Topic: 79' CB650 (674) Project with a 550 tank and CBR front end.

[DaveBarbier]

Very nice! Are those Allen cap screws painted or black oxide? They look great in there.

[Sigmund]

Very nice! Are those Allen cap screws painted or black oxide? They look great in there.

Button heads- you can get stainless or mild in black. They are the nicest looking IMO.
I have all NOS bolts where possible, but over black these blend in well.

Other news: motogadget tiny on the way to somehow neatly slot into the middle (ignition) area of the CBR top tripple. No key for this build. I use android, so will just have proximity with m unit as my key. * Thoughts on this ? Do i want a botton as well? Black braided brake lines also on the way.

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[DaveBarbier]

Those black oxide screws do tend to rust pretty easily. Just saying. Maybe shoot them with some clear or something?

You’ll have a button starter? I gave an mUnit v2 and I have a momentary starter button and it’s double tap to kill. That works well, like it a lot.

[Sigmund]

Those black oxide screws do tend to rust pretty easily. Just saying. Maybe shoot them with some clear or something?

You’ll have a button starter? I gave an mUnit v2 and I have a momentary starter button and it’s double tap to kill. That works well, like it a lot.

Alright, thanks. I'll give them a paint. I'm using normal CBR switches, so will have starter and separate kill still. 

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[Sigmund]

Those black oxide screws do tend to rust pretty easily. Just saying. Maybe shoot them with some clear or something?

You’ll have a button starter? I gave an mUnit v2 and I have a momentary starter button and it’s double tap to kill. That works well, like it a lot.

I guess my only thought was: would I want a switch for on/off? In case it's easier than turning Bluetooth off or whatever.

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[Nicklopic]

When doing your wiring with the factory switches, atleast how my Suzuki stuff was, the starter button and kill switch share a ground and may cause headache trying to wire up your M-unit. My solution was to use a (-) triggered relay to supply power to the ignition that way the kill switch would behave just like factory. Plus I can still double tap the starter button to kill it if I want to.

I also would vote for a key or button still. It would suck to not be able to start your bike if your phone died. I use my phone a lot too and I would not enjoy the extra worry.
(Also hoping things are looking okay for you)

[DaveBarbier]

Those black oxide screws do tend to rust pretty easily. Just saying. Maybe shoot them with some clear or something?

You’ll have a button starter? I gave an mUnit v2 and I have a momentary starter button and it’s double tap to kill. That works well, like it a lot.

I guess my only thought was: would I want a switch for on/off? In case it's easier than turning Bluetooth off or whatever.

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Oh I see, personally I don’t like the idea of relying on my phone to turn my bike on. A switch is far more convenient. If your phone were to run out of battery or something that would be a bummer. I like the idea of a small toggle somewhere if you don’t want to carry keys.

I use an m-lock and have the little rice sized glass RFID vial sewn into the sleeve of my jacket. Works really well and I don’t have to carry a key chain.

[Sigmund]

I have a cam regrind on the way... Close to Std specs at about .300 lift and 10 degrees more duration.
I want it to idle well and not be all in the high end of the rev range. It's from Teigh Cams in QLD Australia. They do heaps of CB750 stuff more commonly, but this was a street CB550 cam that should work well. I bought some nice low km rockers that are fine to use without a "hardweld job" on this mild cam. I'm nearly ready to put this all together. 

[Sigmund]

I have found the dynoman rings to be a pain... They are the hardest I have experienced to get to stay in their grooves.
So, what I'm doing is installing with the barrels removed, and then sitting the barrels (with pistons inserted) over and inserting the pins once lined up. Anyone else do it this way? I can say it's easier on a twin! But it will work with 4 cyl too.
I just want to make sure they are seated perfectly before going any further.

[RAFster122s]

I have a cam regrind on the way... Close to Std specs at about .300 lift and 10 degrees more duration.
I want it to idle well and not be all in the high end of the rev range. It's from Teigh Cams in QLD Australia. They do heaps of CB750 stuff more commonly, but this was a street CB550 cam that should work well. I bought some nice low km rockers that are fine to use without a "hardweld job" on this mild cam. I'm nearly ready to put this all together. 

I thought that the rule of thumb was, if you have the hard weld cam (any regrind cam is hardwelded) you have to use hard weld rocker arms to eliminate any source of wear!
 The hard weld rockers, it is my understanding will wear through the hardened faces of the stock rockers in not very many miles. 


Whether that is very short in thousands (?) or 10s of thousands of mile, etc. (...?) I don’t know. I would  love to know someone like Mike R’s opinion and vast experience w/CB SOHC4 motors the answers to questions of mixing them...be that a cam or rockers that have been hardwelded.
Be it with regards to using stock new rockers or low mileage rockers with a regrouped camshaft.
 How soon are you likely to see the wear on the stock rockers?
 What is a realistic number of miles before you are going to have to be in the motor again to address replacing the rockers.  Wearing through that hardened coating of the rockers is. Not good for the tolerances of your bearings, etc.
I have always wondered... Is a hardened metal still going to be hardened when it is  circulating in the motor after it has been put in suspension in your motor oil due to this increased wear?


SUMMARY or TAKE AWAY:
================
Mixing the two will have you back inside the motor, and that is not in the distant future.

[Sigmund]

I have a cam regrind on the way... Close to Std specs at about .300 lift and 10 degrees more duration.
I want it to idle well and not be all in the high end of the rev range. It's from Teigh Cams in QLD Australia. They do heaps of CB750 stuff more commonly, but this was a street CB550 cam that should work well. I bought some nice low km rockers that are fine to use without a "hardweld job" on this mild cam. I'm nearly ready to put this all together. 

I thought that the rule of thumb was, if you have the hard weld cam (any regrind cam is hardwelded) you have to use hard weld rocker arms to eliminate any source of wear!
 The hard weld rockers, it is my understanding will wear through the hardened faces of the stock rockers in not very many miles. 


Whether that is very short in thousands (?) or 10s of thousands of mile, etc. (...?) I don’t know. I would  love to know someone like Mike R’s opinion and vast experience w/CB SOHC4 motors the answers to questions of mixing them...be that a cam or rockers that have been hardwelded.
Be it with regards to using stock new rockers or low mileage rockers with a regrouped camshaft.
 How soon are you likely to see the wear on the stock rockers?
 What is a realistic number of miles before you are going to have to be in the motor again to address replacing the rockers.  Wearing through that hardened coating of the rockers is. Not good for the tolerances of your bearings, etc.
I have always wondered... Is a hardened metal still going to be hardened when it is  circulating in the motor after it has been put in suspension in your motor oil due to this increased wear?


SUMMARY or TAKE AWAY:
================
Mixing the two will have you back inside the motor, and that is not in the distant future.

So, as far as they are concerned, hardweld rockers are for high lift hot cams that are hardwelded. This is a regrind cam where the extra lift comes from a smaller base circle. Very mild change from std CB650. We shall see I guess. I'll keep an eye on the rockers and wear. Easy to fix if needed.

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[RAFster122s]

How are they hardening the reground camshaft? Just a simple heat treat for a thin layer of hardened metal?

[Sigmund]

How are they hardening the reground camshaft? Just a simple heat treat for a thin layer of hardened metal?

For this regrind: copy/paste below:
Nitriding on regrind steel camshafts is a process of retaining the steel camshaft at a temperature of up to 500 degrees celsius. This gives the steel a higher wearing resistance, higher fatigue resistance and improved corrosion resistance. Only steel with a percentage of nickel will nitride.

[Sigmund]

The 1mm (.043) Cometic Gasket I got is pretty stretched and warped.  It took a little work to line it up. I sat a standard Athena head gasket on and it lined up perfectly, so I'm disappointed in the quality of these. I also have a 1.5mm (.059)  Cometic that fits better, but still not great.

[Sigmund]

The engine is finally together!  Finishing up the frame fabrication. Then off to get painted... Acrylic, 2k or powder? Others I have done in acrylic so I can touch up easily. Hmmmm. Thoughts?

[RAFster122s]

I have seen others complain about three Athena gaskets fitment or quality but it has been a while. Provide the feedback to Cometic..maybe they will respond in a positive manner.

[Matt James]

Nice build! I've got a '79 650 myself and am looking to go through the engine as well. I saw you put in new crank bearings, but I haven't been able to have much luck finding any recently. Any suggestions?

[Sigmund]

CB four in Germany, CSMNL and I found some here in Australia (NOS)
https://www.cb-four.com/cgi-bin/shop/__CB-650-F+C--RC03-05-08-/Engine-P----Gaskets/_06.07.html
https://www.cmsnl.com/honda-cb650-1979-z_model48677/partslist/0078.html#.XkRlOhMzaL8

Con rod/big end bearings are more important IMO. Maybe check the clearance on the crank bearings first. 

[Sigmund]

Polished the covers.

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[DaveBarbier]

Looking good!

[SOHC4 Cafe Racer Fan]

Nice!

[Matt James]

CB four in Germany, CSMNL and I found some here in Australia (NOS)
https://www.cb-four.com/cgi-bin/shop/__CB-650-F+C--RC03-05-08-/Engine-P----Gaskets/_06.07.html
https://www.cmsnl.com/honda-cb650-1979-z_model48677/partslist/0078.html#.XkRlOhMzaL8

Con rod/big end bearings are more important IMO. Maybe check the clearance on the crank bearings first. 

Thanks!

[Sigmund]

I have the cognito front hub and CB750 rear hub to the wheel builder to get spokes made to match new 18x2.5" excel front and 18x3.5" rear.

[Sigmund]

Made a nice little electronics tray and have been working the frame to except mounting points.
The tray is 1mm mild and only 25mm deep. The front enclosure will house the regulator and give it air flow.

[Nicklopic]

What's your plan for electronics and a seat? Your tray may not be deep enough, atleast based on what I did. Idk of you decided to do an M unit or not but it's about 1" tall by itself. If you're using the stock starter solenoid, that's about 2" tall laying down. (I think thats just a bit over 25mm and 50mm respectively)