Topic: "Acid Sunrise" CB750 Chopper

[JLeather]

I know this isn't usually a chopper forum, but there are a few of my fellow delinquents around so I'm posting this anyway.  The build is mostly done so I can get pretty much all of this at one time for you guys that hate waiting.

I bought this bike about 2 years ago.  I didn't have a chop at the time, I was working too much to build one, and I really missed having a CB.  I thought I'd save myself some time and buy a finished running chop, and I love Saviors.  My first chopper was a Savior-framed 750 and it was basically stolen (thanks alot Jeromy Hagemier).  Here she is when I picked her up:



And after some touch-ups (new wheels and tires, new seat, headlights, etc):



So the bike was ready to roll, and I never rode it (well, almost never).  Two major reasons.  One, there was no attachment to the bike.  I just didn't *want* to ride it.  Also, every time I looked at it all I saw were the things I'd have done differently or the things I didn't like.  So it sat, and sat, and sat.  Last year I tried selling it, but no one bought it so it sat some more.

This past March I finally got serious.  No sense having a bike I don't ride, and I had a bunch of parts kicking around waiting for a home, so I dug in.

[JLeather]

I want to smile when I see this bike in the garage.  I'm not usually the type to clean, polish, paint, re-chrome, etc on my builds.  Usually I like crusty bikes.  Hell, the last bike show I went to with a bike the judge said "you could have at least washed it" .  There's just less to worry about and they're cheaper to build.  This time, however, I want clean, painted, and pretty.  I want a bike nice enough to run the ARD mag I've got off a friend's show bike from back in the day.  I've also got a torn down RC 836 motor that I'll build for it if there's time.

I had a snow-day on March 6th so the build officially began then.  I threw on a temp exhaust system that didnt run under the frame so I could see how the stance was.  It had a +6" frontend right when I got it and sits up a little.  I've got a +4" frontend to being it more level, but honestly the nose-up stance seemed more 70's and in the end I stuck with it.  I also tried out all the extra chopper tanks in my shop.

SB&F Prism Tank:





GME Ribbed Peanut Tank:





Axed Tank:





Gary Littlejohn "Space Coffin":





The "Space Coffin" almost did it for me, but just wasn't quite right so I had to hunt around for a tank.  I eventually settled on this Gary Littlejohn Prism:





Unfortunately that tank was in need of a lot of love.  Bad Kreem job inside, layers and layers of paint and bondo.  Lots of work just to get to square-one.

[JLeather]

Once I had the tank figured out I tore the bike the rest of the way down.  It was early May before I had time to do much more than order parts (of which there were many).  While I was working out of town my buddy Matt stopped by and filled in the holes in the fender to prepare for the new seat and sissybar.



I got a new LePera 2-piece seat and a new Paughco sissybar for the bike.  Did a quick mockup:



The sissybar is too long.  Savior frames mount the bar a lot higher than a rigid frame, at the top of the springboxes.  Time to start cutting.  I felt a little bad cutting up a brand new sissybar, but what are you gonna do?  Sawed about 6 inches off each side and then had to come up with new mounts.  Chucked some hex stock in the lathe a cranked out a neat little pair of mounts.  They got set-screwed to the cut off legs and voila.








I had LePera send me a blank pan for the sissybar pad which I trimmed to fit and sent back to be matched to the seat.  Even looking back now it feels like an extravagance, but I really like the look.  I think seats on these choppers are one of the msot overlooked last-minute things that really throw off the overall look if not done right.

[JLeather]

Fast forward another couple of weeks (because of a quick kitchen remodel that killed my spare time) and it was time for the real tear-down.  Everything came apart, frame got sanded back to bare metal and a few little issues fixed.  Also made some weld-in threaded bungs for the tank.





Found some gross surprises in the motor.  Someone tried to port-match it with a chisel it looks like:



It's coming back out this winter for a rebuild.  The 836 motor I was working on had a cracked case, so I'll make 2 outta one once the riding season is over.

Stripped all the Kreem out of the tank and found the lovely rust underneath.  A coating of Caswell took care of that and the tank, frame, and fender went to my buddy's place for some paint.




In the meantime I cleaned up the wheels and rebuilt the forks.  Had to use some other tubes I had laying around, there were vise teeth marks in the seal area of these tubes!

[JLeather]

Also cleaned up the rear suspension parts, which came out way nicer than I expected them to.




The motor got a temporary "rattlecan-rebuild".  Also mounted my cam cover which was engraved by a friend of mine who was killed in a motorcycle wreck last year.  I've had it on a shelf since '09, haven't put together a bike worth mounting it on til now.






About this time I got the frame back and managed to start assembling that.  The tank and fender took longer, in fact they were just finished about 10 days ago.






Also, mostly because I can, I made a set of tapered plugs to press in my new AllBalls bearing races:




And shortly after that the bike was a roller!

[JLeather]

At this point my buddy Matt came over again and wired the bike.  He did a killer job, but unfortunately I don't have any pics.  I stole a nice little custom speedo out of his stash of parts (all his parts are in my garage) and he wired it up fully functional.  Hi beam indicator, neutral light, oil light, etc all from scratch.  Also a solid state reg/rec unit.  It's all tucked away nicely.

Then it was waiting on paint.  I got a few in-progress shots from the painter so I'll post those.

Flake carrier and prism flake:



First round of tape:



More tape:



Now, all I told him was "make it look 70's".  He did this whole kandy job in one night, like 17 straight hours, and this is what I got:

[JLeather]

So, in case you couldn't tell, the name of the bike ended up coming from the tank paint.  It was gonna be called either "Night Moves" or "Burt Reynolds" (because what's more 70's than Burt Reynolds?) but after seeing the finished tank the choice was obvious.

And here she is in all her glory:




Matt came over the following Saturday morning with carb gauges and we proceeded to sync and rough-in the carbs before the shakedown run.



Speaking of which, the bike is running a really cool set of SteelDragon airboxes and the ARD magneto:




Here we are out on the test run:




and here we are returning successfully home 80 miles later:



I almost lost the front motormount bolt.  Both nuts disappeared and the bolt made it 6" out one side before we got home.  Aside from that and a few other growing pains the bike has performed very well.  I have just over 700 miles on it since last Saturday.  We went to NC and rode the "Snake" 2-up and had a blast.






The carbs are still a bit lean at 120's with the needles all the way up (rich).  It's also still really cold-natured but that could just be the permanent 34 degrees of ignition advance   All in all I'm happy, and that's what matters most.  I wlak out into the garage and can't help but smile.  Now, onto the next one.

[andy750]

Looks excellent and the paint job really makes it! I have always wanted a Savoir framed chopper! Very jealous

Enjoy the bike!
cheers
Andy

[seanbarney41]

very cool bike...I like these quick build threads

[754]

Looks cool, did you have troublegetting the mag to work? Start easy..?

 Cool WebleyVickers flat four in the background..

[lwahples]

Came out good! Thanks for sharing.

[toytuff]

Boy, these chopper threads are firing me up! There is one of those frames for sale in PHX but no title and high price.

Great bike. 

tt

[JLeather]

754, actually I'm having a little trouble tuning the carbs.  It's close, but it's hard-starting and has an off-idle stumble for just a second.  It acts like it gets too rich just off idle, but my plug chops at mid-throttle and WOT look good.  I ended up with 120's and the needles all the way rich before it tuned up in the mid-range.  I have 2 theories.  I might need 125's, and I've richened up the needles to make up for part-throttle issues with the main.  This could be giving me too much fuel at just-off-idle.  I could also need to plug the idle screws and I've richened up the needles to compensate for too much air from the screws at off-idle.  Right now what I have to do is kick it at full choke with no throttle and if it starts and stays running I ahve to kind of roll the throttle on while I take the choke off.  If I crack the throttle with the choke on the bike dies immediately, and if I crack the throttle while I kick it the bike won't even try.  So it's just right on the idle mixture, but it's too rich just off-idle.  The mag is locked at 34 degrees and I'm sure that's some of my trouble, but I think I can get closer than this with some more tuning.  The electric start is useless right now.  The mag fires enough to kick out the starter gear but not enough for the engine to catch, so it'll crank a rev or two and then start grinding.


The vw-bike is a local creation.  Story I got was that a guy in MD built a couple of these back in the 70's as sort of a side business.  It's got a mish-mash of parts, IIRC the exhaust boxes are Willis and the trans adapter is a homemade piece turned on a lathe.  It was well done for one of these conversions, using parts of other BMW frames to extend it (I've seen some with angle-iron or round tube and bondo instead of proper BMW oval tubes).  It's a '67 that was built in '71 (based on the '71 builder's title).  I bought it off a friend of my father's a couple years ago, he's owned it for probably 25 years and it spent most of that time in a *relatively* dry barn.  So far I've rebuilt the trans and ridden it a little, still needs all new wiring and eventually a new engine.  I had to fudge a bit and take out the flywheel gasket to get the crank endplay back into spec.  Needs new bearings on the crank.

[SOHC Digger]

I hate when I stumble across a kick-ass build thread that has been here all along.  How have I missed this?  Excellent bike, JLeather! Love the frame and the tank came out beautiful!

[JLeather]

So, a chopper is never really "finished".  Tonight I took mine apart again.  Way apart...  A bit of backstory, a couple years ago I was deep into a turbo motor build for a CB750.  It was before I even owned this bike.  The motor got out of hand; carillo rods, custom forged low-cr pistons, seriously ported head, etc, etc.  I ran out of money, and decided I just wanted to build a simple stock-ish bike so I sold the motor and the turbo kit (actually I sold two different turbo kits to two different guys).  A couple months ago one of the kits I used to own popped back up for sale on the forum and I snapped it up.  It came with a turbo that isn't quite correct, but I had held onto a rebuilt Rayjay B-series along with some other choice parts even when I got rid of most of my turbo bits.  The plan is to throw it on the savior, with the stock motor and just a couple pounds of boost for fun.  Here's where she stands tonight:











The piping is Mr Turbo I'm fairly sure.  The ATP pipe is log-style and won't clear an Amen frame, but this fits fine.  The manifold is ATP.  The turbo shown is a Rayjay F and it's clocked wrong for the feed and drain, plus it's a bit bigger (not physically, just the A/F ratio) than the correct B-series I've got stashed away in the attic.  The pipe hits the cylinder fins on the corner which is what's pushing it off to the side a bit.  Beyond that, the bike needs a new ignition (mag isn't consistent enough for this IMO), and an oil tank with clearance for the turbo.  Then the bike needs a lot of rewiring.  Hope to have it done by the summer...

[madmtnmotors]

Found some gross surprises in the motor.  Someone tried to port-match it with a chisel it looks like:

LOL!

I think you've got a later model engine, either a 75/76F or 77/78K model. I've got heads on the bench right now from an example of each and the intake ports are identical to what you have there (and each other). I think there was some basic porting done at the factory on the later engines, and yeah, it looks like the guy doing it was drunk and the tools were dull!   

Good looking chop, glad you're making it your own! 

[seanbarney41]

yup, that is typical for K2 and later bikes...Hondaman calls it "the swipe"

[JLeather]

The motor is a '71, bur I'm sure it's had at least one topend (and it's overdue for another).

[andy750]

I cant wait to see how this turns out! A turbo chopper! Cool!!

[JLeather]

Well, the turbo didn't end up working out.  I put the bike back together minus the mag and rode it for the last couple years.  Last year me and a buddy did a good long ride on the Blue Ridge Parkway.  As noted in my last post the bike could've used a new top-end back in 2016.  On the last day or so of the trip the bike developed a valve tick.  A couple weeks after that I got hit by a car on my 550.  So here it is, summer again, and I need to get the chopper back on the road.  Since I had to pull the engine anyway I finally got the frame raked another ~5° so I could run a 10"-over CCW girder I picked up.  The girder is cool because it was factory ordered back in the day to accept a stock CB front wheel and brake.

Found the topend tick.  The bike seems to have wiped out both the intake and exhaust rockers and lobes on #4.  The motor was pretty tired anyway so I'm gonna put an 836 kit in it, rebuilt head, and a mild cam.  I also need to figure out why the starter only manages to catch half the time and sounds like a bag of rocks.  I already swapped the starter itself out to no improvement.  Gears look good, must be something in the one-way clutch behind the stator.

[JLeather]

Pics that didn't upload to the last post.

[Don R]

 I love the new rake and forks, the engine problem sucks, sorry to see that. .
  I stumbled on a turbo bike myself, it's in totes mostly. Raked 10* over stock but it's more of a drag bike style rather than a chopper. I plan to see how low it can go with the exhaust over the side rather than under it. It also has a late type ARD mag. I plan to test it on a known running engine.

[Gurp]

Idk how you feel about shipping but there a few a few hours from me who seeks down SOHC4 motors. He's on FB as Drew's Vintage Cycle.