Topic: The Hot Mess - 1975 CB550F1 Frame/1981 CB650 Engine

[Bigsam302]

Don this is going to be an amazing bike!

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Thank you, Sam.  I appreciate it especially coming from you.  I'm so happy your bike is out of the shake-down phase and you can enjoy it!

Thanks Don. It's so much fun! It sucks that this rain has been keeping me off of it. I don't know if I told you, but I'm deploying next week. I'll be checking in as much as possible.

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[SOHC4 Cafe Racer Fan]

this is looking so damn good. what year 650 motor are you working with Don? what's your thoughts on carbs for it?

Nick,

I'm using a 1980 head. The spacing is compatible with 750 carburetors on the 1979-80 head. 

[SOHC4 Cafe Racer Fan]

Don this is going to be an amazing bike!

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Thank you, Sam.  I appreciate it especially coming from you.  I'm so happy your bike is out of the shake-down phase and you can enjoy it!

Thanks Don. It's so much fun! It sucks that this rain has been keeping me off of it. I don't know if I told you, but I'm deploying next week. I'll be checking in as much as possible.

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Cripes!!  I didn't know.  Please stay safe.  If you want to and CAN get together for a ride this Sunday, let me know.

[Bigsam302]

Don this is going to be an amazing bike!

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Thank you, Sam.  I appreciate it especially coming from you.  I'm so happy your bike is out of the shake-down phase and you can enjoy it!

Thanks Don. It's so much fun! It sucks that this rain has been keeping me off of it. I don't know if I told you, but I'm deploying next week. I'll be checking in as much as possible.

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Cripes!!  I didn't know.  Please stay safe.  If you want to and CAN get together for a ride this Sunday, let me know.

I definitely will!

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[sinister902]

this is looking so damn good. what year 650 motor are you working with Don? what's your thoughts on carbs for it?

Nick,

I'm using a 1980 head. The spacing is compatible with 750 carburetors on the 1979-80 head. 

I'm using the same for my extremely similar engine build for my 550 project that's been on the backburner almost 6yrs now.

but I'm going EFI with cbr600rr throttle bodies and microsquirt. the later 81-82 heads work REALLY nicely with mid 80's Mikunis, which are usually pretty cheap to get and rebuild. I did a set of zx600e carbs on an 81 cb650 with excellent results.

I'd say cb750 carbs would be the easiest bet....but if you could find some later 80's model mikuni CV's it would probably be even better if your goal is a lot of streetability.

[SOHC4 Cafe Racer Fan]

this is looking so damn good. what year 650 motor are you working with Don? what's your thoughts on carbs for it?

Nick,

I'm using a 1980 head. The spacing is compatible with 750 carburetors on the 1979-80 head. 

I'm using the same for my extremely similar engine build for my 550 project that's been on the backburner almost 6yrs now.

but I'm going EFI with cbr600rr throttle bodies and microsquirt. the later 81-82 heads work REALLY nicely with mid 80's Mikunis, which are usually pretty cheap to get and rebuild. I did a set of zx600e carbs on an 81 cb650 with excellent results.

I'd say cb750 carbs would be the easiest bet....but if you could find some later 80's model mikuni CV's it would probably be even better if your goal is a lot of streetability.

Nick,

I would love to see some pics of your continuing 650/550 build, especially the EFI conversion.  I am presently inclined to source a set of CR26s racked for a 750/650, unless I find something else compelling.

[sinister902]

Nick,

I would love to see some pics of your continuing 650/550 build, especially the EFI conversion.  I am presently inclined to source a set of CR26s racked for a 750/650, unless I find something else compelling.

I'll get a thread going when things start happening.....right now all I've done is break the motor down and send pieces of it all over the country for things I am not capable of. (Cases just came back yesterday from NILS, trans is at Fast By Gast for Undercutting, Head is with Mike Rieck)

[Restoration Fan]

I'll get a thread going when things start happening.....right now all I've done is break the motor down and send pieces of it all over the country for things I am not capable of. (Cases just came back yesterday from NILS, trans is at Fast By Gast for Undercutting, Head is with Mike Rieck)

With an undercut transmission, are you planning to drag race it?

[sinister902]

I'll get a thread going when things start happening.....right now all I've done is break the motor down and send pieces of it all over the country for things I am not capable of. (Cases just came back yesterday from NILS, trans is at Fast By Gast for Undercutting, Head is with Mike Rieck)

With an undercut transmission, are you planning to drag race it?

not as a specific purpose, but for the price it's worth doing while in there.....it'll NEVER be able to pop out of gear, and I'll know the trans is 100%. I may do some test and tune nights or a vintage day at NYST or something.

[Restoration Fan]

Pardon my ignorance because my knowledge on this is very limited but undercut transmissions just means it won't pop out of gears while gearing up.  It doesn't affect gearing down, correct?

[SOHC4 Cafe Racer Fan]

A back-cut/under-cut transmission should not affect downshifting, but provides a more positive hook up into gear as you accelerate through the gears. Cycle X does the service for about $290 (http://www.cyclexchange.net/Machine%20Work%20&%20Services.htm).  I'm not sure how much Fast by Gast charges (http://www.fastbygast.com/Catagories/Products/Transmissions.htm).

If you are racing the bike, I think it's a good idea especially if you are adding power/torque to the motor.  The last thing you'd want if you are trying to overtake someone is have the transmission pop out of gear.  It becomes less critical with street riding, but doesn't hurt (except your wallet).

[sinister902]

Fast by Gast is a 20 min drive from me, was a no-brainer going there for it. The gist of undercutting is that even if you don't shift 100% into the next gear, the angle of the undercut pulls the gears into 100% engagement EVERY time and prevents it from sliding out. Not necessary, but a nice feature to have....and in the grand scheme of things it's a small expense in relation to the overall cost of the build - in my case at least.

[SOHC4 Cafe Racer Fan]

Fast by Gast is a 20 min drive from me, was a no-brainer going there for it. The gist of undercutting is that even if you don't shift 100% into the next gear, the angle of the undercut pulls the gears into 100% engagement EVERY time and prevents it from sliding out. Not necessary, but a nice feature to have....and in the grand scheme of things it's a small expense in relation to the overall cost of the build - in my case at least.

So many builders don't have time or available funds to work on non-customer bikes, and their personal bikes usually sit on the back burner for a while.  It's nice that you are having an opportunity to work on this bike.  I think the development work (on EFI and charging) if successful, could be commercially beneficial, too.

[sinister902]

Nick - are you cutting both up and down? I'd only do the "up" side for Street.

you got it cal.....up only. and no cutting on 1st gear.

[SOHC4 Cafe Racer Fan]

Well I guess the proverbial cat is out of the bag. A few of us on the forum are presently awaiting the first run of a new CB550 rear hub designed to use a modern Brembo rotor and caliper.  When I asked Devin when he might make one for a CB550, he said he was (apparently long) in the process of prototyping one for Cal.  These are very similar to the ones Devin already makes for the XS650 and CX500.

I'm hoping to have mine soon as the initial run are receiving some machining work.

[SOHC4 Cafe Racer Fan]

Click and weep!!  Mine, Cal's and ??

https://www.instagram.com/p/BP-zxhVAowy/?taken-by=cognitomoto&hl=en

[joeyvans]

Kids with their instabook and facepage these days.....


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[GV1390]

Awaiting the throng of sycophants to hop onboard the cool train! 

 

[GV1390]

Click and weep!!  Mine, Cal's and GV1390's

https://www.instagram.com/p/BP-zxhVAowy/?taken-by=cognitomoto&hl=en

Fixed for you.

[SOHC4 Cafe Racer Fan]

Kids with their instabook and facepage these days.....


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  No monetized, hipster Instagram account for me like the JW. I can't fit into that Leopard "blouse".  That said, I have no issues with Devin making an honest buck - the guy works hard and smart.

[joeyvans]

Agreed.... I don't partake myself, but mainstream social media is an amazing platform for business owners to get the word out about exciting new products.... especially Devin's brand of porn! Everybody is glued to their devices.

Can't wait to see these babies on yous guyses bikes!

[Restoration Fan]

Click and weep!!  Mine, Cal's, Ron's (aka Restoration Fan) and GV1390's

https://www.instagram.com/p/BP-zxhVAowy/?taken-by=cognitomoto&hl=en

Fixed for you.

Fixed the fix for you! 

[SOHC4 Cafe Racer Fan]

Click and weep!!  Mine, Cal's, Ron's (aka Restoration Fan) and GV1390's

https://www.instagram.com/p/BP-zxhVAowy/?taken-by=cognitomoto&hl=en

Fixed for you.

Fixed the fix for you! 

Excellent choice, Ron.

[GV1390]

 

[SOHC4 Cafe Racer Fan]

So for those who want a preview . . .

take one of these (once finished)
IMG_1346_zpsdnavokfl by Donald Leonhardt, on Flickr

add one of these
rotor 1_zpsdya4rjxq by Donald Leonhardt, on Flickr

and one of these
IMG_0626_zpsvjittky3 by Donald Leonhardt, on Flickr

add caliper mount, sprocket, cush drive, rim, spokes and GET THIS!
IMG_2189_zps281p93n5 by Donald Leonhardt, on Flickr

IMG_2248_zpsb6ryfwnc by Donald Leonhardt, on Flickr

NOTE: First and Last Two Photos courtesy of Cognitomoto (not my finished wheel).