Author Topic: CB750K4. Light frame mod and performance upgrades.  (Read 27514 times)

0 Members and 1 Guest are viewing this topic.

Offline D-Ral

  • Enthusiast
  • **
  • Posts: 202
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #75 on: January 05, 2014, 07:09:48 PM »
I'm not really sure how kerf cuts could help in this instance. Would I attempt to sew within the cuts? I'm only making a pleated cover to wrap around higher density foam, so I didn't think I'd need to puff the pleats out too much.

I did kerf the higher density foam I have for when it bends at the end of the pan.



This a 78 CB550 that I'm working on with some friends of mine. In this one we made kerf cuts where the pan bends to cover the tank mount as well as at the tail. Sorry or the IG photo, I don't have the original.

Offline evanphi

  • Apparently I'm an
  • Old Timer
  • ******
  • Posts: 3,107
  • Rhonda the Basket Case
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #76 on: January 06, 2014, 04:52:22 AM »
You can try adjusting the thread tension on the sewing machine. Also, try a thinner, less dense foam, and then stretch that over the thick, comfy foam.
--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

She's a mix-matched (former) basket case, but she's mine.

CB750 Shop Manual (all years), searchable text PDF
Calculating the correct input circumference for digital speedometers connected to the original speedometer drive

Offline D-Ral

  • Enthusiast
  • **
  • Posts: 202
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #77 on: January 06, 2014, 09:29:49 AM »
I managed to get off work early, so I dropped by the fabric store and picked up some 1/4" foam in both low and high density formats to try. I also got some thin polyester to use as backing.

Offline D-Ral

  • Enthusiast
  • **
  • Posts: 202
CB750K4. Light frame mod and performance upgrades.
« Reply #78 on: January 06, 2014, 07:05:33 PM »
Seemed to work well until the thread jammed under the fabric again. I ended up breaking the gear that turns the bobbin teeth.

I could pay for the parts to fix my Singer, but I worry it will just happen again because it's not the right machine for the job. Or that the thread I'm using is #$%* or I'm using the wrong fabrics or all of the above. Or I could spend 200 bucks at an upholstery place. Either way, this is throwing my budget out of wack.

Ugh. How did I get from motorcycles to sewing machines? I think I'll take a break from the seat and concentrate on getting my foot controls mounted.

Offline evanphi

  • Apparently I'm an
  • Old Timer
  • ******
  • Posts: 3,107
  • Rhonda the Basket Case
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #79 on: January 07, 2014, 04:51:21 AM »
Oh no! Broken machines suck. You can always try thrift shops. They usually have some kicking around. Most important thing is to go slow!

EDIT: And use a nice heavy needle!
--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

She's a mix-matched (former) basket case, but she's mine.

CB750 Shop Manual (all years), searchable text PDF
Calculating the correct input circumference for digital speedometers connected to the original speedometer drive

Offline D-Ral

  • Enthusiast
  • **
  • Posts: 202
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #80 on: January 07, 2014, 05:45:02 AM »
Yeah. I ordered all of the gears on eBay for 20 bucks, which is pretty good. I'll do my best to rebuild it when they come in. If I haven't found an industrial machine locally to trade, I'll just give it a go again. I'm determined to make my own.

Offline evanphi

  • Apparently I'm an
  • Old Timer
  • ******
  • Posts: 3,107
  • Rhonda the Basket Case
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #81 on: January 07, 2014, 06:54:01 AM »
Know any old grannies to hit up for some sewing advice?
--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

She's a mix-matched (former) basket case, but she's mine.

CB750 Shop Manual (all years), searchable text PDF
Calculating the correct input circumference for digital speedometers connected to the original speedometer drive

Offline D-Ral

  • Enthusiast
  • **
  • Posts: 202
CB750K4. Light frame mod and performance upgrades.
« Reply #82 on: January 07, 2014, 09:59:11 AM »
Ha. My granny and mom told me I'd end up breaking my machine. That's the advice they had.

When I get  it fixed, I'll try the thinnest foam possible and I'll double check the thread I've been using. Plus, I'll get a leather needle and I'll move a lot slower. I think I was rushing it a bit.
« Last Edit: January 07, 2014, 04:25:16 PM by D-Ral »

Offline evanphi

  • Apparently I'm an
  • Old Timer
  • ******
  • Posts: 3,107
  • Rhonda the Basket Case
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #83 on: January 07, 2014, 11:50:59 AM »
Plus, I'll get a leather needle and I'll move a lot slower. I think I was rushing it a bit.

Thar's what ya need. With the heavy vinyl and foam it creates a TON of friction for the thread. Might be possible to get waxed thread?
--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

She's a mix-matched (former) basket case, but she's mine.

CB750 Shop Manual (all years), searchable text PDF
Calculating the correct input circumference for digital speedometers connected to the original speedometer drive

Offline D-Ral

  • Enthusiast
  • **
  • Posts: 202
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #84 on: January 07, 2014, 04:28:50 PM »
Yeah, I'll check that out. A fellow I met locally when I sold him some spare parts told me he uses a needle that is specifically for auto upholstery. Hmm. Another thing I'm going to check out is a roller presser foot. Seems like a good idea! I tried using a plastic foot, but that obviously didn't help much.

Another thing that I've noticed is that the longest stitch setting my machine has is 6 stitches per inch. Is that low enough?

Offline evanphi

  • Apparently I'm an
  • Old Timer
  • ******
  • Posts: 3,107
  • Rhonda the Basket Case
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #85 on: January 08, 2014, 04:47:53 AM »
Another thing that I've noticed is that the longest stitch setting my machine has is 6 stitches per inch. Is that low enough?

Well you don't want to go too low because of all the material you're working with. Going too low will just cause you to sew through bunched up vinyl/foam, which can cause binding, as you've found out.
--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

She's a mix-matched (former) basket case, but she's mine.

CB750 Shop Manual (all years), searchable text PDF
Calculating the correct input circumference for digital speedometers connected to the original speedometer drive

Offline D-Ral

  • Enthusiast
  • **
  • Posts: 202
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #86 on: January 13, 2014, 12:03:27 PM »
Finally finished grinding and sanding and then resized and mocked up my passenger mounts.



I contacted Rob at Bullit Customs on Friday. He told me my muffler and other stuff would be shipped out in the afternoon.

Also, for twenty bucks I purchased all new stainless hardware.



Not a bad price, I thought.

Offline Retro Rocket

  • Eggs are hard due too a
  • Really Old Timer ...
  • *******
  • Posts: 19,279
  • ROCK & ROLL
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #87 on: January 13, 2014, 03:37:47 PM »
I would sit my foot on those rear peg mounts and make sure they don't interfere with your front foot pegs and controls, they look to be sitting quite low and forward,, nothing wrong with mounting the rear pegs a bit higher, have someone sit on the bike and check for comfort and position....
750 K2 1000cc
750 F1 970cc
750 Bitsa 900cc
If You can't fix it with a hammer, You've got an electrical problem.

Offline snowman

  • Enthusiast
  • **
  • Posts: 114
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #88 on: January 13, 2014, 04:51:09 PM »
The stainless hardware you got, is it to replace all the bolts used on the frame and is it a prepackaged kit you bought?


Sent from my iPad using Tapatalk

Offline D-Ral

  • Enthusiast
  • **
  • Posts: 202
CB750K4. Light frame mod and performance upgrades.
« Reply #89 on: January 14, 2014, 09:21:37 AM »
I would sit my foot on those rear peg mounts and make sure they don't interfere with your front foot pegs and controls, they look to be sitting quite low and forward,, nothing wrong with mounting the rear pegs a bit higher, have someone sit on the bike and check for comfort and position....

With the previous seat and stock pegs, the most comfortable position for me was if I had my toes as forward as heel peg but a set a little lower. Basically, I want the toe peg of my rearsets beside the brake spindle. As it is, if I mounted my pegs to the passenger mount, the toe peg would hit the spindle, so I need to space then out. And yeah, it would be a bit forward. However the spacer plate, or whatever you want to call it, will allow my more mounting options than just right on the mount for the passenger pegs. My idea is to make an aluminum plate, and drill 'speed holes.' I'll thread a few if them so the rearsets will have some adjustability. The plate will be about a half inch thick so the toe peg will clear the spindle.
« Last Edit: January 14, 2014, 09:29:35 AM by D-Ral »

Offline D-Ral

  • Enthusiast
  • **
  • Posts: 202
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #90 on: January 14, 2014, 09:29:01 AM »

The stainless hardware you got, is it to replace all the bolts used on the frame and is it a prepackaged kit you bought?


Sent from my iPad using Tapatalk

I just made a list of every bolt I would need from the parts diagram and went to a local fasteners shop. Even got some extras. I'll probably need to go back and get some more that I have forgotten.

Offline snowman

  • Enthusiast
  • **
  • Posts: 114
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #91 on: January 14, 2014, 06:02:19 PM »
Thanks, the problem I'm having here in Montreal is all the fasteners shop I've contacted so far don't do retail or have a minimum buy, guess I will have to keep looking.


Sent from my iPad using Tapatalk

Offline evanphi

  • Apparently I'm an
  • Old Timer
  • ******
  • Posts: 3,107
  • Rhonda the Basket Case
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #92 on: January 15, 2014, 04:38:22 AM »

The stainless hardware you got, is it to replace all the bolts used on the frame and is it a prepackaged kit you bought?


Sent from my iPad using Tapatalk

I just made a list of every bolt I would need from the parts diagram and went to a local fasteners shop. Even got some extras. I'll probably need to go back and get some more that I have forgotten.

Who did you do this with in Halifax? I'm having trouble in Saint John. Maybe they do mail order from Halifax?
--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

She's a mix-matched (former) basket case, but she's mine.

CB750 Shop Manual (all years), searchable text PDF
Calculating the correct input circumference for digital speedometers connected to the original speedometer drive

Offline D-Ral

  • Enthusiast
  • **
  • Posts: 202
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #93 on: January 15, 2014, 02:14:04 PM »
It's called Transworld and they are on Waddell Avenue in Dartmouth. Super friendly staff.

Offline evanphi

  • Apparently I'm an
  • Old Timer
  • ******
  • Posts: 3,107
  • Rhonda the Basket Case
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #94 on: January 16, 2014, 04:42:25 AM »
Cool thanks.
--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

She's a mix-matched (former) basket case, but she's mine.

CB750 Shop Manual (all years), searchable text PDF
Calculating the correct input circumference for digital speedometers connected to the original speedometer drive

Offline D-Ral

  • Enthusiast
  • **
  • Posts: 202
CB750K4. Light frame mod and performance upgrades.
« Reply #95 on: January 31, 2014, 03:46:19 PM »
Alrighty. Haven't been updating much, but I've been doing #$%*. Sort of. I've decided against my previous idea for rearset mounts. I'll post up my new plan next time.

Currently, I'm working on my seat. Bought a new sewing machine, oiled and cleaned it all up and it works like a dream!

Decided to start by making a pleated seat cover. I originally wanted to add some panels to give it definition, but it seams (ha) easier to start this way.





So what next? How should I attach the pleated cover to the foam? Also, it looks like it'll be hard to do this without a panel of over the heel of the seat. I want cover the foam so that I can use Velcro to attach the finished seat to the pan. That way I can swap out a different seat later after I get some practice!
« Last Edit: February 23, 2014, 10:57:37 AM by D-Ral »

Offline evanphi

  • Apparently I'm an
  • Old Timer
  • ******
  • Posts: 3,107
  • Rhonda the Basket Case
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #96 on: February 03, 2014, 08:45:45 AM »
Unless you want a super loose, sloppy fit, you need something solid to tack to. You could put snaps in the underside of your current frame rails/pan, and then on the pleated cover, but with that you have to get the snaps just right.

Maybe a secondary hard pan? Make a couple if you want to replace a seat in the future.
Easiest way to get it smooth and tight is staples/rivets into a hard pan. That one could then get bolted through to the hard pan you have on there now.
--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

She's a mix-matched (former) basket case, but she's mine.

CB750 Shop Manual (all years), searchable text PDF
Calculating the correct input circumference for digital speedometers connected to the original speedometer drive

Offline D-Ral

  • Enthusiast
  • **
  • Posts: 202
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #97 on: February 03, 2014, 01:00:54 PM »
I hadn't even thought of a second solid pan. Good idea. However, if I use mild steel, will I not have to paint to prevent rust? Seems like a bit of a pain when you consider that this is all trial and error. I wonder if there is something else I could use... A pliable strong plastic, maybe.

Online calj737

  • Really Old Timer ...
  • *******
  • Posts: 21,034
  • I refuse...
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #98 on: February 03, 2014, 01:02:39 PM »
Aluminum. Won't rust, pliable, and lightweight. You can heat it with a torch to allow you to bend or shape it. Cuts easily with a jigsaw. Just use a fine tooth blade and some cutting fluid. And wear gloves and eye protection. Shavings are REALLY sharp.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline evanphi

  • Apparently I'm an
  • Old Timer
  • ******
  • Posts: 3,107
  • Rhonda the Basket Case
Re: CB750K4. Light frame mod and performance upgrades.
« Reply #99 on: February 04, 2014, 07:25:32 AM »
Yep, aluminium will work, or if steel is cheaper, just spray paint it!
--Evan

1975 CB750K "Rhonda"
Delkevic Stainless 4-1 Header, Cone Engineering 18" Quiet Core Reverse Cone, K&N Filter in Drilled Airbox
K5 Crankcase/Frame, K4 Head and Cylinders, K1 Carbs (42;120;1 Turn)

She's a mix-matched (former) basket case, but she's mine.

CB750 Shop Manual (all years), searchable text PDF
Calculating the correct input circumference for digital speedometers connected to the original speedometer drive