Topic: First serious build ever - CB750 K7 Café

[SOHC4 Cafe Racer Fan]

Since you are making a custom triple clamp, I assume you are increasing the offset of the modern forks closer to the stock 750 to stabilize handling.

I was thinking of keeping the rake and trail fairly close to stock.

EDIT: Perhaps improving it a wee bit since I will be running with narrower clip ons. However, as I've never modified trail (and cannot tell precisely how the changes will feel) it might have to be a bit touch and go...

Your stock K7 has 50mm of offset.  Your modern forks have something likely in the range of 30mm.  Depending on the size of wheels you are incorporating into your build, you may want to increase the offset between 45-50 mm.

[cb750tr]

Since you are making a custom triple clamp, I assume you are increasing the offset of the modern forks closer to the stock 750 to stabilize handling.

I was thinking of keeping the rake and trail fairly close to stock.

EDIT: Perhaps improving it a wee bit since I will be running with narrower clip ons. However, as I've never modified trail (and cannot tell precisely how the changes will feel) it might have to be a bit touch and go...

Your stock K7 has 50mm of offset.  Your modern forks have something likely in the range of 30mm.  Depending on the size of wheels you are incorporating into your build, you may want to increase the offset between 45-50 mm.

I see! Thank you! I've got to get someone to help me do the math correctly before I send the top and bottom out to get made. But I can at least make the design before that!

[cb750tr]

Got some more goodies today!

[cb750tr]

I think it will look great with this front end and clipons. Hopefully it'll be okay handling as well!





After I had checked how it looks (don't worry, I won't use these grips) I decided to get on with the ignition. That's when I found this...



Well, #$%* on a stick. I have no idea what the PO have done with this, but it sure as hell made my life a lot #$%*tier. I couldn't get a socket on since it's off center, I couldn't cut a cross without ruining the arm and collar... At this point I was preparing to get a ton of headache due to this #$%*.

At the end I decided to risk it and pry the collar to the side, hoping I wouldn't bend the axle. After that I hammered a socket on (again, hoping I wouldn't damage or bend anything). It worked, thank lord.



Hoping I'll get the exhaust back soon so I can actually try it out...

[cb750tr]

You might want to check the runout of that shaft before you go too much further. If it is bent, and it very well could be from the PO, it will give you ignition fits endlessly.

That's a great idea and something I should have thought of myself. I'll bring an indicator gauge and check it the next time I go wrenching!

[cb750tr]

So, I could use your help.

The stock CBR1000F uses 27°, 4.3 in (110 mm) rake, trail. The shocks are 41mm with 210mm CC and 35mm offset, and 660mm forks, 17" wheel with 120/70-17.

Is there anyone out there who right off the bat knows what offset I should go with on the top triple to get the rake and trail in the ballpark for the CB750? Or is it just as CB750 Cafe Racer Fan (feels silly to type that name :p) said, 45-50mm?

Thanks in advance!

[cb750tr]

Not much has happened the last months, got a colleague who's on paternity leave so I've got a #$%*ton to do.

The exhaust system is not done with the aluminium coating yet (what the heck is taking so long?!) but I did get my top triple done. I think it will look great. It's currently getting milled, or will be as soon as he gets a window.





I ordered new tapered bearings to make the measurements for the steering stem etc but of course it got lost in the mail... So have to wait for new ones. Damnit.

[SOHC4 Cafe Racer Fan]

The triple clamp looks good. What are you using for the stem (transplanting the stock stem)?  What is the offset of your new triple?

[cb750tr]

The triple clamp looks good. What are you using for the stem (transplanting the stock stem)?  What is the offset of your new triple?

Thank you! I'm going to make a new steering stem as well. Just need the tapered bearings first. I think I did 47 or 48 for the offset. Tried to do the math, failed, if it's wrong I'll make new triples.

[cb750tr]

I realized I might have made a mistake. I'm afraid that the bottom of the top triple will hit the steering neck... I don't have access to the frame this week thanks to work. Could someone please inform me how much clearance there is below the stock custom triple? I've hollowed it out to the same diameter as it is stock, but it is thicker than stock (you can see what I mean with the drawing).

Anyone who could add some insight to this? Would hate to postpone the manufacturing until I can go check with my own eyes...

[cb750tr]

The underside of the top clamp rides on a spanner nut above the dust seal. The stem protrudes through the top clamp enough to secure the stem nut. Do that math on your stem and clamps.

I've made the top triple with the same thickness for the steering stem, it's got all the same measurements. However I have added 5mm on the bottom. I'm afraid that will interfere with something, such as the steering neck. 

[cb750tr]

I need some help! Another obstacle to get through. I went to remove the old bearings but the lower one was dead stuck. It took me a good thirty minutes to get it out and when I finally did so, I could see why. There's a ridge almost halfway around with made the bearing get stuck. How do I address this? Is it possible to hone or is the bearing fitment way too precise? Should I try to just sandpaper it down? Please share your tips and knowledge.

http://m.imgur.com/a/Jh5SI

[cb750tr]

Got the exhaust and headers back from aluminium thermal coating!

[mkoski]

Nice job up to this point! Seems like you are doing some interesting work, I like the top triple you have designed. Couple of questions for ya: What's the benefit of the Alum coating on the pipes? Does it help keep the heat from coming through the pipe? And are you going to be painting it over top of the coating?

MK

[cb750tr]

Nice job up to this point! Seems like you are doing some interesting work, I like the top triple you have designed. Couple of questions for ya: What's the benefit of the Alum coating on the pipes? Does it help keep the heat from coming through the pipe? And are you going to be painting it over top of the coating?

MK

Thank you!

The aluminium coating will eliminate external rust, and adds another layer of protection from gravel spray etc. It's very hard and resistant to impacts (even though it doesn't have too much resistance to abrasive force, none of which I plan to exhibit though). I haven't yet decided if I'm going to paint it. The original plan was to paint it black, but it might make for a nice contrast to keep it the grey/white-ish color it is now. I'm planning to have bright silver highlights in the paint job, so it might do nicely!

[Mace]

cb750tr

Just want to say that I love that exhaust. An absolutely incredible sound, im definitely going to get one on order for mine!

Ive got a quick question also, where did you get that engine allen kit? Only im looking for one myself for my cb500.

Love the build by the way.

Cheers

[cb750tr]

cb750tr

Just want to say that I love that exhaust. An absolutely incredible sound, im definitely going to get one on order for mine!

Ive got a quick question also, where did you get that engine allen kit? Only im looking for one myself for my cb500.

Love the build by the way.

Cheers

Thank you!

The exhaust is definitely killer! You can't replicate the gorgeous sound on video, it's way better in real life!

I bought the screw kit off Ebay, this is the item;

http://www.ebay.com/itm/HONDA-CB750-K7-K8-F0-to-F3-1977-1978-Engine-stainless-allen-screw-kit-2-/122004039458?hash=item1c6801e722

[cb750tr]

I'm pretty much done with the top triple. Just need to get some more details ironed out, such as the diameter of http://jokermachine.com/products/cafe-racer/honda-cb750-parts/cb750-steering-stem-nut.html to incorporate it. It's cheaper to purchase that than to manufacture a one-off nut.



The closer I get to getting it done, the more I'm starting to second guess my decisions with it...

[cb750tr]

Things are really going along nicely!

Bryan Warren at jokermachine.com hooked me up with a killer top nut ( http://jokermachine.com/products/cafe-racer/honda-cb750-parts/cb750-steering-stem-nut.html ) and a replacement steering stem nut ( http://jokermachine.com/products/honda-cb750-triple-tree-black.html ). I've adjusted the top triple now to sink the top nut down, kind of like they've done here;



Which means I can finally start the process of getting it milled. SO STOKED! The front conversion is the biggest rebuild of my entire bike, and I can almost see the finish line!

I also ordered an Acewell 4554 today. Heard a lot of great things about this tach, so I hope it lives up to the expectations!

http://www.acewell-meter.co.uk/Acewell%20Speedometers/ACE-4xxx/ACE-4554AB.htm?action=full&id=42

[Mace]

I like the tacho you have there, how are you mounting it exactly?

Sent from my E2303 using Tapatalk

[cb750tr]

I like the tacho you have there, how are you mounting it exactly?

Sent from my E2303 using Tapatalk

I haven't decided yet! Will make a bracket and thread into the top triple.

[cb750tr]

I've decided on a color. The frame will be black, and the tank and seat will be deep gun metal, with silver details.

Like this;

[cb750tr]

Got the items from http://jokermachine.com today! Can't wait to get my entire setup together, this is frickin' awesome! Alloy top nut and steering stem nut. It's going to be killer!

Still waiting for the material (ended up with 7075 T6 aluminum) which will most likely turn up in the end of next week which means I should have this whole thing assembled in the coming 2-3 weeks! Absolutely stoked, and damn sure that I've messed something up so that this triple becomes a fancy paper weight...

Anyway, here are the nuts, last piece of the puzzle!

[cb750tr]

Woot woot!

[cb750tr]

FINALLY received the triple!!! And of course he forgot to thread the steering stem.

Oh well, that's easily done. Time to go and see how it looks!