Author Topic: 1975 Supersport, performance cafe  (Read 121296 times)

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Offline tweakin

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Re: Hot Street 1975 CB750F
« Reply #125 on: July 15, 2010, 05:55:03 AM »
The engine looks great.  To bad about the dowels but you are getting closer.  I wish I could find more time to complete my bike.  It seems like I am so close to completing the build but still have quite a few things to sort out for my liking. Maybe this weekend.  By the way, are you a medical dr.?  just curious because I work in the medical field.

Offline 754

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Re: Hot Street 1975 CB750F
« Reply #126 on: July 15, 2010, 09:53:50 AM »
 I thought maybe he was a demented radio show host.. ???


   ;)   ;D
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Doctor_D

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Re: Hot Street 1975 CB750F
« Reply #127 on: July 15, 2010, 10:39:47 AM »
By the way, are you a medical dr.?  just curious because I work in the medical field.

Sorry, but no.  My first initials are D.R., and my little brother's are M.D. - as the folks wanted a Doc in the family.  Closest I got was  being a 91-Bravo in the Army Reserves in the late-80's, early 90's, when I was in fact planning on going to medical school. Alas, plans change and paths diverge... but the nickname Doc stuck with me.
Take care,
David
___________________________________________
1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

Offline hapakev

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Re: Hot Street 1975 CB750F
« Reply #128 on: July 15, 2010, 11:51:27 AM »
Awesome build!  Cant wait to see the Finale!
Smoking Jack
1978 CB750F(ish)

"Keep moving forward, until you can no longer move" KP

Offline Doctor_D

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Re: Hot Street 1975 CB750F
« Reply #129 on: July 16, 2010, 08:08:42 PM »
OK, we're at a crossroads.

My fabricator has what sounds like good advice: mock-up, assemble, dyno, test ride -- then disassemble, powder, paint, and reassemble.

On the other hand, I've always trusted to my torque wrench and other measuring devices, and had parts finished as they're ready to install.

The former will add months to the schedule, while the latter may leave me with compromises I'd rather not make.

Thoughts?
Take care,
David
___________________________________________
1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

Offline Industrial Rat400f Killer

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Re: Hot Street 1975 CB750F
« Reply #130 on: July 16, 2010, 08:14:10 PM »
I think you'll yield the best results by following the fabricators advice, there's always something you wish you had done or changed after it's put together. I guess it all just depends on what level you are building the bike to.

Offline tweakin

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Re: Hot Street 1975 CB750F
« Reply #131 on: July 16, 2010, 08:36:28 PM »
I agree with rat on this one.  Build it, ride it, dial it in then tear down to powder and paint.  I wish I would have waited to powder the frame in case I decide I want to fab up some rear sets in the future.  I decided against the rearsets in the beginning but know hope I will not regret fabing some up prior to powdercoating the frame.


Offline Doctor_D

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Re: Hot Street 1975 CB750F
« Reply #132 on: July 29, 2010, 08:22:40 PM »
Moving ahead over the last couple of days, and there's quite a bit to report.

- mounted the oil cooler
- mounted steering damper
- "completed" the factory welds on the frame
- gusseted the frame
- tacked up the exhaust
- finished welding the rearset brackets
- moved the oil tank inboard to line up with the frame

The correct header pipes tuck in just a teensy bit more than the first set I was sent.  ;) The CB650 cooler is rubber mounted to a small bracket behind it and to one bolt that was welded to the steer tube.





Here you can see the rear gusset.  Also, we moved the oil-tank brackets inboard.  We'll trim the extra brackets off the oil tank and remove the two dimples before it goes off to be painted to match the fuel tank.  Think I'll have the winged HM logo painted on the side of the oil tank as well. The new location mean I need a 1" longer front oil line and a 1/2" longer rear one.



Here's a shot of the whole thing.  For the mock-up we found a set of used CBX shocks to replicate the taller 14" 1205B Progressives that'll go on the bike until I can get some alloy Works Performance ones.



The exhaust bracket is an overlapping 2-piece design with a welded nut on the back of the lower tab. It's held together with a small bolt that comes through from the inside of the bike.  Somewhat hidden behind the pipes, and hopefully robust enough not to crack from engine vibrations. (Its not finished in this photo, so ignore the orientation of the megaphones.)



I'll finish assembly on the engine this weekend and put a punch-list together for "kickover." At first glance, looks like I need a drive-chain, clutch-lever and cable, clip-ons, throttle and throttle cable, battery, oil-lines and ignition.  That should be enough to fire it up on the dyno. Oil-lines are the only parts that should have any real lead time.  Could be running, albeit far from road-worthy, in a week or so.


« Last Edit: August 22, 2012, 02:02:06 PM by Doctor_D »
Take care,
David
___________________________________________
1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

Offline MRieck

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Re: Hot Street 1975 CB750F
« Reply #133 on: July 29, 2010, 08:28:59 PM »
 It was nice meeting you and your wife Dave.
Owner of the "Million Dollar CB"

Offline Doctor_D

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Re: Hot Street 1975 CB750F
« Reply #134 on: July 29, 2010, 08:46:59 PM »
It was nice meeting you and your wife Dave.

Great meeting you too Mike.  Thanks for the tour and the beers.  Next time the beverages are on me.
Take care,
David
___________________________________________
1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

Offline Kemp

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Re: Hot Street 1975 CB750F
« Reply #135 on: July 30, 2010, 08:26:19 AM »
Interested in the CB650 oil cooler you are using on this amazing project. Is this a cooler from a nighthawk model?

Offline Doctor_D

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Re: Hot Street 1975 CB750F
« Reply #136 on: July 30, 2010, 09:24:45 AM »
Interested in the CB650 oil cooler you are using on this amazing project. Is this a cooler from a nighthawk model?

Thanks for the compliment.

Yes the cooler was from a Nighthawk, hence I'm not able to use the stock adapter plate that fits under the oil-filter. The earlier CB650 coolers are supposed to be a bit more plug and play. On the plus side it was only $18, including shipping, on EBay and the hardware for the lines will work nicely. I'll pick up an adapter plate from CycleX (or something similar) and have the lines re-done in braided stainless next week.
Take care,
David
___________________________________________
1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

Offline lordmoonpie

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Re: Hot Street 1975 CB750F
« Reply #137 on: July 31, 2010, 01:03:30 AM »
Looking good Dave and those exhaust brackets are very neat - they're close to the CR style so can't see any prolems with vibration. Mind you - you haven't heard those suckers fire up yet have you, don't stand behind them when you do :-)
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1951 Ducati 50cc Cucciolo
1981 Yamaha XV750 SE

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Re: Hot Street 1975 CB750F
« Reply #138 on: July 31, 2010, 09:43:55 AM »
Looks good, Dave.

It couldn't have been easy to mod those expensive pipes. :-\

~Joe

Offline Doctor_D

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Re: Hot Street 1975 CB750F
« Reply #139 on: July 31, 2010, 05:18:24 PM »

It couldn't have been easy to mod those expensive pipes. :-\


Not that tough, once we realized that Simon had sent the wrong #1 & #4 header pipes.  After that minor nightmare, he sent the correct pipes and it was a piece of cake.
Take care,
David
___________________________________________
1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

Offline Doctor_D

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Re: Hot Street 1975 CB750F
« Reply #140 on: July 31, 2010, 05:48:34 PM »
Today was another minor milestone, as the basic engine assembly was completed.  Piston rings were absolutely spot on out of the box (.012 top, .014 2nd).  To think I'd finally broken down and bought a ring-gapping tool for this build...

Degree'd in the 125-65 cam.  Used most of the adjustment to get it right, but all the valve events occur at the correct times - and that's good enough for me.
 


Mike Rieck's super nuts went on without a hitch - despite his warning that the rocker-towers might need to be relieved a bit.



The 836 headgasket from CycleX (D&K?) needed some holes elongated before it would lay flat, but that was the day's only drama.  Everything I need to dyno it is on it's way and I've booked dyno time for the weekend after next to run it in. Pretty damn excited to be honest.
« Last Edit: August 22, 2012, 02:04:05 PM by Doctor_D »
Take care,
David
___________________________________________
1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

Offline tweakin

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Re: Hot Street 1975 CB750F
« Reply #141 on: July 31, 2010, 06:02:38 PM »
Sounds like you had a great day David.  I look forward to seeing this one complete.

Offline MRieck

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Re: Hot Street 1975 CB750F
« Reply #142 on: July 31, 2010, 07:32:10 PM »
Today was another minor milestone, as the basic engine assembly was completed.  Piston rings were absolutely spot on out of the box (.012 top, .014 2nd).  To think I'd finally broken down and bought a ring-gapping tool for this build...

Degree'd in the 65A cam.  Used most of the adjustment to get it right, but all the valve events occur at the correct times - and that's good enough for me.
 


Mike Rieck's super nuts went on without a hitch - despite his warning that the rocker-towers might need to be relieved a bit.



The 836 headgasket from CycleX (D&K?) needed some holes elongated before it would lay flat, but that was the day's only drama.  Everything I need to dyno it is on it's way and I've booked dyno time for the weekend after next to run it in. Pretty damn excited to be honest.
Hmmmmmmmm. Lends itself to comments Dave. ;) :D Looks beautiful sir.
Owner of the "Million Dollar CB"

Offline jaguar

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Re: Hot Street 1975 CB750F
« Reply #143 on: August 01, 2010, 08:18:10 AM »
looking really good.
cant wait to see the dyno numbers

Offline Doctor_D

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Re: Hot Street 1975 CB750F
« Reply #144 on: August 08, 2010, 03:19:09 PM »
So, we're one week away from kick-over. Here's what we did Saturday to get within spitting-distance of running in the motor on the dyno:

Junk motor was pulled out of the frame, Woodcraft clip-ons, Moose racing clutch lever, and Gunnar Gasser throttle were installed.



Rear sprocket was installed and wheel was balanced.


Motor was buttoned up - but only as much as necessary to keep the weight down.


Installed the motor, exhaust, and clutch - which turned into a minor nightmare.

Seems I had a different year clutch-basket that the Barnett extra-plate kit didn't want to fit.  Took a moment to figure out if the parts were wrong, or if my nicely drilled clutch-basket was wrong.  It was the latter.  Dug through the spare motors, pulled one out that was serviceable, blasted the rust off of it... then the clutch-lifter plate cracked when torqued.  Given the damage to the clutch-center (found earlier) and all of the other buggered components - the next problem we found made perfect sense.

Every part of the gearshift clock-works were bent, loose, trashed, and beyond any hope of reasonable shifting.  With the clutch buggered, I can only imagine the force that was required to shift the bike, which is likely the reason for the damage.  We had low-mile donor equipment handy and were on our way after only half and hour of sorting and inspection.

At the end of the day, we had this.


Chain needs to be shortened, oil lines made up, clutch and throttle cables installed, ignition installed and static timed - and we're ready for start-up. It'll be run off a battery sitting on the floor and an I.V. bottle gas tank, but we'll have a sense of where we are with the motor anyway.
« Last Edit: August 22, 2012, 06:23:13 PM by Doctor_D »
Take care,
David
___________________________________________
1975 CB 750F - Project page: http://forums.sohc4.net/index.php?topic=66026.msg725479#msg725479
1978 CX500
1971 Norton Commando

Offline tweakin

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Re: Hot Street 1975 CB750F
« Reply #145 on: August 08, 2010, 06:11:28 PM »
Looks amazing David!  I had similar issues with my Barnett clutch I bought, even broke my lifter plate.  I got my clutch on ebay so it's probably my fault.  I think I am going to try the A.P.E extra plate clutch and see how that works.  I put my stock clutch plates back in for now so I could put some miles on and break in the engine.

Seeing your bike getting closer makes me wish I had spoked wheels on mine.  That should make for a good winter project. 

Offline MRieck

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Re: Hot Street 1975 CB750F
« Reply #146 on: August 08, 2010, 08:30:57 PM »
Looks amazing David!  I had similar issues with my Barnett clutch I bought, even broke my lifter plate.  I got my clutch on ebay so it's probably my fault.  I think I am going to try the A.P.E extra plate clutch and see how that works.  I put my stock clutch plates back in for now so I could put some miles on and break in the engine.

Seeing your bike getting closer makes me wish I had spoked wheels on mine.  That should make for a good winter project. 
The stock fiber/steel plates are fine. Just use the Barnett springs. Believe me.
Owner of the "Million Dollar CB"

Offline tweakin

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Re: Hot Street 1975 CB750F
« Reply #147 on: August 08, 2010, 08:51:57 PM »
Thanks, I appreciate the comment.  It was crazy, as soon as I went back to the stock plates/fibers everything was fine.  I am using the springs.
Looks amazing David!  I had similar issues with my Barnett clutch I bought, even broke my lifter plate.  I got my clutch on ebay so it's probably my fault.  I think I am going to try the A.P.E extra plate clutch and see how that works.  I put my stock clutch plates back in for now so I could put some miles on and break in the engine.

Seeing your bike getting closer makes me wish I had spoked wheels on mine.  That should make for a good winter project. 
The stock fiber/steel plates are fine. Just use the Barnett springs. Believe me.

Offline lordmoonpie

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Re: Hot Street 1975 CB750F
« Reply #148 on: August 09, 2010, 04:46:42 AM »
+1 to what Mike said - if KOS can use standard plates in his factory racers you know they'll do fine in most of our applications. I too broke my first lifter plate when installing - it seems it needs to be torqued down a half turn per bolt at a time as it's a very thin casting. Nearly there David - can't wait to see your dyno figures  ;)
1994 Ducati 888 SP5
1951 Ducati 50cc Cucciolo
1981 Yamaha XV750 SE

Offline jaguar

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Re: Hot Street 1975 CB750F
« Reply #149 on: August 09, 2010, 10:36:31 AM »
what makes the stock clutches better?
i hear that alot.

looking very good, stoked to see the dyno run vid too...lol