Half-Caf: my '80 cb750f SS cafe project

[Half-Caf]

Over TWO MONTHS since my last post!
Bet you all thought I was dead

Now let me do my best to fill you all in...
Last update I posted was when I finally installed the 900 engine I built and found that something in the trans was locking up
Truth be told, I lost a lot of steam with the build after the engine I spent 2 months building didn't work out.
I also got pretty lazy with the pics because I no longer have my little point and shoot (also why all these pics are off my phone)

Anyway, I ended up stealing my newly painted parts off the 900 engine and slapped them on the 750.
I kept the 900 carbs because they were clean, blocked, and rebuilt. I added another accel "super coil" which gave me a matching set. Of course, I got some fancy new plug wires to go with

Then, I fired up the bike and she ran  (and shifted) Although I shouldn't have been surprised, I was definitely relieved...

Next came the carb synching. When I started, I had absolutely no idea what I was doing: basically just a dummy with a screwdriver. But after a little fiddling and some reading I figured it out and it wasn't too bad.


I started to get excited about actually RIDING, so my attention turned to making this thing street legal again. With a little experimentation, I was able to sort out the wire map for my snazzy LED tail unit.
Crimped connectors made the testing much easier


It cleaned up nicely after soldering and some cable sheathing


Finally: TEST RIDE
...
...
...only to find a horrid metallic noise from my front discs. Turns out the axle spacing was off, causing the discs to rub on the actual bodies of the calipers  I guess that's what you get for running a cbr front end with the original comstar.
The problem turned out to be that the speedo drive was too wide. Naturally, I wipped out my dremel and said, "no problem, I got this"

I outlined the raised portion with a sharpie for reference


and made some very rough progress


I quickly went to Home Depot and picked up a proper carbide bit which did wonders. I was left with a nice, flat clean surface that my phone had a particularly difficult time capturing
However, after all that, I found the cylindrical portion where the cable goes in was ALSO contributing to it's width.
Oy vey... I used my fancy carbide grinder to make a small groove on the bottom of my fork tube and was left with a picture perfect fit (which ironically, I have no picture of)

Next on the list was to sort out that rat's nest of cabling I had


The bracket helped bring a little order to the chaos


But mad skill and raw talent really finished it off

[Hellbilly429]

Awesome man, so is it rideable yet?

[Half-Caf]

This week was the first time ALL YEAR that I was actually out for a proper ride. It does feel good to be out there again.
And of course, I wouldn't leave you all without some more crappy cellphone pics!

Snapped this on my day-long quest to find a 90 degree screwdriver for my carbs


And this morning I even took her out to see the sunrise (which was less than spectacular)
But the bike looked good!


Here you can see how nicely the rear end came together


As you can see from the pics, my newly painted gas tank made a visit to the garage floor one day and has the scars to show for it. But that leads me to what my weekend plans are:
Instead of filling the dent and going back to the norm, I am going to taker a hammer to both sides and make some nice handlebar indents. 99% of the time the bars have enough clearance, but I swear I am going to break my thumb one day backing out of my garage or turing around in an alley.
I will also be doing a muffler repack and hopefully get around to a little fine tuning of my fuel mixture.

[Hellbilly429]

That's great half-calf, looks good! How's the power with your 900 swap?

[Half-Caf]

Hellbilly429 wrote

That's great half-calf, looks good! How's the power with your 900 swap?

Ended up having to put the 750 motor back in due to 900 trans issues.
My guess is that the shifter forks went in wrong. I had one hell of a time with those...

Not sure if I wanna tear the entire thing down again to check the forks or if I will just steal the 900 cams and cut my losses. Either way, I'll save that for down the road.

[TOOLS1]

2 Months. In my world when someone disappears, for 2 months, they are probably in jail.
On your 900 trans, all you need to do is turn the engine upside down, and take the bottom case off. No need to tear the whole thing down.
TOOLS

[shinyribs]

Aw man! NO 900!?   Well,poo


It's all good.Your bike still looks killer and that tank is just suh-weet!

Good to see ya around-alive and kickin'

[Half-Caf]

TOOLS1 wrote

On your 900 trans, all you need to do is turn the engine upside down, and take the bottom case off. No need to tear the whole thing down.
TOOLS

Thanks for the tip. I thought there was one bolt under the jugs I needed to remove
I will definitely be checkin it out this winter -for now, I'm more than happy to be out there riding.

I fit a wonderful ride/hike into my morning today. Definitely better than just bumming around the house.
I wrote up a full post with pics that you can heck out here.

Also, I noticed that my avatar picture was a little dated. Can you spot the differences between the two?

[Half-Caf]

Update on that muffler repack: I was getting ready to open it up for some new stuffin when I found out it had a different baffle type.
Check out this pic looking in from the tail pipe


As you can see from the pic, my muffler internals look something like this:
   ___________________
  |                                     |
  |            -----------------------------                        
  |            ____________________     <- from engine                  
--------------------            |
______________            |                  
  |                                     |
  ----------------------------

I tried to remove the end cap (had a small bolt going through it) but I think it may be rusted in place.
I love the look of this muffler, but guess I will be sticking with the sound.

If I could get it open, I would try to pop one or two of these stainless scrubbers over the pipes inside


They're supposed to work pretty well and I bet they'd make it sound a little less hollow.

[Hellbilly429]

I was unsuccessful in pulling the baffle out of my old muffler as well, I just decided it was easier (and actually cheaper) just to put a glasspack on it

Hard to believe that muffler is not a straight-through design, must be really small baffle pipes in there?

[fire101]

Dude your bike is Awesome! I love the Seat with the LED tail light! i would love to set up my Bike with something like that too. Also Your gauges look different What did you do? Also what kind of handle bars  do you have.? Where did you get them and where can I get some?  

[Half-Caf]

fire101 wrote

Dude your bike is Awesome!

Well thanks

fire101 wrote

I love the Seat with the LED tail light! i would love to set up my Bike with something like that too.

Seat is a one-off. The tail light is an aftermarket unit for either a ducati monster or a cbr (cant remember).
The frame and taillight were both modified to give it that nice fit.

fire101 wrote

Also Your gauges look different What did you do?

They are the 2.5 mini gauges from dime city

fire101 wrote

Also what kind of handle bars  do you have.? Where did you get them and where can I get some?

The entire front end was swapped out for one off of a cbr f2 -so the bars are f2 clip-ons (41mm vs stock 35mm)
And I cobbled the original 750 wheel in there 'cause I like it that way

[seestheday]

How the hell did I miss this entire build.  This is awesome.  Great work dude.

btw, have you seen all of the performance tips for these DOHC engines?

Like taking a little bit of metal off the shifter to eliminate the false neutral commonly found between 4-5 during aggressive riding?

With all of the work that you've done it seems like you would be up for a lot of the easier ones.

For the really extreme ones you really ought to have 900F or greater for it to make sense.  Some of the mods people have done to the 1100F's are crazy.

Once I get my 750K up and running I'm planning on picking up a 900F and going to town.

I just need to buy a new house with a bigger garage first....

[shinyribs]

How did you miss this build?!?!  No offense to anyone else's bike,but I think this is the coolest bike ever put together on this board. In the time I've been here,at least.

[shinyribs]

Half-Caf wrote

shinyribs wrote

What front end are you using exactly.I know its a CBR,but what year? I need something mo' better...

It's off a 94 CBR600F2. All the F2 front ends are the same (I think they ran 90-94).
I wouldn't consider it a "golden solution" just yet, though; I'm still waiting to see if the stem length will work out (fingers crossed!)

Once I get those tapered bearings in I'll mock it up and see how it looks.

I went digging back through here to see what front end you were using. I couldn't remember. The GSXR front end on Hackjob is just too different to work without custom trees. Or work right,at least. On these CBR trees,how did the offset compare to your stock trees?It looks like the CBR trees dont have nearly the same amount of offset as the DOHC trees I have here at my place. I think I may go this route (CBR) instead. Are you happy with the brakes and ride? And one more: are those the original CBR calipers on those forks and did the line up (diameter wise) with the stock rotors off your original wheel?

[Half-Caf]

seestheday wrote

btw, have you seen all of the performance tips for these DOHC engines?

Like taking a little bit of metal off the shifter to eliminate the false neutral commonly found between 4-5 during aggressive riding?

With all of the work that you've done it seems like you would be up for a lot of the easier ones.

Welcome to my thread, it's good o have you
These "performance tips" intrigue me. I guess the most common one I've heard of is the 900 cam swap. Other than that, I'm all ears

As for the false neutral, I've never had any problems between 4-5. Now, if you could help me avoid shifting into neutral instead of 2nd during aggressive riding you would be my hero!

[Half-Caf]

shinyribs wrote

I went digging back through here to see what front end you were using. I couldn't remember. The GSXR front end on Hackjob is just too different to work without custom trees. Or work right,at least.

Whaa? I thought you had that all worked out? Didn't you weld the new stem in and everything?

shinyribs wrote

On these CBR trees,how did the offset compare to your stock trees?It looks like the CBR trees dont have nearly the same amount of offset as the DOHC trees I have here at my place. I think I may go this route (CBR) instead.

Now, maybe my bike should be called hackjob, I didn't worry so much about the numbers, just figured the shoe fit so I wore it. Despite the fact that I have 2 DOHC's, I don't actually have any original trees to compare. But, just by looks alone, the stock DOHC triple tree would appear much more triangular than a cbr tree even if they had the same offset -this is due to the fact that the forks are much wider on the cbr. Also, the diameter of the tubes is much larger on the cbr, so that might play tricks on your eyes as well. I believe both forks are close in length and both have the axle mounts directly in line with the forks (unlike some of the sohc mounts) Also, if we're talking offset, it probably helps that I have the original 19" wheel mounted on there instead of a little 16" like the cbr had.

shinyribs wrote

Are you happy with the brakes and ride? And one more: are those the original CBR calipers on those forks and did the line up (diameter wise) with the stock rotors off your original wheel?

Given all this talk about measurements and specs, my opinion is that it rides great! I'm very happy with the suspension: it feels solid in the corners and eats up potholes that I can't see coming.
I am running the cbr calipers with the original DOHC wheel and rotors, and yes, the diameter is perfect. The axle spacing is the trickiest part as they have to fit perfectly or else the rotors will rub on the calipers -there is not much wiggle room.
Apart from all the gloom and doom, the brakes work really well and once I got the spacing dialed in, I haven't had to mess with them one bit.

A couple more take-aways because I'm in a generous mood :
-keep in mind that if you run 750 rotors with (more) modern calipers, the pads won't use nearly as much braking surface (more like 1/2 - 2/3). If you're super anal about things, you might not like this.
-If you get an F2 front end, try to get a '94 as the internals are slightly nicer than the 92-93 variants
-stay away from the f3 forks unless you don't mind losing your speedometer (they went digital)-they also had different caliper mounts.  Although, if you really want to stay true to the hackjob theme, you could run the F3 tubes and internals inside the F2 lowers and get the best of both worlds.

Whatever you do, I would be sad if you ditched the USD's 

[seestheday]

Here is shifter mod thread: http://www.cb1100f.net/modules.php?name=Forums&file=viewtopic&t=8228&highlight=shifter+mod

In general, read through some of the build threads on that site.  Some truly epic DOHC insanity.

Check this one out: http://www.cb1100f.net/modules.php?name=Forums&file=viewtopic&t=50904

cb750, cb900, cb1000 and cb1100 are all built on the same basic architecture (there are apparently key differences as this warning thread points out: http://www.cb1100f.net/modules.php?name=Forums&file=viewtopic&t=2450)

[Half-Caf]

I registered with the 1100F forum today


There is some interesting stuff over there. This RSC division is news to me -very interesting news, too

[shinyribs]

lol@ Haffa Cafson

Thanks for the info on the forks bud. I've been doing some research and found that CBR trees run 45mm of offset and 25* of rake. A SOHC CB runs 60 mm of offset and 27* of rake. My USD's were originally setup to run at 24* of rake. So the difference between the CBR rake and the GSXR rake is only 1*. That's not enough for me to warrant dropping the USD's. Either on would have me running way too much trail. I might just look into pulling my rake back a bit the correct my geometry.

Either way,thanks for all of that info. While I might not use it on the hackjob bike I'm thinking of doing a front end swap on my other bike,so it was still very helpful.