CB360 - Monoshock Brat

compoundcycles

New Member
Hello. I've been lurking in these forums for a little while now and love all the information and inspiration they provide. I'm starting a build and want to post the log here for further support and ideas.

Donor Bike: 75' Honda CB360

Build Goals: Monoshock, Cafe/Brat spirit, Custom exhaust, Stealthy wiring, Healthy tires (Dunlop K70's maybe), Tach only.

Here's the donor bike...
 

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compoundcycles

New Member
First thing first, strip the bike...

This went pretty fast with the help of my roommate. The pistons, rings, and cylinders were in great shape...despite being slightly dirty. The cylinder head camshaft cradle and rocker arms have some excessive wear. This will be replaced. Broke down the carbs and found them to be fairly clean to begin with.

I was thinking about replacing the stock Keihin carbs with this kit from DCC.

http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-motorcycle-carburetor-parts-mikuni-30mm-carburetor-mikuni30mm-001-247.html

Does anyone have experience with these "pre-jetted" carbs for cb360's? How worth it are these over the stock carbs as far as performance. Any jetting tips for the stock carbs that would bring them up to their full potential?
 

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compoundcycles

New Member
I'm kicking off this build by knocking off any tabs and brackets I don't need and grinding down any excess weld slag from the factory.

I'm shortening the seat as this will be a single rider bike. Mocking up the rear loop with a temp piece for now. I was thinking it might be aesthetically pleasing to have the rear of the seat loop centered over the rear axel. Any thoughts?

Any good tips on bending the rear hoops or welding a bunch of links together to make one? I'm assuming I'll be searching for someone who does pipe bending in the near future. I'll eventually need a U bent for the swing arm brace as well.
 

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7aliveatlast7

the bearded hessian
i personally find that subframe setup to be a bit too stubby, but that's just my .o2. interested to see how your monoshock goes in as i recently did that to my kz440. nice work so far!
 

compoundcycles

New Member
Thanks 7aliveatlast7. I too am interested to see how the monoshock goes in ;) I'm going to retain the original swing arm and reinforce it with a secondary one, very similar the the first picture in the inspiration images I posted. Stubby yes, but hopefully it can stay compact, I really dig smaller bikes.

I love pipes and exhaust on your kz440, it a very cool looking bike. Nice work.
 

compoundcycles

New Member
While I think more about what needs to happen with the frame and acquiring a shock I figured I'd get to cleaning and painting the motor.

Lots of taping, blasting, and spraying in my near future. Taping by far takes the longest. Starting with the cylinder I might remove the paint from the edges of the fins to let the aluminum show through after its cured.

I'm using Duplicolor Engine Enamel (Black Gloss). It rated up to 500 degrees. Does anyone here have experience with this paint and how it holds up used on cooling fins, or general motorcycle engine areas? Would be good to know first hand before spraying the whole thing.

I'm leaning towards polishing all the covers...clutch, points, generator so they will be silver against the black of the engine.
 

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compoundcycles

New Member
Thanks for the info about the tires Swivel, they're something I don't know much about. I had a pair of K70's on my first bike and they seemed decent to me. Although they were cheap in price, which usually means cheap in quality too.

I was mostly referring to knocking off the factory slag around the tabs I was removing. However, in some welds I've actually found loose wire feed from whatever arc welder they were using the in factory...that, I'm certainly getting rid of. All good points about keeping the strength of the welds though.

I know I've got my work cut out for me with the monoshock, but I'm in no rush, and the challenge is half the fun (or frustration). I really want to work on my fabrication skills. Thanks for checking out the thread.
 

Kanticoy

Mad Science!
DTT BOTM WINNER
Re: Re: Re: CB360 - Monoshock Brat

Swivel said:
Don't copy that thing.Whoever built that Honda had no engineering knowledge regarding monoshock setups.Bad shock geometry,weak and flexy.I'm surprized the rear shock mount hasn't bent or broken off.
Thanks swivel. I built it. I ride it regularly, and it works just fine. Do your fucking research before you spout off your lack of knowledge to people who are trying to learn. The bike you're bashing is a well documented build that goes safely down the road regularly. I normally withhold my comments from your posts and give you the benefit of the doubt in most cases, but don't comment on anything you aren't 100% sure about.

Sorry for the derail OP. Have fun with your build and if you need any help, let me know.
 

cyclefreak

New Member
Re: Re: CB360 - Monoshock Brat

Big Rich said:
Hahaha! Imagine that, Swivel talking out his arse.......

Swivel, why don't you show us your welds? Or the frame they are on? Or anything other than your close minded opinions? Or just shove off.,....which is the popular vote here.
Rich I think there was actually a thread STARTED BY swivel that is supposed to show all of his expertise..........Oh wait he never posted anything he has done on it either.
 

cyclefreak

New Member
Re: Re: Re: CB360 - Monoshock Brat

Swivel said:
Go find a hate Swivel thread somewhere and avoid threadjacking this guys topic:capiche?
Every place you show up turns into a "hate swivel" thread.
 

VonYinzer

Active Member
Compoundcycles: Sorry to see your thread turn into this. Monoshocking a 360 is a HUGE undertaking, but as pointed out by Kanticoy, its completely possible. No matter Swivels need to find fault with everyone and everything, Kanticoys bike has about a week of research done for every hour of fabrication time. Its a sturdy and completely real world functional design. As you'll notice with the more time you spend here, Swivel has a lot to say yet has shown us no reason to trust his "knowledge".

That said, Ill repeat, monoshocking a 360 is HUGE undertaking. You need to determine a large number of things before beginning. Shock angle and spring rate. Material strength and frame geometry. You need to be sure of your welding capabilities and techniques. Ths list goes on and on, but don't let the difficulties sway you. Its 100% possible, as Kanticoy has shown. Just remember that during the process safety and proper engineering is of the utmost concern.



Swiv, wheres your bike.
 

cyclefreak

New Member
I need to apologize also for hijacking your thread. Like Von said it is doable but whether it is a mono shock conversion or any other major redesign of the bike a lot of research should be done. There are many knowledgeable people here (like Vonyinzer and Kanticoy) who are great guys and more than willing to help you out.
 

neevo

New Member
Have a look at an RD350LC shock as a springer if you're keen to go down this path. It's not hard, just a little complicated and you need to be considered and thoughtful in your approach.

The RD shock is linkage-less (good) and comes in a 290mm eye to eye version. Swingarm brace is required along with sturdy mounts at frame and on swingarm (5mm plate is good and solid).

Watch clearance at the top with the spring (against the frame) and get a pro to bend the swingarm brace out of something strong like 25.4mm or 22mm x 2mm stock.

I'm in the middle of doing mine and working out spring rates and weights. Can share some thoughts if required, however I'm no expert, just took the feedback from here (including Swivel's who's helped me a bunch) to get to where I am at now.
 

compoundcycles

New Member
Whoa! I step away for one minute... hahah.

Kanticoy - Your bike looks awesome. What shock did you use? How did you figure out which one? I was thinking of finding a bike of a similar weight to get the shock from. Do you have a build thread?

Neevo - I just finished scanning through all 94 pages of your build. Looking good. Awesome build and documentation. Thanks for the info, can't wait to see more updates from you.

Thanks everyone for the encouragement. I will have lots of questions weeks to come. I'm trying to learn as much as possible in the meantime. I'm spinning my wheels prepping parts for blasting and painting while the weather is wet.
 

neevo

New Member
Yeah it's a bit out of control the thread, hopefully it helps someone out though as I've made a few errors over the time ;)

There are plenty of great minds on this site, use them well. They've steered me along the way.
 

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