Author Topic: my "crashed doing 80 and somehow lived" k4 750 rebuild (Read 8386 times)

nobody · « **on:** May 10, 2016, 07:58:13 PM »

It's due time I start this thread. On 10/10/15 I hit a bump, nothing special, a small bump you wouldn't even notice in your car. The rear wheel began a dance, a soft wiggle quickly became a violent weave. I was like a cowboy at a rodeo, trying desperately to hold on but to no avail. I got tossed off the right side, bounced and rolled about six times, hit nothing, got hit by nothing, broke nothing. ALL THE GEAR ALL THE TIME OR DIE! Seriously, I probably should have died.

So not only did I get lucky enough to be on my feet after that but my bike actually got luckier. Laid down pretty smoothly on the right exhaust, bars, and pegs, not much else. It was kind of odd to see flashes of sparks in between somersaults trying to figure out what way was up and when it would all come to a stop. Anyway, I decided to kick it over to see if it would start, and what would you know? First kick.

Longest. Scariest. #$%*test. Ride. Home. Ever.

So upon tear down I find no frame cracks, everything measures straight, lucky again. What I do find is worn out rear shocks, 1/8 inch of play in the swing arm, 40 year old oil in the front forks, steering and wheel bearings just as old. So I plan to rebuild and replace all of that, plus the damaged bits, and do some custom stuff that I've always wanted to do.

the bike as it sits today

the "to do" list

some parts I painted

two inspirational bikes

nobody · « **Reply #1 on:** May 10, 2016, 08:02:38 PM »

So I did the fork seals tonight, those things did not want to come out. I found a tip about getting them hot.

solution

Used a small amount of gasket maker when installing the new ones. used the old seals to help push the new ones into place. Now for the first potential problem, theres about 1/8 inch between the seals and the circlips is this going to be a problem?

SOHC4 Cafe Racer Fan · « **Reply #2 on:** May 10, 2016, 08:27:47 PM »

Glad you were okay and wearing the right gear.

Replacing/servicing all of those items -- bearings, shocks, forks bushings -- should help sort out your handling/wobble issues.

Bigsam302 · « **Reply #3 on:** May 10, 2016, 08:43:07 PM »

That's crazy. I'm glad to hear that you are okay. I can't wait to see what you are going to do to your bike. It sounds like a pretty sweet project.

Sent from my Nexus 5X using Tapatalk

Stev-o · « **Reply #4 on:** May 10, 2016, 08:51:24 PM »

+1....good to hear you are ok. I've felt the bounce of work out shocks, not a good feeling.

Here's a link to swing arm bushings....

http://www.ebay.com/itm/281973932498?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

...I just installed a set last week. The gap in your fork seals will be no problem.

JWExperience · « **Reply #5 on:** May 12, 2016, 03:20:49 PM »

IIRC, the seals should be just under the cir clips. I don't know that it would cause much of an issue though as long as they are square and riding correctly on the fork stantion. Probably better chance of being square since they are flush to the bottom of the lower anyways.
Been a while since I rebuilt mine but I read recently that there were two different size seals available, maybe the larger one fills that gap.

Sent from my iPhone using Tapatalk

nobody · « **Reply #6 on:** May 13, 2016, 10:20:39 AM »

Could be, I suppose I'll see what they do when they're back on the bike, if I have to redo them so be it.

I'll post some more pictures soon, finally done painting stuff and ready to start reassembly.

nobody · « **Reply #7 on:** May 14, 2016, 11:58:11 AM »

made a little progress this morning

nobody · « **Reply #8 on:** May 14, 2016, 12:04:09 PM »

need to repaint my grab bar, chipped it while test mounting

so now i'm grumpy and hungry... off to get some food and ice cream

nobody · « **Reply #9 on:** May 15, 2016, 06:12:23 PM »

Made a bracket for my tail light today from some home depot pieces I found. It came out pretty well but I'm not completely satisfied, I might get more materials and see if I can make it a little cleaner.

my fabrication station

I'm a little worried about potential clearance issues with the rear tire, only 2 inches... Of course with no swing arm and no shocks I'm probably not pulling an accurate measurement here.

Stev-o · « **Reply #10 on:** May 15, 2016, 06:35:54 PM »

Do you know a shop that powdercoats? Would be much more duable.

nobody · « **Reply #11 on:** May 16, 2016, 10:46:47 AM »

I'm looking into the powdercoating now that you mention it, don't want to have to take the bike apart again just to repaint stuff.

These projects always seem to take longer and cost more than initially intended... Sigh.

It'll be worth it in the end.

nobody · « **Reply #12 on:** July 27, 2016, 10:02:38 AM »

So it's been too long. After a broken computer, a sister in the hospital, and a couple dates with some pretty girls, I'm back with progress.

I got my parts back from the powdercoater

Got some shiny parts in the mail

Cleaned and installed new rear brake shoes

Finished installing my All Balls steering bearings

nobody · « **Reply #13 on:** July 27, 2016, 10:14:01 AM »

Here's the old girl with the tank and bars temporarily mounted, I can almost imagine myself riding it again one day.

Then this happened...

The brake pedal pivot return spring seems to have broken, the upper half that presumably connects to something has disappeared. So now the hunt a for small and probably difficult to find part begins.

Anybody know what this part is actually called or where I can source a replacement?

SOHC4 Cafe Racer Fan · « **Reply #14 on:** July 27, 2016, 10:29:49 AM »

Did you powdercoat the tops of your fork tubes (the portion that was previously pitted)? Will the thickness of the PC allow the forks to pass through the triple trees? If so, that's a great solution.

nobody · « **Reply #15 on:** July 27, 2016, 10:34:46 AM »

I did have the fork uppers powdercoated, I haven't yet tried to mount them but I'm sure I can get them in with a little bit of grease and maybe some slight prying to open the triples up a hair.

riverfever · « **Reply #16 on:** July 27, 2016, 10:35:54 AM »

This is an ignorant question but important. How do you know when the shocks are worn out? I know mine are probably original and quite done for. I really haven't ridden mine much in the 2.5 years I've owned it but definitely plan on replacing them when it's seeing reliable riding time.

Glad you are ok.

nobody · « **Reply #17 on:** July 27, 2016, 12:19:35 PM »

With a car if you bounce your weight off each corner you can watch how quickly it rebounds. If it goes right back and stops they're good, if they go up and down a couple times like a water bed they're old as dirt. For a motorcycle, it's hard to say except if the rear feels soft at all on you. I'd say that if they're original they're probably well due for replacement or a rebuild.

riverfever · « **Reply #18 on:** July 27, 2016, 12:30:41 PM »

Quote from: matthew gabrielse on July 27, 2016, 12:19:35 PM

With a car if you bounce your weight off each corner you can watch how quickly it rebounds. If it goes right back and stops they're good, if they go up and down a couple times like a water bed they're old as dirt. For a motorcycle, it's hard to say except if the rear feels soft at all on you. I'd say that if they're original they're probably well due for replacement or a rebuild.

That's precisely why I asked. I know how to tell on a vehicle. Just not a motorcycle. Thanks.

SOHC4 Cafe Racer Fan · « **Reply #19 on:** July 27, 2016, 02:26:08 PM »

If they are stock, they are shot.
You can go on the cheaper side with Hagon, Progressive. If you're feeling a little more spendy, then IKON. If you are going for it, then Works or Race Tech.

70CB750 · « **Reply #20 on:** July 28, 2016, 05:01:02 AM »

How on earth did I missed this thread?

Glad you made it and you have the spirit to get back on, following.

P.S. After a nice long slide with my wife and motorcycle in the middle of the road,it took me two years or so to feel comfortable on the road again.

nobody · « **Reply #21 on:** August 01, 2016, 08:38:11 AM »

Didn't work on it as much as planned but still got a few more things done this weekend, gonna be standing on it's own two feet soon!

nobody · « **Reply #22 on:** August 03, 2016, 05:11:16 PM »

So the last few days have been an adventure of disassembly and reassembly, followed by more disassembly and more reassembly.

see here:
http://forums.sohc4.net/index.php/topic,159808

Now it seems the back wheel must come off once more as I've noticed that the sprocket carrier isn't seated correctly.

Also, there seems to be a clunk coming from somewhere in/around the drum when I spin the wheel and operate the pedal. It appears to gradually brake, as well as quick brake, seems to function, just that each time the wheel comes to a stop it goes CLUNK! Any ideas?

Are these marks supposed to line up?

mrbreeze · « **Reply #23 on:** August 03, 2016, 10:28:38 PM »

Glad you made it through your get off. The way you described it reminded me of the first time I took my bike on the super slab out here in California. I got onto highway 99 in Modesto which is a fairly fast moving grooved concrete road. After getting up to speed and changing lanes my bike was wobbling something fierce. I quickly got off at the next exit thinking I had a flat tire except it was fine. Turns out I had bad swing arm bushings that I never had really noticed till then. I figure highway speed and catching those damned grooves brought it to my attention real quick like! I fixed it myself but the money I spent at the dealership on parts could have been better spent sending the swing arm to Hondaman in Colorado and having him do it. Unfortunately I didn't know of Hondaman back then! The fork seals you installed are supposed to be like that. I think the first time the forks dive they go into their position and stay put. I hope you used good seals though or you'll be back changing them out soon. That's one of the items that are best to be genuine Honda parts.

nobody · « **Reply #24 on:** August 04, 2016, 10:33:46 AM »

You know, the craziest part was that just a week prior I had a small wiggle doing about 105, I thought I imagined it.

News:

Author Topic: my "crashed doing 80 and somehow lived" k4 750 rebuild (Read 8386 times)

JWExperience