Author Topic: 1975 CB750 Build! "Kona" - Sold and gone. (Read 69542 times)

Ravie · « **Reply #51 on:** July 11, 2014, 08:08:35 PM »

In doing a lot of reading and thinking, I think I've decided what I want to do is a more mild rebuild. Pull the pistons from the wrist pins while they're still in the crank, do a medium grit hone on the cylinders (if they're not too far out of spec), new rings, obviously new gaskets, etc..

As cheap as clutch friction rings are I feel like...if it's not too terribly huge of a job, I'm going to change them and put some new EBC springs in. I'll still do a rebuild on the carbs, etc. Just won't crack the case and do bearings and things.

I was looking at the replacement face gauges from the ad over that way ---> and they're all greenish with red overlimit sections. The ones that came off of my bike Have Blue backgrounds with White overlimit sections. Are mine normal and that's just the way they repro them?

calj737 · « **Reply #52 on:** July 11, 2014, 11:12:46 PM »

Stock clutch springs are perfectly fine and should still be available. Be careful reinstalling the outer plate; they're prone to cracking if you get zealous.

Often, sun fade is the culprit on discolored gauges, but not 100% on your stock colors.

Ravie · « **Reply #53 on:** July 12, 2014, 01:30:32 PM »

The ingredients for a fiberglass seat form. Excited!

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Ravie · « **Reply #54 on:** July 14, 2014, 03:24:44 PM »

Yay! Now I can start engine tear down!

Started blasting my tank today. Going in early for other parts tomorrow. Making progress!

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Ravie · « **Reply #55 on:** July 16, 2014, 06:42:18 AM »

Has anyone that has used the por-15 fuel tank sealer NOT used their metal prep zinc/phosphorous etch liquid?

I plan to use this to seal my tank.

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Ravie · « **Reply #56 on:** July 17, 2014, 06:56:29 AM »

Got a bunch of smaller parts blasted here at work in my off the clock spare time. Started painting them last nigt. Got the oil tank, battery and tool cradle and electronics bracket sprayed. I used rustoleum flat black. Looks good. I'll get pics at some point. I need to get the top end of the engine torn down so I can bring it to the media blaster with the frame and swingarm.

Does anyone offer an engine screw kit? If not I was thinking I may buy a couple sets and offer them up for other 750 guys all pre packaged and labeled as to their respective spots. Just an idea I had.

Definitely going with the por-15 motorcycle fuel tank kit. Gotta modify the mounting bracket on my cx500 tank first.

I have to find a solution to my side covers. I'm not going to run one on the oil tank side but ill need one for the left side and I think both of mine are ruined beyond repair. Maybe I can make a small form from the old one and make my own.

Need to get myself a spoke wrench so I can disassemble my wheels.

Really enjoying this build. Why did it take me so long to get a motorcycle?!

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calj737 · « **Reply #57 on:** July 17, 2014, 08:29:26 AM »

You're getting lazy, Ravie...

http://alloyboltz.com/catalog/product_info.php?cPath=316_358_370&products_id=2152&osCsid=kq23l6b31461jlp34vnu5ksrk3

Member frankenstuff makes and sells them. They're very high quality repos and used widely.

Ravie · « **Reply #58 on:** July 17, 2014, 08:56:17 AM »

Haha, yeah I'm on my mobile and didn't search. I see dcc has a kit too. Same price and Allen head as well...

I'll look for info on those covers, thanks.

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greenjeans · « **Reply #59 on:** July 17, 2014, 01:44:42 PM »

I'll second frankenstuff's side covers. I have 3 sets of them.

Ravie · « **Reply #60 on:** July 17, 2014, 09:14:50 PM »

I looked them/him up earlier today. Awesome price and look great. I'll definitely be getting a set. Thanks for the recommendation there.

Started tearing down the engine today. I will be getting an impact driver tomorrow. Was hoping I could do it with the JIS drivers I bought...but some of those top cover screws...I'm pretty sure they've been there since 1975.

I'm so sorry I don't have fun pictures. I have a bunch of flat black engine parts and a sandblasted fuel tank... I'm in the process of removing the bracket on the CX tank so I can relocate it. After eyeing up the tank and bracket on the frame I came to the conclusion that the tank does not need to be modified, only the rear mounting bracket. So I'll cut it off and simply re-weld it further "up" the tank to line up with the stock mounting location.

After that It'll get sealed, then body work and paint can happen.

edwardmorris · « **Reply #61 on:** July 17, 2014, 10:04:23 PM »

Member ilbikes/Gordon here sells the best JIS tools and impact drivers, PM him and see if he has any left in stock, pricing for members is pretty generous.

calj737 · « **Reply #62 on:** July 18, 2014, 05:18:55 AM »

Or, if you are replacing the JIS screws with socket heads, drill them off with left hand bit. Typically, only the top few threads are stuck, and once you shear the head off, the shank turns out by hand. But an impact works well too.

I've used my cordless impact driver on all of them and had great success. Besides, I use it for other things around the house and shop.

Ravie · « **Reply #63 on:** July 18, 2014, 06:57:30 AM »

Yeah ill be doing Allen heads. I used my dremel for one yesterday...just cut a slot and used a flathead.

I need an impact driver anyway.

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Ravie · « **Reply #64 on:** July 19, 2014, 11:00:13 AM »

Best. Tool. Purchase. Ever.

Nice thing is, I got one if their little rewards card things before I bought our new bed set last march and had 14 bucks on it, so I walked out the door for 9 bucks ans change which is what the crappy HF one would have cost AND now I have one with a lifetime warranty.

It did a spectacular job with a number 3 bit. One screw broke in the cover but thankfully it was just a weak spot and after I got the valve cover off it was easy to unscrew with pliers. I was worried about the threads but it turned out fine.

Working on getting the rockers and cam off. I need to read the shop manual for the correct steps.

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Ravie · « **Reply #65 on:** July 20, 2014, 06:23:23 PM »

Been spending a lot of time going slow.

The Cam seems to be in spec, according to Hondaman (Mark would know, right?!). Looks pretty good so I'll run it.

Got the head and cylinder block off today. The cylinders are smooth as glass and I can tell the bike has sat on multiple occasions because there are two different rust rings in them. I pulled my hone and oil out and hit one of the cylinders just out of curiosity and even after a few seconds of honing, there are some definite ridges. (I didn't get a pic of this). I pulled off a piston and looked at it closely and both skirts are pretty well worn so I'm going to safely say it's time for a bore/hone up to the next size. I kinda figured that in the beginning with a 26k mile engine.

Random picture of a cleaned Valve cover in there... The pieces of engine I remove will be glass blasted.

The combustion/valve area of the heads were about as nasty/crusty as they could possibly be. I need to get ahold of the right valve spring compressor so I can take it apart. I'm planning on lapping the valves myself.

Any thought on valve springs? Checking heights, etc? After that many miles should I just replace them? I don't want to just willy nilly spend money but i also want to make sure I'm covering the important bases.

Ravie · « **Reply #66 on:** July 22, 2014, 10:19:47 AM »

I'm really toying with whether I should just go ahead and pull the whole engine apart. With the looks of the top end I can only imagine how worn the original bearings are. More expense but peace of mind and done "the right way"...

Hrmmmm.

Oh, and we came up with a name for the bike.

"Dark Roast"

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SOHC4 Cafe Racer Fan · « **Reply #67 on:** July 22, 2014, 11:21:15 AM »

Quote from: Ravie on July 22, 2014, 10:19:47 AM

I'm really toying with whether I should just go ahead and pull the whole engine apart. With the looks of the top end I can only imagine how worn the original bearings are. More expense but peace of mind and done "the right way"...

Hrmmmm.

Oh, and we came up with a name for the bike.

"Dark Roast"

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There are some that would say, if it ain't broke, don't fix it AND OTHERS that would say if you are going to invest so much in the upper half, why not make sure the bottom half doesn't have any lurking issues (peace of mind). Hey, it's only time and money!

On my 550 with 8K miles, I did not crack the crankcases, but gave the upper half a refresh of new caskets, inspected the valves, cam chain/chain tensioner. That motor was pretty clean and had been kept in running condition. For a previously seized motor, you may go deeper.

calj737 · « **Reply #68 on:** July 22, 2014, 11:25:54 AM »

I'd replace the primary chain, seals and rebuild oilpump. Bearings are probably good as they are unless badly marred. You can remove to inspect, but keep them organized if they look good and reinstall exactly as came out.

Ravie · « **Reply #69 on:** July 22, 2014, 11:26:26 AM »

Exactly my quandary!

Is the alternator (yes?) Area supposed to have oil in it? Looked like it did..

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edwardmorris · « **Reply #70 on:** July 22, 2014, 11:48:04 AM »

I don't know if it is supposed to be there, but mine also had some. I just cleaned it with a electronics cleaner spray from the local auto shop, good as new.

Your pacing seems adequate to get the whole engine redone quickly, so like Calj, I too, will suggest you at least inspect it and reuse what you can and replace the wearbles. This should give you a good rider for a while, but if you're planning to tear it down again to rebuild, say this winter, then stick with just the top end.

Ravie · « **Reply #71 on:** July 22, 2014, 12:13:31 PM »

No, cause I don't really want to have to tear it down again. Probably go slow. I haven't had a bike ever, so one more season won't kill me..

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Ravie · « **Reply #72 on:** July 22, 2014, 03:40:01 PM »

Hey, while I have your attn..

Anyone tell me what this little speaker lookin thing is?

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Tews19 · « **Reply #73 on:** July 22, 2014, 03:44:18 PM »

Quote from: Ravie on July 22, 2014, 03:40:01 PM

Hey, while I have your attn..

Anyone tell me what this little speaker lookin thing is?

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Come on now! Seriously that is a microphone! You can speak into it without being plugged into the bike and it will echo loudly!

Ravie · « **Reply #74 on:** July 22, 2014, 03:46:53 PM »

Quote from: Tews19 on July 22, 2014, 03:44:18 PM

Quote from: Ravie on July 22, 2014, 03:40:01 PM
Hey, while I have your attn..

Anyone tell me what this little speaker lookin thing is?

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Come on now! Seriously that is a microphone! You can speak into it without being plugged into the bike and it will echo loudly!

Hahahaha..

I would *almost* believe that.

First thought was it was some kind of speed warning sensor or something.

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Author Topic: 1975 CB750 Build! "Kona" - Sold and gone. (Read 69542 times)