Topic: 1975 CB750 K5 "Rhonda the Honda"

[przjohn]

Also covered my boat for the winter.

That day always seems to come too soon every year.

[evanphi]

... but no point now with that HUGE crack in my slab.

Have you considered filling the crack?

http://www.zoro.com/crack-stix-concrete-joint-crack-fill-12-d-125ft-2051/i/G8522893/?gclid=CN3qoOXszckCFQaJaQodyVQJHA&gclsrc=aw.ds

Interesting. Had never thought of that.

[evanphi]

Bought some concrete fill!

[evanphi]

WINTER 2016... The work begins!

I'm focusing on the front end this winter. New fork tubes, progressive springs, neck bearings, centering the front wheel, and a single front brake line.

PICS from yesterday.

Front wheel off! To get the axle nut off, I used a 15/16" deep impact socket on the nut and an 18mm open wrench on the other side. Came right off, no worries of rounding, and now I can torque it back to spec when it goes back together. Also removed... fender and brake.


Wheel mounted on the truing stand. I need to center the rim on the hub. I'll probably use a plumb line to achieve this to avoid removing the tire.


Headlight off...


Bars and controls off. Going to be buying a Renthal Ultra Low bar to replace this flimsy Emgo.


Forks out!


Races removed. I used an 8" long brass drift to get these out. Pretty easy!


These next two pictures demonstrate just why I'm doing this work. Bent (and rusty) fork tubes, and notched bearing races. The tip of the hex bit in the gap of the fork tubes is 8mm wide.



Click here to see the notchy steering in action! https://gfycat.com/SimilarCourteousArcticduck

Years of leaky brake fluid have killed the paint on the triples. I am going to polish the upper... no problemo. The lower, though, needs some work. Likely have it sandblasted and repainted.


Here's last night's work all laid out... Forks came apart no problem. I still hate the smell of old fork oil. I'll be re-purposing the straighter of the two fork tubes as my official "seal driver" using this method:

[Stev-o]

Good winter project, I did similar on my K4 two years ago. 

Suggest powdercoat for the lower triple, I rattle canned mine and bubbled a small area when a little brake fluid leaked on it.

[evanphi]

Good winter project, I did similar on my K4 two years ago. 

Suggest powdercoat for the lower triple, I rattle canned mine and bubbled a small area when a little brake fluid leaked on it.

I'll be going to a single line, so that won't be a problem. Might just sand it back to good paint and rattle it.

ORRRR maybe polish and clear-coat?

[evanphi]

Isn't the lower clamp steel? Hard to polish that one...

sorry, i  meant strip raw and clear coat.

[evanphi]

Isn't the lower clamp steel? Hard to polish that one...

sorry, i  meant strip raw and clear coat.

I was double-checking my info, not questioning you. Either way, as Stev-o said, its a great winter project

Yeah I'm looking forward to it. A trip to the polishing/sanding wheel is in order then!

[evanphi]

Some more prep before re-painting the spots that brake fluid attacked on the trees...

removed the lower race, going to use the thin washer for the AllBalls kit. It is about .5mm shorter than the previous stack, but that will raise the fork/frame stoppers a bit. They were hitting right at the edges before!

New fork bits should arrive today from the stealership (piston rings, copper washers, hex bolts, and disk brake washers).

I leveled my truing stand, and it turns out my wheel is only a few mm off to one side, so I will be centering it less than I thought. The big offset I saw earlier was likely from the forks being so bent, and the fender is looking like it is skewed to one side, too. I'll straighten the fender legs.

This project is moving much faster than last year's! If not for paint, I could have it all back together by tonight!

Still to order:
Single brake line from Slingshot
Renthal Ulltra Low bar

[evanphi]

Progress...

Here's all my fork stuff laid out. Just waiting on a few more parts from the dealership.



ON the right you'll see the CB750 FORK SEAL DRIVER... OF SCIENCE!




PAINT!

Both fork holders needed paint after some run-ins with brake fluid.

Cleaned and prepped:


After two coats in the affected areas, then two coats over the whole piece to even out the slight difference in colour, all is hanging until I get to them on my next shop night, to install the bearings.

[evanphi]

Put in my fork seals.

[evanphi]

Plan for tonight...

Chase the M10x1.25 and M8x1.25 threaded holes in the triples to remove the paint
Remove any paint from flat bits of bar clamp and inside fork holders
Grease roller bearings
install roller bearing to steering stem with thin washer for spacer
install tapered cups to frame
install triples
install fork tubes and add oil and cap the forks off (I'll be devising some sort of clamp for this, I think... video may follow)

That'll probably be it for the night! Next I'll work on truing my wheels.

Ordered a new single brake hose from Slingshot (used code SOHC4 for 10% off!), and a Renthal LOW street bar so they will go on next week.

[evanphi]

Turns out my PO was trying to kill me!

Got my new fork tubes from CycleX all nice and installed


Then I am installing the left side fender/caliper bolts (6mm), and they just keep turning and tuuuuurning... FACK.


Them's some nice stripped out holes. Might even have been some remains of blue loctite... BAH. The 8mm on bottom is fine, thankfully. That is what kept me alive these past three years of ownership!

Has anyone successfully Helicoiled these holes before? This is really my only option at this point... other than a plug weld and re-tap, but I don't want to alter the structural integrity of the fork lower by adding so much heat.

[evanphi]

Now where were we...

Ah yes!

Cleaned out all those painted threads. No problem!

Upper and lower races both just pressed in most of the way. Couple taps with a bearing driver and they were both fully seated.



I used the THIN spacer under my bearings. The thick one was the buffer against the PVC tube I used to get the bearing to seat. A 2x4 under the lower triple-tree keeps it from getting scratched, as well as on top of the PVC to allow one or two sharp hits to drive it into place.



Installed everything on top! AllBalls includes a small washer to go UNDER the steering adjustment nut that fits in the grooves. It fits very nicely and now we have a rubber seal on top, too. Tighten that adjuster nut with the shock spanner until it just starts to get stiff (mine didn't LOCK, just got tight). Back off, then go again until tight, loosen 1/4 turn. Then put on the upper triple. Add the big washer, and finally the big nut. This needs to be very tight, as it locks the steering adjuster nut (I did the final tightening AFTER the fork tubes were installed).


MMM PURTY. Installing the progressive springs with spacer was a LITTLE difficult. Having the front end elevated helped. I just used a 15/16" deep socket to push down, and then turned 1/4 turn at a time to get it started. Once the threads caught you can tighten down. 225ml of 10W fork oil were added to each side first, as spec'd in the shop manual for dry forks.



What is dees?


Renthal Road LOW bar. Very lightweight. I'm going to have to open up the hole for the wires in the Right control switch housing because of no holes in the bar.


Continued...

[Stev-o]

Nice write up.  Did you consider polishing your lowers?

[evanphi]

I was going to put the front end all back together when I discovered that the upper two caliper/fender holes were stripped! Cold sweats and thoughts of mangled front breaks brakes ensued. Wife wasn't too happy when I told her about this:

"YOU COULD HAVE DIED!?"
"But I didn't!"

Anywho. The repair:

Stripped threads


I decided to Helicoil these. A couple users responded to my question (quoted a few posts above), saying helicoil would be fine.

Supplies:
1. M6 Helicoil kit (only one place in the city had individual size kits. Only 40$. Yes a whole kit is more economical, but I needed just this one size and wanted to keep cost as low as possible. Those new fork tubes are expensive!)
2. Tap handle (this kit was on sale from 49.99$ to 8.39$ LAST WEEK but one of the store clerks forgot to take the sale price off the shelf. LUCKY ME!)
3. Red thread locker, for extra security.


The kit:
Comes with a bunch of coils, the tap, and a neat tool for inserting. This is an actual HeliCoil brand kit, too. Part number is 5546-6.


Drilled with 1/4" bit.


Tapped:


The coil holder tool. It pre-threads the coil the same as the tap so it doesn't get all wobbly when going in.


Inserted with red thread locker, 1 turn below surface!

Cleaned up:


Then you just punch out the extended piece that helps turn it into the hole. I used a 3/8" punch.

Done!

Front end will be put back together tomorrow, and I'll also be working on truing my front wheel. I found a neat trick to see how far off to one side the wheel is... stay tuned!

[evanphi]

Nice write up.  Did you consider polishing your lowers?

Never did. I'm not really one for lots of shine. In fact, someone is sending me a set of side covers and a second tank so Rhonda can have a more "ugly bike" look. I plan to strip the tank and clear-coat it and just rattle-can black the side covers.

Then I can change the sidecovers and tank out as I see fit, depending on the mood I'm in that summer/week/month/ride.

[evanphi]

Front end mostly back together...

[evanphi]

Here's that trick to see how much offset your wheel has without removing the tire/tube/rim-strip. It'll be about 5mm, this was standard from factory... but this will also help you get it well centered.

I'm silly. Don't use string hanging over a tire. That'll just be inaccurate. Use a straight edge on the hub about a foot long, and then measure to the lip on the rim. The rest is the same:

Measure the closer side

Zero your caliper

Measure the further side

And there's your offset!

Now you can center your wheel. The distance should be the same on both sides.

If you have a dial gauge, you would set it on one side, then adjust the wheel over towards center HALF the value you got for offset. If you don't have a dial gauge, you'll have to re-measure using the above method.

[evanphi]

Protip:

If your grips are not sticking to your bar, you probably have some of this around the house...



I don't know why, but these grips held fine on my previous chromed bars. They wouldn't stick on the powdercoated Renthal, though, even with the knurled grip area.

[evanphi]

Front wheel is all trued up... less than 1mm deviation axially and radially. That was fun! Lots of oil on the nipples. 

Now just waiting on my brake line from Slingshot, plus another package from a forum member. Rhonda's getting a set of play clothes (as my daughter would call them).

[SOHC4 Cafe Racer Fan]

That was fun! Lots of oil on the nipples. 

Mind in the gutter!   

[evanphi]

Took apart my clutch side switch to polish and grease the contacts for the horn and beam select switches. Nice and shiny now.



Front wheel is all trued up and centered, and disk is back on. All that's left now is to torque up the bolts and put back on the bike along with the handlebar. Rhonda will ride again soon! Next weekend I pick up my brake line...

[Stev-o]

That polished lever is pretty shiny for someone...

... not really one for lots of shine.

[evanphi]

Front wheel back together... torqued axle bolt to 45#. (this photo was before I did final torque on the disk nuts, that's why the tongues aren't bent over yet)


Wheel and bars installed


Bucket on, wires routed (Rhonda's puking after a long winter bender)


Assembled!




Now I just need that brake line, which I am picking up next Saturday.