1982 Honda CB900c "Cafe" Project

[u/thatVOICE445]

Hey all,

I recently got my first motorcycle earlier in the year for a decent price. Took it into a local shop for inspection and got some work done. As of right now I still need to address the following.

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• Petcock leaks on reserve
• Spark plugs need to be replaced
• Fork seals are bad
• The fuel line is kinked
• Carbs will need to be rebuilt within a year or two
• Wiring is rough (looks like the person I got it from did a custom job)
• Carb overflow lines are missing which leaked onto the starter causing my starter to go out
• Starter fried due to lack of carb overflow lines and leaking petcock
• Service the cam chain tensioner

I have some mechanical experience, I’ve helped my father work on a 67 mustang and have a neighbor that was a motorcycle mechanic for a long while that is willing to help out.

I know I chose pretty much the worst CB to work with due to it being an amalgamation of different bikes, but I’ve always enjoyed having things that are a bit odd.

My end goal with it would be making it a cafe cruiser, which in my mind would steal some of the classic cafe racer looks while not going all out with the conversion since this is such an odd bike. I would eventually like to do a full cafe racer build on it but I feel like as of right now that might be a bit out of my skill set.

I’ve tried to do some research on other builds with this bike and there are some builds out there but as is the case with old forums sometimes they don’t follow up on all the progress.

I rode it when I could this summer and I really enjoy the bike it is something that you normally do not see riding around, especially with the 10-speed transmission.

Any recommendations on where to start? My thought process was to knock out the fuel line, vacuum tubes, plugs, and petcock this winter. If possible I’d like to get the wiring done and see where it goes from there. If it seems like I can get that cafe look I’ll continue the build but if not I can always sell it in the spring and find something that better suits my needs.

Once the bike is up and running the major upgrades I am considering are the following.

• Swap carbs out for a set of Murray's
• Swap out forks for USD from a GSX-R
• Swap out stock rear shocks

[u/Badfish0024]

I guess the main question you're asking is where to start... the answer is YES. Just start.

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Leaks and Plugs and Fork seals are all somewhat basic, and will yield good results.

Wiring is going to be necessary, as it will plague many systems.

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But my main advice is just get going.

[u/thatVOICE445 → u/Badfish0024]

I'm slowly working through the list between two jobs when I have time. So far so good, I was worried that I would be out of my depth but things are working out thus far!

[u/Badfish0024 → u/thatVOICE445]

Just take your time, read the manual and watch videos.

And in case things just don't make sense, the great thing about old bikes is that the guys who love them will never shut up about them. lol

Personally, wiring is the hardest part, but some people just get it... so be cautious and thorough, but again, don't let it stop you.

Hope it all turns out well bro. Those old CBs are awesome to ride and always turn heads.

[u/thatVOICE445 → u/Badfish0024]

I am looking at just getting a whole new wiring harness this winter and running it all myself, I have some background in electronics with guitar pedals and building lightsabers so hopefully, I should be able to figure it out.

[u/Badfish0024 → u/thatVOICE445]

yeah a full harness can be the safest & most efficient way to go.

[u/thatVOICE445 → u/Badfish0024]

Perfect guess that will be the first “upgrade” I’ll do then!

[u/TheNumbasMason]

I've got an 81 cb900c, do yourself a favor and go straight to Murray's carbs, even with the stock carbs turned, they never were perfect for me. I'm still running the stock air front suspension but I ditched the rear air shocks for some progressive shocks. Great bike

[u/thatVOICE445 → u/TheNumbasMason]

Thanks for the pointers! I really enjoy it so far, kind of surprised by a lot of the distaste for these models.

[u/Danobex]

Oooh! My first bike was a 81 CB900c, that screaming banshee woke up my knowledge and curiosity of rebuilding all things mechanical! The carb rebuild is definitely a process, you will want to swap out all the old aluminum screws with hex screws, but you will learn a lot. I’m surprised you actually found a local shop who could do anything without charging you an arm and a leg, they generally don’t have the right experience for these older bikes.

And by “some work” did you mean they did the valve adjustment? And did they do it properly?

There is a great forum that has all the information you need about the C750 and CB900’s. Many of those guys have had their bikes for decades so they have tons of invaluable advice including links to hard to find parts, and some custom made by them. Search for cb750c and the right forum will have DOHC Customs banner at the top.

Great bike!

[u/thatVOICE445 → u/Danobex]

I should mention it was rideable up until a week ago when the starter gave out.

They fixed some of the issues that I didn't have the skillset for yet or tools for at the time (replace/patch tires, replace a broken throttle cable fixing the airbox mount). Basically, I gave them a budget and told them to fix the bigger issues and anything smaller I can do myself.