Author Topic: 1978 CB750K skill builder (read: low budget)  (Read 10734 times)

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Offline Davez134

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Re: 1978 CB750K skill builder (read: low budget)
« Reply #150 on: August 06, 2018, 07:35:31 am »
You got some skills, Dave.

Thanks Don! Hey, did you see the post above my last one? About the rear sets? Any input or ideas?

Offline Stev-o

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Re: 1978 CB750K skill builder (read: low budget)
« Reply #151 on: August 06, 2018, 07:44:53 am »
You got some skills, Dave.

+1.  Good time to have some foam insulation sprayed in that ceiling.

As far as your brake issue, could you install spacer to have it out farther so as not to hit the shaft?

'74 "Big Bang" Honda 750K [836].....'71 Honda 750K project.....'76 Honda 550F.....K3 Park Racer.....K5 Fiddy Dolla Special!......CB500 Fiddy Dolla Special too!!............plus plus plus.........

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Re: 1978 CB750K skill builder (read: low budget)
« Reply #152 on: August 06, 2018, 08:26:49 am »
You got some skills, Dave.

Thanks Don! Hey, did you see the post above my last one? About the rear sets? Any input or ideas?

Hey Dave,

I missed seeing that earlier post about the rear set brake lever interference with the spline.  If you want to keep the same peg position, I think you'll need a modified brake arm that curves below the spline and comes back up.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2014 MV Agusta Brutale Dragster 800
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold

Offline algophobe

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Re: 1978 CB750K skill builder (read: low budget)
« Reply #153 on: August 06, 2018, 09:38:04 am »
beautiful work! btw, any interest in doing remodels in socal? business is boom and can't seem to get people to come a do remodels out here. they would come to give estimates and then flake and not even all us with the numbers.
Honda cb750 café 1972 "Satmui"
Kawasaki zx6r 2005 "Garuda"
Kawasaki zx7r 1998 "Dharma" (stolen)
Honda Magna V4 1982 (sold)

Offline Davez134

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Re: 1978 CB750K skill builder (read: low budget)
« Reply #154 on: August 06, 2018, 02:39:35 pm »
Thanks for the replies guys. I think I'll make a spacer first and see how that works out. If not I'll go with a lever that goes under the shaft/spline.

Offline Davez134

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Re: 1978 CB750K skill builder (read: low budget)
« Reply #155 on: August 06, 2018, 02:42:24 pm »
beautiful work! btw, any interest in doing remodels in socal? business is boom and can't seem to get people to come a do remodels out here. they would come to give estimates and then flake and not even all us with the numbers.
Thanks! I barely have time to do my own place, let alone try and take up jobs in another state. The construction industry is booming out here too. This is what my wife does for business. She's a designer who does complete remodels. She can barely get her good contractors to stay on schedule because of all the work!

Offline Stev-o

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Re: 1978 CB750K skill builder (read: low budget)
« Reply #156 on: August 06, 2018, 03:22:20 pm »
beautiful work! btw, any interest in doing remodels in socal? business is boom and can't seem to get people to come a do remodels out here. they would come to give estimates and then flake and not even all us with the numbers.
Thanks! I barely have time to do my own place, let alone try and take up jobs in another state. The construction industry is booming out here too. This is what my wife does for business. She's a designer who does complete remodels. She can barely get her good contractors to stay on schedule because of all the work!

I have the same issue at work [I'm a project manager].  Austin is booming and everyone in the construction trade is slammed, I have to bug my subcontractors to send me the bids.
'74 "Big Bang" Honda 750K [836].....'71 Honda 750K project.....'76 Honda 550F.....K3 Park Racer.....K5 Fiddy Dolla Special!......CB500 Fiddy Dolla Special too!!............plus plus plus.........

Offline algophobe

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Re: 1978 CB750K skill builder (read: low budget)
« Reply #157 on: August 06, 2018, 04:19:26 pm »
beautiful work! btw, any interest in doing remodels in socal? business is boom and can't seem to get people to come a do remodels out here. they would come to give estimates and then flake and not even all us with the numbers.
Thanks! I barely have time to do my own place, let alone try and take up jobs in another state. The construction industry is booming out here too. This is what my wife does for business. She's a designer who does complete remodels. She can barely get her good contractors to stay on schedule because of all the work!

I have the same issue at work [I'm a project manager].  Austin is booming and everyone in the construction trade is slammed, I have to bug my subcontractors to send me the bids.
I just bought a house in our downtown built in 1910 that's split into three units for my parents (a great investment for aging parents who HAAATE each other). Pretty well kept considering its over 100 yrs old. need some work for updating and building out of the studio into a 1 bedroom garage. This garage is phenomenal in size with rolling industrial metal garage doors. wish it was part of my house. its very been difficult to find someone to see it. anyways my apologies for thread jacking.
Honda cb750 café 1972 "Satmui"
Kawasaki zx6r 2005 "Garuda"
Kawasaki zx7r 1998 "Dharma" (stolen)
Honda Magna V4 1982 (sold)

Offline timmytim

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Re: 1978 CB750K skill builder (read: low budget)
« Reply #158 on: December 03, 2018, 01:21:09 pm »
I'm having the same problem with my current build with the brake contacting the spline on the cam. I have the same Cognito brackets with Tarozzi rearsets. If I try and space them out with a spacer I run out of thread on the rearset to tighten down on the back. Anyone solve this issue with the same set up?
67 Puch 250 SGS
71 CB350
75 CB550
76 CB750
04 CRF230
07 CRF150
Doodlebug 6.5HP Minibike

Offline Davez134

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Re: 1978 CB750K skill builder. Almost done, electrical help!
« Reply #159 on: December 20, 2018, 10:30:35 am »
I've had time this week to finish up this project. I had to remove and clean the carbs again since it had sat for so long. got it all buttoned up and went to start it. I noticed a smell after hooking up the battery, like something was hot. I felt the fuse holders and they were so hot they burned my hand (this is with the key out of the ignition, nothing powered on!) after just sitting there the battery voltage dropped to under 11v in just over a couple minutes. I don't even know where to start ( I did clean all the fuse contacts and put new ones in ) As soon as I get this figured out, the bike is done!

Offline madmtnmotors

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Re: 1978 CB750K skill builder (read: low budget) Electrical help!
« Reply #160 on: December 20, 2018, 10:53:28 am »
You have a dead short. Disconnect the battery and do not reconnect it until you find the short.
TAMTF...


Wilbur



My most recent project "Evolution": http://forums.sohc4.net/index.php?topic=100352.0
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
                                           http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
                                           http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                           http://oldmanhonda.com/MC/wiring750K1.html
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279

Sent from my Tandy TRS-80!

Offline Davez134

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Re: 1978 CB750K skill builder (read: low budget) Electrical help!
« Reply #161 on: December 20, 2018, 12:59:17 pm »
Ok. Yeah, battery is disconnected. Not sure where to start. I guess I’ll disconnect everything and start over.

Offline Davez134

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Re: 1978 CB750K skill builder (read: low budget) Electrical help!
« Reply #162 on: December 20, 2018, 03:56:35 pm »
The fuses stop heating up when I unplug the 3 yellow wires coming from alternator. I don’t know what to look for with my meter, so I just started removing connections until the fuse stopped getting warm. So far I’ve disconnected headlight, tail light, ignition switch, turn signals. (They are still all disconnected, fuse still got warm until I disconnected yellow alternator wires)

Offline madmtnmotors

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Re: 1978 CB750K skill builder (read: low budget) Electrical help!
« Reply #163 on: December 20, 2018, 07:51:19 pm »
Ack! Your methods could very well have led to more damage and/or spectacular failure/meltdown of the battery itself. Connecting the battery and using the overheating fuse block as a measure of function is a recipe for disaster. To find a dead short is simple, first you DISCONNECT THE BATTERY then you take your meter/continuity tester and start checking every wire that would normally be carrying 12+ for continuity to ground.

EZPZ  8)

Sounds like you have narrowed the culprit, however unwittingly, down to the stator, rectifier, or both. Start testing these components per the manual to see if either of these fail their prescribed tests. You could still have a "hot" wire connected to ground, so carefully inspect your connections as you move forwards with troubleshooting before reconnecting the battery.
TAMTF...


Wilbur



My most recent project "Evolution": http://forums.sohc4.net/index.php?topic=100352.0
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
                                           http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
                                           http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                           http://oldmanhonda.com/MC/wiring750K1.html
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279

Sent from my Tandy TRS-80!

Offline Davez134

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Re: 1978 CB750K skill builder (read: low budget) Electrical help!
« Reply #164 on: December 20, 2018, 07:57:54 pm »
Battery is out and disconnected. I will start checking continuity in the morning. Thanks.

Offline Stev-o

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Re: 1978 CB750K skill builder (read: low budget) Electrical help!
« Reply #165 on: December 21, 2018, 07:56:12 am »
Hey Dave...check the stator wires where they pass through the case/cover opening. 
I once had a wire pinched there that caused my issue.
'74 "Big Bang" Honda 750K [836].....'71 Honda 750K project.....'76 Honda 550F.....K3 Park Racer.....K5 Fiddy Dolla Special!......CB500 Fiddy Dolla Special too!!............plus plus plus.........

Offline Davez134

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Re: 1978 CB750K skill builder (read: low budget) Electrical help!
« Reply #166 on: January 04, 2019, 05:28:48 am »
Hours with the multimeter an I found the cause. The wires from the Pamco ignition were lightly rubbing on the nut at the end of the advancer shaft and it finally wore through the jacket of the wire.

Offline Davez134

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Re: 1978 CB750K skill builder (read: low budget) Electrical help!
« Reply #167 on: January 07, 2019, 04:33:53 pm »
It’s finished. Rode it today for about 10 miles, then my buddy picked it up. It was fun, but I still like my K2 better





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Offline Stev-o

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Re: 1978 CB750K skill builder (read: low budget) Electrical help!
« Reply #168 on: January 07, 2019, 05:03:01 pm »
Nice job, I like it!

Was going to nominate you for BOTM but I believe you must be in possession of the bike...
'74 "Big Bang" Honda 750K [836].....'71 Honda 750K project.....'76 Honda 550F.....K3 Park Racer.....K5 Fiddy Dolla Special!......CB500 Fiddy Dolla Special too!!............plus plus plus.........

Offline Davez134

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Re: 1978 CB750K skill builder (read: low budget) Electrical help!
« Reply #169 on: January 07, 2019, 05:35:39 pm »
Nice job, I like it!

Was going to nominate you for BOTM but I believe you must be in possession of the bike...

I finished it and gave up possession in the same day haha. I needed the space in my shop, so I just busted my butt to get it done this week. I'll have him take some pictures of it in the sunlight because the pearl orange really stands out in good light.

Offline seanbarney41

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Re: 1978 CB750K skill builder (read: low budget) Electrical help!
« Reply #170 on: January 07, 2019, 05:43:25 pm »
hell yeah!
If it works good, it looks good...

Offline Davez134

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Re: 1978 CB750K skill builder (read: low budget) Electrical help!
« Reply #171 on: January 07, 2019, 08:59:42 pm »
For those just looking at this for the first time, check out the beginning of the thread. This started as a 78 K bike


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Offline SOHC4 Cafe Racer Fan

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Re: 1978 CB750K skill builder (read: low budget) Electrical help!
« Reply #172 on: January 07, 2019, 09:35:07 pm »
Great bike, Dave. I, too, prefer your K2, but this is fantastic work. Your buddy must be stoked.
1975 CB550K1 "Blue" Stockish Restomod (http://forums.sohc4.net/index.php?topic=135005.0)
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (http://forums.sohc4.net/index.php/topic,150220.0.html)
2014 MV Agusta Brutale Dragster 800
2016+ Triumph Thruxton 1200 R (http://forums.sohc4.net/index.php/topic,170198.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (http://www.latexnet.org/~csmith/sausage.html)

Sold/Emeritus
1973 CB750K2 "Bionic Mongrel" (http://forums.sohc4.net/index.php?topic=132734.0) - Sold
1977 CB750K7 "Nine Lives" Restomod (http://forums.sohc4.net/index.php?topic=50490.0) - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold

Offline Davez134

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Re: 1978 CB750K skill builder (read: low budget)
« Reply #173 on: January 18, 2019, 05:33:20 pm »
I have the bike back in my garage to fine tune the carbs. I talked him into ditching the pods and buying an airbox from Cognito Moto. This is really the first time I've messed with the PD carbs, so that's why it's back. He said it was having trouble starting the day after he got it home, and was really hesitating on acceleration. Plugs are black so I'm assuming it was really rich.  I may need some help from some experts on these carbs. I found a great rebuild thread that I worked off of and it really helped. I opened them back up and saw the main jets were 140's. Seems way to big. Anyways, more pics and results to come in the next week or so while I get this dialed in.
« Last Edit: January 18, 2019, 06:35:35 pm by Davez134 »

Offline Davez134

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Re: 1978 CB750K skill builder (read: low budget)
« Reply #174 on: February 09, 2019, 05:22:47 pm »
I finally started working on getting this thing running right. Here’s the setup so far. Hopefully I remember everything.
Stock head/cam/pistons.
Cognitions Moro airbox.
4 into 1 pipe (looks like a Carpy one)
PD carbs 35 slow jets, 130 main, IMS turned 1 3/4 out.
Just replaced the accelerator pump diaphragm due to a leak. 

I just vacuum synched them, re checked timing. All good. Idle is smooth, at about 1100. The problem is there is a huge flat spot from when I first roll on the throttle until over 1/2 throttle. I tried turning the mixture screws with no changes. Idle plug chop shows a light brown. No difference when I tried a plug chop holding 1:2 throttle while riding. I don’t have any experience with these carbs and I honestly don’t know where to go next. Main jets is my guess ? I don’t believe the needles are adjustable like my round tops right? Let me know if I’m missing anything.

Anyways here’s some pictures of it with the airbox and out in the sun




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« Last Edit: February 09, 2019, 06:04:08 pm by Davez134 »

 

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