Topic: Phaedrus: CB750 RestoMod - Update: 09/23/21 w/ new video

[MCRider]

Again..

Nice pics and dialogue Ron.  That old porting job you have there looks just fine to me.  I tend to agree that a little roughness..rather than mirror finish seems to result in more predictable performance.  Guess it depends on the type of carbs used..as well as distance between carbs and valves. I always felt that if in doubt..a more thorough mixture getting into the cylinders was preferable to absolute maximum flow.  In any event..your mods can't help but be an improvement over stock..I feel.

I'm starting to get impatient to see Phaedrus II's engine come together..

Later,

Al

Thanks for the comments! I have enough experience with different heads to think, like the Branch Flowmetrics article alludes, any porting job is beneficial (as long as its not a hack job). Branch actually said something like the most latent horsepower of the CB750 is locked up in the head.

I will be using Mikuni Smoothbore 29s. I had these on Phaedrus I and with a minimal of effort they worked perfectly. Little choke on start up, quick warmup, and no flat spots throughout the rev range. Not to say others would not do the same or better, I just have these and know they work.

AS far as impatience ME TOO. APE just called and told me my tranny is done. They said all parts were in good shape and they undercut the upshifts from 1-2,2-3,3-4, and the 3-2 downshift. It will be back to me in a week.

Coincidentally, I just got back from UPS shipping off my crank to APE. It was already lightened balanced and knife edged from P I, but it has some miles on it. They will inspect it and if its OK, they will install the APE/Crower rods and ship it back.

Bit by bit....  

[Terry in Australia]

Head came off of a parts bike, don't know the K model of origin. (Any way to tell?) The sealless exhaust guides were installed by choice as all 8 guides are new. They get removed in the porting process.

I gotta admit, I like having parts around, and trick with a story is better. I had a cam chain tensioner built by a machinist in Seattle for my CB77. He takes the original, removes the old brittle wheel (in my case, the worn out seized wheel) and replaces it with a fresh one from a current Kawasaki and installs a needle bearing instead of the original brass bushing. Very trick.

G'Day Ron, I just looked again and realized that yours isn't a K0 head (the K0 head has one less drilling in front of the cam chain tunnel) but other than that, I wouldn't know what model yours is off.

I love that old stuff too, apart from my K0, I've got a K1, K2, K3 and F2, and enough bits to build a couple more. I love trick parts and have been fortunate enough to amass a big pile of aftermarket parts like big cams, big bore kits, 29mm Mikuni smooth bore carbs etc, and my latest acquisition is a genuine Yoshimura 4 into one street pipe, in remarkably good condition that a local guy swapped me for my old 4 into 2, because the Yosh made his center stand redundant. Not sure what I'll do with it all, but I do like looking at it, ha ha! Cheers, Terry.

[MCRider]

Head came off of a parts bike, don't know the K model of origin. (Any way to tell?) The sealless exhaust guides were installed by choice as all 8 guides are new. They get removed in the porting process.

I gotta admit, I like having parts around, and trick with a story is better. I had a cam chain tensioner built by a machinist in Seattle for my CB77. He takes the original, removes the old brittle wheel (in my case, the worn out seized wheel) and replaces it with a fresh one from a current Kawasaki and installs a needle bearing instead of the original brass bushing. Very trick.

G'Day Ron, I just looked again and realized that yours isn't a K0 head (the K0 head has one less drilling in front of the cam chain tunnel) but other than that, I wouldn't know what model yours is off.

I love that old stuff too, apart from my K0, I've got a K1, K2, K3 and F2, and enough bits to build a couple more. I love trick parts and have been fortunate enough to amass a big pile of aftermarket parts like big cams, big bore kits, 29mm Mikuni smooth bore carbs etc, and my latest acquisition is a genuine Yoshimura 4 into one street pipe, in remarkably good condition that a local guy swapped me for my old 4 into 2, because the Yosh made his center stand redundant. Not sure what I'll do with it all, but I do like looking at it, ha ha! Cheers, Terry.

That Yosh pipe would be a treat!  I have a handmade (welded together from bits) replica of the CB900F BolDor pipe i will use on my cafe project, looks a lot like the Yosh. A guy named Robert Banes (RB Racing) made it. he's still in business but primarily with high performance Harley stuff. He sold it to me as he was getting out of the Jap stuff. I actually had it on Phaedrus I for a while, but not being able to use the centerstand was very unsuitable for a pseudo-touring bike. But it made good power and sound.

Parts is parts!

[MCRider]

Not too much to report. Sent the crank to APE on Wednesday (pics in previous posts). Took well over an hour to box it, address it, take it to UPS. Everything takes time.

Started in to polishing my rear hub. (pic of polisher in prior posts) The black cutting rouge was doing a nice job, coming close to the mirror finish the pro had put on it.  I was using the 8" wheel that came on the polisher.  So I was keen to change wheels and go finer on the rouge, but the spindle was 5/8, and the additional wheels I bought, also from Harbor Freight where i got the polisher, were at least 1". BUMMER. Didn't want to drive, had chores to do etc. Ended up getting some 6" wheels with a 5/8 center from LOWE'S, will try to get back on the polishing this week.

Here's my tubes and lower legs I'll be using. the tubes are from Forking by Franks. The box is dated Aug 1999, so yes this project has been stalled for a while. The tubes are 2" over stock to restore some ride height if needed with the 17" wheel. This is the "old style" front end with the movable bushings. I had it in my head that it was better than the newer ones, maybe not, but that's what i've got. I'll bet any of the forks with emulators are better than either as stockers. I have emulators in my 650 Hawk what a difference. But they weren't period.

Here you'll see the bushings. The bottom one is green, this is industrial teflon coating. The inside of the top one is green also, teflon (can't see it). Very slick and the extra thickness, while very thin, serves to take up any slop.

Here is the Kawasaki ZL900 fender I'm hoping can be made to fit. Its for an 18" wheel and being short may look OK on a 17 incher. We'll see, I'm not firm on it yet.


See my post in SOHC/4 about the fork dust covers for K1s, and about putting a CL450 tank on a 76F.

[Terry in Australia]

Where are the pics Ron?

[MCRider]

Where are the pics Ron?

For what?

You mean here: http://forums.sohc4.net/index.php?topic=41893.0

and here: http://forums.sohc4.net/index.php?topic=41359.0

?? 

[Terry in Australia]

Sorry mate, the pics of your forks and fender didn't come up last time, but I see them now. Honda made a nice chrome brace-less front fender for one of their 250 twins (with 18 inch front wheel) in the early 1980's, that'd probably look nice on your beastie? Like you, I'm not sure that the Kawasaki fender will work on your bike. Cheers, Terry.

[mkramer1121]

G'Day Ron, I just looked again and realized that yours isn't a K0 head (the K0 head has one less drilling in front of the cam chain tunnel) but other than that, I wouldn't know what model yours is off.

I love that old stuff too, apart from my K0, I've got a K1, K2, K3 and F2, and enough bits to build a couple more. I love trick parts and have been fortunate enough to amass a big pile of aftermarket parts like big cams, big bore kits, 29mm Mikuni smooth bore carbs etc, and my latest acquisition is a genuine Yoshimura 4 into one street pipe, in remarkably good condition that a local guy swapped me for my old 4 into 2, because the Yosh made his center stand redundant. Not sure what I'll do with it all, but I do like looking at it, ha ha! Cheers, Terry.

send it my way terry, i'll put it to good use!

[Terry in Australia]

send it my way terry, i'll put it to good use!

Ha ha, well of course I would love to send you that Yoshimura pipe mate, but it's too big for me to mail it to you? Oh well, I guess I'll just put it on my bike instead................... 

[MCRider]

Sorry mate, the pics of your forks and fender didn't come up last time, but I see them now. Honda made a nice chrome brace-less front fender for one of their 250 twins (with 18 inch front wheel) in the early 1980's, that'd probably look nice on your beastie? Like you, I'm not sure that the Kawasaki fender will work on your bike. Cheers, Terry.

That might be better for my "theme" as well. I don't want anything on it that wasn't available in the era that the bike was made, up to 1978. The ZL fender is 1985 or so. So I may not use it and look for an older Honda fender. I figure with help from a good machinist, nearly anything can be made to fit.

I know my rods weren't "made" pre-1978, but heavy duty rods were available, so it's the "spirit" in that case.

[mkramer1121]

send it my way terry, i'll put it to good use!

Ha ha, well of course I would love to send you that Yoshimura pipe mate, but it's too big for me to mail it to you? Oh well, I guess I'll just put it on my bike instead................... 

it got to Australia somehow, didn't it?   

[Terry in Australia]

Yeah mate, back in the days (before 9/11) when "sea mail" was still an option................. Damn you Osama!

[MCRider]

No updates today. Futzed around polishing my rear hub and I may actually be getting the hang of it. Experimented with some O-Rings to tidy up the Dust Covers on the Forks. But I've got some business to catch up on before taking a vacation to Pokagon State Park in NE Indiana. we go there every year this time. They have wireless internet so I may take my laptop and stay in touch.

My wife drives the school bus and the Fall Break is coming up. She loves driving the bus. We don't have kids so she has patience to lavish on them for what is really just a few minutes each day. Still more than many of them get at home.

I might get some pics posted before we leave Wednesday.

[Terry in Australia]

Have a good holiday Ron, and how about posting a couple of pics of Phaedrus I? I'd love to see it in more detail than your avatar pic? Cheers, Terry.

[MCRider]

Have a good holiday Ron, and how about posting a couple of pics of Phaedrus I? I'd love to see it in more detail than your avatar pic? Cheers, Terry.

The avatar was dubbed simply "the Black Bike" by my friends at the time. It was stolen in 1972.

Phaedrus I was created from the remains of Free Bird I, my 750cc road racer in 1980. It roamed the highways and byways as an 888cc "heavy tourer" (no hard bags though, just soft) till 1995 when the leaks from every conceivable orifice sidelined it. I'll get some pics. Gotta scan them in from an album. Pre-digital. It was fun and laid a lot of rubber. You've now got the remains of the front wheel.

[MCRider]

I'm finally back to work on Phaedrus II. Hard to believe 2+ weeks can slip by that quickly. vacation and personal stuff. So today, we had to clean up a bit, rearrange shelves etc. Found my 1968 CB77 seat, cleaned it and filed it away for next project, making room for current parts. It is the original and I've been offered more for the seat from restorers than I paid for the bike.

There's been a spare CB750 crank laying on my workbench for months, so we blew it apart, tagged and bagged it to open up some room on the bench. Should get my crank back from APE soon.

Dug out the rod box to ship out some I've sold and try to sell the rest.
Typed up the list of frame/swingarm mods for the machinist. Frame:
1   Straighten Left Front Engine Guard. Fill in slot and redrill at end of slot for 10mm motor mount.
2   Weld triangle motor mount onto right front engine guard.  Fill in upper mount slot and redrill at end of slot for 10mm motor mount.
3   Gas Tank: cut front u brackets to allow tank to move forward 3/16”. Weld stop tab.
4   Smooth and Fill all welds.
5   Steering Damper Bracket: A. Raise so angle of damper is same as angle of lower tree. B.  Move back so lower tree hits the original “lock to lock” steering stop points.
6   Rear Footpegs: Object: Footpegs mount lug welded on at same angle as adjacent frame tube. (Swept back about 45 degrees.)  Idea: Turn down rod to insert into frame hole. Drill peg mounting stub to fit peg as well. Weld onto frame.
7   Mufffler Hanger: tab on bottom side of right side footpeg rail. Ten mm hole with threads on backside? or through bolt.
8   Fill and smooth backside of right front motor mounts.
9   Oil Cooler: Weld mounting strap across front of frame as indicated with template. Drill mounting holes.
10   Front Rail Gussets: Weld tabs to frame with threaded backsides per template. Cut triangles gussets to bolt to tabs and removable frame rails.
Swingarm:
1   Remove tabs on left top. Smooth.
2   Fill and smooth old zerk fitting holes
3   Reposition brake stay mount if necessary. Remove and grind down old one, reweld new one.

A little Off Topic, my wife dressed up in costume to drive the school bus Friday morning. The elementary kids were scared and some wouldn't get on the bus at first.

[Terry in Australia]

Sounds good Ron, why do you want to move the tank forward though? Isn't there more chance of the forks denting it when you turn the bars from lock to lock?

Hey there are a few women in my neighborhood who look just like that pic, funny though, we don't celebrate Halloween.................. 

[MCRider]

Sounds good Ron, why do you want to move the tank forward though? Isn't there more chance of the forks denting it when you turn the bars from lock to lock?

Hey there are a few women in my neighborhood who look just like that pic, funny though, we don't celebrate Halloween.................. 

I was wondering if anuyone would catch that, I had nearly forgotten about it myself as i mocked up the tank a few months ago. Background: The K2 and earlier tank has the petcock on the right side. This is the only bike I've ever owned that did, and the only one I've known of that did. When I ride I always go to reserve before filling. But on a busy highway that means losing power AND taking one's hand off the throttle to switch to reserve, not fun surrounded by trucks at 80mph. So my goal was to switch to a later tank that has the petcock on the left, like all real motorcycles should. I figured there would be no further things to worry about. So I got a tank with a left petcock.

So I put a megadollar paint job on the tank before mocking it up. I put the tank on a few months ago and (pictures in this thread) ...the rubber hld down tab in the back won't loop over the tang, nor will the seat close! After much back and forth between the original K2 tank and the one I have now, its determined the newer tank sits further back on the frame, about 3/16". Maybe the newer frames have the mounts in front further forward, I don't know. Easiest thing for me it seems is to releave the "U" brackets on the front of the tank, probably with a cutoff wheel on a Dremel or some such and let the tank move forward to where the hold down rubber fits and the seat closes.

Anyone ever run into this?

[Terry in Australia]

Geez that's weird Ron, I couldn't resist the temptation, so I went out to my garage and tried a K6 (left hand petcock) tank on my K2 frame, with no problems.

I took the rear rubber hold down tab off and sat each tank on the frame (with the front rubber mounts in place) and they both sat in the exact same position. I've never heard of this problem before, and switching tanks is common with guys who install F2 carbs on K1-K3 CB750's.

I wonder if your new tank is somehow faulty? Either way, your suggested "fix" might work, the trouble I see is that the pieces you want to cut out are what stops it from sliding forward, which it might, under brakes with a full fuel load? You could counter this with the judicious use of some 10mm wide metal strap riveted (to avoid welding burns in your new paint) to the remains of the old "U" brackets, bent to form another "U", but back 3/16". What a shame that you've already painted it!

[MCRider]

Geez that's weird Ron, I couldn't resist the temptation, so I went out to my garage and tried a K6 (left hand petcock) tank on my K2 frame, with no problems.

I took the rear rubber hold down tab off and sat each tank on the frame (with the front rubber mounts in place) and they both sat in the exact same position. I've never heard of this problem before, and switching tanks is common with guys who install F2 carbs on K1-K3 CB750's.

I wonder if your new tank is somehow faulty? Either way, your suggested "fix" might work, the trouble I see is that the pieces you want to cut out are what stops it from sliding forward, which it might, under brakes with a full fuel load? You could counter this with the judicious use of some 10mm wide metal strap riveted (to avoid welding burns in your new paint) to the remains of the old "U" brackets, bent to form another "U", but back 3/16". What a shame that you've already painted it!

Thanks for the feedback. I truly don't know what's up with my tanks! Maybe I got holt of a CB450 tank? Anyway I compared my K2 up against the new mystery tank everywhich way but loose. Simply put the U brackets on the left petcock tank are placed further forward than on my K2!

YEs I do think it is fixable as mentioned and yes I have a plan to keep it from sliding forward, though i like your idea as good or better.

A lesson to all builders. If you take forever like I do, hold off the paint till last. I had mine painted years ago, before I knew the proper ways to prep an old tank. I used Muriatic acid inside and out. Cleaned the rust beautifully, but the flash rust came back quick. The paint is bubbling and I'm not sure if the tank will hold gas now or not.  Best to use a phosphoric acid based rust remover/metal treatment that leaves a primer chemical behind.

I won't worry about that till I'm further along. I can always use the Phaedrus I tank.

NOW, Hold still for the next post, coming soon!

[MCRider]

TA DAAA!!!


















Purdeee

The crank had already been lightened locally. Big Jay siad they got some more off of it (which is obvious to me) and balanced it closer. It'll spin up like a CBR!

[MCRider]

I got the transmission back a few weeks ago, no pictures as there is not much to see. I'll refer you to this APE page which explains undercutting. Rather than the standard cuts for the 4 upshifts, APE accommodated me with 3 upshifts; 1-2, 2-3, 3-4 and one downshift 3-2. I thought this made more sense as who ever missed a 4-5 upshift?
http://aperaceparts.com/transmissions.html

Scroll down for explanation.

[Terry in Australia]

That's beautiful Ron, I must go out to the garage and fondle my new Ape crank that's still sitting in a box there somewhere, ha ha!

Hey I was thinking about your tank dilemma, as I lay in bed while visions of sugar-plums danced in my head (well not really, but Christmas IS coming................) and it came to me that instead of cutting your tank at all, all you need to do is make up some new front mounting rubbers.

All you need is some solid rubber "bar" of the same diameter as the two front mounts (or even some alloy bar with some rubber, or even O rings wrapped around the OD to insulate them from the tank) and just drill the peg holes 3/16" "off centre". This will allow the tank to be moved forward without any other work involved.

If you can't find the right size rubber and you'd prefer aluminum and you'd like me to machine up a pair, (or maybe three in case you lose one) let me know? Cheers, Terry.

[mystic_1]

That crankshaft is a thing of beauty.  I'm suitably jealous

I had the same thought as Terry, modify the mounting rubbers.  You could test the theory by cutting some material off of some old mounting rubbers to see if that'll get you the clearance you need.

mystic_1

[MCRider]

Terry and Mystic: Thanks guys. I'm eggsited.

I'll try the rubber mount thingie. I think I have some extra rubber mounts.

I've never seen "rubber bar" but I've never looked, but I could even use wood, so I'll give her a go.