Author Topic: 78 CB750F "Modular-ish" cafe build?  (Read 59346 times)

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Offline madScientist

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #200 on: July 01, 2013, 07:05:36 AM »
Rode about 200 miles yesterday....WOW! I've forgotten how much fun this thing is to ride!

I've been riding the "straight line" bike for so long I forgot how much fun dropping into corners is. On the VS1400 I say a quick prayer and drop in...on this thing i just lean and go!

I haven't been pushing it too hard as I'm still getting used to it but man this sucker is NIMBLE and QUICK!

Phase 1 is almost complete. Still need to order the fork brace and rear shocks. Also want to rebuild and powdercoat the rear dual piston brake setup. This weekend I'm making the seat pan and dropping it at the upholsterer.

here's some more glamour shots:







« Last Edit: April 10, 2014, 05:45:06 AM by madScientist »
You CAN do great things...with enough beer.


78 cb750f
http://forums.sohc4.net/index.php?topic=113293.0
70 CL350 Street Tracker / Cafe
http://forums.sohc4.net/index.php?topic=125641.0
83 KZ1100ltd
76 GL1000
71 Kaw H2 (to be built)
77 cb750A (sold)
74 cb125s (sold)

Offline brandEn

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #201 on: July 01, 2013, 08:37:07 AM »
So those RS34's are working pretty good it sounds. I am still debating on getting those. Your bike sure looks good. Have you put the other seat on yet? Haven't seen that modular part of the build yet with the new paint!

Offline cheftuskey121

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #202 on: July 01, 2013, 08:37:18 AM »
wow man, absolutely gorgeous. is it done done? I want to nominate you for BOTM

Offline madScientist

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #203 on: July 01, 2013, 08:44:38 AM »
The RS34's are pretty pimp. They are a tad rich from the numbers on the wideband but, in all fairness, I haven't monkey'd with them much yet. I want to turn the screws in 1/2 turn or so to lean it out a little and set the accelerator pump to come in later. Their is definitely no shortage of power / fuel with them. I'm still in my break in cycle so i'm trying my hardest not to mess with them yet.

Chef -- She isn't done done yet. I'm going to get the seat pan setup and off to the upholsterer this weekend and shocks and stuff. Probably be another couple weeks until it's complete. Thanks for the upcoming nomination :-D

Branden -- I have another stock seat (it's perfect) but it's at my parents (3hrs away). I'm going to have them ship it down so that i can fit it up and check everything out.

I have to say too that without this site...the people, the information, the vendors...i could never have done this. I can't thank everyone here enough for helping.
You CAN do great things...with enough beer.


78 cb750f
http://forums.sohc4.net/index.php?topic=113293.0
70 CL350 Street Tracker / Cafe
http://forums.sohc4.net/index.php?topic=125641.0
83 KZ1100ltd
76 GL1000
71 Kaw H2 (to be built)
77 cb750A (sold)
74 cb125s (sold)

Offline cheftuskey121

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #204 on: July 01, 2013, 08:46:07 AM »
no problem, I'll be watching for when its done to nominate. I love everything about it. I want one ;)

Offline sethdhawkins

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #205 on: July 01, 2013, 08:57:43 AM »
Chase,

I'm gonna want some data, bubba! Bike looks seriously sweet.
All a man needs in this world is someone to love, if you can't give him that, give him hope, if you can't give him hope...just give him something to do!

1972-ish CB750K
1974 CB450
1974 CB360
1976 136' Ocean Going Tug

Offline tweakin

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #206 on: July 01, 2013, 03:27:43 PM »
Awesome MS!  Looks great and nothing beats the initial rip!

Offline madScientist

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #207 on: July 01, 2013, 06:45:17 PM »
Just got back from a ride sweeping 3000 - 6500. The wideband and my ears tell me she's running richer than I would like in that range. So I'm going to pull the clip up a position on the needles and see where it falls.

I also think the pump is hitting too early for my riding style so I'm going to back that out another turn or two.

These mikunis are like holley carburetors when it comes to tune-ability.
You CAN do great things...with enough beer.


78 cb750f
http://forums.sohc4.net/index.php?topic=113293.0
70 CL350 Street Tracker / Cafe
http://forums.sohc4.net/index.php?topic=125641.0
83 KZ1100ltd
76 GL1000
71 Kaw H2 (to be built)
77 cb750A (sold)
74 cb125s (sold)

Offline madScientist

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #208 on: July 08, 2013, 07:45:18 AM »
Made the seat pan this weekend. I'm partial to fiberglass. Not sure if anyone's ever documented on how to make a fiberglass pan so here's how I do it.

Mask off everything you dont want ruined :-D



Go to the hardware store and get some aluminum ducting tape and tape over the masking tape.



At this point, if you haven't already, put on some nitril gloves. You do NOT want this stuff on your skin. It's REAL sticky and will stay with you a long time. I'm pretty sure it isn't good for you either. And who wants to walk around with some fiberglass stuck to your fingers?

Use some paste type car wax and HEAVILY wax it (but dont remove the wax...leave it on there or else you're going to have a hell of a time peeling the finished glassing off).  Then cut some fiber glass fabric roughly the size you're wanting the finished pan to be however leave plenty of hang off. You're going to be trimming it to size later.



Cut some of the fiber glass matting into 2 x 4 inch strips and cut some into 2x2 inch squares. Mix up the resin. I use a foam brush to distribute the resin. I pore a good portion of the resin onto the fabric, spread it out, and then start layering the glassing in strips but make sure to overlap some. I make 3-4 layers which comes out to about 1/4" thick product. It's real firm after it drys. I let mine sit over night before final shaping.



After its dry pry it off carefully and shape it. To shape it I use a metal cutoff wheel. Sketch out the form and then cut on the lines. Then use a die grinder wheel to shape it further. For final shaping use a 100grit flap wheel.

I also setup the mounting points. I neglected to get a picture of the final product but will try and get one tonight. For mounting I'm using M6 bolts with 2 mounting points where I can reasonably get to them to remove the seat for accessing the cowel mounting bolt. To stick the bolts to the seat pan I used JB weld but you can also mix up some resin and use that.
« Last Edit: April 10, 2014, 05:45:33 AM by madScientist »
You CAN do great things...with enough beer.


78 cb750f
http://forums.sohc4.net/index.php?topic=113293.0
70 CL350 Street Tracker / Cafe
http://forums.sohc4.net/index.php?topic=125641.0
83 KZ1100ltd
76 GL1000
71 Kaw H2 (to be built)
77 cb750A (sold)
74 cb125s (sold)

Offline madScientist

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #209 on: July 08, 2013, 07:51:19 AM »
Oh and I played with the carbs this weekend.

Pulled the tops off because I wanted to lower the needles a little to lean it up. After pulling #2 I noticed the slide adjustment sitting in the cage !DOH!!

So I rebalanced the carbs this time making certain all adjusters were tight. I changed the needle clip to the #3 slot and took it for a ride. I had previously scaled down the accelerator pump to 1/2 throttle on 3/4 throttle off. Going on a ride it was much improved but whacking on it...it seemed it wanted more fuel.

So i set the accelerator pump to 1/4 on 3/4 off. Took it for a ride and when shifting from 4 - 5 and hammering it felt the front wheel come off. I think I'm getting close :-D

Here's the setup:

Air screws: 1 turn (wideband 12.8)
Needles: slot 3 (wideband avg 13.5)
Mains: 125 (i still haven't opened it up yet to see how it carries...probably do that this week at some point)
Acc pump: set to 1/4 open and pump all the way through 3/4 throttle

The wideband stays pretty consistent around the 13.5 marker which I think is pretty comfortable. I could probably lean it out a tad more. However I'm afraid moving the needles down another notch might put it a little too lean for my liking. Would prefer to not blow a hole in the pistons...
You CAN do great things...with enough beer.


78 cb750f
http://forums.sohc4.net/index.php?topic=113293.0
70 CL350 Street Tracker / Cafe
http://forums.sohc4.net/index.php?topic=125641.0
83 KZ1100ltd
76 GL1000
71 Kaw H2 (to be built)
77 cb750A (sold)
74 cb125s (sold)

Offline Retro Rocket

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #210 on: July 08, 2013, 03:08:18 PM »
I would have just used a generous amount of release wax on the seat base, no tape or foil at all.... Mask the rest off just like if you were painting stripes... ;)
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750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.

Offline sethdhawkins

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #211 on: July 08, 2013, 11:29:14 PM »
Chase, I loctited the synch screws, as mine rattled loose after a ride. Your carb setup sounds the same as mine, except I'm still fiddling with the pump for initial throttle response-still lean when I get on it hard. You must be having fun at this point ;)
All a man needs in this world is someone to love, if you can't give him that, give him hope, if you can't give him hope...just give him something to do!

1972-ish CB750K
1974 CB450
1974 CB360
1976 136' Ocean Going Tug

Offline madScientist

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #212 on: July 09, 2013, 05:27:52 AM »
I'm having a BLAST!!!

It's been a long time since i've ridden a quick light weight bike and forgot how much fun it is!

I have lots more testing to go on those carbs but that setup is close. I was amazed to hear how much the exhaust note changed after I leaned it out. Before it was a little "blatty" and obnoxious but now it's a nice mellow, rich tone...until I romp on it.
You CAN do great things...with enough beer.


78 cb750f
http://forums.sohc4.net/index.php?topic=113293.0
70 CL350 Street Tracker / Cafe
http://forums.sohc4.net/index.php?topic=125641.0
83 KZ1100ltd
76 GL1000
71 Kaw H2 (to be built)
77 cb750A (sold)
74 cb125s (sold)

Offline HonderCB

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #213 on: August 02, 2013, 05:07:22 PM »
awesome build man!  I cant believe I haven't seen this thread until now.  Its always nice to see someone else in the StL area on this board (especially someone with an F model.)  Your SS looks killer, hopefully I get to see it in person sometime at one of the vintage bike nights in the city.  There is at least one other guy on this board who goes to them too.  I haven't been in a couple months (been busy) but plan on getting to a couple more before the season is over.

Good luck getting everything buttoned up!
-Scott, just a F'er from Illinois-

77' CB750F
81' CB650C - SOLD

Offline madScientist

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #214 on: August 12, 2013, 05:54:00 AM »
And I'm back!

Thanks Honder! It's been a LOT of fun building. When and where are the vintage bike nights? I'll hit one up!

I've only been back in town for a couple days but since then I've put on the new Ikon's and lowered the needles a little more. I dont think I like the needles in the #2 slot. I think I put it over the edge of lean so I'll be reversing that tonight.

I have to take a short hiatus to button up my 66 mustang rear suspension. Had to fix frame rails and put in new springs to handle the power boost I'm giving it this winter.

ALSO!! I have my next motorcycle project in hand! My wife's brother collects bikes (old dirt racers) and parts out bikes. He's had a 70 CL350 I've been trying to talk him out of for awhile now and he finally relented! It's in pretty solid condition and I plan on making a street tracker out of it. But first...get all the other projects done :-D
You CAN do great things...with enough beer.


78 cb750f
http://forums.sohc4.net/index.php?topic=113293.0
70 CL350 Street Tracker / Cafe
http://forums.sohc4.net/index.php?topic=125641.0
83 KZ1100ltd
76 GL1000
71 Kaw H2 (to be built)
77 cb750A (sold)
74 cb125s (sold)

Offline Bankerdanny

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #215 on: August 12, 2013, 10:30:32 AM »
I have always loved the scramblers.
"The problem with quotes on the Internet is that you never know if they're true" - Abraham Lincoln

Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki K10 80, '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline tweakin

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #216 on: August 12, 2013, 01:54:58 PM »
Great news about the CL, I love riding around on the 76cl360 I recently built.

Offline HonderCB

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #217 on: August 13, 2013, 03:33:47 PM »
And I'm back!

Thanks Honder! It's been a LOT of fun building. When and where are the vintage bike nights? I'll hit one up!


The first Monday of each month (except next month i think its on a Tuesday) they have a vintage bike night at the schlafly bottleworks in Maplewood, across the road from flying tiger motorcycles.  They have a facebook page if you want to look it up, its called "Vintage Bike Night Saint Louis."   They also have bike nights at the Moto Europa/Triumph Grill on Locust St. in the city.  They post them on their facebook page as well (Moto Europa).  Hope to see ya some time.
-Scott, just a F'er from Illinois-

77' CB750F
81' CB650C - SOLD

Offline snowman

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #218 on: August 13, 2013, 04:04:37 PM »
Made the seat pan this weekend. I'm partial to fiberglass. Not sure if anyone's ever documented on how to make a fiberglass pan so here's how I do it.

Mask off everything you dont want ruined :-D



Go to the hardware store and get some aluminum ducting tape and tape over the masking tape.



At this point, if you haven't already, put on some nitril gloves. You do NOT want this stuff on your skin. It's REAL sticky and will stay with you a long time. I'm pretty sure it isn't good for you either. And who wants to walk around with some fiberglass stuck to your fingers?

Use some paste type car wax and HEAVILY wax it (but dont remove the wax...leave it on there or else you're going to have a hell of a time peeling the finished glassing off).  Then cut some fiber glass fabric roughly the size you're wanting the finished pan to be however leave plenty of hang off. You're going to be trimming it to size later.



Cut some of the fiber glass matting into 2 x 4 inch strips and cut some into 2x2 inch squares. Mix up the resin. I use a foam brush to distribute the resin. I pore a good portion of the resin onto the fabric, spread it out, and then start layering the glassing in strips but make sure to overlap some. I make 3-4 layers which comes out to about 1/4" thick product. It's real firm after it drys. I let mine sit over night before final shaping.



After its dry pry it off carefully and shape it. To shape it I use a metal cutoff wheel. Sketch out the form and then cut on the lines. Then use a die grinder wheel to shape it further. For final shaping use a 100grit flap wheel.

I also setup the mounting points. I neglected to get a picture of the final product but will try and get one tonight. For mounting I'm using M6 bolts with 2 mounting points where I can reasonably get to them to remove the seat for accessing the cowel mounting bolt. To stick the bolts to the seat pan I used JB weld but you can also mix up some resin and use that.

Waiting to see the final product and the other pics of the mounting bolts. My seat is on its way and will need to make a pan once it arrives.

Looking good.

Offline madScientist

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #219 on: August 15, 2013, 05:26:06 AM »
Shoot sorry Snowman I'll get it tonight and post it tomorrow.

I richened the needles up a little because it was running lean in the mid's. However, this morning, at low idle (1500 (my idle) - about 3000), it sounds like there's a cylinder that's not hitting. I do know the Pamco that I have has the 2,3 lead too far advanced however 1,4 are spot on. When I had this problem before I had the whole bloody thing advanced too far so I guess I'll see if I can pull that 2,3 lead closer to the mark.

I think a combination of the 55 degree weather and the ignition advance might be contributing. The other thing to note is that before when this happened it ran fine in the afternoon when the weather warmed up. This weekend I'm making a plate to cover the oil cooler since I dont have a bypass. Hopefully that's enough blockage to raise the temp's a little in cooler weather. Since in MO it can be hotter than hell one day and then frigid cold the next...
You CAN do great things...with enough beer.


78 cb750f
http://forums.sohc4.net/index.php?topic=113293.0
70 CL350 Street Tracker / Cafe
http://forums.sohc4.net/index.php?topic=125641.0
83 KZ1100ltd
76 GL1000
71 Kaw H2 (to be built)
77 cb750A (sold)
74 cb125s (sold)

Offline madScientist

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #220 on: August 17, 2013, 09:35:26 AM »
Covering the oil cooler seems to have helped. All cylinders were firing great yesterday morning in 55 degree weather. I have since removed it since it's 85 now.

Picture of the seat pan...not pretty but should serve it's purpose:



This morning I "finished" the seat conversion. I quoted it because I want to weld the supports I made for the extended tail light bracket. Right now i just sheet metal screwed them. I recovered the seat a few weeks back in preparation for this. Everything bolted up like I expected it to. Alignment seems to be pretty good. I'm not super happy with how the tail light bracket is lined over the wheel...it's not perfectly straight and it's kind of annoying me but I'll roll with it for now. This should also stop the "when are you going to get a seat" questions from virtually everyone I meet. I contacted Seat Guy John in St Charles, IL to do the cafe seat since I haven't found anyone locally that I trust enough to do it. Plus with my schedule it's easier to mail it off to have done that drive somewhere...if you can believe that. Here are some photos of the conversion...let me know what you guys think or what I could change / do better.



The "HONDA" badge that goes on the rear cowel is painted and drying. But I do have it. I might strip the paint back off and polish it lightly like I did the tank badges








Quick side tangent and rant....i went to car show last night. Rode this bike. It was well received and I did a lot of BS-ing with people there. All-in-all it was a lot of fun. However why do Harley riders (oddly enough the crotch rocket guys didn't do this) want to race? Several people, with brand new (under warranty) Harleys badgered me to go run them up the street. First off I dont condone unsanctioned street racing...it's not only dangerous but a little stupid not to mention illegal. Second, your bike is under warranty...if you blow it up you can go get it fixed. If I blow mine up I have to fix it. Plus this is my only bike right now. I'm not going to risk blowing it up just so you can say you raced a cafe bike. Yes my bike is quick and I built it to be quick but I didn't build it to drag race. I built it to corner well, be reliable, and most of all be fun. So no...i will not "drag race" you. Stepping off soap box...

And here's a picture of the CL

« Last Edit: April 10, 2014, 05:47:00 AM by madScientist »
You CAN do great things...with enough beer.


78 cb750f
http://forums.sohc4.net/index.php?topic=113293.0
70 CL350 Street Tracker / Cafe
http://forums.sohc4.net/index.php?topic=125641.0
83 KZ1100ltd
76 GL1000
71 Kaw H2 (to be built)
77 cb750A (sold)
74 cb125s (sold)

Offline Zaipai

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #221 on: August 17, 2013, 09:43:51 AM »
Great looking bike, love the colors and the mods..!

.: Scott :.
Its my Avatar..

75 CB550F  | 


Offline brandEn

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #222 on: August 17, 2013, 12:27:05 PM »
Looks great man.

Offline madScientist

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #223 on: August 17, 2013, 01:33:34 PM »
Thanks guys. The stock seat feels WAY different than the cowl. Aside from my touche not falling asleep it's also about 3 inches taller. Takes a bit to get used to thats for sure. Plus my short, stubby little legs are almost on tip toes.
You CAN do great things...with enough beer.


78 cb750f
http://forums.sohc4.net/index.php?topic=113293.0
70 CL350 Street Tracker / Cafe
http://forums.sohc4.net/index.php?topic=125641.0
83 KZ1100ltd
76 GL1000
71 Kaw H2 (to be built)
77 cb750A (sold)
74 cb125s (sold)

Offline RainsongCB750F

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Re: 78 CB750F "Modular-ish" cafe build?
« Reply #224 on: August 23, 2013, 11:02:02 AM »
I am in love with this bike. Truly beautiful work my friend.
1978 CB750F
When Jesus comes back he will ride an SOHC4.