Counter Balance Cycles Shop Race Bike

[westonboege]

Couple more from last night... need to find a MC and run a brake line and stay. Then itll be really close to riding!

 

[member3480]

Yep going to need exhaust soon so I will pm you on what I need. I have made many drag race arms out of square tube and just made block sliders to attach axle.

 

[westonboege]

Yeah, There are a couple people out there cutting mild steel dropouts... Hardest thing will be finding the right size tube for the swingarm, so i can cut the inside for the swingarm bushings...

 

[member3480]

I have used SCH 40 1x3 and it works well. I would just cut up a old swingarm and weld the tube with the bearings to it. I have pictures but trying to get them from other computer. If not I will draw you up a design I have used in the past. Material is about $50.00 or less. Here are a couple pictures maybe this will help. I know you can make this LOL

 

[mrtwowheel]

That looks like a stiffy DaddyG. I'm guessing that the axle area is strengthened with a solid piece of rectangle welded at the end of the swing arm?

Scott

 

[member3480]

I don't know what a stiffy is but I have built these like this and they took 250 hp on a drag bike . So to make one up with WES's welding skills may be a new money maker for him. Every bike XS650 that I have built the first thing out of there mouth is can we do a cleaner swingarm. The square tube style can be made up with different holes in the axle block if you want to extend the arm or just run it stock length. One of the pictures show that.
Blue bike went 8:70 1/4 mile and white bike went 9:10 1/4 mile never twisted arm.

 

[fredintoon]

Hi DaddyG,
I reckon Scott means that your RHS swingarm looks really stiff &/or that he gets sexually aroused by looking at the photo.
But what's Sch 40's wall thickness when you apply that pipe designation to a rectangular hollow section?
And me, I'd have bored right through the RHS to fit the bearing tube so the welds went all round it to avoid those 180º welds
tendency to warp the tube out of round.

 

[westonboege]

Are those cut and welded at the bends? Wondering how hard it would be to set my bender up to bend square tube... /rect tube.

My plan was to make it out of tube, possibly with an underbrace.. Square would be stronger but i dont know if i can bend it properly...

 

[member3480]

No you take the square tube and cut it 3/4 threw and bend it in and weld it up. Never used a bender on square tube. So you measure up how long you want it then do two 3/4 cuts to tube . Now it can bend in and weld those two ends to bearing tube that connect to frame. Then weld in cross piece. I setup the rear holes for axle first on both long square bar. Make a 20mm or 3/4" slot the same as axle. Then I make up the alum. blocks that slide inside square bar and drill 20mm or 3/4" hole in those. Drill and tap rear of block for threaded bolt to stick out back of arm for the adjustment. Then I measure make bends and weld it all up on a flat table with square tube held down. Look at picture you will see bends.

 

[mrtwowheel]

Oh yeah, positively yeah.

 

[westonboege]

Ah thats what i was wondering Daddyg! I know they make square tube bending dies, but it does deform the inner and outer faces of the square tube.

I should probably just use rectangle tubing huh... way stronger that round tube...

 

[fredintoon]

Ah thats what i was wondering Daddyg! I know they make square tube bending dies, but it does deform the inner and outer faces of the square tube.
I should probably just use rectangle tubing huh... way stronger that round tube...

Hi westonboege,
if it's the same steel and the same cross-sectional area the tensional strength will be identical.
It's the cross-sectional shape that controls the stiffness and while a tube beats an RHS in torsion
the RHS's 3" vertical dimension is stiffer in the up and down direction than is the equivalent ~2-1/2" tube.
And an RHS weld preps are far easier to do.

 

[westonboege]

Hmmm... Sounds like with dirt track and some hillclimbing(mostly snow) id probably want more torsional rigidity rather than in the up and down direction... Or am i wrong?

 

[TwoManyXS1Bs]

While riding straight up, or stable in a turn, there's not much demand on the swingarm's torsional rigidity.

Changes in direction (changing lean angle), entering a turn, exiting a turn, and hitting bumps while in a lean, induce torsional stresses on the swingarm.

Weave and wobble also induce torsional stresses...

 

[member3480]

Like I said before I have made these up for drag bikes up to 10" over with over 200 hp and for street bikes and not once did I have a problem with turns or bumps. Its a swingarm square not round and works the same but looks a hell of a lot nicer than what came with bike and if you want you can attach lower brace for looks. Good set of shocks and away you go.

 

[westonboege]

I know they work good. Its just im set up well for round tube( have a few sets of dies for the bender), so i was thinking i would make it tube. Im just wondering if its way better to do rect tube.... or if you dont really gain much from round tube.

 

[mrtwowheel]

Using the 1" wide rectangle steel, as DG did, the axle would have to be about 1" longer, right? I mean, the stock axle would be too short?

Gotta say, some Yamaha swing arms have been the flimsiest that I have ever worked with, while Honda swing arms are usually much stronger. A 650 Maxim was so weak that it could be tweaked any way that I wanted it bare handed, scary to think what went on back there with only casual riding.


Scott

 

[krob]

Looking good so far. Watching this one.

 

[westonboege]

I was in the shop yesterday waiting on a customer to drop off a seat, so i grabbed the clutch side engine cover and started drilling! Nice free performance upgrade lol! Also yanked the charging system out of there. But once i removed it i realized i didnt have a way to check the timing now... So ill probably have to bolt it back in and make some marks on the engine cover and crank spindle... Might just mount an aluminum plate with some marks scribed in...

Also got the rear of the frame cut back a little bit... have some more pics later on that...

 

[timbeck]

I love speed holes and they are probably good for an additional 10 MPH on the top end. lol
tim