CB350 cafe, a mix of old school & new


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Owned a few bikes over the years, and always wanted to build a cafe. Found & joined this forum recently. Have gotten some ideas and inspiration - Thanks!

I like some of the cues of the old school with the seats, tanks, rear sets and paint schemes. Also like new technology, so a mono-shock swingarm & inverted forks are on the list. Planning on keeping the 350 engine and do some performance mods. Not too radical. Maybe a Megacycle cam, Wiseco pistons, port & polish the heads and a custom exhaust.

This won't be a quick project. Hope to have it done by spring/2014.
Here's a few pics of the bike, parts and work so far.
Welcome any suggestions & comments you might have. Thanks

1972 CB350 just after I got it.

'99 CBR600 swingarm & brakes (probably not the best choice, but the price was right)

'08 GSX-R750 forks

Not sure these will work, but they're from a Yamaha Rhino.

Thinking about this for the speedo & tach. The gauges can be ordered with just about any span, and they can swap the speedo & tach, so the tach is the larger gauge. Not 100% sure... its kinda large, 4" dia., and its a bit pricey


Plan on using the stock rear CBR wheel and front GSXR wheel. Front wheel hasn't arrived yet, but here's the rear in the process of blasting it before powder coat.

The stock CBR axle is larger (and longer) than the CB350, so I took out the frame bushings by heating the frame tube with a propane torch and working them out with a brass drift.

Put them on the lathe and opened the holes. Only had a 25/32 bit and I needed another 0.002", so I used a brake hone to finish sizing them. Here they are back in the frame. I'll weld outer supports to frame also.

Pic after frame was media blasted, some brackets removed and the swingarm in position (before bushings were re-sized)

Sprocket alignment will be a challenge. With a rough measurement; it looks like the CBR rear sprocket is wider by about an inch, compared to the stock engine sprocket on the 350.

Initial thought is to weld a section of a counter shaft onto the original. This will take machinery I don't have. Fortunately; I have a friend that might be able to help me out. Let me know if you have any other suggestions.


New Member
Thanks Rich

Thanks Gman, barn was built in 1992 and slowly morphed into a place where I work on cars & bikes.

Won't be using a CBR600 engine. Plans are to keep the 350 and do some performance upgrades.

Not a lot to update, but did install the All Balls conversion. Went smoothly; only hitch was the bottom of the frame head had to be ground to allow clearance for the triple tree.

Marker lines is how much had to be taken off.

After installing the forks; strapped the frame to the hoist and put the front & rear wheel on.

Initially set the ride height & rake angle by using a piece of scrap strap.

Used a piece of angle iron to replace the strap. The rear suspension and sprocket alignment are next.
Here's a few pics of the work so far.



New Member
Took the engine apart to clean it a bit. Put the cases, cylinder & head back together to check sprocket alignment.

Here's some pics of the engine

Engine back in frame (temporarily)

Waiting on the rear sprocket. Then I can start to look at how to align them. Rough measurement is about 3/4" offset from one sprocket to the other.


New Member
Took some time off. Sorry for the delay. Haven't done a whole lot, but here's some updates.

Bracing for mono shock top connection (pic before final welding)

Right side bushing in place ('99 & '00 CBR swingarm has a fixed right bearing, and the left one floats in/out)

Left hand bushing in place - pipe section is just a spacer. Wasn't going to have outrigger supports, but they'll be part of the final frame, more on this later



New Member
Thanks guys

More pics (forgot some...)
CBR600 rear sets - final supports are in the works

Center support

1" tubing was contoured and slid into position (very tight fit) - tacked in place

Lower end welded in place

If you look closely at the tubing you'll noticed some metal re-enforcement. The bolts where the air filters were will be tightened down, cut and welded in place. Will do this after frame is final welded.

Hope to have more updates next week.


New Member
Outrigger supports. Left is removable, Right is welded in place. Additional strut bars installed.



New Member
Overkill for sure...

Some updates

Been working on the frame, just about got it ready for powder coat. Refitted the engine shell with countershaft to align & take the offset measurement between the rear & front sprocket. My initial take was about 3/4". I was way off. Ended up at 34mm (about 1 5/16"). Three options. Two of which involved making an offset sprocket. The other was to extend the shaft out 34mm. I went with extending the shaft. Lots of research and homework went into this. Since I'm into cars too; many customs have cut & welded half shafts (drive shafts) successfully. There is some tricky spots, but here's my approach after consulting with Miller Welding, Alloy Metal Treating and multiple web sites.

-Purchased another counter shaft.
-Dropped both shafts off to be annealed
-Cut one shaft to the right length
-Threaded the shafts so they can be held together
-Beveled the edges for welding

I had .002" runout on the stock, original shaft. After welding; its at .003". The shaft is currently getting heat stressed (checks the welding and insures a good starting point for heat treating (60 durameter) finish. Heat treating may also "grow" the shaft, so we'll see how it turns out.

Here's a few shots before welding. I'll post more updates when I get the shaft back.
Oh... some of my friends think this is a science experiment... we'll see :eek:

Going with a 525 chain versus the 530 (CBR swingarm sprocket will be kept stock, 525/45T). The 530 is wider than the 525, so had to come up with a way to turn a sprocket down. Ended up using the reminder of the cut off countershaft, welded on the collar for the seal, then trued the inner surface. Drill and tapped the end.

Another shot with the sprocket mounted & machined down on each side.

Made up a seat pan out of 16ga steel. Didn't have a big enough piece, so thought I'd try to join two together. Not real happy how it turned out. Too narrow by about 1/4", and the the seam in the middle was bugging me.

Went to the mill store (they're getting to know me by first name). Bought a piece of 18ga ($5), and formed the bends with a piece of pipe and angle iron resting in the V blocks of the press

Pic of the newer (2nd try) seat pan with the rear CB175 tank section. Still a lot to do to get this to work, but its coming along (shown before upper tubes get cut, which will bring seat/cowl forward about 3 1/2")


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You can't be... we know you got a pretty good grasp on the science stuff ;)

The weather & my procrastination have me about a month behind schedule :(

Some updates

Extended countershaft with bearing and collar pressed back on

Mounted in case with other gear cluster

Tray for the battery & electrical. Tacked in, just need to finalize and weld it it.

Decided to go another direction with the voltmeter. Ended using a small digital type in a piece of machined aluminum (pressed into triple tree). Not the best pic, but gives you an idea of what it'll look like.

Starting to mock things up.

Will need to increase the diameter of the stop bushing... headlight brackets hit :? :(

Much more to do.
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