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Discussion Starter #44
Ok. Got the O-ring situation all figured out. I have bought a 500pc kit from MacMaster-Carr that are normal Buna-N and individual packets of Viton O-rings where they are needed. I did plan on buying the Viton kit but realized that the $100 price tag would most likely be way more than the price of the individual ones that I will need.

Oh, and after looking at charts and measuring some originals, I also figured out that these O-rings are not JIS (Japanese Industrial Standard). They are just Metric (Photo below).

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Thank you Charlie
 

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I'd suggest keeping the under engine step brace to keep the frame as rigid as possible. It appears the mounting plates are intact on the frame so cutting the ends off the old one, if it still exists, and bolting it in place would work well. Weight isn't really an issue since it's below the CG and actually helps lower the CG to a degree.
 

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Discussion Starter #46
Luckily I still have the brace (and it's painted too) and the mounting brackets on the frame. That is a really good point about the weight being so low down. Looks like there is nothing else to do but make two cuts (Photo below). One question though, will the open end, where the cut will be made, will that have a tubular opening, and if so should I weld it closed?

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Thanks for the advice guys.:thumbsup:
 

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That's where to cut. It's a solid bar so no open ends, just round the cut edges off so you don't have anything sharp there to cut you.
Here's a frame image showing where you'd weld a cross member
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Discussion Starter #48
Convenient that it is solid. I have cut off each end, trying to leave as much welded material (connecting the brackets to the tubes) as possible. However, I am not going to call it a final product and paint it, until I get the frame back from powder coating; just so I can see if it sticks out too far.

LDR, I wish I had read your other posts on making a cross-member prior to powder coating. Hopefully, this will work out.

As for the void, where the bracket is wrapped around the bar, do you think I could fill that in with epoxy, JB Weld, body filler? Just trying to avoid more welding expenses.

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BB, you are welcome, LDR nailed it with that mod. And you nailed it in fabbing, jbweld is good. But bondo well let you smooth it all out, leaving no place for water or dirt, but it is not nessesary. After looking at the pic, how much weld do you have left on the brace rod to end connectors?

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Discussion Starter #50
Thanks Charlie. I tried to leave as much weld as possible; I would say that there is about an inch on both ends. The brackets are only welded on the top and not on the connecting section on the bottom.

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Discussion Starter #53
Believe it or not, this is the exact video I watched when I originally painted the frame myself (see prior log posts), and the very reason I opened an account on Honda twins. The end product with my fame was a prepped surface with a filler job that took me days. I primed and wet sanded the surface 3 times and did the same with the spray VHT paint (40+ hour of work). The end result looked incredible and I became an expert with rattle cans but when I installed the swingarm I soon realized how easy it chipped. As for the reason, I disassembled and am now having it professionally done. I originally didn't want to pay for something that I could do myself but when I told the powder coater my story they just felt so bad for me and gave me a pretty good price.

On a side note do you guys have any suggestions on rims?:D
 

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Discussion Starter #54
Update 7/6/2019:

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Still waiting for powder coating

Have been prepping for the engine rebuild, masking and sandblasting (With a really janky homemade sandblaster) all of the outer cases. After washing and drying, I am pretty satisfied with the results. My only worry is the mating surfaces. All of the 40-year-old gaskets have been baked on and require countless hours removal (using acetone and plastic razor blades), had to take a break recently, as the acetone just keeps creeping its way into all of the cuts on my palms and fingers. I have taken some photos and would like to know if the surfaces are good enough for proper sealing.

Second thing being that I need to figure out what professional work needs to be done, whether it be boring, honing, and a valve job, or all three and then some (other things I am unaware of). I have read that a lot of people send off parts to Bore-Tech, but when visiting their website it looks as if the owner is starting to quiet things down. Are there any other places that anyone can recommend?

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Your gasket mating surfaces are fine. Any competent machine shop can check your clearances, and do the work. At a minimum, to me, looks like a bore and hone are required, those cylinders look pretty tired.

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Discussion Starter #56
Thanks Nova, such a relief to hear that. When I get the cylinders bored (Just by a local machine shop???) is their a specific bore size that needs to be done. I have seen places sell larger than stock piston kits. Do these match up to a set bore? Hopefully that makes sense.


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Unless there's something badly wrong with the valve seats that isn't obvious in the above pictures, or you want to go do something like replacing the valve guides you should be more than capable of handling the valve job yourself. It's just a case of lapping (read turning) the valve edges against the seats with grinding paste. You should be able to pick up grinding paste (coarse and fine) on eBay for a couple of bucks. There's a number of decent videos on YouTube on how to do it.

And from one who knows, it's worth sticking some medium grit sandpaper to a completely flat surface (like a piece of glass or MDF) and running the head gasket mating faces over it until they're flat (the top face of the barrels and the underside of the head). It's another very simple job; the idea is to get as much of the surfaces as uniform as you can so the pressure they exert on the head gasket we be more or less equal all the way around. And you only need the majority of the areas uniform; don't expect to get every little bump out.

Whilst it's not a textbook demonstration, you'll get the idea watching this kid's video:


I like him 'cos he's enthusiastic, candid and real world. The flatting bit kicks in from about 10:30 onwards, but if you watch the rest of it you'll see how he dealt with gasket residue. The advantage you've got is that the faces you're dealing with are smaller, so you can put the parts onto the grinding surface face down and let gravity do a lot of the work.

It's not essential, but I've had to pull two motors after rebuild because I thought the faces were flat when they weren't, so now I do it every time I build a new one. Takes ten or fifteen minutes and can save you a whole load of pain. But if you don't fancy it, tell the machine shop you want them to check those surfaces and if necessary, deck them.
 

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Let the machine shop - and I'd try to find one that has motorcycle experience, or send your cylinders/pistons to HT member Tools - measure the cylinders and tell you how far out of stock (or already previously bored) spec they are, then make the decision as to which oversize pistons you buy accordingly. Pistons sizes are in .25mm increments up to 1mm oversize. Here's a set that many here have used

https://www.cruzinimage.net/2017/08/17/68-73-honda-cb350k-0-5mm-oversize-pistons-set/
 

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Discussion Starter #59
Thanks so much for the help guys. I am a fan of GoldGuy and followed I believe his CB750 build. It was nice to see that I am not the only person running into the gasket problem. I have heard some negative things about the 3M Bristle Wheel that he used but I think I will buy one and do a test spot (looked like a a miracle product in his video).

I will be contacting a local machine shop shortly and try to sus things out with them. I like the idea of the Glass/Sandpaper method for planing but I will see how much the machinist cost (to do it professionally) first before I go ahead with that.

Again thanks for the help, much appreciated.

Finally, if any of you have the time I could use some advice on spokes and rims (as listed in previous posts).


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2. The next step, while there is some downtime, with the majority of the larger parts (Clutter) is to figure out what rims and laces to purchase. I would do the work to restore the original rims, but it seems that they are rusted and dented beyond possible repair. As for the laces, I have been sanding and polishing the originals but when looking at my bleeding fingers and the cheap price tag of new ones, I am just about ready to throw out the emery paper. I will continue to work on them if I can be assured that I am not removing a protective layer of clear coat. I am worried that once they are put to use, they will rust all over again. As far as rims go I have seen sets ranging in price from $120 - $$$$. 4into1.com has a set with laces by “Rising Sun” for $160 however, I have been reading other threads exclaiming that “Buchanon’s” makes/sells the best rims. I am sure that they make great products but I have to wake up to my high school budget reality. ------ Rims to buy, and are the original laces worth saving?
Starting with the last question about the spokes, it all depends on your budget, whether you have any desire to maintain originality and by extension, whether you intend to keep the wheel sizes standard and quite how far your patience extends. Given that you're going away from stock, the originality thing doesn't seem to be any kind of barrier, so it's down to the other three factors. As you're already finding, cleaning spokes is a thankless task and having tried any number of options myself in the past, I generally end up throwing in the towel and buying new; that goes double when replacements are easily available (I baulked at the cost of getting custom sets made for the SL350s, but still went that way in the end 'cos stainless . . . ). AFAIK, the factory finish was galvanised and not lacquered, so polish away if that's your thing.

Those same factors will also inform your rim choices. You can always pick up secondhand rims, bearing in mind that original chrome is almost always better than new aftermarket chrome (although custom chrome is of a higher standard than what's churned out from a factory these days). So again, for every question you pose, you'll get several back - like how long d'you intend to keep the bike for, d'you expect it to be show quality, d'you want an ultralight (if so, go aluminium or similar), will a 'functional' standard work for now so you can upgrade later, d'you intend to expose the bike to rain/how durable does the finish need to be and so on. All of those things will influence your decision making.

Being on the other side of the pond, I can't speak for any of the outfits you've mentioned and I have no idea who makes the 'best' rims. Personally, I pay very little attention to that sort of thing because there's rarely one 'best' of anything; what I look for is what's right for my situation. I'm not all that fussed about show quality, I want nice but not at all costs, mine are unlikely to get exposed to inclement weather or particularly hard riding, I don't need ultralight, I kinda like the ease of stock. My budget isn't sky high, so I'll generally I'll keep an eye out for a decent used rim or just go with something like the rims and spokes offered by David Silvers (I'm guessing they originate in Thailand). I've used their wheels on my CB450 and they've held up fine for the last eight years or so. The only change I'd consider making is if stainless rims/spokes were available, but either way, I know I can upgrade later if I want to. Having built the wheels for my CB750 more than ten years ago and kept them clean, I've never felt the urge to.

After I built my second set, I realised that wheels are the kind of bits I could spend a lot of time researching before making a decision and then completely ignoring them once they're on. Your experience may vary, but - and I'm really hoping this (actually, any of this post) doesn't sound patronising - don't get too hung up on them.
 
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