Topic: 1975 CB550 - back to the front burner after 5+yrs

[sinister902]

Guess I'll start putting updates together at least for my own sake.

So, remembering the past. The Day I bought the bike....parked in the garage at the Ritz where Beast had it parked.



After a few years tinkering it last looked like this (when I blew the motor)



I tore it down almost 6yrs ago and sold off the motor, carbs, dual disc front end, disc rear setup, wheels, tank, etc. It's been a nearly bare frame sitting in my basement since that time as I had huge plans that got back-burnered in favor of other things.

A couple weeks ago GV1390 lit a fire under my ass and got me back into this thing.

we took an afternoon and tore down a tired old CB650 motor I had picked up a few years ago to save for this.





Boxed up the empty cases and covers to send to Restocycle (Nils does phenomenal work) to have everything vapor blasted



Dropped the Transmission parts off to Fast by Gast for undercutting 2nd through 5th gears, bead blasting, and general inspection/cleaning

Head was sent straight from Restocycle to JMR porting for a "stage 2.5" port and polish treatment courtesy Mike Rieck.

Guess I'll share the collection of parts I've been grabbing as deals came up over the past 5yrs or so....

TL1000S inverted front end



Wards Riverside Tank





Grabbed a few different monoshock rear swingarms to see what fits/works best.....no pics.

scored a set of RickPaul 19F/18R cb750f disc model mag wheels (borrowed pic of lesters, they look exactly like this but polished faces of spokes)



GSXR1000 forged H-beam rods



Other plans include a Dynoman DP674cc piston kit, C5 electronic ignition kit, Hindle 4-2-1 exhaust, Megacycle 126-20 camshaft, cbr600rr throttle bodies ran off a microsquirt for EFI conversion, and a lot of fab work

I'm planning on building a 3/4 frame using the stock neck and bottom 1/4 of the frame, with a removeable subframe for the seat (will fab custom seat fairing and upholstery as well)

Engine cases came back yesterday....it'll be 3-4 wks before I get the head and trans back to begin assembly.

Also have to sort out some type of charging system upgrade/conversion. Grabbed a 2005 R6 flywheel on ebay because the mounting taper is the same angle, and at $34 shipped I want to see if it happens to fit the end of the crank

Oh, and since the megacycle cam requires being degree'd in, I grabbed a spare rocker cover to mill off the cam sprocket hump so I can adjust the slotted sprocket on assembly then swap my normal cover on






only parts I don't have is the piston kit and the electronics. Should be fun to finally get my first bike back on the road.

[SOHC4 Cafe Racer Fan]

Woohoo, Nick!  Nice project. 

Some really great ideas.  The motor is essentially identical to mine (I didn't back cut my trans), but the rest is the same (674 kit, MR 2.5 porting, Megacycle 126-20).  Dave Barbier's motor is pretty much a triplet, too.

I like the TL front.  Not as many builds have resurrected the widowmaker (TL-R) front.

I am particularly excited to see your generator mod and EFI set up.  A forum member Anders is developing a 32 amp charging system for the 550 (has already done one for the 750).  If there was enough interest (not likely), he might do a 650 system, but it looks like you will be the trailblazer.  A few of us would likely be interested to be able to power accessories, etc.  EFI will be interesting because those who have done the conversion so far have not eeked out appreciable additional performance but mainly more fuel efficiency.

Thanks for doing a build thread on this one.

SUBSCRIBED!!

[sinister902]

Thanks Don, Yeah I scored the TL front end for like $225 to my door a couple years ago.

I know there's upgraded charging systems for 550 and 750, but the 650 isn't compatible with either one so I need to come up with SOMETHING for piece of mind running all the EFI hardware and such.

I really hope to prove there's power gains to be had with EFI on this motor, esp with the upgrades on the engine that will be further optimized by EFI. I'm just not impressed with the rideability of the Keihin CR's on the few bikes I've ridden equipped with them....and early 750 carbs are basically a simpler version with similar issues as far as REALLY dialing in the mixture throughout the revs. I was really into the tuner car scene before getting into a vintage bike....so I'm much more familiar with fuel injection and how to tune it than I was with carbs when I got into them. crazy to think 13yrs ago I was tuning my own street car with a laptop and then a year later bought a bike 11yrs older than me and had to teach myself the wizardry of carburetors.

[SOHC4 Cafe Racer Fan]

Thanks Don, Yeah I scored the TL front end for like $225 to my door a couple years ago.

I know there's upgraded charging systems for 550 and 750, but the 650 isn't compatible with either one so I need to come up with SOMETHING for piece of mind running all the EFI hardware and such.

I really hope to prove there's power gains to be had with EFI on this motor, esp with the upgrades on the engine that will be further optimized by EFI. I'm just not impressed with the rideability of the Keihin CR's on the few bikes I've ridden equipped with them....and early 750 carbs are basically a simpler version with similar issues as far as REALLY dialing in the mixture throughout the revs. I was really into the tuner car scene before getting into a vintage bike....so I'm much more familiar with fuel injection and how to tune it than I was with carbs when I got into them. crazy to think 13yrs ago I was tuning my own street car with a laptop and then a year later bought a bike 11yrs older than me and had to teach myself the wizardry of carburetors.

Nick,

If you can work out a solution to the charging and EFI set up, I have a feeling you might have some interested folks on this forum as to your set up.  See if you can design something that you can replicate without too much brain damage. 

[sinister902]

Nick,

If you can work out a solution to the charging and EFI set up, I have a feeling you might have some interested folks on this forum as to your set up.  See if you can design something that you can replicate without too much brain damage. 

the EFI stuff isn't really rocket science. the 600rr throttle bodies WITH the cbr600rr isolators fit right to the 79-80 cb650 head (which means they'd also fit 550 and 500 fours). The tune file would really be the only hurdle. but I will absolutely publicly share my file so others can use it as a start-up map to get theirs fired up and have a place to start tweaking from....

but def. want to figure out the charging system. I know I read of a VFR system being adapted but IIRC that was on a 550. I'll post my findings with the R6 flywheel.....

[joeyvans]

An awfully ambitious  650/550 project! Going to be fun to follow this one, Nick! Subscribed!

I think the 3 650/550 builds (Don, Dave, Nick) that I know of are really going to pave the way for many more future member builds like them. I know I will have my head on a swivel looking for a 650 motor! Fun to look at specs from Paulages build too.


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[firebane]

An awfully ambitious  650/550 project! Going to be fun to follow this one, Nick! Subscribed!

I think the 3 650/550 builds (Don, Dave, Nick) that I know of are really going to pave the way for many more future member builds like them. I know I will have my head on a swivel looking for a 650 motor! Fun to look at specs from Paulages build too.


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I'm another who will be looking to do a 550/650 hybrid. In fact I'm in talks with GV1390 right now about a possible camshaft LOL.

These old 550s make a great platform for a fun bike and this looks like it'll be a fun bike for sure.

[sinister902]

An awfully ambitious  650/550 project! Going to be fun to follow this one, Nick! Subscribed!

I think the 3 650/550 builds (Don, Dave, Nick) that I know of are really going to pave the way for many more future member builds like them. I know I will have my head on a swivel looking for a 650 motor! Fun to look at specs from Paulages build too.


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I had originally planned to do a paulages 741cc build with the wiseco 836 kit 65mm pistons.....actually HAVE the pistons and had purchased a set of cb750 cylinders to start with.....but given that there's no knowledge of the actual specs on modifying the skirts of the pistons for that, I decided to scale back and just do the DP674 kit.

[SOHC4 Cafe Racer Fan]

An awfully ambitious  650/550 project! Going to be fun to follow this one, Nick! Subscribed!

I think the 3 650/550 builds (Don, Dave, Nick) that I know of are really going to pave the way for many more future member builds like them. I know I will have my head on a swivel looking for a 650 motor! Fun to look at specs from Paulages build too.


Sent from my iPhone using Tapatalk

I had originally planned to do a paulages 741cc build with the wiseco 836 kit 65mm pistons.....actually HAVE the pistons and had purchased a set of cb750 cylinders to start with.....but given that there's no knowledge of the actual specs on modifying the skirts of the pistons for that, I decided to scale back and just do the DP674 kit.

No doubt.  Shoehorning the overlapping 750 sleeves into the 650 block is no joke.  Kudos to Paulages and Chevelle for finding machinists who can do this finesse work:

[SOHC4 Cafe Racer Fan]

Hey, Nick. I presume you are using a 1979 or 1980 head, right?

[Restoration Fan]

Nick,

If you can work out a solution to the charging and EFI set up, I have a feeling you might have some interested folks on this forum as to your set up.  See if you can design something that you can replicate without too much brain damage.

Yep.  I would be one of those.  I would love to see a successful EFI setup like that.

Definitely subscribing to this build. 

[Stev-o]

Looks to be a great project, subscribed.  Interesting choice for fuel tank...

[Camrector]

All the YES Nick! Can't wait to see your handiwork! Don't knock the CRs though. Those bikes had "other issues".

[SF]

Subscribed


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[GV1390]

Glad I could give you the push homie! Looking forward to helping you on this one.

[GV1390]

Nick's cases have arrived!

[mothgils]

Count me in!

Also, may have gotten the bug from Gennaro and am slowly stockpiling some 650 parts!

[GV1390]

Count me in!

Also, may have gotten the bug from Gennaro and am slowly stockpiling some 650 parts!

Now make both of your build threads on here. Woot woot!

[SF]

Nick's cases have arrived!

Let's see some pics!


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[SOHC4 Cafe Racer Fan]

Looks like Nils did an awesome job of packing the crankcase.  Lots of padding and the box looks unscathed.

[sinister902]

Little side-work stuff to get some pics in here for you guys.....GV1390 and I split in on a set of lesters and totally refurbished them. He soda blasted the hell out of them, we put brand new bearings in, and I taped them off and laid a fresh coat of single stage flat black on them. Came out really really good.









Also, R6 flywheel compared to cb650 flywheel:



same taper, but at a different size if that makes sense. R6 flywheel bottoms out at the crank seal before the taper meets the crank end taper.

Going to take measurements and draw up a tapered collar to adapt the R6 flywheel to the cb650 crank....then send my file to emachineshop.com for a quote.

then next would be buying a used R6 stator cover and cutting up both that and a spare stock cb650 stator cover to make an R6 stator fit into a cb650 cover.....if it all works, I'll CAD the modified stator cover and submit THAT to emachineshop for a quote.....maybe I can come up with a kit if this works!

[SOHC4 Cafe Racer Fan]

Nick,

Keep me in mind for an alternator kit.  I am not going EFI, but I would appreciate an improved charging system.

Don

[Restoration Fan]

Glad those Lesters turned out to look that good.  GV was getting ready to go blast them in 29 degree weather when he & I were texting so it's a good thing they came out so nice! 

[GV1390]

Glad those Lesters turned out to look that good.  GV was getting ready to go blast them in 29 degree weather when he & I were texting so it's a good thing they came out so nice! 

Ron, you're being modest! I thought it was going to be 26 instead it was 19 degrees out. BURRRR.

[Restoration Fan]

Well I was trying to make it sound like you're smarter than you apparently are for going out in that!