Cafe Racer Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
51 Posts
Discussion Starter #1
I'm buildingba 74 cb350 four and wanted to push the rear back a bit, around a couple inches. I was somewhat curious as to if any longer singarms will bolt up, or if there are any that with minimal modification will work and hiw to go about those modifications. Thanks in advance!
 

·
Registered
Joined
·
10,489 Posts
For what reason?

 

·
Registered
Joined
·
51 Posts
Discussion Starter #3
sorry about the typos in the original post. fat finger syndrome today. anyway, the reason being the customer wants a little more length on the bike. The fork is being swapped already. He originally wanted a boxed swingarm made but he had a budget in mind and that put it over the top. In all reality it is an aesthetic feature. To each their own.
 

·
Registered
Joined
·
10,489 Posts
So now you are a shop?
Really?
You have to be kidding.

And then you talk about this just being a game of dress up?

How about you make like leaf, and get the fuck out.
 

·
Registered
Joined
·
51 Posts
Discussion Starter #9
Maybe I was wrong to assume that asking would be helpful. I have never had the need to extend a swingarm before, so I don't have the experience in doing so. when someone asks for a modification like this I tend to ask when. usually ends up with the answer "because". I understand that keeping the same geometry is preferable, and my bikes at most thus far have been fork, and shock swap. I guess I gave the majority of contributors to this forum too much credit for being decent people. Anyway I found a boxed swingarm and milled the ends down, had the bushings made and its finished. thanks for the help, and by that I mean, thanks for being everything a forum contributor shouldn't be. I do my best with the three years I have been building. I never said I was a shop. I build out of my garage in hopes of possibly gaining enough knowledge to take things further.
 

·
Registered
Joined
·
1,399 Posts
Did you figure out a way to transfer the liability of what you are doing back to the owner? You have no idea how to do a simple mod, but worse dont seem to care about the adverse effects to changing the front AND extending the rear. Did you do the trail calcs? What if the guy crashes the bike and sues you?


Just some thing to think about and maybe you have.
 

·
Registered
Joined
·
51 Posts
Discussion Starter #11
Messed around in solidworks for a few weeks before I even said id think about doing it. got things as close as possible with the longer wheelbase taken into account. I tried to get him to change his mind, but that didn't go over to well. Made him sign a liability waver before anything was changed.
 

·
Registered
Joined
·
51 Posts
Discussion Starter #12
Also if you read the comments previously, I never said I was going to fabricate a new swingarm. I was asking if it were possible to swap a swingarm on to the stock frame without much modification. It was a question before the decision was actually made to do so. I made numerous phone calls to a few of my friends who were in the same engineering program as I was at Michigan tech. Two of which work in the industry. If it would have been a drastic change it would have been a no go. The axle was pushed back a total of 2.05 inches. very similar to the stock swingarm I cut two years ago and extended. I have modified a swingarm for a personal bike before and it was a very slight change in handling characteristics. Nothing drastic at all over the 18k that I put on it before selling it. I do have enough skill in the engineering and componentry development field, but in all reality I just had a few questions when it came down to simple swaps as I have never used a boxed swingarm from an existing bike. I was looking for a compatible fork that would allow for the stock axle to be used if at all possible. Ended up calling a guy by the name of Hido Takada in Minneapolis who from what I have been told used to work for Honda north America. Anyway long story short, there were swingarms that would nearly drop right in, but some machining was required. the stock axle wouldn't work either so the hub and drum needed a bit of Bridgeport work. new spacers, linkages, and everything bolted in without any issues. The bike was finished in april and hasn't had any issues. I do know that there is some risk involved, but it wasn't an excessive stretch like you would see on most modern sport bikes
 

·
Registered
Joined
·
10,489 Posts
 
  • Like
Reactions: Old Nail

·
Registered
Joined
·
4,508 Posts
Also if you read the comments previously, I never said I was going to fabricate a new swingarm. I was asking if it were possible to swap a swingarm on to the stock frame without much modification. It was a question before the decision was actually made to do so. I made numerous phone calls to a few of my friends who were in the same engineering program as I was at Michigan tech. Two of which work in the industry. If it would have been a drastic change it would have been a no go. The axle was pushed back a total of 2.05 inches. very similar to the stock swingarm I cut two years ago and extended. I have modified a swingarm for a personal bike before and it was a very slight change in handling characteristics. Nothing drastic at all over the 18k that I put on it before selling it. I do have enough skill in the engineering and componentry development field, but in all reality I just had a few questions when it came down to simple swaps as I have never used a boxed swingarm from an existing bike. I was looking for a compatible fork that would allow for the stock axle to be used if at all possible. Ended up calling a guy by the name of Hido Takada in Minneapolis who from what I have been told used to work for Honda north America. Anyway long story short, there were swingarms that would nearly drop right in, but some machining was required. the stock axle wouldn't work either so the hub and drum needed a bit of Bridgeport work. new spacers, linkages, and everything bolted in without any issues. The bike was finished in april and hasn't had any issues. I do know that there is some risk involved, but it wasn't an excessive stretch like you would see on most modern sport bikes
You know if you added a few pictures with this post might have gone a long way towards quieting the nay sayers.

There's quite a few folks that have lengthened the swingarm on their vintage race bikes. And the handling has actually improved. They must have been wrong too.
 

·
Registered
Joined
·
1,399 Posts
Not saying it's a bad idea...I haven't seen the math....what is a bad idea is doing it for someone else without liability insurance or a clue as to what you are actually doing.
 

·
Registered
Joined
·
7,014 Posts
Liability waver only covers simple negligence, it won't cover Gross negligence. And without due diligence in the design of a custom swing arm, it might fall into this category if someone gets hurt with one of your custom items. You can't sign away some rights whether you signed a waiver or not.
 

·
Registered
Joined
·
5,780 Posts
You guys are a bunch of yahoos. I am gonna stick up for a local cheesehead and agree with Craig. Why you might ask? Because he is right, that is why!!! How do you know you might ask? Because the swingarm on my CB350 racebike was extended by 2" and it had the desired effect. It put some more weight on the front end and made the bike more stable through high speed(a relative term for a cb350) sweepers, like the carousel at Grattan, for instance. The swingarm was lengthened and braced by Framecrafters. Also with CB350 racebikes some people put an SL350 swingarm on them because it is longer. Anybody wanna guess how much longer? That is right, 2"!!! You guys don't know crap, except how to tell people it won't work and somebody is going to die and the builder is gonna get sued and it is gross negligence and if you have to ask you can't do it and then you throw up some stupid meme that you think makes you look clever but the reality is that it only reinforces your circle jerk friends to keep piling on like a bunch of 5th grade wanna be bullies.

So, OP, why don't you stop by around Christmas time, when I will be back at my garage, and I can show you my extended and braced 350 swingarm. My bikes live about 30 minutes from you. We will laugh, drink a beer and take some pics of my racebikes, a selection of swingarms and stuff and see if we can get some armchair engineers, lawyers and racers to pee their pants a little bit. I am 8 miles north of Menomonie off state hwy 25.
 
  • Like
Reactions: Stephen J

·
Registered
Joined
·
7,014 Posts
You guys are a bunch of yahoos. I am gonna stick up for a local cheesehead and agree with Craig. Why you might ask? Because he is right, that is why!!! How do you know you might ask? Because the swingarm on my CB350 racebike was extended by 2" and it had the desired effect. It put some more weight on the front end and made the bike more stable through high speed(a relative term for a cb350) sweepers, like the carousel at Grattan, for instance. The swingarm was lengthened and braced by Framecrafters. Also with CB350 racebikes some people put an SL350 swingarm on them because it is longer. Anybody wanna guess how much longer? That is right, 2"!!! You guys don't know crap, except how to tell people it won't work and somebody is going to die and the builder is gonna get sued and it is gross negligence and if you have to ask you can't do it and then you throw up some stupid meme that you think makes you look clever but the reality is that it only reinforces your circle jerk friends to keep piling on like a bunch of 5th grade wanna be bullies.

So, OP, why don't you stop by around Christmas time, when I will be back at my garage, and I can show you my extended and braced 350 swingarm. My bikes live about 30 minutes from you. We will laugh, drink a beer and take some pics of my racebikes, a selection of swingarms and stuff and see if we can get some armchair engineers, lawyers and racers to pee their pants a little bit. I am 8 miles north of Menomonie off state hwy 25.
I hope you weren't referring to anything I said because I never advised him on anything about the swing arm. I merely stated some legalese when people bring up liability wavers. In many cases they mean jack. Contain your comments to those who are bad mouthing the lengthening of the arm.
 

·
Registered
Joined
·
5,780 Posts
Oh Yeah, says who!!! I'll spread my comments wherever I feel like it. If the shoe fits... Plus this is the internet, not reality. I was working up a good rant and you know those can never be directed at a single target, you have to spread it around and see what sticks. It isn't like I care very much about any of this, I am just entertaining myself. I had hoped that I was so over the top that the sarcasm was readily identifiable. Of course, I have been to Dawsonville so maybe I expected too much? However, as with any worthwhile rant there has to be at least a small kernel of truth, in this case it is lighten up, there are many valid reasons for wanting a different length swingarm and not all of them are stupid or dangerous.

And, everybody should know that liability waivers aren't worth the paper they are printed on. I must have signed hundreds of those things over the years racing and if I got killed my family could still sue all kinds of people and win something if there was negligence.
 
  • Like
Reactions: Joep7
1 - 20 of 20 Posts
Top