Topic: G’day! I’m an Aussie in Canada with a 1979 CB650! Cafe Resto-Mod style build.

[DANFROMOZ]

Does anyone know if it’s likely that I’ll need any of the brackets on the tube under where the rear swing arm is? I’ll attach some pics. I was planning on cutting and grinding off the old center stand brackets, but there’s also a hook and another linkage bracket thing. The hook was a guide for the tubes coming from the carbs bowls from memory (excess gas?), would the new CR carbs still require that? Any idea if I’ll need the other “bracket thing”?
I’ll be cutting off the old drum brake mechanism brackets and bulky heel guard sections too, and try to make the new rear disc set up cleaner looking.

[DANFROMOZ]

I went with a 17-tooth offset sprocket for a 520 chain -- offset since I went with a wider than stock wheel/tire.

Ok, I think I’d follow suit then. So I don’t think I need the offset sprocket because I have the disc brake conversion hub, and I’m pretty sure they already took into account the 4.25 rear wheel as it came in the same order, something else I’ll double check. Thanks again.

Just thought I'd point out something regarding this previous post, it turned out that I did need an offset, separately to the rear hub/disc brake conversion components, Cognito Moto has the gear but it is an extra cost and was needed because I'm running the 4.25 rear wheel. They've sent me a spacer for the rear hub sprocket and an offset front sprocket. They also included some new bolts for the rear hub which need to be switched out, that needs to be specifically requested if needed. Here’s some pics. So I’d already ordered a new front sprocket when I ordered the black rear sprocket from Sprocket Specialists, so that’s no longer needed. I’m still waiting on the offset front sprocket from Cognito Moto, it’s on back order, but I have the spacer and bolts for the rear. I’ll have to take a look and see what I need to do to get the OG bolts out.....

[rusty2078]

Does anyone know if it’s likely that I’ll need any of the brackets on the tube under where the rear swing arm is? I’ll attach some pics. I was planning on cutting and grinding off the old center stand brackets, but there’s also a hook and another linkage bracket thing. The hook was a guide for the tubes coming from the carbs bowls from memory (excess gas?), would the new CR carbs still require that? Any idea if I’ll need the other “bracket thing”?
I’ll be cutting off the old drum brake mechanism brackets and bulky heel guard sections too, and try to make the new rear disc set up cleaner looking.

I can't speak to 650 frames, however you'll still require a route for overflow tubing from your carb bowls, I'm assuming visually speaking that the "hook" for these is somewhat hidden behind the side of the frame, and that in order to see it one would have to look closely behind the engine, or straight from behind...nice to have it off to the side

[DANFROMOZ]

Does anyone know if it’s likely that I’ll need any of the brackets on the tube under where the rear swing arm is? I’ll attach some pics. I was planning on cutting and grinding off the old center stand brackets, but there’s also a hook and another linkage bracket thing. The hook was a guide for the tubes coming from the carbs bowls from memory (excess gas?), would the new CR carbs still require that? Any idea if I’ll need the other “bracket thing”?
I’ll be cutting off the old drum brake mechanism brackets and bulky heel guard sections too, and try to make the new rear disc set up cleaner looking.

I can't speak to 650 frames, however you'll still require a route for overflow tubing from your carb bowls, I'm assuming visually speaking that the "hook" for these is somewhat hidden behind the side of the frame, and that in order to see it one would have to look closely behind the engine, or straight from behind...nice to have it off to the side

Ok, I’ll probably keep em then if I’ll still need overflow tubes, they are kinda tucked away.

[VTEC]

Here’s some more pics.

How is the clearance in swing arm with tire bieng 160/60/18?

[DANFROMOZ]

Here’s some more pics.

How is the clearance in swing arm with tire bieng 160/60/18?

Hi VTEC, so when I did my research back when I ordered the wheels and tires, etc, it all seemed to check out, I think I ran it past Nick/Devin at Cognito Moto and they figured that was about the limit. Did turn out that I needed offset sprockets front and back as I mentioned a few posts back. I’ve had the rear wheel/tire in the general position on the swing arm and there seemed to be some room either side so I think I’ll be good, but I’ll be mocking it all up once I get the rear of the bike welded up and engine parts back from the machine shop in the next few weeks, should know for sure then. Here’s a photo when I had the rear wheel in, but it wasn’t in the correct position really so just thought it might give you a bit of an idea. Not the best angle, but there seemed to be some room.

[Nicklopic]

For the bracket stuff, all that is really only needed if you keep your center stand. It doesn't look like you are so cut all those little tabs off. That's what I did on mine, as well as cut the triangles for the passenger pegs off.

[SOHC4 Cafe Racer Fan]

Dan,

Are you going to run the stock cam or a 126-20.  If you go with the 126-20 you will need to do further mods to the valvetrain.  Ask DaveBarbier or Mike Reick if you do.

Hi SOHC4, The fella from Dynoman's suggested the stock CB650 cam was a fairly good match for the oversized billet pistons and the CR carbs so that sounded good to me. The engine was running quite well previously, as far as the previous owner was saying, so I probably didn't need to do the pistons, but just thought why not. You've got me a bit curious now though, so I'll research the cam. And thanks for the suggestions for people to connect with, there's nothing better than advice from people who know what's what.

You can extract more power with the 126-20 cam but it comes with a price of having to use modified valves for clearance. 

[VTEC]

Here’s some more pics.

How is the clearance in swing arm with tire bieng 160/60/18?

Hi VTEC, so when I did my research back when I ordered the wheels and tires, etc, it all seemed to check out, I think I ran it past Nick/Devin at Cognito Moto and they figured that was about the limit. Did turn out that I needed offset sprockets front and back as I mentioned a few posts back. I’ve had the rear wheel/tire in the general position on the swing arm and there seemed to be some room either side so I think I’ll be good, but I’ll be mocking it all up once I get the rear of the bike welded up and engine parts back from the machine shop in the next few weeks, should know for sure then. Here’s a photo when I had the rear wheel in, but it wasn’t in the correct position really so just thought it might give you a bit of an idea. Not the best angle, but there seemed to be some room.

Thanks for the info.  Looking good!

[DANFROMOZ]

    Ok, so I’ve really been in two minds regarding splitting the crankcase. I have no real reason to do it, as far as I know everything is fine, the previous owner, who I know well, said it was working just fine, but I do like the idea of preventative maintenance and hate regret with a passion.
    I’ve researched it on here and on the CB650 forum for weeks (procrastinating) and it does seem like a bit of a PITA!
    Just the fact I have to mess with the clutch, oil pump, generator rotor just seems like a hassle.... I saw somewhere that you might not need to remove all that stuff just to open the crankcase, as all I was going to do is check the main bearings and maybe the con-rod bearings for heavy wear.
    Any reassuring words anyone? What would you do? I have the Hondabond on its way and got the full gasket set instead of the upper gasket set I had, and some permatex assembly lube, etc, so I figure I’m doing it, just looking for any areas of concern you guys might point out early?
     One thought is that I’d probably have to re-adjust all those extra PITA items, clutch, timing, etc anyway, so it doesn’t matter if I pull them off, but I see I’ll need a slide hammer and possibly a gear puller, which I don’t have, I could get them but are there other alternatives, best options? I see something about the rear axle, but I also see people have struggled with that....

[DANFROMOZ]

Btw, the odometer reads 38,267km’s, I figure that’s original Km’s, if that makes any difference.

[jgger]

You will need to pull some of the items you listed to change some/a seal. To go that deep and no new seal at the crank is rather silly, IMHO.

[DANFROMOZ]

Thanks Jgger, that’s the kinda push I need, any ideas on whether I really do require a hammer pull and gear puller for those jobs, or is there a sneaky trick?

[DANFROMOZ]

Here’s what the manual calls for.

[DANFROMOZ]

Ok, well I’ve tracked down a hammer pull and a gear pull that I can use when the time comes from a mate whose a mechanic, so I think I’ll just get to it. Again, any hints or tricks are much appreciated!

[DANFROMOZ]

Gday all. I received block, head and valve-train back from the machinist. He mentioned how much bigger the pistons were than stock and how much he took off the cylinders, he thought it should make a big difference, so that’s interesting to hear from someone who does it a lot. I’ll include some pics and a list of the things he did. The valve-train just had a cracked bolt hole that I wanted welded up so I can bolt the cover on properly. He cleaned up the combustion chamber and valves nicely and said they needed quite a bit of work. Glad I got him to check.

[DANFROMOZ]

Tipped the engine upside down and pulled the sump cover off. Looked ok, didn’t see any metal shavings in the oil, but it was pretty sludgy and black. Pulled the clutch cover off and loosening the twenty-something bolts of the crankcase. Was going to work on getting the primary drive off after that but went to work on getting the oil pump off. Those oil pump screws are pretty tight and I used my JIS screw drivers but couldn’t get much leverage, as the screws were already a bit worn. I sprayed them with some PB blaster, but still not moving. Any suggestions on easiest, best way to get them out now? The JIS screw drivers I got have the metal end so I smacked them with a hammer numerous times, but still nothing....  any assistance would be great, I’ll need to find better replacement screws once they’re out.

[DANFROMOZ]

Here’s some pics of where I’m at. Any idea where I’m supposed to mark the ignition timing plate for easier installation later? It mentioned it in the manual, like a base mark to start at when you put it back on? Considering I’m pulling just about everything apart, I’m not sure how relevant that may be, but I’ve never done it before so I don’t really know I suppose.... here’s some more pics.

[scunny]

it's on the base plate, 4th picture down. just mark the plate in alignment with the bottom screw.

[DANFROMOZ]

Thanks Skunny! Good to know. That's what I'll do. I'll keep going on getting the crankcase split and I'll work on the screws for the oil pump later.

[DANFROMOZ]

Anyone know what the best type replacement screws I should use to replace the stripped JIS screws? I was thinking stainless Allen/hex button head screws with a dab of anti-seize.....?

[calj737]

That is a perfect replacement and application.

[DANFROMOZ]

That is a perfect replacement and application.

Great Calj737, thanks for the reply.

[DANFROMOZ]

Hi All, well after a few months, and a pandemic, I’ve been back in the shed again lately. I finally got out the pesky JIS screws out of the bottom end of the engine that were stripped and also chopped the frame a bit more. I’ve left the frame with a local welder whose going to weld the rear hoop on for me. Hopefully I’ll have that back in a week or two.

[DANFROMOZ]

So the other day I managed to get the rotor loose using the rear axle trick, which was handy. It was the main thing holding me back from opening up the crankcase to check the crank bearing wear, etc. Today I loosened (& removed) all the bolts on the top and the bottom of the cases and took the timing plate off. I’ve since noticed that there are some videos out there where people are removing the bottom of the crankcase with the rotor still in place, which was weird to see because I was under the impression it had to be removed.... anyway I’ve left it on for now and just hand tightened the screw.
   So today I tried pulling the case halves apart and it didn’t really budge at all. I didn’t try prying too much, but wanted to ask if anyone could take a look at my pics and let me know their thoughts on if I need to remove anything else from the cases to get them apart. The owners manual is telling me to take everything off, clutch, rotor, all kinds of stuff, but it seems that’s not necessary..... or is it? Any help would be handy.... at this stage, considering by what the previous owner has said, I probably don’t even need to get in there really, he said it was running fine and it’s only done 38,000kms.... I might just bolt it back up and finish the top end!