1991 cb750 nighthawk brat

[harley497]

Hey guys

Here you go 1991 nighthawk build. I’m looking forward simple clean looking brat style and the build is rather exercise for myself to try and gain some experience in engine top end, carb settings, frame modifications.. Bought the bike about 6 month ago. Never meant as a quick journey, I also got family and job to follow-up..)

Couple original pics. Imported from japan in 2013 (fun thing it have no VIN at all) and stayed in garage for most of the time since that time:

Did a few test rides in garage before disassembly. (russian license plates size is a bad joke)) Engine was running very good, brakes fine, just wash it and ride)

But disassembly was inevitable, here you go funny timelapse:

https://youtu.be/GNRhuWV7C34

sht, this ended up as a huge post and I feel exhausted now) as you might noticed from the video, seat area of stock frame is a horrible mess. and it’s been quite some progress on frame recently, will come back soon with more pics..

 

[harley497]

Yeah so anyone who would try to build something from 199x cb750, beware of pretty messy tubing

swings up in the middle of seat

looking upside down is a pain

Just had to cut all that

And then using dime city's frame loop set, put it on top. Managed to keep stock upper shock mounts and very glad about that.

Tank is some '79 cb750

I considered few options on seat/rear solution, and somehow liking/moving towards upsweft seat, no cafe cowl..

Cheers!

 

[harley497]

Bulid's going on.

Aluminium parts cleaned and polished

Engine getting almost done after top end overhaul with clean covers on

Wheels painted and assembled

New tank mounts in progress

Bike wont make it for 2016 gentleman's ride.. But next year for sure, winter is long..

 

[harley497]

Some progress with tank, halfway done. About to throw some stripes in stock paint style and some more stuff.

https://youtu.be/n1JZDVsb6z8

Aluminum electric tray in progress and lipo battery found its place in swingarm:

 

[cxman]

nice work on the bike

i am doing one the same year i really like ytour module/ wiring layout

i have a bit deeper tray under the seat and my battery is there as well

i just installed a hydraulic clutch in mine i hope to do the tear down for powder and paint this week

right now its pretty raw

 

[Weasel]

Very creative vision on a bike that's overlooked. Nice work. Looking forward to seeing the completed motorcycle.

 

[harley497]

Guys who did tank repaint, they mostly do bobbers with all that gold leafing and flaking stuff.. So it went totally other direction with me comparing to what I originally thought and ended up pretty wild. Still somehow looks good) Anyway repainting is the easiest part, now about to assemble this alltogether..

In fact '79 tank fits 1991 frame very bad, due to backbone raising high. So tank is too high and too far from neck and with petcock hitting carbs. Its fotoshopped desired placement here.. Will figure out actual fitment on next garage session..

 

[cxman]

i used a 78 tank and had some of the same issues but i am getting there a few more days and i will tear it all down to make it pretty

 

[doc_rot]

The paint looks great. hope you get the fitment sorted out.

 

[harley497]

Ok so electrics (version 1 at least) seems pretty much done now

With starter relay found its place under seat

And some connections towards handlebar hidden under the tank.. And new tacho looking awsome..

With seat pan, looks clean and nice..

And tank finally sits properly in place

Feels excited on how nice it all comes together so far.. Front end is next for assembly, let's see..

 

[harley497]

Aah it looks I made a huge mistake back at the time of seat loop installation!! Frame was sitting flat top on the floor and I was leveling seat subframe with frame's bottom tubing..

As it turns out, with suspension and wheels on, frame is tilted with front upwards = my seat loop is totally downslope. More or less level if I slide front fork to lower it 2-3 inch, and with rear couple inches higher, which is already quite some impact on trail. And with rider on, rear will go down even more. Sad. Looks like I will have to fully cut loop from frame and fix it inch or higher at rear upper shock mount.. Hell, I totally overlooked this, with tank, electricity tray and seat almost done)

 

[harley497]

Ok so loop has been cut. With half-inch plywood in between already looks much better. Unfortunately not enough 'meat' or will be unpretty with existing downtubes. Already bought another frame, going to replace whole struts. Wasnt sure about seat length, seemed a bit too long. But with friend sitting on bike, looking good as a whole thing. Will keep that way for a while.

 

[esmoojee]

you could go with cbr 600 f2 or f3 front end. It would drop your front down an 1" and you could use the stock triples. You may have to make some spacers for the wheel. It's an option. Or see if you could find a euro cb750 rc42 front wheel. It should drop right in and you'd have dual front disc brakes and 17" wheel.

 

[harley497]

Slowly but surely.. Seat subframe tacked finally in right place, electrics fully done, handlebar done, seat ready for upholstering.. Next few days hope to fire up engine first time after top end overhaul..

 

[vwrabbit]

Wow, that seat frame looks great! Even before the fubar.

 

[harley497]

Finally, it's alive! What a milestone for me, works pretty fine, a bit unexpected though)

https://youtu.be/YuMYBPL8hgY

 

[Supergyro]

You do quick work sir! And it looks good to boot!

 

[harley497]

Ok so frame been finished a while ago, repainted and now assembly is in the progress. So far so good. Rear shocks probably too long but will see later. New foot controls and kickstand look good..

 

[themountain]

Amazing build..congrats! I think the shocks are fine as they are and with this incredible Tank it will look the dogs bollocks. 8)

 

[cxman]

unless you are heavy enough to drop the frame down on those shocks

the chain will grind the top of the swing arm the way you have it set up