Topic: Any benefits to an extended swingarm?

[KB02]

So I have come to a point in my build that I have an option available to me that I need advise on:

 What is the propose / benefit of an extended swing arm?

I did a search but really didn't find the answers I was looking for. I understand that drag racers put extended swingarms on their bikes for better stability in a straight line, but how do they handle in the curves (since a lot of sport bikes boast about their short wheel base)? Aside from the whole "look" factor, what benefit would one have one have on a street bike?

[RRRToolSolutions]

You only want to do it to control lift. It slows the steering and turn-in, plus the increased angle means you have to re-think your shocks too - you'll need longer and heavier springs since the angle will increase. I have 3 identical model H2's of 1974 and 1975 - one of which has a 3" over extended swingarm. The handling is certainly different in the turns. It's something you get used to in minutes, but there are no improvements to handling. Do you need wheelie prevention? If not, I suggest staying away from it.

This one should have been 5". It has caught me by surprise on occassions and hooked the tire for a quick look at the sky......

Gordon

[Soos]

I guess it would help reducing the ability of wheelies(bad things IMO however).,

I put a longer ('81cb650c) swingarm on my '79cb650.
Offhand can't remember the length change, but I wanted it mainly 'cause the swingarm was longer, and the shock mounts are further back, so with the shocks I am using it would lower the seat height.
Have been running it a while now, and like Ilbikes said, the handling differences are quickly adapted to.

l8r

[voxonda]

Changing the length of the swing can drastically change the way the bike behaves. It will not change a bad steering bike in a razor sharp steering Moto GP bike, there are a lot of things to be taken in consideration. In my projekt replica racer I have put in a homebuild box swingarm which is 1" longer than stock. Have done that 'cause the 750 has the tendency to tie itself in knots in fast bends. A longer swing will make the bike more stable at speed. By making it more rigid it will behave better in turns. Think about the position of the shocks, I use Koni's from the 900 DOHC which are longer, or stock length Hagon's. Depending on the circuit. Prefer the stock length. To cope with the somewhat heavier steering, you can lower the front end or, in my case, use a 18" front wheel.

Taken during the build.

cheers, Rob

[greenjeans]

Are all the CB750's swing arms the same length ?  Seems like I remember one or more of them being longer....
But, then again,  I have a bunch of hair-brained tidbits stuffed into my box of rocks between my ears.

[Bouncer]

Are all the CB750's swing arms the same length ?  Seems like I remember one or more of them being longer....
But, then again,  I have a bunch of hair-brained tidbits stuffed into my box of rocks between my ears.

From what I have read the later CB750's (77-78) arms are a bit longer then the earlier 70's models. I can measure my 78 F's arm when I get a chance. 

[KB02]

Well, the thought has come up because my Parts bike ('88 Suzuki Katana 600), which I am steeling the front end out of, has a swing arm that is three inches longer than the CB's, plus it has a fully adjustable Monoshock. I could use the swing arm in the Honda with very little modification and do a Monoshock conversion, but it puts the rear tire about two inches further back than stock.

I have seen some ridiculously long extentions and I know they are for dragging. I think they just look silly sometimes, you know?

I might ponder this some more...

[greenjeans]

2" further back won't look ridiculous....what diameter tire were you considering ?   I'm contemplating putting a longer swingarm on my '72.  Mocked up, I have it between 2" -2.5 " back of where the original was with the chain on and it doesn't change  "the look" much at all.  I am using a bit of a taller tire than stock, but not much.

I have always thought about a mono-shock for these things, coupled with a more modern inverted fork for the front.
Sure would be killer - haven't really seem but a handfull of attemps.   

I say go for it.

[low-side]

Most of the extended swingarms for these are tubular or box section and therefore much more rigid and handle much better.  It might get more expensive than you want though because you will probably want different shocks and possibly even have to modify the fender if you go too long.  I have a tubular 3" extended swingarm with shocks that are 15" eye to eye and I barely get away with  the stock fender. 

[754]

You have to decide how you ride MOST of the time..


If you are mostly on the highway and not seeking out the twisties daily, you will like it..

I am running 6 over but it is a bit long (also lowered about 4 inches).. hard to turn around.. but I can go down to about 10 or 15 mph with no hands on the bars.

2 inches you may barely notice unless you are roadracing or spending all your time in corners.

Iam thinking of shortening mine an inch, so I can run 120 link chain with big sprockets. I extended the stock arm by adding to the front, easy and cheap, but I run bushings and no shocks..

[KB02]

Well, I wouldn't have to worry about the fender as I am doing the Cafe thing and the fender is going away anyway. The tire is about two inches smalled diameter than stock (roughly) so that takes away an inch from the length of the arm.

Twisties are my preferred riding areas, so I'll have to take that into consideration.

I'll have to double check my measurements when I get both bikes stripped down. I can do a test fit of the other swingarm and see just how much longer it really us.

[Industrial Cafe]

i know this is an old thread but, you can use a late 80's gsxr750 swingarm. it's aluminum box frame, it's much wider, and an inch or so longer... i think.
 you can get shock mounts welded on the cheap.

oh, and it fits in the yoke on the frame.

[Retro Rocket]

I have used the late 80's GSXR 1100 swingarm, and i ha to have it shortened it is now about 20mm longer than stock and looks awesome, and it fitted straight in the frame...

Mick

[Bouncer]

I have used the late 80's GSXR 1100 swingarm, and i ha to have it shortened it is now about 20mm longer than stock and looks awesome, and it fitted straight in the frame...

Mick

Picture(s) please!

[Industrial Cafe]

well, I didn't find the gsxr750 swingarm yet but I did find a honda cbr1100rr swingarm and front fork.

[Industrial Cafe]

here's a pic I found a long time ago,
if I remember correctly it's the extended swingarm of a gsxr750

[Retro Rocket]

My daughter has gone away for the week and has the camera with her, as soon as she gets back i'll post some pics. Also the GSXR 1100K front end i am using only needed the standard Honda steering stem pressed in for the conversion.....it was a perfect fit....
Pics to come.

Mick