'73 CB250 - Doing it right this time round.

[xb33bsa]

I 'think' I may have sourced a cl350 brake lever to modify so I can connect my rear sets properly. Going off of cmsnl, it looks like it will mount directly to k4 frame using the same mounting bolt.

Does anyone have the dimensions of the rear brake pivot bolt, or one lying around they don't need?

i am sure i have one but there is a simpler more reliable,better feel,better action, more efficient solution,and much more elegant
proven in literally billions of militasry pleasure and commercial aircraft flight hours,in fact i would bet money 99% of the airplanes ever flown use cable and pulley for flight control ,jillions of sailing and racing powerboat hours,used in countless industrial applications (elevators for one)
using a simple cable and one pulley mounted in close proximity to the swinger pivot
all that it requires ,strictly requires is an adjustable up stop at pedal and a good strong spring return at backing plate lever
i can draw a simple schematic if you are interested

 

[Green199]

Thanks for the offer XB but I don't really want to go down the cable route on this bike. Trying to keep the brake setup as clean as possible and the looping cable just doesn't sit well with me. I'm not a heavy rear brake user so the added efficiency and performance a cable offer isn't a necessity for me at the minute, although in future it may be revisited.

I think I have sourced a pivot bolt now, so I will use the stock brake linkage and rear brake pivot, and just connect my rear set to that.

 

[xb33bsa]

Thanks for the offer XB but I don't really want to go down the cable route on this bike. Trying to keep the brake setup as clean as possible and the looping cable just doesn't sit well with me. I'm not a heavy rear brake user so the added efficiency and performance a cable offer isn't a necessity for me at the minute, although in future it may be revisited.

I think I have sourced a pivot bolt now, so I will use the stock brake linkage and rear brake pivot, and just connect my rear set to that.

you will be fine with that the main thing is you will have an upstop adjustable brake again !
but the cable pulley deal is a much cleaner less complex function and look
i am are talking about a single strand of 1/8" diameterr extra flexible cable like a compound bow has but of course aircraft use it as well
it would run from rearset forward behind the frame not out in plain view pulley hidden from casual view behind frame as well
its an almost invisible syste\m the only thing really seen is the single skinny 1/8'' cable run to the rear
in fact an outdated compound bow is a great donor of cable and a pulley
the wrap around 180 degrees is not an issue at all because in a single action application, as this is, the entire basis of the design is the cable is always in tension the level of tension varies but it cannot go slack
i was thinking you could grasp the concept,why i brought it up
the only way for slack is failure of the return spring

 

[Green199]

yeah I can picture the setup, but it will be cheaper and easier for me at the minute to go down the modified bell crank and mechanical linkage as it saves on fabrication and part sourcing.

Got a few days over the Christmas holiday where I am back in Cornwall, and trying to finish the bike completely in that time.

 

[Green199]

Right, back in Cornwall for a few days over Christmas so I'm hoping I can get the majority of the stuff left to do finished.

Overnight I sprayed my gear linkage, just need to find suitable bolts to connect it.

I also had to wrap my pipes because I couldn't clean up the rust spots. I prefer the unwrapped look but this will do for the time being and looks a bit cleaner I guess.

I got the eBay brake arm through and it looks in pretty good condition, so tomorrow I am going to make a start on the rear brake linkage and bellcrank. Also going to clean up and paint the fairing brackets.

 

[Green199]

Modified, tidied up and painted the fairing brackets. They are drying over night so pictures will come tomorrow.

I also fabricated the rear brake bell crank to connect to the rear set.

I don't have the return spring (cut the frame mount off years ago :-[ :) or the brake adjuster as the lever didn't have it. If the spring from the drum brake itself aren't strong enough to return the lever satisfactorily I will get a spring and use a bolt tapped into the frame as the mount.

hopefully I will be doing the linkage tomorrow when I can collect my tap and die set from storage.

 

[Green199]

Sprayed the bellcrank overnight, and fitted it this morning. Works a treat. Think I may just have to add a return spring in future and possibly try and gain more clearance to the exhaust for when the new brake shoes wear. At the minute it stops about 1-2mm short of the exhaust at full engagement, but obviously this will increase in future.

The bellcrank meant I could run a stock brake light switch, so its tidied that area of the bike up now!

I also sprayed up my fairing brackets and my speedo mount as I didn't want it chrome any more, so out with the gloss black!

So its just 2 small indicator brackets, swapping out a few bits of hardware for stainless + brass, and then a few little wiring issues to sort.

I've lost spark on one coil and my on/off switch isn't working right now, so I will take another look at them soon.

 

[Green199]

Re: '73 CB250 - "Alil".

Presenting.....Alil.

Stands for 'A Lesson In Learning', as I wanted to teach myself how to do everything I wanted done on this bike myself. Sure I could have got other to do certain things which would have been tidier and quicker, but I wanted to do everything on this so I know the ins and outs of what was done. I appreciate all the help I have got along the way from all on this forum! Definitely what got me through more than half the build!

Apart from a bit of tinkering with the wiring (on/off switch still isn't playing nicely, only running on one cylinder at the minute) and some new simple rear indicator brackets....she's finished! Hopefully will sort them out and get her MOT'd when i'm back around Easter.

So I got a few finished shots from Dartmoor for you as I know how much you all love pictures.

 

[AgentX]

Fantastic work!!

 

[HerrDeacon]

Without a doubt one of my favorite bikes on DTT.

 

[smarsh]

Really is one sharp & well executed build.

 

[Green199]

Thanks very much for the kind words guys! Happy new year to you all!

 

[Erskine]

Well done mate, this is true class.
Happy New Year!

 

[Green199]

Well done mate, this is true class.
Happy New Year!

Thanks very much Steff, Happy new year to you too mate!

 

[Steve-E]

If I wore a hat, I'd take off to you..... Nicely done.

 

[yorkie350]

Class pic's class build class paint scheme gotta be proud mate great thread wots next haha

 

[Green199]

Thanks gents!

Whats next hey? Fuck all hahaha. Get this one 100% during Easter then get some bloody miles on her! ;D

 

[yorkie350]

Haha that's what I said then I found myself in DK motors in Stoke buying a gs550e now i'me at it again , keep going mate soon be riding weather

 

[Green199]

Haha that's what I said then I found myself in DK motors in Stoke buying a gs550e now i'me at it again , keep going mate soon be riding weather

Just saw you got another one! Gonna be watching it mate!

 

[Green199]

Thanks to Herrdeacon, I have been nominated for BOTM (again, 2nd time lucky! haha). Really appreciate that my effort that I put into the build has been recognized by fellow builders here - win or lose.

Cheers for all the kinds words fellas!