Counter Balance Cycles Shop Race Bike

[westonboege]

Its been a while since ive built an xs. I just drug the chopper out of the corner to finish, and ive been dying to build a race bike for years. I was originally planning to vintage road race, but the way i want to build this i think would put me in an unlimited class.

I want to build it as a weekend shop race bike that could dirt track, street track, or hillclimb. I have a few sets of wheels that i could set up to work well for each. I pulled the bike out of the corner of the yard and the motor was seized.. I oiled it up and drug it into the garage. It should free up by tomorrow...

This will probably be a slow build process but i want to really get into building a race bike. I plan on working with aluminum as much as possible with this, and try to get more comfortable with it. I plan to run the motor on 110 race fuel. Possibly oxygenated but im not sure yet...

Anyways... heres a depressing shot of the bike as it sits seized and all...

 

[figure8]

This will be a fun one to watch!

 

[MrBultaco]

I'll watch........

 

[timbeck]

Hey Wes---This is what the "Big Prov" needs, a shop built multi track weekend racer. Take lots of pics.
tim

 

[Jim]

Watching.

 

[westonboege]

Should be a fun one. Im looking to shave weight... everywhere. Came across those Motolanna aluminum swingarms. They look stout... anyone use one?

 

[westonboege]

Oh and the motor freed up! Tried to kick it again right before i called it a night. Motor kicks through and has compression. Im just gonna get it running off of a battery and see how it sounds. Im doing this as low budget as i can, so if i have to open up the motor it will be only the essentials..... for now! lol

 

[gggGary]

Anything that you do to that sad little bike you're starting with will be a good thing!

 

[Mailman]

Looking forward to watching this!

 

[halfmile]

Hey Wes. I know of a really talented upholsterer in RI. He does "Killer" seats.

 

[westonboege]

@halfmile That looks familiar! Hope you like it man!!

 

[westonboege]

Got a little more work done yesterday... Got most everything torn off. Grabbed a set of biltwell tracker bars and some stock risers from the junk pile..

Next up is figuring out the back wheel. I been reading up and it looks like i can use a 19" front wheel (high shoulder alum) and use omars wheel adapter kit to run the 19" spoke on the back with a disc brake. Is this correct? If so that will be a huge help!

 

[westonboege]

Got a few spare minutes today between getting some seats made. Rough cut most of the tabs off the frame. Shaved a few more pounds.. Still debating how crazy i should get with the rear end. Im still thinking about the Motolanna Aluminum swingarm... although i havent heard anything about them... Im also thinking about cutting most of the rear end off ... making some mounts, and fabbing an aluminum subframe alot like the way the rear section of the early BMWs bolt on. I think the weight savings could be big.... especially if i can minimize the foot peg area... This might be something that I do after I get the other components working...

Also ordered an Omars front wheel adapter. Dug in my parts pile today and found a couple 19" front wheels. Ill use the shouldered alum 19 in the rear, and maybe just set the front up with a steelie for now. Next swap meet i should be able to find a decent alum shouldered front wheel...

Might scavenge some parts from some other xs's to get this one running for now... see what this motor sounds like...

 

[TwoManyXS1Bs]

Wes, could probably shed another coupla pounds changing out the motor mounts to aluminum plate...

 

[westonboege]

@TwoManyXS1Bs yeah ive thought about that, the back mounts would be easy. Front mount wouldnt be too hard, but would be nice to have a cnc for! Lol. Eventuall the swingarm - foot pegs mounts - rear section all will be redone lighter. But i really want to focus on unsprung weight first.

Can lose 5 lbs or so switching to this motolanna swingarm... has anyone used one of these? they weight 3.5Kg (7.7lbs) Stock swing weighs around 11-12lbs.

 

[gggGary]

We're all just too danged cheap! but I always hear good about anything from motolanna. IIRC He has two different arms, one cast, one welded??

yeah here's the other.



us po-boys search out radian swingarms.

 

[westonboege]

Ive been searching for radian swingarms but i havent found any for sale yet. But i also read that there are some mods you have to do to mount the radian too correct? Have to buy a bearing kit or something?

I know the radian is stiffer/longer and you can fit a bigger tire... is it any lighter?

 

[westonboege]

Im pretty far from the swingarm right now... have alot of other stuff to figure out... just trying to think ahead before the next swap meet! Get my grocery list together! haha

 

[fredintoon]

Ive been searching for radian swingarms but i havent found any for sale yet. But i also read that there are some mods you have to do to mount the radian too correct? Have to buy a bearing kit or something?
I know the radian is stiffer/longer and you can fit a bigger tire... is it any lighter?

Hi westonboege,
to "simplificate and add lightness" is always a good thing. Some thoughts on that:-
Bolt-on aluminum rear frame. Great but bolt-ups need careful design to avoid the hinge effect.
Wider tire with Radian swingarm. Regardless of which swingarm is used, any tire wider than the Special's 130 width will hit the chain
unless you run the rear wheel dogtracked to the right.
&FWIW I checked the weight of an XS650 front aluminum rim wire wheel vs an XS650 front cast wheel some years back.
Within the accuracy limits of balancing each wheel on a bathroom scale, I couldn't see a difference.
Mind you, replacing the giant manhole cover the XS65 uses for a brake disk with something modern could save a pound or two.

 

[westonboege]

Thanks @fredintoon i kind of forgot that the chain would be the choke point. I have that omars kit coming, now i just have to bite the bullet and see if a 7.5 dirt track tire will fit in the back.

Ive worked on a few bmws... the rear section on those is bolted in four places. I couldnt believe that they only used 4 small like m8 bolts to hold the whole rear. Idk originally I thought it would be cool to have a bolt on rear section. Could swap them out depending on the geometry I want. Its probably not worth the time.

I think id be better off cutting out the rear section and rebuilding it with some 4130 chromoly tubing...