Topic: 1976 CB750K Stock/Cafe Hybrid

[articblue]

Just started on the all balls tapered bearings myself. Bonus for me my lower triple tree wasn't powder coated.

A sanding disc / wire wheel on a drill or dremel will get the powder coat off effectively.
It's not too tough.

You'll need to pull most of the powder coat off of the end of the stem up to where the taper starts.

Then once that's done: http://forums.sohc4.net/index.php?topic=1516.125 this should go to the place in the thread where it talks about freezing / heating the pieces to coax them on easier.

[heyjones]

Thanks for the link. I read another post where someone's swing arm bushings got coated and he used aircraft stripper to remove the powder coating. I had a whole can of it from when I stripped my brake calipers, so I've taped it off and sprayed it. The powder coating is already starting to peel off, so I guess that's a good sign. I'll post some photos after I go out and scrape it down. Then it's going back in the freezer.

[heyjones]

The aircraft stripper worked great. But for future reference: don't get the spray stuff! It's a pain to try and tape everything off, and even if you tape it it still seems to seem through the edges. Next time I'll go with the brush on kind.





But anyways, it really took that powder coating off well, then I threw it in the freezer and the bearing went right on, just a couple of taps with a mallet and a 1" piece of pvc pipe. I'm still a little confused on the order of the bearings / seals / spacers, though. I've seen a couple of posts here where they suggest that you put the spacer in between the bearing race and the steering column, but then in Hondaman's book it says to put the spacer in at the bottom of the triple tree. I ended up doing the latter, but not before the former and deciding that didn't look right, so I had to drive the bottom bearing off again. It looked a little tweaked, I'm hoping that doesn't come back to bite me in the ass.

Oh, and also during assembly I noticed that I either lost, or did not get back from the powder coater, the adjusting nut for the top of the triple tree! So I've got it loosely assembled until I can get a replacement. Does anybody have one of those lying around?

[heyjones]

I got my new pistons in the mail today from Z1. In case you're on the fence about ordering from them, do it! I took the new pistons, the cylinders and the head over to the machine shop to have the cylinders bored 2 over, and I gave him the tolerances from Hondaman's book of 0.0008"-0.0010"/0.020-0.025mm. He thought I was crazy! He said that was way too tight, and that he'd recommend going 0.0025"-0.0030". So I called Z1 and spoke to their support, gave him the tolerances from the machine shop and told him that I had gotten tighter numbers from a book... when he cut me off and said "Oh, Mark Paris' book?" Ha! So I pulled out the shop manual to cross reference the tolerances, and the shop manual recommends 0.0004"-0.0016", way below the machine shop's recommendation and surrounding Mark's tolerances.

So the moral of the story: take everyone's advice with a grain of salt, and when in doubt: read the shop manual!

[heyjones]

The plot thins!

The machine shop called me back after speaking with his buddy that has a long history of building TQ motors (still not really sure what that means), but now he's recommending a clearance of 0.008"! I've got an e-mail out to Mark to have him weigh in, though between his book and the shop manual (The Bible), I'm having a hard time letting the guy convince me to go that far over.

For the record, I like the guy at the machine shop, and I do trust his opinion, but I consider Mark to be an authority on these bikes (as I'm sure almost everyone does), and I get the feeling that Honda had some good reasons for making their tolerances so tight. I've even read posts here saying that they've bored to a ZERO clearance with no issues!

[heyjones]

Called the machine shop this morning and had him bore it to 0.001" clearance and check the valves for leaks. Should have those back early next week. I also shot an e-mail to "the architect" to order one of his low-profile gauge brackets:

http://forums.sohc4.net/index.php?topic=63166.msg708826#msg708826

So I took the opportunity to start putting my carbs back together after I got a replacement jet and o-rings from Cycle Recycle, and the new jet they sent me snapped in half, too! So I just cleaned up one of my old ones and threw it in, it'll be fine.

[heyjones]

I got the carbs all put back together, just trying to get the linkage adjusted. It's been a lot of back and forth, open and close, etc. and I'm still trying to get them to close at the same time. I'm going to try to get that all sorted out in the morning and get them bench synced.



Doing some research now on painting the bottom end of the engine, but I would assume I can just tape off the side covers, etc. and go to town with the aircraft stripper, then degrease and paint. Hopefully I'll have the top end back early next week and the engine back in the frame by the end of next week.

[heyjones]

Decided to pull the oil pump out and inspect it, but I can't get the thing apart! I upgraded my "work bench" from the trunk of my car to a Big Lots! work bench with plywood screwed to the top.



Everything seems alright, there were a couple of small metal pieces in the oil pump screen:



... but we've definitely seen worse.

http://forums.sohc4.net/index.php?topic=54893.msg590426#msg590426

I'm going to dunk it in oil and "burp" it to get all the air out and throw it back in. A couple of questions before I seal it up:

1) Since I can get to this roller and it looks pretty chewed up, should I (or can I) go ahead and replace it?



2) Any suggestions for getting this clean? I've been using dish soap and a nylon brush, but I'm sure there's some insanely caustic chemical I could be using...



3) I've noticed everything in this engine is kind of "stained" gold. Could that happen from burning up oil? Do I have to try and clean this all up or is it cosmetic?

[heyjones]

I've got the carbs all bench synced, took about 3 minutes using the 1/8" drill bit method. I finally have got the engine out of the back of my car and onto my "work bench". I covered it in a trash bag since I'm keeping it in the carport. That should be sufficient in keeping dust out, right?

Note to self: Simple Green > Dish Soap

[KB02]

The golder color is simply from the old oil in the engine. The darker the color indicates that more oil changes are necessary. For the most part, it is just cosmetic. It's rare to see the inside of an engine that doesn't have that color.

[HondaMan]

Aaargh! What's the best way to remove the powder coating?

Scrape with a knife to break it up, then sand it off. 

[MCRider]

re: the primary chain tensioner roller. You should replace this. You can't get just the roller, it comes mounted on the bracket with the spring. Its the spring that is really fagged out, usually, though your roller is shot as well.

Do you have the cases split? that's what it takes to replace the primary chain roller. If that wasn't in your plan, carry on.

[heyjones]

My timeframe for getting this thing finished has just been stretched out a bit, so I think I might get into the bottom end. I can replace those rollers and the cam chain, and it's going to make painting the engine a hell of a lot easier. I've got everything back from the machine shop, all bead blasted. It looks great! Do you have to paint the fins, or are they alright to leave bare? I also had them resurface the brake rotor. I got my new gauge bracket put on this morning, along with the headlight, turn signals, etc. Baby steps...





I'm considering mounting the oil pressure light in the center of the bracket, since I don't think I'm going to keep any of the other idiot lights. I would put the ignition there, but it seems too narrow for that.

[Zig]

VHT paint for the cyl block head and cases and an oil pressure guage would look good between those clocks. your doing great work.

[heyjones]

Thanks for the encouragement! I've got some photos of the progress on my tank, greasy j is working on it and he's been super communicative throughout this whole process. He describes the color as "molten root beer"! I can't wait to see it with the decals and clear coat, I think it's going to look killer:









In case anybody digs the color, here's all the info on it. It's an Envirobase color for a Volvo of all things, but I thought it was a pretty close match for the Maxim Brown:

[KB02]

Looking good.

[traveler]

nice color....looks great!

~Joe

[Lee in Ottawa]

I'm lovin your front turn signals, Where did you get the stems and lights from. I see two different short stems on partmore but can't tell which ones your using

[Lee in Ottawa]

Forgot to ask, what stems and lights are you using for the rear?

[heyjones]

I actually don't have those yet. I'll use the same shape as the front signals, but since I haven't decided on what to do about the grab bar I've been holding off on buying anything. I like going on longer trips, so I'm trying to do something with the back of the bike that will hold my camping gear but not look too bulky. I was going to put a cowl on the back, but finding one that matches up with the stock seat isn't working out so well. Something removable would be nice... I like the look of this one, maybe if it was positioned over the back end of the seat, though:



Any ideas?

[MCRider]

I'm lovin your front turn signals, Where did you get the stems and lights from. I see two different short stems on partmore but can't tell which ones your using

The lights are standard Honda pre-K3. The stems are the short ones used pre-K2.

I like that combo too.

[MCRider]

I actually don't have those yet. I'll use the same shape as the front signals, but since I haven't decided on what to do about the grab bar I've been holding off on buying anything. I like going on longer trips, so I'm trying to do something with the back of the bike that will hold my camping gear but not look too bulky. I was going to put a cowl on the back, but finding one that matches up with the stock seat isn't working out so well. Something removable would be nice... I like the look of this one, maybe if it was positioned over the back end of the seat, though:



Any ideas?

You could use the same stems and lights as on the front. Thread them into the holes that mount the fender. You can drill out the threads in the fender and use nuts on the stems for more flexibility in getting them to draw up tight. If you are using throwover saddlebags, the lights will be covered up. In that instance, you can mount them on a bracket that traverses the licenseplate bracket, side to side.

I have a rack idea, but I'll get some pictures for you.

[heyjones]

Yeah, it keeps everything tight and looks somewhat stock; or at least better than those tiny "bullet" signals (in my opinion). My only gripe about the signals is that they're plastic, but they don't look too cheap once you get them on the bike. I believe they're Bikemaster brand...

http://www.bikemaster.com/bmstrv2.nsf/Products/38492C8F4D3426E0862576EB006D0FFD?opendocument

[heyjones]

Here's a photo of the tank with the decal on it...

[MCRider]

Yeah, it keeps everything tight and looks somewhat stock; or at least better than those tiny "bullet" signals (in my opinion). My only gripe about the signals is that they're plastic, but they don't look too cheap once you get them on the bike. I believe they're Bikemaster brand...

http://www.bikemaster.com/bmstrv2.nsf/Products/38492C8F4D3426E0862576EB006D0FFD?opendocument

Really? The signals on the front are plastic? They look good. Keep an eye out for good used ones or metal reproductions, they are out there, if you feel the need.

Any way, here's my rack from Ventura systems:


Ventura is in New Zealand.
http://www.ventura-bike.com/
When I bot mine years ago, they told me the CB750 was their first bike they made a rack for, and had 1 left in the warehouse, which I got. I'll bet with the huge success the company has had and the resurgence of CB750 interest, they have more now.  The 2 arms mount one on each side, then the rack drops into them.

IF you remove the rack, there is (was) a bar that connects the two arms in the form of a grabrail. Also, they have all sorts of luggage to fit the rack.
Not exactly cheap, but a thought.

BTW, I'll be using bullet signals, I was crushed to hear you didn't like them.    


Your bike is looking good.