1980 CB750F for $180, modern suspension and upgrades for a cafe racer build

djmaynard

Member
japstar said:
But why? :p
Nothing goes more hand in hand with the cafe racer spirit as swearing on your goddamn bike while getting the carbs just right.
And than screaming of joy when riding the bitch with those sexy ass air pods 8)
I had bought pods for my bike as well, but chose to stay with the air box so it would be easier to tune. LOVE the look of the pods, just couldn't tune it in.


82 Honda CB900C is my first attempt of a bike upgrade
 

grandpaul

Author, "Old Bikes"
DTT SUPPORTER
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"Left turn, Clyde"

-Philo Beddoe (Clint Eastwood), to his orangutan buddy, in "Any which way but Loose"
 

Papinbrew

New Member
Currently stuck sorting out ignition problems. I bought CBR600 coils, tested them to find I wasn't getting spark from the right coil (cyl 2-3), so I tested igniters, tested both coils, and found my problem to be one of my pulse generator coils. I found a local shop yesterday that let me pull a PG from a CB900F, only to get it home and find out that the opposite coil was dead too. So I've got two PG assemblies with opposing faults. I'm going to swing back by that shop to see if he's got another one I can test with my multimeter before I spend my time pulling it, and if not then my Franken pulse generator project will begin. I'll end up having to pop the connecter pins from the connecter, and attempt to thread the leads through the harness wrap, and then assemble two known good halves into a single working unit. This kinda sucks, I wish there was an affordable aftermarket solution that I could perform instead of having to source used ones that may or may not work. I've seriously lost sleep obsessing over this build, and through a process of elimination I WILL conquer this project.
 

Papinbrew

New Member
Got a new PG from another 750 donor engine. Tested exactly equal on each coil. Spent a bout 4 hours last night ultrasonic cleaning and hand scrubbing the panels and side covers to get a bunch of grooooossss shit out of, got the new PG in, buttoned up, and tested the ignition system. 8ve got a solid spark on all four plugs now, and it was too late for me to fire it up so I left the project for later today. Gonna attach my carb bank and fire it up hopefully! 8)
 

Papinbrew

New Member
I fired it up over the weekend. Pretty easy start too! Turns out I've got some engine work to do, the rings are not good in cyl 3 and 4. Will be pulling the top end soon. Any advice for rehoning with factory size rings, or should I get the speedmotoco 823 kit and bore out? Should I replace crankshaft bearings as well? I'm trying to compile a list before I fully jump on in this pool.

https://youtu.be/sIx4x30pJhc
 

Papinbrew

New Member
Got the frame fully stripped this last weekend. Ordered some cam bolts, viton valve seals, and polished stainless dress up bolts for the engine. All parts tucked away until I get the time to start scrubbing them. Any ideas for getting frozen caliper pistons out?

Engine is set aside, still need to get a space and the headset to start disassembling to see if I can just hone and re ring, or if I'll be boring the jugs and dropping CB900 pistons in. We'll see. I'm still pretty nervous about pulling the engine fully apart especially because I have absolutely no experience, but live and learn. .

As of now, I'm considering a golden bronzed powdercoat for the frame, calipers, and a couple engine covers, the engine and forks gloss black, and the fuel tank a candy metallic red. Lots of time still before I will be ready.
 

Attachments

K

Kamn

Guest
Toss your calipers in a pot and boil with lemon juice and water for a little while
That should free up the Pistons some what so you can pull them out nicely
 

MotorbikeBruno

Active Member
Kamn said:
Toss your calipers in a pot and boil with lemon juice and water for a little while
That should free up the Pistons some what so you can pull them out nicely
Yep^ works for me if they are a complete pain to get apart.
 

Psycrow

Member
drain remove Bango bolt and replace bleeder screw. Wrap a towl around it and hit the banjo fitting with compressed air. ... jam a stepped air end in there for a good seal. be prepared for a heck of a pop... I've done dozens like this but it's not for everyone... ymmv
Psy

Sent from my SM-G903W using Tapatalk
 

Papinbrew

New Member
Psycrow said:
drain remove Bango bolt and replace bleeder screw. Wrap a towl around it and hit the banjo fitting with compressed air. ... jam a stepped air end in there for a good seal. be prepared for a heck of a pop... I've done dozens like this but it's not for everyone... ymmv
Psy

Sent from my SM-G903W using Tapatalk
I'm bringing them by my local custom shop tomorrow to attempt just that. If that doesn't work I'll give the lemon juice boiler technique a try, or dip em in pines ol or simple green in my USC for a day or two.


Unrelated, has anyone had any luck finding swingarm needle bearings for this style bike? OE part number is:

52108-425-831
 

Papinbrew

New Member
Got two of the calipers apart. I soaked them in Kroil, and compressed them with a clamp, then used a screwdriver and a pair of pliers with a rag to pull them apart, but the third one is giving me some real grief. Gross. Looks just as bad as my 85 MAGNA when I did them. At least I know I'll be powdercoating these so the paint doesn't matter.
 

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Papinbrew

New Member
Bugger. I ruined the third caliper; stripped the threads clean out of the bleeder hole. Looks like I'll be hitting up the boneyard for a new one. Oh well, 36 years old and sitting outside for 11, it's gonna have issues.

Well I was also able to pull my diaphragms out of the carbs again, and polished up the internal sliders. My carb 3 diaphragm was sticking, now it's totally smooth and free.
 

Papinbrew

New Member
Ordered a grip of parts today, getting my shit done!

Engine gasket kit
Headlight with integrated LED SIGNALS
Chinese ebay master cylinder controls
Swingarm bearings
Front Wheel bearings
Rear wheel bearings
Brake pads x6
Steering head bearing
Valve lapping tools
Valve lapping compound
Two k&n oil filters
Por15 starter kit to seal the tank
Fuel petcock
Updated starter solenoid
Torque wrench


Next pay period will decide, either new rings and a rehone, or a bigbore kit.

On the list is Shinko 705 tires Front and rear. I think that this color scheme of Gold frame, gold calipers, gloss black forks, gaitors, black rims with gold trim, black rear shocks with gold trim, gold chain, and black leather seat with maroon stitching, black grips and bars, and a marbled candy wine red tank with the Fenrir wolf decal in gold from FFVII on each side of the tank..... drools. I can't wait
 

MotorbikeBruno

Active Member
adventurco said:
I like my Shinkos.

If you need some custom decals made I'm your guy.
I agree. A few years back I would have agreed with you XVRacer. But they've come a long way. I've got a similar set if not the same on the wife's bike. 2k miles and they still look new, ride great in the rain and go down a dirt road quite nicely too :)
 

XS750AU

Member
Hi Papinbrew
You are probably going to strip more than one thread on a project like yours! Bloody expensive to get a replacement casting every time, especially if it is an engine case. Suggest you try a Hellicoil to fix the thread. It means you need to drill out the hole, tape a new thread and screw in the thread coil (looks like a spring) and your done. The kits are a little expensive but from then you can replace many more threads. There are cheaper thread repair kits on EBay which are OK. The caliper is a good cheap place to start!
Good luck
Tim
 

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