1980 CB750F Project

Here is a series of 6 Spencer videos of AMA superbike racing. Should give you a good look from all angles.

All you old school race fans will love this old footage...


Mike



<iframe src="http://www.youtube.com/embed/PZo7-NyBvqk" allowfullscreen="" width="480" frameborder="0" height="390"></iframe>

WHat was the racers name in there number 88 with the Simpson Model 30 helmet witht he star on it? Loved that paint job on that helmet! It was Roberto Pietri wasn't it?

You must not have watched the videos


Roberto Pietri... his son is now racing in the US.






Mike

CB750F Project: Part III


After two failed attempts with fiberglass, I was finally able to make a solid shell today. My previous attempts were doomed partly because of my inexperience (first time working with fiberglass), and partly because I was dealing with a not-so-good resin. So, still discouraged despite the many wasted hours, I trashed the bastard creations along with the bad resin, and went to a local parts store to get something better. This time, things actually worked better.
I ended up using fiberglass mat instead of cloth for the base. While this is considerably stronger than the cloth, I quickly discovered that working the resin into the mat can be pretty tricky. The loose strands like to stick to the brush, and eventually end up clumping in the resin. I'm sure by now some experienced fiberglass guru is laughing his ass off at me, but hey, at least I try. Anyway, three layers of mat followed by a single layer of cloth for a smoother finish, I ended up with a usable shell. I can't even begin to count how many hours and how much money it cost me.

Now comes the part where I have to make a decision. My initial idea was to leave the tailsection open, looking something like this (not the end product - trimming, sanding still needed)

​

But then I played around with the idea of incorporating the stock fender into the design.

​

And then I thought of yet another setup.

​

Well, at this points it is still up in the air, although I'm leaning towards incorporating the stock rear fender.

On a positive note: Yesterday I received my new handlebars. After much consideration I went with "superbike" bars, as they allow for more comfort and actually clear the tank at a full turn. So far, without the seat foam in place, the riding position feels rather comfortable.

Completely agree. I don't think there's anything that can be done to improve upon the stock body lines of these bikes but there's certainly a lot of ways to ugly them up.

Hey, you purist you!

Okay, lets see about this one: Do you even like the stock taillight?

So, what is the opinion on this setup. Yeah, it's not a cafe and it's not stock. I still have some cutting and smoothing out to do, but I broke my cutoff wheel and the hardware store is closed.

Yes, no, fugly, it works, get the hell out of here....say it as you feel it.

Yes, yes I do! I even like the stock monstrousity turn signals.

But this is your bike and your build Henry. Build this thing as you see fit and don't be concerned about what I or anyone else thinks.
Personally I think the '70s bikes make an excellent base for a cafe build--which I think you were looking for to begin with.
But then you'd probably have someone else telling you to leave it stock.

Hey, the turn signals are....huge!

I wasn't really looking for a cafe build. This model is way too long for a cafe, has wrong lines in the back (for a cafe), and the choice of bars is limited with the stock tank due to clearances. When I look at Carpy's bikes, I find them interesting, but not appealing. Personally, a model 10 year older would be a better cafe choice.

I'm not too concerned about what others say, after all this will be my bike. But, from a pure aesthetics point of view, I'm interested to hear what others think. Opinions do vary, and curiosity is a bitch to satisfy

As for leaving it stock, well, it's an option. But, the seat and bars on my specimen were just plain wrong and needed to be changed no matter what. Hey, I'm just a man playing with fiberglass and hating every minute of it.

When I see pics of the Airtech rear seat for the DOHC model, I find it quite upsetting.

On mine, I did a smaller taillight, but not tiny. I LIKE to be seen from the rear on a bike for some reason.....and I left the stock tail as you see in that above pic. Personally since you asked what we think, I don't like the cafe look at all on this platform, if it were a CB750K, that would be bitchin and cool. But it is an F and they are soooo sexy stock with little mods to the blinkers and tail light and look totally bitchin.

Agreed, that's your problem right there. Fat round flat bottomed tank against your sharper lined and shaped tank. Maybe you should swap in another tank first, to get the lines right for what you plan to do. Something that is not shaped to accept side covers, and something that has more roundness to it

I think the Spencer superbike is pure magic. Like someone said before it's hard to beat the look of the rear cowl. I would ditch the fender.

Izz'at yours Sniper? Damn I've lusted after one for years. Got a K2 750 that I would sell in a heartbeat if I could get my hands on one of those babies!!

Apologies to original thread starter, but ya, to me the OEM whale tail/side panels/tank design is sex on wheels, ginormous turn signals and big rectangular tail/brake light included

My all time fav Honda back ends are these two: with honorable mention to the original CBX 6, CX650E (and the CX500Turbo that I owned)







If you are attempting more foam shaping/carving work, and are tired of the expanding goop that you have to let dry and is very messy, may I suggest buying some plain old rigid styrofoam insulation in like 2" thick sheets, and simply gluing a few of them together with wood glue (the white stuff) into a block, the aproximate shape you are thinking of.

In the past this has worked very well for me

All the best with your project!







but I still love the 750/900/1100F bodywork

Now, the VF I like

Funny you should mention the foam. Guess where I was about 6 hours ago -- Home Depot, buying a sheet of 2" foam. Started cutting it into strips before dinner, and am about to go down and start gluing

I'm going to try for a completely different end. (well, maybe). And, maybe it was misunderstood, but I want to keep the stock tank and the side covers. I love the lines of the covers and the tank. The tail...not so much.

Lessons learned? Plenty: take my time; use rigid foam and not the crappy expanding stuff in a can; draw before you cut (hmm, sounds obvious, doesn't it?); fiberglass is a learning process; a better, more expensive resin does not stink as bad as the cheap stuff; mat is stronger than cloth; and time (again) -- don't try to rush it.

Thus armed with my newly acquired knowledge, I bought some pink rigid foam at Home Depot, got some 3M glue, and got going again. This time, I started with a solid block of glued-up foam layers. I went below the frame rails, as I want those to be hidden, for a nice, clean look.

Here is the current concept for the tail section. Don't laugh at my drawing in-abilities.

​

And here is the clean, blank block of foam.

​

From the rear (decreasing width like the gas tank).

​

And after I cut the lower portion to follow the stock lines of the side covers.

​

In the end, this may not work out. I'm having fun with some foam and a rasp nevertheless.

You could just carve a hole in the middle of it and put beer in there

You do have an uphill battle since the original tails on those bikes were so cool looking, but nothing is beyond improvement and/or personalization. The drawing looks pretty good to me.

I could put some beer in there - maybe even a 12 pack. Hey, it might even go well with the KLR seat, and put some KLR touches on the project. We could call it the "inconspicuous cooler - convert your slick Honda to an all-purpose KLR machine".

Yes, I know it is an uphill battle. At the same time, I want a recessed single seat (somewhat recessed), and the stock tail would not work with that. You wouldn't believe how much the riding position changes by lowering the seat a couple of inches. With the superbike bars, lower seat, and stock footpegs and controls, I find it rather comfortable for my height (5'10"). I'd sacrifice looks for comfort any day, as my old back is not up to the crouching position anymore.
For me, this is about finding a position that works, than do the design around it, instead of having a cool bike that I won't ride more than 10 miles.
Most of the bikes on TV/Magazines these days are all about looks, but too many fail its purpose. Small tanks, uncomfortable seats, horrible ergonomics... I'm not the guy who rides to an ice-cream stand once a week to show off. When I saddle up, I stay in the seat for hours.

Okay, I'm saying too much again. I'll shut up now.

Started sculpting a bit last night...well, shaving bits and pieces off with a rasp. It started looking a bit bulky in 3D, so I'm making some cuts here and there. Still playing at this point, but things are starting to take shape (a shape)

So, here is a revised drawing. I would like to incorporate the flat, raised line on top, just like on the tank.

Not a final product, as it still needs sanding and a little shaping.