Author Topic: Greasing the swing arm on a 76 K model (Read 5799 times)

mycb750k6 · « **on:** February 09, 2009, 03:00:13 PM »

I'm just about finished with my CB750 K6 and was checking all the settings and values and read in my shop manual supplement for 76 that the 76 K6 had the swing arm grease fittings moved from the sides of the swing arm to a fitting in the center bottom of the swing arm but I can't find it. Can someone straiten me out here and if it's supposed to be there, will any old grease gun work on the fitting?

GammaFlat · « **Reply #1 on:** February 09, 2009, 03:51:30 PM »

Mine ('76K) was in middle bottom-ish. Yours may be broken off - but don't fret if it is - pretty easy to replace. I think (trying to remember and now curious enough to go look) that it was pointing toward the back some. My fitting was snug and it made me pause for thought. I think lots of folks put "American" or standard fittings on them after finding out that the original (Japanese) fitting was smaller than they expected (grease everywhere

. Once connected, I shot in grease til it came out from a couple locations.

HondaMan talks about the grease fittings and swingarms at length somewhere on this forum and I think we would both do well to heed his advice which is to put grease fittings on at the ends.

Also, how many miles are on your bike? It may make sense to "re-bush" the swingarm. If you need work on your swingarm, HondaMan is the guy to do it I hear.

mycb750k6 · « **Reply #2 on:** February 09, 2009, 04:36:09 PM »

Thanks GammaFlat. That's the kind of quality answer I've come to expect from this forum - top notch. I'll go check as well. My bike only has 6K miles on it but it sat long enough to accumulate a lot of rust so I've got to assume the grease is dried up as well. I'm wondering now if it might be more cost effective to get a swing arm from ebay with the fittings in the side rather than retro fit them to mine.

GammaFlat · « **Reply #3 on:** February 09, 2009, 04:44:16 PM »

I'll trade yours for mine

Seriously, with 6K miles, you're probably fine but if your planning on racking up miles, you may want to find a better way to grease than just the fitting from the factory.

If you're really worried about your bushings (with your mileage, I wouldn't be), you can get new bushings (no need for a new swingarm and you'd probably have a hard time finding one in better shape than yours). There are lots of posts regarding bushing replacement. One of most interest to you might be how to go about testing your swingarm - which is essentially checking the condition of you bushings. I'll look for the post but essentially, you're looking for lateral play.

mycb750k6 · « **Reply #4 on:** February 12, 2009, 06:27:18 AM »

Great and thanks again. One more question and I'll get to it.
I've ordered a pivot bolt with the stock zerks on the ends and I've read all the instructions on this site in detail. My plan is to re-tap with new American zerks per the instructions noted in this forum.

My question is:-> Can I just put the bike on the center stand, pull the pivot bolt out and put a new one in without disassembling the rear end or removing the rear wheel? Not that I'm lazy but I just had this apart for a new tire and why make work if I don't need to. If I can do this the swing arm should drop down at the pivot bolt end so I can decrease and blow it out before reassembly and inspect everything including the bushings. Will this work?

goon 1492 · « **Reply #5 on:** February 12, 2009, 06:41:59 AM »

My zert on my 750k6 is in the middle on the bottom too, I didn'teven know it had one until I had the bike apart with the back wheel off. I squeezed alot of grease in mine, I also checked the swing arm when I had the shocks off too and it was tight and smooth still.
If you have to its not much to pull the back wheel off at least to take the weight off l little but if you have stock exhaust still you have to drop part of them to get the shock bolts off to get to more of the swing arm.

mystic_1 · « **Reply #6 on:** February 12, 2009, 08:57:45 AM »

Quote from: mycb750k6 on February 12, 2009, 06:27:18 AM

My question is:-> Can I just put the bike on the center stand, pull the pivot bolt out and put a new one in without disassembling the rear end or removing the rear wheel? Not that I'm lazy but I just had this apart for a new tire and why make work if I don't need to. If I can do this the swing arm should drop down at the pivot bolt end so I can decrease and blow it out before reassembly and inspect everything including the bushings. Will this work?

This may be possible, but to my mind it's more trouble than it's worth. You'll have a bear of a time getting everything back in place, the endcaps on the swingarm love to fall off when you're reinstalling. Just pull it apart, should only take a few hours to do the whole job.

mystic_1

goon 1492 · « **Reply #7 on:** February 12, 2009, 09:36:37 AM »

If you do take pics and show off so we and new folks can have a walk thru...
Please...

bryanj · « **Reply #8 on:** February 13, 2009, 10:12:38 AM »

No reason you cant push one bolt out with the other, its not mandatory to go in one way round

mystic_1 · « **Reply #9 on:** February 13, 2009, 10:35:39 AM »

Well, he wants to drop the swingarm to degrease and inspect the inside of the pivot. Otherwise I agree that'd be a good way to just swap the bolt.

mystic_1

mycb750k6 · « **Reply #10 on:** February 13, 2009, 12:40:54 PM »

OK, when the bolt gets here (Ho hum) and I've re-tapped it for US zerks, I will take pictures and post them here. I love an audience. I might just take pictures of the entire process including the tapping as I've photo-documented most everything else already.

Raul CB750K1 · « **Reply #11 on:** February 13, 2009, 02:48:40 PM »

Trail already blazed.....

http://forums.sohc4.net/index.php?topic=18857.0

mycb750k6 · « **Reply #12 on:** February 13, 2009, 03:29:43 PM »

Yes I saw this Raul. That's kinda what got me started down this path. Nice work. My question was whether I could swap out my zerkless 1976 K model pivot bolt with one like you've made without removing the swing arm. Just push the bolt and pivot collar through, inspect the bushings and install the zerky bolt and the collar with the old style grooves.

Well my bolt just arrived just now via UPS and the bolt has screw-on US zerks just like yours. What are the chances of that?

However the 1976 bushing appear to have a 'lip' on the outer end like this:

http://cgi.ebay.com/ebaymotors/Honda-CB750-CB500-Bronze-Swingarm-Bushing-Set-New_W0QQcmdZViewItemQQitemZ350158452072QQptZMotorcyclesQ5fPartsQ5fAccessories

So since the bushings are different starting in 1976, I'm wondering is the pivot bolt and pivot collar are different too and or will work.

Yikes - this has become complicated all of a sudden.

HondaMan · « **Reply #13 on:** February 13, 2009, 07:37:23 PM »

Simply replacing the no-zerk bolt with the 2-zerk bolt won't solve this problem, because the pivot collar on the 1-zerk systems have no grease holes to lube the insides of the bushings. This is not to say you can't drill your own (I've done quite a few), as it only takes a 3/16" hole through both side of the collar to do the job. Also, add some grease grooves with a Dremel tool and cutoff wheel to spread the grease around, and the system will last a lot longer.

Here's 2 pix: the first one is the 4 types of collars that Honda has sold over the years for the 750/500/550 and the "F" models. From left to right, they are CB750K0 thru CB500-4, then the second is Honda's current replacement part for the early "K" models, partly modified for a wider grease groove, then a nice CB750K2 shaft (lightly used). The one on the right appeared first in the 550F and then in the CB750K5 and all later SOHC4 frames: it goes with the 1-zerk arms, provides no grease patch at all. These also have phenolic bushings (very spongy) with flaned outside edges that often break off. You can convert an "F" type shaft as shown in the second picture, using a Dremel tool and a drill.

bryanj · « **Reply #14 on:** February 14, 2009, 02:18:28 AM »

Question you asked was can i change the bolt without stripping the rear down to which the answer is yes

You didnt ask if it was a good idea or would work without other mods to which the answer is no

mycb750k6 · « **Reply #15 on:** February 14, 2009, 09:37:38 AM »

So now I know I can't just replace the bolt because I need the new collar - see pic. Also now I know my bushings are flanged and not like earlier years - see pics. So the question now is can I use the 74 bolt and collar on my 76 because I'm concerned the dimensions might be different, length, IO, OD, because of the bushing flange. So Hondaman do you think these 74 parts will work or do I have to do a RAul and zerk my bolt and a Hondaman and groove my collar and toss the 74 parts in the spares box. I'm all about measuring twice and cutting once so that's why I want to be sure before beginning.

bryanj · « **Reply #16 on:** February 14, 2009, 10:26:00 AM »

Eary bushes that are parrallel and have seperate fiber thrusts can be replaces with the flanged bushes, and i know the od and id of the collars are the same, I also THINK the length is the same but cant guarantee that.

Try fitting the early sleeve into the swing arm you have and if the collar ends are flush with the bush ends(actualy should stick out a tiny amount) you are good to go

HondaMan · « **Reply #17 on:** February 14, 2009, 12:54:37 PM »

If these are pictures of your existing collar, then someone has already replaced it with the pre-1975 version, which is great in this situation!

This collar will work OK with your new 2-zerk bolt, just be sure to clean the old grease out of the pass-thru holes before reassembling. The old grease can create a nasty plug that won't let the new grease in from below the bearing surface.

All of the bushings are interchangeable size-wise, and the older style holes-and-grooves collars (like in your pictures) will work with ALL years and models of the SOHC4s. Take a look at the pix I posted and you will see the "new" style collars had neither grease holes nor grooves: what they do have is this: the inside bearing surface (toward the center of the collar, between there and the recessed groove in the midst of the bearing area) is smaller diameter than the outer half of the surface, by about .001". This was supposed to let the grease from the center of the arm squeeze its way toward the middle groove: in practice I have rarely seen it work, though.

There is just one drawback to using flanged bushings with the "old" style hole-and-grooves collar: when you grease it, the grease will easily work its way through, showing when it is full, BUT...this same passageway allows water from the high-pressure carwashes to push its way back inside, too. So, grease often, being mindful of the last time you carwashed it, and maybe with a mind toward greasing soon after washes to push that water back out before it rusts the collar.

If you "convert" to the older setup, it includes non-flanged (i.e., "plain") bushings, with a wool washer that soaks up grease and makes a decent water seal, and phenolic end caps that do a good job of centering the arm while holding those washers in place inside. This arrangement does require that the grease come from the inside bolt, however. So, you should be in good shape now.

mycb750k6 · « **Reply #18 on:** February 14, 2009, 01:08:16 PM »

OK Hondaman. I understand fully now and thanks for your patience.

I just wish now that pivot bolt I bought wasn't BENT!!!!!!!! Urgh! Why do people do this?

HondaMan · « **Reply #19 on:** February 14, 2009, 05:59:11 PM »

Quote from: mycb750k6 on February 14, 2009, 01:08:16 PM

OK Hondaman. I understand fully now and thanks for your patience.

I just wish now that pivot bolt I bought wasn't BENT!!!!!!!! Urgh! Why do people do this?

If it doesn't straighten easily, try this: lay the bolt on a flat surface and put a steel shim under the ends, so the center rests on the steel surface. Then, with a cold chisel and a significant hammer, smack it once in thr middle of the bolt. Although not intuitive, this will pull the center of the bolt up, toward the chisel. This technique is used to straighten cams after a valve crash, works perfectly.

mycb750k6 · « **Reply #20 on:** February 15, 2009, 07:13:13 AM »

You're right, this doesn't sound intuitive. You mean the bolt positioned like a smile with the shims under each end? It doesn't seem like this would do anything. Or do you mean the bolt positioned like a frown with the high point in the middle to hammer on. In that case I wouldn't need shims. Don't get it but then again, I'm old.

mycb750k6 · « **Reply #21 on:** February 15, 2009, 07:15:43 AM »

In the meantime I'm looking for another pivot bolt as the guy who sold me this one in good condition is in hiding. This is my first negative ebay experience.

HondaMan · « **Reply #22 on:** February 15, 2009, 09:12:38 AM »

Quote from: mycb750k6 on February 15, 2009, 07:13:13 AM

You're right, this doesn't sound intuitive. You mean the bolt positioned like a smile with the shims under each end? It doesn't seem like this would do anything. Or do you mean the bolt positioned like a frown with the high point in the middle to hammer on. In that case I wouldn't need shims. Don't get it but then again, I'm old.

Place it like a smile. What happens is this: when the nick in the metal is displaced, it cause a stretch that pulls against the metal next to the nick. On smaller diamter shafts, this then physically shortens that side of the shaft by a couple of thousandths of an inch.

A good way to practice: get some 1/2" bolts, straight ones, and put a few practice nicks into them. You'll figure it out. These are about the same diameter (.540") as the swingarm bolt. Don't make a deep chisel mark, as this can cause other problems with fit and strength: the bolt only has .002" clearance through the pivot collar to begin with, and even after the nick trick is used, you'll probably have to file off the slightly raised edges around the nick to get it to slip through easily.

Or, if you have a bumper hitch on your car (or a bench vise?) and a 3/4" or 1" pipe, you can gingerly straighten that long bolt, too. Slip the pipe onto the threaded end, up to about the middle, and bend it the other way, then do it again at 1/4 of the length. It won't be dead straight, but when it gets tightened (to about 40 ft-lbs), it will straighten enough.

Also: check to make sure your collar isn't full of rust. This is pretty common, too. I have some 12mm ball hones that I clear them out with when I get rusty ones on rebuilds. It doesn't take much to prevent the bolt from going through the collar: it's a fairly precision fit, to ensure good swingarm alignment.

mycb750k6 · « **Reply #23 on:** February 15, 2009, 09:41:56 AM »

Thanks again. I'll try the bash it first approach just to learn how to do it and if that doesn't work for me I'll grab a water pipe from my old Harley tool box next to the pipe wrench

So I originally thought the collar was scored inside too so I honed it out trying for the fit before it dawned on me the bolt was bent so I may have gone a bit too far with the honing. How critical is the bolt in collar fit? I know the collar in bushing fit needs to be correct but a bit over sized collar ID might let more grease flow??? Wishful thinking?

HondaMan · « **Reply #24 on:** February 16, 2009, 05:48:21 AM »

Quote from: mycb750k6 on February 15, 2009, 09:41:56 AM

Thanks again. I'll try the bash it first approach just to learn how to do it and if that doesn't work for me I'll grab a water pipe from my old Harley tool box next to the pipe wrench

So I originally thought the collar was scored inside too so I honed it out trying for the fit before it dawned on me the bolt was bent so I may have gone a bit too far with the honing. How critical is the bolt in collar fit? I know the collar in bushing fit needs to be correct but a bit over sized collar ID might let more grease flow??? Wishful thinking?

When it's all bolted back together and the bike is accelerated hard the first time, the clearance in the collar-bolt area closes up toward the back of the bolt. This makes the swingarm pull to the left a little. The amount is predictable: the pivot length is 18", so if the clearance is .001" (new), this deflection is .018". If the clearance is .003", the shift is .054", about 1/16". It usually stays there after that, if the bolt is sufficiently tight. I like small clearances here, for obvious reasons...the offset can then be corrected with a wheel alignment, and the chain adjusting marks on the left side must be "mentally offset" by the wise rider to ensure a straight wheel track afterward.

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Author Topic: Greasing the swing arm on a 76 K model (Read 5799 times)