CL350 Rear Swing Arm Options

[mtbike]

Hi all. Looking at one of my CLs that I am starting to modify and thinking it would look better with a longer swing arm to set the rear wheel back a little. only thinking about 2 or 3 inches. Has anyone had experience with this and have found a ready made dooner that bolts up?

 

[Barnburner]

I don't believe any other OEM swingarm will bolt into a CL350 except one from a CB350, which is virtually identical. SL350 swingarm is longer and wider than CL and CB but probably the closest in design. Most people who want to extend their swingarm do so by cutting the arms, and welding in plugged extensions.

 

[mtbike]

BB thanks for your input. I looked at both the CB and SL and they both looked to be roughly the same length as the CL but I didn't actually put a tape on them. I had considered finding someone to lengthen them for me. I can do some rough farm fab but for something like this I'll have to spend some money.

 

[Barnburner]

Just curious - is there another reason for you to lengthen the swingarm besides aesthetics? Are you changing front ends on the bike or any other frame dimensions (rake/trail)? IMO, stock CB and CLs are actually not poorly setup. They're smaller and not quite flickable like a dirtbike but the handling is nice and quick. I'm not a professional but I think that lengthening the swingarm would worsen handling in all but a straight line.

 

[Tune-A-Fish]

When you chop cut extend, you need to add back the shock length or you will squat the pivot axle and lower the back end.

Several swingarms will work with modification but the FZ6 box seems to be one of the best options along with an offset counter sprocket and the pivot axle mod in my CBK2 build below. Not all CB's are alike so you will need to do some measuring and some searching, first off... what is the width with grease caps on your swingarm, this is a critical number and the tolerances need to be tight.

My CBK2 has 3.5" of extension, but looks like 6, the way I made it look longer was to shorten the rear cowl and the seat (that looks long), a little magic can go a long way.

 

[mtbike]

Yes only doing for looks. I'm sure it would not add to the bike's handling but if I don't go crazy (no more than 4") hopefully it wouldn't make it too terrible. Lowering the rear a inch to two is my end goal anyway so the rear dropping is not a negative other than the shocks will be at a raked angle. Fish, mine is a CL not that it is prob. different. Not to excited about having to deal with offset sprokets and axle mods. May lean more toward extending existing arm.

 

[Tune-A-Fish]

Super easy then, just keep the spread in mind.

Make a nice deep alignment notch for later... make the cuts and find some tight fit tube to fit inside. Drill the swingarm and filler tube with say a 3/8" drill all the way through both sides... then slide the filler tube cut from a chunk of donor tube off another swinger for best fitment on, then slide all together. Leave a small gap between the parts or bevel them all then weld the 360's, after that plug weld the 6 holes closed penetrating the inside tube, grind/flap wheel it all suuhhmoooth mang.

You can do all that and take it to a weld shop to get it stitched also.

If you stick it way out, you may consider some ladder bracing on the under side, that's a whole nuther convo.

 

[Rider52]

I don't know if this will work on a CB/CL 350 frame, but I saw a SL350 with a Honda Rebel 250 swingarm and rear wheel. It is quite a bit longer then the stock 350 swingarm. The owner claimed it was a bolt on and go.

 

[mtbike]

Just saw RawFish's write up. Nice bike. Had some good info on stretching the swing arm. Sounds like 4" is about the magic number.

 

[mtbike]

I don't know if this will work on a CB/CL 350 frame, but I saw a SL350 with a Honda Rebel 250 swingarm and rear wheel. It is quite a bit longer then the stock 350 swingarm. The owner claimed it was a bolt on and go.

Thanks R52. I may have to do a little digging on that. Any idea how much longer "quite a bit" is? I don't want to go overboard either.

 

[VonYinzer]

For what it's worth, years ago I had my CB350 swinger lengthened by 4" or so... At the time I didn't know any better, so the shock mounts all stayed where Honda wanted them. Dropped the ass an inch or so. Maybe more. Thought it was super cool. Rode it for awhile (maybe 100 miles max) before I grenade the top end.

Fast forward to now.

I've had several bikes since then. From hardtail chops, to all stock early 80s first Gen go fast stuff. Current daily is a '77 GS750 (all stock). Having, over the past so many years, ridden this multitude of bikes (plus several others) I've learned a few things. I've also been lucky enough to glean a good bit of knowledge from this site and the friends in the hobby that I've been lucky enough to meet. I've also made several mistakes in a number of builds, which as we all know is the best way to learn a lesson. Why am I rambling on about this you ask?

Because I want you to understand that what follows isn't some random Internet hate. I'm miles away from being as talented or skilled as many here but, I'm pretty good at learning what works and what doesn't (even if it sometimes takes a minute to sink in).

Don't lengthen this swinger. You really don't want to, and here's why.

By lengthening this swinger, and not compensating for the massive change in rear suspension function you've made something infinitely worse than stock.

You mention lowering the bike by 2.5" as a goal. This will also effectively ruin this motorcycles ability to function correctly.

By adding 4" in wheelbase length, you will need to also lengthen the chain allowing for a ton of slop. There are ways to fix this but now you're complicating a simple system with no benefit. Not to mention the fact that during rough conditions, the chain will likely rub the swinger (ask me how I know).

You're making a massive structural change to the swinger, which in stock trim is spindly and flexes, effectively weakening it. Add that to that the new shock angle and it makes for a terribly squirrelly ass end (again, ask how I know).

I think know you get what I'm after here... I'll quit being a stick in the mud now.

Just make sure you COMPLETELY think these things through. There's a lot of wasted time, money and effort that can be avoided by a few hours in the garage, a cold beer and an extra set of eyes (and no chop saws ).

 

[mtbike]

Von, Thanks for sharing. I have a fully stock '72 cl350 that's my current rider. At the end of the day I want this other '72 cl350 to be a lot different in the looks department. Although I've owned five or six bikes I still have much to learn. This is my second build, my first being a Shadow 1100, but first cafe. I am not interested in riding a ridged. To old for that. I am planing on lowering the forks in the triple the same amount as the rear is dropped to hopefully keep things closer to happy. I'm 5'11" so the bike is ok but looks none too big physically. If I lengthen the SA I know that will lower the rear and I wasn't planning on trying to go lower yet after that. So I guess my decisions falls more to lengthening the SA or just running shorter rear shocks with stock length SA. That rear wheel is just so tucked up under there. She looks short. I have a friend with a 70's 700s Triumph that stock is like 6" longer over all. Makes my cl look like a kids bike parked next to it.

Here she is. Playing with tank options and fairing.

 

[mtbike]

Here's the direction I'm thinking of going. I know there's big differences between bikes pictured but I'm still working it out in the naugin.

 

[DohcBikes]

Now that you have responded reasonably, if you still want someone to lengthen your stock swingarm I can do it for you. I won't lengthen it more than 2"

 

[doc_rot]

You could lengthen that spindly piece of crap and have a noodle for rear end, or swap for a longer stiffer swingarm for probably about the same it would cost to have a swingarm lengthened(if you arent doing the fabrication yourself). if you find a swingarm with the same pivot and axle diameters and use your existing wheels it wont be too difficult. you can also swap wheel bearings to get it to work with a larger axle diameter. plus it would add to the custom factor more than a stock looking swingarm. just my .02

 

[doc_rot]

BTW don't put the rear axle above the swingarm pivot like that last bike. This will cause the bike to squat under acceleration, which is the opposite of what you want in a turn.

 

[Tune-A-Fish]

why not just swap to a better swingarm? You could lengthen that spindly piece of crap and have a noodle for rear end, or swap for a longer stiffer swingarm for probably about the same it would cost to have a swingarm lengthened. plus it would add to the custom factor more than a stock looking swingarm. just my .02

If he keeps the two shock I don't get how it could "noodle" ??

 

[DohcBikes]

If I lengthened it, it would end up stronger than stock.

 

[doc_rot]

If he keeps the two shock I don't get how it could "noodle" ??

I just meant that by extending an already flexible swingarm he is going to make it more flexible. I guess you could put thick tube inside to compensate but a bigger diameter has more to do with rigidity than a thicker wall does. Hence the move of manufacturers to big diameter hollow axles and the like

 

[Tune-A-Fish]

So basically you didn't think it through

The simple solution is to extend and strengthen.


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