Topic: CB750 K2 restomod to "originalish" condition // Forkbrace added ! ! !

[Stev-o]

New York City is also has crazy drivers. Don't ride when you go there!
Last time I was there, thought I was going to die in the taxi cab.

[Viktor.J]

New York City is also has crazy drivers. Don't ride when you go there!
Last time I was there, thought I was going to die in the taxi cab.

If you mean motorcycle it will be hard since im going there january
Otherwhice I think they drive like #$%* in south europe, worst kind of driving i have experienced is in greece, turkey and the balkans.

They drive fine in the asian countries I've visited, japan,china, hong kong and the phillipines but worst roads had the phillipines This is me riding a "regional road" not the "national road" which is the biggest, this is one "step" smaller. That day we spent 7 hour constant riding, cause apperently they dont only build sucky roads, they also dont know how to draw a correct map the distance wasn't really accurate
The roads consist of rocks of between 5-30 cm in diameter, that makes a bumpy ride
 
And dont hate on the "protection gears" it was a hooliday

Me..

My friend..

[Viktor.J]

Well I've been home this weekend and had some time to fix some things..
I've changed the handlebars now, soooo much sweeter driving position and she looks much more slim *thums up* ... I was planning in fitting the fork ears, fork boots and everything but the Ebay seller #$%*ed up, so I'm still waiting on a replacement fork ear I want that stock front ! ! !




I've also started to take some basic measurements for the dual disc conversion...
And i found some problem that i seek answer for

- Is it impossible to run stock front fender with dual calipers ? mine doest look to fit !
- You guys who made the conversion with the early brackets did you mill of "everything" ? And then use washer or distances to get it right ? cause now It's way to tight...even if I use washers or spacers its going to be tight as you can se of the following pictures

Back


FRont


Fender (two different mountings):

[Terry in Australia]

Yeah mate, I ran twin discs on my first K1 with the stock fender bracket, (I riveted a CB400 fender onto the bracket to make it look a bit "sportier" back in the day) the right side caliper bracket sits outboard of the fender bracket, and from memory, you might need to "shim" the caliper bracket with washers. Cheers, Terry.

[Viktor.J]

Yeah mate, I ran twin discs on my first K1 with the stock fender bracket, (I riveted a CB400 fender onto the bracket to make it look a bit "sportier" back in the day) the right side caliper bracket sits outboard of the fender bracket, and from memory, you might need to "shim" the caliper bracket with washers. Cheers, Terry.

Great Thats what i thought you could do, but wanted to see if anyone who actually done could give some input. Yeah this fender is already chopped up in the front, and Im going to cut it up in the back as well for the sportier look

HAha im going to shim the braced, or first shim and then make some distances.
But I also think i will have to mill down a lot of material...

[Rookster]

You have to take some material off the lower mount boss on the caliper bracket.  The correct spacers for the top 2 mounts are 1/2".  I did a write up with pics on my dual disk early front end.  I have Lester wheels so the speedo drive set-up was a little different.

http://forums.sohc4.net/index.php?topic=91781.0

Scott

[Viktor.J]

You have to take some material off the lower mount boss on the caliper bracket.  The correct spacers for the top 2 mounts are 1/2".  I did a write up with pics on my dual disk early front end.  I have Lester wheels so the speedo drive set-up was a little different.

http://forums.sohc4.net/index.php?topic=91781.0

Scott

Thanks for the input, really helpful !
It's always nice to get some feedback to your thought, especially when they get confirmed I did some start up measurement and I got it to 15 mm spacers = 1/2 " so thats sweet

Once again, thanks !

[Viktor.J]

I was planning on mount the second caliper and caliper bracket buuuuuuuut after a wash the bike wont start (see a seperate thread)

Anyway, Since Im planing on decrome the cylinder head, generator and sprocket cover I've got the info that i need to remove the engine from the frame (for the cylinder head).
When I have the engine out of the frame, is there anything you guys recomend I do ? anything I should change in a pro-active purpose ?
I would love to get a few more Hp (or get all the originals back ) is there any easy or good way to get this as Im having the engine out anyway ?

[Viktor.J]

As I earlier mentioned this is a slow working progress, and since it's my first bike Im not planing to do anything "over the top", I still want to drive it when spring comes to Sweden

Any how I spent some time with the bike this weekend and have some questions.

I've made some "distances" to the right side caliper bracket. But how well "centrated" are your brackets over the rotor ? Of course the should be parallel, but a few mm offset would be OK right ?

This is what I mean (Paint is the #$%*)


This is what i looks like on the the right side.


The left (original side) have a bigger offset.


Then, since the front fender already was cut up in front, and PO sent me a stock, Im going to cut it up in the back.


Any one know if this will cause any trouble... Like vibrations and such ? I would love to get a CR750 style fender but since they are expensive as moneky #$%* I think I have to prioritise other parts on the bike.


This is my speedo drive modification from ebay. Some guy in germany does them. Now when I know how everything is suppose to be assembled I regret that i didnt made one myself. This design wants you to drill and thread two holes in the hub, which is idiotic IMO.  So Im planing on cut the sides of and weld on some "flaps"/stoppers or bend it around the straight edges to prevent it from rotating, cause as I figured out thats the only purpose ?





Since I dissemblance the whole front brake system the MC now sits in my hand. I didn't plan on rebuilding it since i think it works fine, seems hard and the repair kits are expensive. IS it ok of it sits like this ? nothing that going to dry out or something ? Im going to out on braded steel hoses and now brake fluid after the brake Restoration.




Now all the prake parts for the double discs sits in some vinegar,acetone and high concentration soap solution. I went nuts and thought, better safe then sorry I think it will sit there for a few days/ a week and then om going to clean them and then sand the calipers and disc center for painting. Im also going to CNC drill the stock rotor, since my other is drilled

A Nice warm bath anyone ?

[Viktor.J]

Today I modified the already modified Speedo drive for the dual discs. This design wanted me to drill and thread holes in the hub, but since I don't want to do any damage to the stock parts i modified it.

This is the final resault, think it will do perfect !



I also cut the back of the fender. Unfortunately ill have to wait until the Christmas weekend to fit the things to the bike

[Rookster]

With new pads the caliper arm should not be centered over the disk.  It is offset on the stock Honda single disk side so the 2nd disk side should be offset as well.  The 2nd rotor isn't the same distance from the fork leg as the stock side so don't get hung up on making the brackets the same distance from the fork leg.  Instead make your measurements from the disk to the bracket.

Here is the stock set-up with brand new pads:


The caliper arm covers about 1/3 or less of the disk.  On the 2nd disk make sure the arm is parallel to the disk and this is what you should get:






Scott

[Viktor.J]

Today i planned to drill my rotors.. It was a learning experience.

The thought was to put it in the CNC and then drill the s*it out of it 
So i machined a adapter to fit in the CNC vise, It was a living hell trying to locate the centrum of the rotor with the tool.
When the rotor was centered i started the program but kinda fast realized that the "aluminum core" was to flexible hence, the force of the drill was to big and the disc flexed for every drill. Unfortunately we didn't have any self centered super drills in my size 8mm. So we used a small drill to pre-drill all the holes to make it easier for manually drilling after.

In the CNC



So i machined a pice to "counter push" the rotor as I drilled it with the vertical drill by hand
I did 21 holes in 1 hour, 89 more to go

After one hour.

[Viktor.J]

With new pads the caliper arm should not be centered over the disk.  It is offset on the stock Honda single disk side so the 2nd disk side should be offset as well.  The 2nd rotor isn't the same distance from the fork leg as the stock side so don't get hung up on making the brackets the same distance from the fork leg.  Instead make your measurements from the disk to the bracket.

Here is the stock set-up with brand new pads:


The caliper arm covers about 1/3 or less of the disk.  On the 2nd disk make sure the arm is parallel to the disk and this is what you should get:






Scott

Ok, so the right caliper should be as "offset" as the left one. I thought it didn't matter cause the pads can "adapt". But thats no problem, i have a few spacers, and since it's almost straight over the disc now it would need like only 3-4 mm. Maybe I'll machine a new distance if time is found

But a big thanks for the input scott !

[scottly]

Did you ever figure out your ignition system problem?

[Viktor.J]

I haven't had time since the bike isn't stored where I Lived. But my father told me that the bike runs now, runs great.
So my conclusion is water somewhere where it shouldn't be But on the Christmas hooliday and during the winter I will spend some time with it, so I'm going to take a look and se what MAY caused trouble, post the picture of what i find here for your judgment

[Stev-o]

Good to hear Viktor.  I never spray water o clean my bikes...

[Viktor.J]

How do you keep them nice and Tidy ?

[Stev-o]

How do you keep them nice and Tidy ?

I use cotton rags with the appropriate cleaning product.

[Greg H]

Just out of interest , did you weigh the disc before/after drilling ? . The last one I did weighed exactly 1lb less , after drilling .  As it's significant  reduction in unsprung  weight, there are benefits to be had in the handling department as well as a simple reduction in weight  .

[Viktor.J]

Just out of interest , did you weigh the disc before/after drilling ? . The last one I did weighed exactly 1lb less , after drilling .  As it's significant  reduction in unsprung  weight, there are benefits to be had in the handling department as well as a simple reduction in weight  .

No i didn't weight it before. BUT I will check the weight as it is now, drill a hole and then weight again. Calculate the density      and totalt weight loss after my 10 holes a 8 mm:)

How do you keep them nice and Tidy ?

I use cotton rags with the appropriate cleaning product.

Ok so no water ? I will keep this in mind for next bike season, when it rains then? I mean I should be able to ride it in rain

[Viktor.J]

I completed the drilling of my rotor today. I think it came out nice.. one question is, the weight difference between the rotors are 40 g, is that much ? its only due to difference in disc thickness, as the drilling faces are identical, any problem ?

Just out of interest , did you weigh the disc before/after drilling ? . The last one I did weighed exactly 1lb less , after drilling .  As it's significant  reduction in unsprung  weight, there are benefits to be had in the handling department as well as a simple reduction in weight  .

oh, thats quite a lot, how much did it weight from the start ?
I did weight the disc after drilling one hole buuuuuuut i didn't get any stable numbers, first hole showed a aprox. 2 g loss, the second hole showed aprox 2,5 g. I cleaned them of with a brush so there might be some other #$%* in the holes and such. But that gives the density to 6120-7650 kg/m^3...

My rotor should then be aprox. 100x2,5 = 250 g = 0,55 lbs...  And i think that I have many holes, can you give me a picture of yours ?

[Viktor.J]

Well today I spent some time trying to remove paint from disc, calipers and caiper brackets. after a few hourse and destroyed fingers I gave up
Im leaving them to a friend to glass-blasting I also (not that kind of a big deal) decided which coulor to paint them. all black or something else. I fell for the "CR" theme, with alu-coloured calipers and bracket and black discs. Thing that will looks nice with double discs !

I Want my front brakes will look similar to this...


Caliper bracket after removing the paint

[scottly]

Caliper bracket after removing the paint

The "T" bracket on the right will not bolt up to the K2 fork lower. You need another "C" bracket, with the matching arm, like in the left.

[Viktor.J]

Dont worry scotty, thats a spare bracket i got With My caliper assembly

[Bradf7]

Neat progress on this build...

love the CNC shots from earlier posts...