Author Topic: Hmmmm, I have been told to cut the springs  (Read 4052 times)

0 Members and 1 Guest are viewing this topic.

Offline Really?

  • I've come to the conclusion that I AM a
  • Really Old Timer ...
  • *******
  • Posts: 5,290
Hmmmm, I have been told to cut the springs
« on: October 28, 2008, 12:18:37 PM »
Hey Y'all.  A few of you have suggested to me to cut the front springs a couple inches to lower the front end further than sliding the tubes up the tree's.  I can dig that.

I cannot find springs already cut and Progressive does not have any.  I read through the forums here looking for a description or a picture of what they did to cut thier springs.

How are y'all cutting the springs?  Straight cut or making it flat across the top/bottom of the springs like I have seen on uncut springs.  Are y'all cutting the top or bottom (if it matters)?

What is your method and what are you cutting them with? 

I wonder what the spring rate is changed to once they are cut.
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline mlinder

  • "Kitten Puncher"
  • Really Old Timer ...
  • *******
  • Posts: 5,013
  • Stop Global Tilting now!
    • Moto Northwest
Re: Hmmmm, I have been told to cut the springs
« Reply #1 on: October 28, 2008, 01:19:04 PM »
In my opinion. cutting springs is not a good idea.
look at the ends of the spring they are flat to spread out the load... and you will lose stiffness.... which is low on stock springs (which I think you have).
Why do you want to cut them? (havent seen the thread where people are telling you to cut them.)
No.


Offline turboguzzi

  • Old Timer
  • ******
  • Posts: 4,088
Re: Hmmmm, I have been told to cut the springs
« Reply #2 on: October 28, 2008, 01:21:57 PM »
sorry, have to ask, who told you to cut the springs and what are you trying to achieve.

Although it's true that by cutting the springs you will:

1. lower the front end
2. have a stiffer spring rate

You will also reduce the available fork travel to absorb bumps, more chances of fork bottoming.

there will also be plenty of "free stroke" unless you put a spacer under the damper rod.

I did shorten them on my racer (for stiffer rate) but also added a spacer under the fork cap to maintain the right static sag.

I cut them with a grinder, bent the end so it touched the last coil and then ground the last bit flat. be sure to put the cut end at the top so it doesnt rub inside the tube

TG

Offline Really?

  • I've come to the conclusion that I AM a
  • Really Old Timer ...
  • *******
  • Posts: 5,290
Re: Hmmmm, I have been told to cut the springs
« Reply #3 on: October 28, 2008, 01:22:50 PM »
I want to bring the front end down 2-3 inches.  I have slid the forks up the tree already to just about touching the bars.  The rear is already down two inches and hoping this rim order comes in so I get work on getting down a bit more on the 16" rim.  Seat foam has already been cut down.

The wife is inseam challenged.

http://forums.sohc4.net/index.php?topic=40612.msg418423#msg418423
« Last Edit: October 28, 2008, 01:25:55 PM by GigaWhiskey »
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

KingCustomCycles.com

  • Guest
Re: Hmmmm, I have been told to cut the springs
« Reply #4 on: October 28, 2008, 01:39:42 PM »
I cut every set on every bobber I build.  I remove 1-2 inches off the top of each spring with a muffler cut-off tool or die grinder with cutting wheel, if you prefer.  I cut at an angle and try to keep things as flat as possible. They will bottom more readily but with no rear brake either, I ride rather conservatively. 

Offline chrislib

  • Hot Shot
  • ***
  • Posts: 345
Re: Hmmmm, I have been told to cut the springs
« Reply #5 on: October 28, 2008, 03:05:24 PM »
Mine are cut 1.5in. I cut the coils and then used an angle grinder to flatten the cut edge so the spring sits flat against the cap at the top of the fork. I`ve been riding the thing all summer with no ill effects, i.e. poor handling,bottoming out etc (altho I am a pretty conservative rider). If I were building the bike for performance or doing a resto I would not cut anything but my bike is neither so...
Chris...closet Idlefiddler
#1975
1973 CB750K...CANDY BACCHUS OLIVE

Offline dp2275

  • Enthusiast
  • **
  • Posts: 122
Re: Hmmmm, I have been told to cut the springs
« Reply #6 on: October 29, 2008, 02:51:25 PM »
i shortened stock 750 springs by 2" and installed them in cb500 fork tubes which are already almost 2" shorter than stock.  also slid the tubes up in the triples.  total lowering is around 4"...i do have some travel, but shes fairly stiff as it needs to be to prevent the headers from sittin on the ground  ;D


Offline Really?

  • I've come to the conclusion that I AM a
  • Really Old Timer ...
  • *******
  • Posts: 5,290
Re: Hmmmm, I have been told to cut the springs
« Reply #7 on: October 29, 2008, 03:08:26 PM »
I saw that pic during my searches on this subject, that is waaay low.

The fender does not hit the pipes when it bottoms?
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline dp2275

  • Enthusiast
  • **
  • Posts: 122
Re: Hmmmm, I have been told to cut the springs
« Reply #8 on: October 29, 2008, 03:40:11 PM »
I saw that pic during my searches on this subject, that is waaay low.

The fender does not hit the pipes when it bottoms?

it would be close if it bottomed ALL the way, but the fender is also sitting an inch up off the tire.  there is more clearance than appears in the picture but im moving the fender mounting points so the fender tucks in closer to the tire anyways and then there shouldnt be any problems even under full compression.  the fender also gets a little close to the bottom of the headlight bucket.. 8)

Offline 754

  • Really Old Timer ...
  • *******
  • Posts: 29,058
Re: Hmmmm, I have been told to cut the springs
« Reply #9 on: October 29, 2008, 09:15:19 PM »
Giga, you coud rake your frame..or make highpipes.. my frame is less than 5 inches off the ground.

 If you can fab you may consider the following, cut and lower the frame in the oil tank area, and make a new seat.. this will  require modding the oil tank, frame, and making sidecovers..

..or just build headers that are higher up..

Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Really?

  • I've come to the conclusion that I AM a
  • Really Old Timer ...
  • *******
  • Posts: 5,290
Re: Hmmmm, I have been told to cut the springs
« Reply #10 on: October 30, 2008, 07:53:55 AM »
Hey 754, you are a scary dude, JK.  You are putting ideas in my head and now I wonder if I can even get them accomplished.  I am not a fabricator but yanno, wish I had some of that talent.

  • Let's see rake the front to drop it some, I have seen some and they look really nice.
  • Have the frame cut and lowered under her backside.
  • Make a new low seat.

Her inseam challenges would be over, so would a bunch of money I would assume.  I love the idea and my brain is a mess now, lol.  ;)
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline heffay

  • Really Old Timer ...
  • *******
  • Posts: 7,874
Re: Hmmmm, I have been told to cut the springs
« Reply #11 on: October 30, 2008, 07:59:27 AM »
giga... does your wife actually operate the bike?

i don't see what the problem is if all she does is sit behind you.
Today: '73 cb350f, '96 Ducati 900 Supersport
Past Rides: '72 tc125, '94 cbr600f2, '76 rd400, '89 ex500, '93 KTM-125exc, '92 zx7r, '93 Banshee, '83 ATC250R, 77/75 cb400f

Offline Really?

  • I've come to the conclusion that I AM a
  • Really Old Timer ...
  • *******
  • Posts: 5,290
Re: Hmmmm, I have been told to cut the springs
« Reply #12 on: October 30, 2008, 08:04:31 AM »
Hey, nope she does not operate the bike.  It was purchased for her to operate and me have a whole lotta fun making it that way and modding it.

I would not 2up this bike as I am spoiled to my XVZ12DN when it comes to that.  So, this would be a 1up bike but maybe take the kids around the block a few times too young to go any further.

Hopefully, someday, we can both ride together on our own bikes.  She is fine on the back of my bike but she would like her own too.

Oh, do not get me wrong, I will prolly ride the k5 too.  Once i get to a point with hers, I will want one for myself (I do already).
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline heffay

  • Really Old Timer ...
  • *******
  • Posts: 7,874
Re: Hmmmm, I have been told to cut the springs
« Reply #13 on: October 30, 2008, 08:07:27 AM »
did you just say you're making a lowered bike for no one to operate?     ???

if you're wife will not be on it... why lower it for her?
if you're the only one on it... are you vertically challenged as well?
i don't think you're kids will be able to reach the ground for a while.   ;)
Today: '73 cb350f, '96 Ducati 900 Supersport
Past Rides: '72 tc125, '94 cbr600f2, '76 rd400, '89 ex500, '93 KTM-125exc, '92 zx7r, '93 Banshee, '83 ATC250R, 77/75 cb400f

Offline mystic_1

  • Really Old Timer ...
  • *******
  • Posts: 6,071
  • 1970 CB750K
Re: Hmmmm, I have been told to cut the springs
« Reply #14 on: October 30, 2008, 08:22:08 AM »
If you're particularly ambitious, check out the www.hondachopper.com site and research a process that's come to be known as "Konging a frame".  It involves cutting up and rewelding the frame from the rear shock mounts to the downtubes, to give you something like this:



which can then be turned into something like this:



Some links to more info:

http://hondachopper.yuku.com/topic/8791/t/Konging-a-frame.html

http://www.hondachopper.yuku.com/topic/6205/t/konged-frame.html

http://www.negwebdesign.com/x/sohc750/kong/

http://konga750.blogspot.com/


There are some downsides to this approach that must be considered, and don't even think about it unless you're supremely confident in your welding, fabrication, and engineering abilities.

cheers
mystic_1
"A ship in harbor is safe, but that is not what ships are built for."
- John Augustus Shedd

My build thread:  http://forums.sohc4.net/index.php?topic=68952.0

Offline Really?

  • I've come to the conclusion that I AM a
  • Really Old Timer ...
  • *******
  • Posts: 5,290
Re: Hmmmm, I have been told to cut the springs
« Reply #15 on: October 30, 2008, 08:23:27 AM »
She does not operate it yet, she will when I can get it low enough for her.  I am not vertically challenged, I can handle a 32+ inch seat height.

She is good for a max 27" seat height.  This frame and seat is so wide it lowers her seat height ability.
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline Really?

  • I've come to the conclusion that I AM a
  • Really Old Timer ...
  • *******
  • Posts: 5,290
Re: Hmmmm, I have been told to cut the springs
« Reply #16 on: October 30, 2008, 08:27:32 AM »
Konging the frame looks like a kewl idea but someone else will have to do it.  Not looking for the chopper look though.

I want to keep what I think I am going for ( i could be wrong considering all the different views on styles) - cafe/bobber/old school mix.  Something I think I have seen a lot in the SOHC4 gallery.
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline speedy gonzalais

  • Hot Shot
  • ***
  • Posts: 417
Re: Hmmmm, I have been told to cut the springs
« Reply #17 on: October 30, 2008, 09:28:24 AM »
I wouldnt advise cutting the springs your self or getting any1 else to do it, I doubt you will get both springs exactly the same lenth and i think the cut ends will bend thru time and cause other problems as they wear. come to think of it the word dangerous just popped into my head. any right minded person wouldnt want to endanger there own life let alone suggest it to some one else!
82' C90
87' yamaha T80
79' CB125T/CD200 project
82' CB650z
80s kawasaki ae50/150cc project
92' Suzuki GSXR600
80' CB250N

Offline mystic_1

  • Really Old Timer ...
  • *******
  • Posts: 6,071
  • 1970 CB750K
Re: Hmmmm, I have been told to cut the springs
« Reply #18 on: October 30, 2008, 11:20:19 AM »

  • Let's see rake the front to drop it some, I have seen some and they look really nice.
  • Have the frame cut and lowered under her backside.
  • Make a new low seat.


Konging could accomplish all three of these things, you don't have to build a chopper to use the technique.  Just lower the seat rails without extending the front downtubes.

Of course, simply getting shorter front forks would probably be way easier.  You could also put sleeves on the damper rods to lower the shocks, similar to the Progressive Suspension front lowering kits for Harleys., look into those online for inspiration.  Do believe you'd have to cut the springs or get shorter ones to make that work.


mystic_1
"A ship in harbor is safe, but that is not what ships are built for."
- John Augustus Shedd

My build thread:  http://forums.sohc4.net/index.php?topic=68952.0

fuzzybutt

  • Guest
Re: Hmmmm, I have been told to cut the springs
« Reply #19 on: October 30, 2008, 11:28:33 AM »
get a set of cycle-x short for tubes and some shortened shocks, a cafe seat would also work for lowering the seat height as they usually use very little padding

Offline Really?

  • I've come to the conclusion that I AM a
  • Really Old Timer ...
  • *******
  • Posts: 5,290
Re: Hmmmm, I have been told to cut the springs
« Reply #20 on: October 30, 2008, 11:43:33 AM »
get a set of cycle-x short for tubes and some shortened shocks, a cafe seat would also work for lowering the seat height as they usually use very little padding

I have emailed Ken and Sue at cyclex a couple times to see if they would cut a set of springs for me to go with these -2 tubes.  The reason for asking them about the springs is if he can build what he does, I would expect him to do the job of cutting them right.  But, I have not had a response from them.

I know they are backed up with recent issues but I thought they would have responded in some way other than none.

Done the 11" shocks on the rear already.  16" rim has arrived, still waiting on the spokes.  I have had a couple inches of foam removed from the seat too.  The wife wants to keep the king/queen.  She has seen the cafe seats and has been spoiled to the sofa on my XVZ12DN (she has fallen asleep back behind me a few times).  If and when the frame is konged, I will have to be quite inventive on the seat, lol.
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline Triffecpa

  • Hot Shot
  • ***
  • Posts: 477
Re: Hmmmm, I have been told to cut the springs
« Reply #21 on: October 30, 2008, 02:19:32 PM »

Cutting fork springs is not a dangerous or risky thing to do.  (Assuming that you don't manage to cut your finger off in the process).  You can grind the cut end flat on a bench grinder.  I've done it lots of times and they won't even consider my application for the Rocket Scientist club.

If you are going to shorten the forks, getting shorter tubes really isn't necessary.  Disassemble the forks and put a solid spacer into the bottom of the fork tube (the length of the spacer dictates how much shortened the fork will be) and then reinsert the damper rod and top out spring.  Reassemble the forks and then put your old spring in the top.  Mark it so that you get about an inch of preload on the spring with the cap installed.  Cut it with an angle grinder using a cut off wheel.  You can put a flat metal washer on top of the spring if you're worried about sharp ends etc, but generally grinding the end flat will alleviate any problems.  The springs are pretty captive inside the fork.  There isn't going to be lots of moving around of hard parts to wear anything out. 

Cut off the end of the fork spring that has the closely spaced coils.  The forks will be stiffer than before. 

Tracy

Offline heffay

  • Really Old Timer ...
  • *******
  • Posts: 7,874
Re: Hmmmm, I have been told to cut the springs
« Reply #22 on: October 30, 2008, 05:23:16 PM »
^ listen to that last guy!  i just rode his bike on the track this weekend and he's a definite tuner/race setup guy!   ;D

and, my opinion?... he's right... grind it down, good as new.
Today: '73 cb350f, '96 Ducati 900 Supersport
Past Rides: '72 tc125, '94 cbr600f2, '76 rd400, '89 ex500, '93 KTM-125exc, '92 zx7r, '93 Banshee, '83 ATC250R, 77/75 cb400f

Offline Really?

  • I've come to the conclusion that I AM a
  • Really Old Timer ...
  • *******
  • Posts: 5,290
Re: Hmmmm, I have been told to cut the springs
« Reply #23 on: October 30, 2008, 06:37:08 PM »
Hey Tracy, thanks for the lowering steps on the forks.  Although, how that part works like that, I cannot quite grasp yet, I have so see it I guess and pictures I have seen does not make me see it in my mind.

Anyway, got a couple questions.  The spacers, what should they be made out of?  Read here http://forums.sohc4.net/index.php?topic=19405.msg202853#msg202853 that PVC pipe was used.  Will this hold?  Also, will I need a longer bolt?  Last question, with this setup, what weight oil would you recommend?

It would be interesting to make this work on the cheap.  Well, I guess I need a die grinder.
I don't have a motorcycle, sold it ('85 Yamaha Venture Royale).  Haven't had a CB750 for over 40 years.

The Wife's Bike - 750K5
The Kid's Bike - 750K3

Offline 754

  • Really Old Timer ...
  • *******
  • Posts: 29,058
Re: Hmmmm, I have been told to cut the springs
« Reply #24 on: October 30, 2008, 08:15:08 PM »
This should have been mentioned,

When the spring is cut the end should be heated and rebent in a manner that allows the spring to be ground flat, with it having contact most of the circle.. ie.. like the stock ends..


CB 450 forks are around3/4 inch shorter than CB 750 forks, and should have shorter springs.

I forgot why you did not want to slide them up a few inches, early 750 needs barbacks, but 77/78 I think allows them to go waaaayyyy up..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way