Author Topic: Alan's CB750K3 RestoMod version 2.0 (Read 51232 times)

Alan F. · « **Reply #25 on:** February 12, 2009, 09:08:22 PM »

Thanks Cdoggy, It's hard to find time to work on it sometimes, but some nights I get a few hours in.

I wonder how it's gonna ride with the 130/70-17 rear that I have (it was a great deal, couldn't pass it up) and a 120/70-17 on the front....... I've gotta remember to measure the shocks I'll be using, maybe they're a little shorter than stock and my trail measurement will be alright. Fingers crossed.

Retro Rocket · « **Reply #26 on:** February 12, 2009, 10:49:20 PM »

Hi Alan, i would think you'll need longer shocks as the 17 inch rear wheel already looses you an inch in height. I am going after the stock height on my bike and because of the 17's i am using i have to get longer shocks.

Mick

Alan F. · « **Reply #27 on:** February 13, 2009, 06:01:18 AM »

Well the way I calculate it the stock rear tire size is 110/90-18 having a radius of 12.90"......and my 130/70-17 has a radius of 12.08"......so the rear axle centerline is only about .82" or 21mm lower than it was stock, I was counting on using that difference to offset any trail lost by changing front tire size, which with a 120/70-17, which brings my front axle down 1.24" or 31.5mm....... $:-\$ so if the shocks I've got from an '82 model are a bit shorter, I'll effectively change the neck rake, and gain some trail. But they don't seem any different just by looking at them, I'll measure to be sure later on.

andy750 · « **Reply #28 on:** February 13, 2009, 07:13:22 AM »

Hey Alan,

Just to give you a little inspiration...this Greek guy used many modern parts...and look what he managed...

Good luck and dont forget we like photos

cheers
Andy

78CB750CAFE · « **Reply #29 on:** February 13, 2009, 07:29:50 AM »

the DupliColor wheel paint you got works very well. I also suggest you try some of their clear wheel paint as a top coat. I used black DupliColor engine paint on my spoked wheels with a top coat of their clear wheel paint and they look great with nearly 3,000 miles on them in all sorts of weather.

Alan F. · « **Reply #30 on:** February 13, 2009, 04:38:39 PM »

HEY Andy! Wow! is that what a Drouin supercharger looks like? He's got the oil tank in the tail too, unless I'm folowing the wrong lines...
I think that bike's more new than old... I'll be going for more retro than techno, but pretty cool. Maybe that one should go in the Inspiration Gallery?

Quote

try some of their clear wheel paint as a top coat

Thanks 78CB750CAFE, I hadn't seen the clear yet and was scratching my head about which clear to shoot on top. It's also nice to hear that it holds up well.
Nice Bike! I was wondering, but I guess it's a 78....

Alan F. · « **Reply #31 on:** February 15, 2009, 04:20:30 PM »

After a little uncertainty about front wheel and tire sizes front and rear, I've picked up an earlier CBR front wheel to allow the use of a 110/80-17 front that I'd been planning on. A note to anyone planning to swap different wheels onto their bike, pay attention to the range of tire sizes that a certain width of rim will allow before you make any other decisions. two web pages you can find this info on are:

http://www.kawtriple.com/mraxl/tire_rim.htm

and

http://www.dropbears.com/u/utilities/tyrerim.htm

MMICAFE · « **Reply #32 on:** February 15, 2009, 05:52:19 PM »

Quote from: andy750 on February 13, 2009, 07:13:22 AM

Hey Alan,

Just to give you a little inspiration...this Greek guy used many modern parts...and look what he managed...

Good luck and dont forget we like photos

cheers
Andy

that thing is actually errrr likeable and badass

Alan F. · « **Reply #33 on:** February 15, 2009, 08:51:47 PM »

A little progress this weekend after all, I modified (I know) the Nighthawk upper triple tree to accept my K3's tach/speedo mount. I milled off the clutch cable loop and ignition switch bracket, drilled two holes for the bracket and there I was. I had to file a flat on each of the flat washers to fit them close to the edge of the casting at the bottom of the tree, but other than that it's perfect. I'm unsure how drastically the gauge's mount angle has changed, but I think it's pretty cool having the idiot light panel a touch higher than the bottom of the gauges. Looks pretty cool to me, what'cha think?

andy750 · « **Reply #34 on:** February 16, 2009, 04:36:01 AM »

Looking good Alan,

I have a better looking blue-faced tach if you need it. Yours is looking a little damp in the center

cheers
Andy

Alan F. · « **Reply #35 on:** February 16, 2009, 05:24:49 AM »

Thanks Andy, I'll take you up on that tach some convenient time. The old tach isn't currently damp, I think it had that coloration when I got the bike, and it still works if memory serves. Anyway I'm gonna try to make it Thusday night to Jakes. Don't I still owe you a pint or two for that seat?

Alan F. · « **Reply #36 on:** October 14, 2009, 08:50:23 PM »

Holy Cow has it been That long since I updated this thread? I found it burried on page 12!

Well I finally painted my K3's frame tonight.

I've been prepping it for a few weeks, sanded the rusty bits with 240 grit and then roughed the whole frame with 400 grit. I followed that with a wipe down with denatured alcohol and a coat of Clean-Strip rust converter (good stuff) I let that cure for two days then sanded smooth the areas that'll show when the bike's assembled. The rest is fairly smooth, but I want gloss where the frame peeks out. Another wipe down with denatured alcohol and dozen light coats of black appliance epoxy followed by a thick coat on those aforementioned areas and it's done for now. I'll let it dry for an hour or so with good ventilation (it's in a corner of my basement in a makeshift spraybooth of plastic dropcloths with a pair of fans blowing out an open window, and I opened a few other windows to draw in fresh air) After that I'll shut the windows and keep a dehumidifier going for a few days.

Alan F. · « **Reply #37 on:** October 15, 2009, 08:09:30 PM »

Alright, worthless without pics...most boring thread in the shop...I know.
I took a ton of pics to update the thread.
Here goes:

Alan F. · « **Reply #38 on:** October 15, 2009, 08:18:34 PM »

In the early spring I had fabbed some aluminum fork ears and painted them with the graphite gray duplicolor wheel paint and wheel clear many other parts on this bike are wearing, here's a look at them with my headlight bucket.

Alan F. · « **Reply #39 on:** October 15, 2009, 08:24:33 PM »

I've still got to buy a few parts to completely rebuild the 90's 750 Nighthawk forks, but here's an idea of how they'll look, between the gaiters and the fork ears there is a reflector that threads onto the lower triple, but it was too bright to photograph so I left it out. The gaiters are from offroad truck shocks but they fit perfectly and were very inexpensive, I'll have to look up the info on them and post it sometime.

Alan F. · « **Reply #40 on:** October 15, 2009, 08:48:03 PM »

I haven't posted any pics or info of the wheels I'll be using, here's a few pics, the rear is a 4"x17" 91-03 CB750 Nighthawk wearing a Michelin Pilot Activ 130/70-17, it will be completely stock and is soon to have new bearings. The front is a 2.5"x17" 88-89 CBR600 Hurricane it will be stock and have new bearings, only the left brake rotor will be used as the Nighthawk's braking system is only single disc with a twin-piston caliper, just like a CBR Hurricane.
The Nighthawk and the CBR Hurricane use the same brake components, axle and speedometer drive. They even use the same bearings and seals, it's such a simple swap, it's almost embarassing. The rear Nighthawk wheel unfortunately uses a 17mm axle but it has plenty of length for use in my K3's swingarm, I'll just have to get creative and make myself some 'top-hat' shaped spacers to complete the rear. The Nighthawk's stock sprocket carrier will still be used, along with a 44 tooth sprocket from a 1982 CB750F, which bolts right on. To keep the chain inline I'll source a 3/8" offset front sprocket from Cycle-X, probably a 17 tooth to keep the gearing just a hair higher than stock at 2.588 vs stock 18/48's 2.666

Here's the wheel pix, I sanded the lip of both wheels with 800 grit and masked it off, sprayed a few good coats of the duplicolor graphite gray and then shot clear over the whole thing. The 800 grit made things nice and bright without being too smooth for the clear to stick.

Alan F. · « **Reply #41 on:** October 16, 2009, 04:39:28 AM »

Here's the old mockup pic from the beginning of this thread, just for comparison. I think the gloss black will really look good.

And here's an MSpaint version with the new wheel paint (I know the wheels are inverted and the brake is on the wrong side, it's just for color comparison/perspective)

andy750 · « **Reply #42 on:** October 16, 2009, 05:06:14 AM »

Very nice work Alan and great photos. I really like the fork ears -very cool! Are you planning on adding a strip/swoosh or something to the tank/sidecovers to break up the grey?

Personally I think you should use the Nighthawk swingarm and sell me your rebuilt K3 swingarm ;-)

Glad to see progress is being made!

good luck!
Andy

Alan F. · « **Reply #43 on:** October 16, 2009, 06:05:23 AM »

Thanks Andy!

I'm not sure just what to do to break up all that gray, I'll be repainting the tank and I'm not sure if I'll be using those side covers even.
Plus I'll most likely be painting the airbox once I've got everything running well enough, so some distraction from the gray will be a welcome change at that point.

I'm thinking about a .100" thick aluminum side cover panel with a single convex curve similar to the Honda side covers, maybe I could cut out the early style cooling slots and polish them up? That'd be different but it's a thought in progress at this point only.

I'll be polishing the valvetrain cover, and the engine side covers, I have finned covers for the starter and points (just need to sand the peeling chrome away and polish them) the engine will get VHT alloy gray, and I have some cheapo Auto-Zone car door trim to attempt to trim the lower edge of the tank with.

I'm also planning to dab a little yellow paint on each torqued nut to add a mysterious factory touch.

Connito · « **Reply #44 on:** October 16, 2009, 07:18:05 AM »

Very nice Alan! Thanks for sharing it with us!

Alan F. · « **Reply #45 on:** October 16, 2009, 02:16:17 PM »

Quote from: andy750 on October 16, 2009, 05:06:14 AM

Are you planning on adding a strip/swoosh or something to the tank/sidecovers to break up the grey?

I'm hatching an idea for a stripe/emblem to attach that should do the trick.
What would you think of a polished piece of aluminum sheet in the shape of an original tank stripe, attached to the tank with the double-sided tape automotive emblems are held on with?

It might be tough to follow the contour of the tank, but maybe I can make it work.
-Alan

andy750 · « **Reply #46 on:** October 16, 2009, 02:43:08 PM »

Personally I think the small round black badges with a silver wing would work well on the grey tank. But hey anything will be interesting...

good luck
Andy

Alan F. · « **Reply #47 on:** October 16, 2009, 03:12:59 PM »

Those badges are cool too. I also like these emblems like Greenjeans had used. I forget which member made those but they're certainly cool enough.

I'm looking for something a little different, something that nobody's done before...

I've always liked the style of the older Hondas with chrome sides on the tanks and the rubber knee pads stuck on, I'm drawing some inspiration from those and a few other sources too. It'll be interesting to see where the concept leads me if I can get to to work.

I'll have to look at more new Bonnevilles and W650's for some inspiration before I try anything, maybe I'll look at the Detroit Brothers' bikes too....
-Alan

Alan F. · « **Reply #48 on:** October 20, 2009, 05:06:24 AM »

I've been asked about my avitar image, I made it up in MSpaint here's a larger view.

cb350twin · « **Reply #49 on:** October 20, 2009, 01:01:12 PM »

Just seen the thread now. Pretty cool.

Hey have you ever thought about selling those fork ears? Bet there would be a demand for this.

News:

Author Topic: Alan's CB750K3 RestoMod version 2.0 (Read 51232 times)