41 on February 07, 2014, 01:26:23 PM

Ed, it's kinda tricky 'cuz you got two screw holes and the actual fuel outlet hole...so what I have done is make a little metal plate, drill it for the two screws and then screw it on with some rubber(I cut a piece out of a heavy duty rubber glove) or gasket material sandwiched between the plate and the tank.

Great idea! I should have enough crap around the house to rig it up. Thanks!

Terry in Australia · « **Reply #339 on:** February 07, 2014, 07:30:09 PM »

Have fun with the electrolysis Ed, I've done it but it was so slow I gave it the arse and used phosphoric acid (the stuff they put in Coca Cola, chrome polish etc) and it removed all the rust in a couple of hours.

Be aware also that you need plenty of ventilation with electrolysis, as you're also creating hydrogen gas, and any spark can cause it to explode. If you're a smoker, or there's a furnace in your basement, be very, very careful......... Cheers, Terry.

edwardmorris · « **Reply #340 on:** February 07, 2014, 08:04:47 PM »

Quote from: Terry in Australia on February 07, 2014, 07:30:09 PM

Have fun with the electrolysis Ed, I've done it but it was so slow I gave it the arse and used phosphoric acid (the stuff they put in Coca Cola, chrome polish etc) and it removed all the rust in a couple of hours.

Be aware also that you need plenty of ventilation with electrolysis, as you're also creating hydrogen gas, and any spark can cause it to explode. If you're a smoker, or there's a furnace in your basement, be very, very careful......... Cheers, Terry.

Good looking out Terry, I'll leave it out in the garage and keep checking in between work shifts. I picked up a nice steel rod to use, already have a good batter charger, just need to go get me some salt and rig up a nice petcock hole blocker.

In the meantime, I picked up the goodies from the machine shop! Everything looks cleeeeen, but my damned cell phone is on the charger. Pix coming up in a few hours...

edwardmorris · « **Reply #341 on:** February 07, 2014, 09:27:18 PM »

Here they are! I feel bad handling these in dirty gloves but oh well, I'll be cleaning them compulsively anyway

edwardmorris · « **Reply #342 on:** February 07, 2014, 09:29:33 PM »

The head got resurfaced on the house, rider-to-rider deal

and the fins cleaned up nice.

edwardmorris · « **Reply #343 on:** February 07, 2014, 09:34:54 PM »

The cylinders are done with 0.001" clearance and cross hatch hone. He was impressed with the yamiya pistons, said he'd never seen all four measure the same. Resurfaced and clean fins

edwardmorris · « **Reply #344 on:** February 07, 2014, 09:42:43 PM »

AND FINALLY the icing on the cake! Perseverance is all it took. I found a shop all the way out in Lowell IN, Midwest Accurate Grinding, and they widened the grooves on my SKF replacements! They are a very nice business. Of the three bearing I sent them, one of them (pic 3) already was the correct size so they called me and let me know they didn't have to work on it. Pricing was reasonable too.

After chatting with them, it turns out that the bulk of the work is in "setting up" for grinding. Once its set, they can grind out as many as you need, so if you'd like to save, have multiple sets done together. Its about a 40min drive and they don't work on weekends, so I just shipped them my set and they shipped it back in a 5 day turn around time. If you're looking to get some done, give them a call.

RRRToolSolutions · « **Reply #345 on:** February 08, 2014, 06:08:30 AM »

Hi Ed, Gordon here. I've had dozens of cases, heads, and cylinders beadblasted over the years. You have to visualize that the blast material is sandpaper inside your engine. You have to get it out. I have a large plastic storage bin that will hold a crankcase.

I start off with a very high-pressure nozzle and wearing safety goggles, I blow into every hole, crack, and corner. Do not run the tap through the holes unless you have a damaged one - the tap removes tread material. Make sure every threaded hole is clean.

I then soak the casting in solvent (I use gasoline outside, but it's not proper nor safe) and I rock the bin side to side, soak some more, rock, soak, rock - until every piece is what I think is pure metal. I then remove it and blow with high-pressure again.

Lastly, I fill that same bin with hot-soapy water. I mean I get buckets of hot water out of the tub faucet and Dawn dish washing soap and soak/aggitate those castings again and again. I then take them to an outside drain and lay them on the bin's lid and run my garden hose over them and then blow again with the high pressure. I let them dry and and only then do I feel they are ready for assembly.

Please note that even after all this cleaning, the first oil change is something I do at 100 miles. There will still be some media in the filter.

Best Regards, Gordon

SOHC4 Cafe Racer Fan · « **Reply #346 on:** February 08, 2014, 06:52:45 AM »

Quote from: Ilbikes on February 08, 2014, 06:08:30 AM

Hi Ed, Gordon here. I've had dozens of cases, heads, and cylinders beadblasted over the years. You have to visualize that the blast material is sandpaper inside your engine. You have to get it out. I have a large plastic storage bin that will hold a crankcase.

I start off with a very high-pressure nozzle and wearing safety goggles, I blow into every hole, crack, and corner. Do not run the tap through the holes unless you have a damaged one - the tap removes tread material. Make sure every threaded hole is clean.

I then soak the casting in solvent (I use gasoline outside, but it's not proper nor safe) and I rock the bin side to side, soak some more, rock, soak, rock - until every piece is what I think is pure metal. I then remove it and blow with high-pressure again.

Lastly, I fill that same bin with hot-soapy water. I mean I get buckets of hot water out of the tub faucet and Dawn dish washing soap and soak/aggitate those castings again and again. I then take them to an outside drain and lay them on the bin's lid and run my garden hose over them and then blow again with the high pressure. I let them dry and and only then do I feel they are ready for assembly.

Please note that even after all this cleaning, the first oil change is something I do at 100 miles. There will still be some media in the filter.

Best Regards, Gordon

Gordon,
Even with that cleaning regimen you still find media in the first oil change! Yikes.

BPellerine · « **Reply #347 on:** February 08, 2014, 11:29:19 AM »

your stuff looks great ed!nice to have some pretty stuff to look at I bet!bill

Terry in Australia · « **Reply #348 on:** February 08, 2014, 01:57:39 PM »

Looking good Ed, just to add emphasis to Gordon's words, i.e., the need to thoroughly clean all of the castings that have been blasted, including your cylinder block.

I put each casting in a tub full of hot soapy water and use a range of gun cleaning brushes, tooth brushes and even pipe cleaners to make sure that every hole, slot, oilway, etc is thoroughly clean.

I haven't used the "solvent dip" that Gordon describes (because I have a fear of exploding) but I can see the benefits. The main thing is not to skimp on elbow grease and lots of flushing with clean water and poking a high pressure hose up every orifice in every casting. You'll be surprised at how much grit comes out.

You'll need to clean, dry and lightly oil your new bores after thoroughly washing the cylinder block to avoid flash rusting, but you can't leave it out, but it has to be done too. Cheers, Terry.

edwardmorris · « **Reply #349 on:** February 08, 2014, 08:47:26 PM »

Thanks guys, it is somewhat in the lines of what I had in mind

I have a good compressor with a tiny nozzle attachment that should be handy for all the tiny nooks and crannys. I already have large bins that fit the cases (I cleaned them up with simple green before getting them blasted) so definitely doing the hot soapy water soak a few times. Not sure about a gasoline soak but I can flush everything passage with some mineral spirits (which I've found is as good a degreaser as diesel) and then hot soapy soak again. I tend to get obsessive when it comes to cleaning anyway so hopefully I'll clean it out well.

Looong snowy day, but small good news though, Yamiya got the K2 sets back in stock again

so electrolysis is on the back burner for now (I know I know, big dreams, small wallet :p but I think I'll be able to save by the time I'm ready to ride this thing).

Only had a little bit of time today to work on a couple things. Cleaned up the alternator cover after removing the coils. Once again, the impacta came in handy and again with my luck, there was one bastard that wouldn't budge. BUT, I have the big beast as well and it whacked it right outta there.

Now am I not seeing it or looking in the wrong place? Where is the circlip to detach the basket from the primary drive?

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Author Topic: 1972 CB750 Four K2 -- Rebuilt to NEW OLD STOCK -- PIX ON PAGE 50 (Read 241152 times)