Learn me; Cafe Racers/brats/scramblers

My girlfriend has always wanted a bike to putt around on during the summer. Well during one of her long rants waxing poetic about motorcycles a buddy of mine mentioned he'd just give her one of his bikes that's been sitting around awhile. Great. Another project. I haven't laid eyes on it so I can't comment on it's shape/condition but he says it's complete and he rode it into the garage a year or so ago. It's an '81 Honda CB750, supposedly all stock. 

I've nailed down her desired aesthetic for the bike and it basically sounds like she wants a cafe racer/brat type bike but she commutes to a farm 6 months of the year for a haunted attraction and I figured something with knobbier tires/softer suspension would go a long way for her enjoyment.

How many of you guys have bikes? Modded bikes? Have you messed with striping down a bike to a brat-like state? Are there go-to forums/mods/things to avoid? Is fuel injection possible on that old of a motor?

I guess I should renew my motorcycle endorsement.

Just so you know, - There's a separate motorcycle forum here. 

Which CB750 is it?  There were a couple different ones in '81.

How much riding experience does she have?  How far is the commute?   How much of the commute is street/highway/unimproved roads?   Does she have to carry anything bigger than what can fit in a backpack on the commute?

Regardless, I don't think an early '80s UJM is a very good choice for this sort of use/modification.    If you are going to strip something down, start with something that is light, simple, and can take the punishment to begin with.

Kreb (Forum Supporter) said:

Just so you know, - There's a separate motorcycle forum here. 

Well, sorta.

I have almost the exact same bike, modified for the Cafe Racer look. '79 CB650. It is a perfect starting point for this type of modification and has been done a million times.

Mechanically they are almost identical to work on. The engine is pretty robust and tolerant of idiots like me. The only weak point is the ignition system, which was Honda's first try at transistorized or not-points ignition. I had problems, so I junked it and swapped in GM HEI stuff.

It will not be that fast. Any modern 600 will be way faster. It's more like a modern 450. Mine runs like crap so it's more like a 300. 

To get that cafe racer or brat look, you need to swap out the seat for something flat and uncomfortable as a trade off for style. There are kits to do this that retain the hinged storage compartment under the seat. You also have to chop off the rear-most part of the frame. You can buy a "U" shaped piece of tube to weld in. Mine doesn't have it, just chopped ends of frame. 

You also need to swap out the handle bars. Search for "club" or "drag" bars, 7/8" diameter. My back got sore from such low, flat handlebars that I swapped out for the low-rise "CB400" bars, which are a good compromise. Also the drag bars hit my tank at full lock. But if you're used to a sportbike and this is just a toy for putting around, might as well lean into the style of it. 

4into1.com is your new rockauto for this bike. They have literally everything for it. Obligatory build thread:

https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/first-bike-not-powered-by-my-legs/154893/page1/

I could see a CB750 making a nice cafe racer, but it's a bit heavy to use as a scrambler, or for a newbie rider.

On the flip side, the sort of light weight bikes that make good scramblers are also quite newbie friendly.  You could start with some '70s era Japanese twin, or maybe modify a dual sport to look more cafe racer ish.

I'd just get the cb750 into nice riding condition. 

Likely it will need a lot of work, but clean carbs, fresh ignition, fork oil present, good brakes and new tires will make for a bike that is a joy to ride. Maybe replace the clutch and throttle cables too. 

Then, if she still don't like it, go for the cafe look. Haha.

Cooter said:

Which CB750 is it?  There were a couple different ones in '81.

How much riding experience does she have?  How far is the commute?   How much of the commute is street/highway/unimproved roads?   Does she have to carry anything bigger than what can fit in a backpack on the commute?

Regardless, I don't think an early '80s UJM is a very good choice for this sort of use/modification.    If you are going to strip something down, start with something that is light, simple, and can take the punishment to begin with.

Sounds like this "free" bike will be anything but. As usual. Figured as much. Commute will be about 20 miles. Mixed windy rural backroads/freeway. She usually has to move her tools and junk to the farm once but the regular commute is just her/lunch

In reply to maschinenbau :

That's a slick looking bike. And almost exactly what she's after. She's a bit desensitized to what's "comfortable" as she dailys the e30truck I made and that doesn't have carpet. Or a water tight cabin... So I imagine she'll be fine with form over function mods. I'll check out your build thread, thanks.

In reply to Robbie (Forum Supporter) :

Agree 100% with what Robbie said. 

And yes F.I. Is doable with Micro Squirt- involved but doable & as was mentioned also should do an ignition upgrade. 

There are two versions: The CB750F (sport version) and the CB750C (custom) 

First note both of these bikes are 550-575lbs; even after stripping off all the goodies they will still be at least 500lbs.

Performance wise they ran a mid 13s 1/4  mile and were good for about 120mph.

They are really good solid bikes; I've ridden an 81 CB750F extensively.

As for the Cafe look, you can build a Freddie Spencer Superbike replica. Better shocks, header, rear sets flat bars and cut down the front half of the seat. If you want to actually perform there are other things like bolting on the same year Gold Wings forks/wheel. 

I had a 73 CB350 Scrambler as well as an 82 CB750.  The 82 I turned into a Cafe-looking ride by removing some of the tail body work.  Heavy and slow, but reliable and fun to ride.

Agreed with Maschinenbau... the ignition might give you fits, but it's better than the older points style that Honda used in the 70s.  Plenty of upgrades out there if they're still made.  Find yourself a Bassani muffler.  Loud, but what a brilliant sound on these CBs

I had a Suzuki GS750 for a while, which is similar to that Honda. Had a few old Honda twins, too. Brakes on these old bikes are typically not great, nor is handling. Noodly forks, soft springs, damping rods instead of modern shim stack valves, and frame geometry that didn't always make a lot of sense. It's all fixable, but something to be aware of going in. Not a problem if you expect it, but worth thinking about to make sure your expectations are set. Most of my old bikes needed new shocks, fork springs, heavier fork oil, new old or retrofitted modern brakes, and fiddling with fork height and sag before they didn't feel like I was riding around one quirk or another. No different than driving a '70s car vs. a modern one.

They're heavier than you'd think for how small they are. I think my GS750 was every bit of 500 lbs, and I don't think the CB750s are much different. The twins are lighter, but don't really have much power if it's going to spend any time on the highway. Great around town, though.

All these old bikes have only a few inches of suspension travel. Stock softness usually hurts you on dirt roads because they are so easy to bottom out, and bottoming out makes a bike super unpredictable, but if she is fine idling through stuff or keep a relatively thick seat on it, it won't be too bad. Stock seats are a big part of the suspension system lol. If dirt and knobs are on the menu, maybe take an XT500, XT/TT350, XT600, something like that, lower it a little? It will also be lighter, and the single cylinder engines are easier to maintain. I had an XT350 so am a little partial to those, but many old dual sports are great bikes. That said, a free bike is hard to pass up.

My old GS:

And my current "old bike" on the right, a Honda CX500 that is way more fun than it has any right to be. And is shockingly good off road.

MadScientistMatt said:

I could see a CB750 making a nice cafe racer, but it's a bit heavy to use as a scrambler, or for a newbie rider.

On the flip side, the sort of light weight bikes that make good scramblers are also quite newbie friendly.  You could start with some '70s era Japanese twin, or maybe modify a dual sport to look more cafe racer ish.

I would have definitely chosen a smaller bike for her but you know how "free" goes...

Have you messed with striping down a bike to a brat-like state? - yes and it is more involved than I expected. Took a lot to get to to the point where it didn't look unfinished, and was never very comfortable but maybe just because I'm too tall to fit most older UJMs.

Are there go-to forums/mods/things to avoid? Avoid the sawzall lol. Plenty of forums, I think sohc750.com was a forum I used for a while for the Hondas. dotheton.com has a lot of hacks but some good info. I've had more luck with bike-specific forums than with "brat" or "cafe racer" forums.

Is fuel injection possible on that old of a motor? Possible but challenging. Charging systems are usually pretty weak because there wasn't much in the way of electronics. The carbs generally work fine if they are cleaned, tuned, and synced properly, the latter of which can be a little frustrating on the 4 cylinders but is absolutely required for them to run well. Removing the airbox, if it has CV carbs, usually causes a lot of problems. Pods look cool but take a lot of work to get right. Also, if it idles funny or doesn't start right, check the valve clearances. Being on the tight end of spec can really drop your effective compression, and it's more obvious at low engine speed.

Yeah, I'd focus on getting it running nice first. Clean and balance the carbs. Valve adjustment. I had a 78 CB750K done cafe light, seat and clubmans. I have a stripped TW200 in the brat scrambler aesthetic. I'd get it running, get a flat seat on it, bars with mild rise, and maybe an ADV looking tire on there. 

Dotheton is a cafe related forum. Carpy is apparently still around. He caters almost exclusively to cafed 750s. 4 into 1 has a ton of inexpensive cafe items.

I did this to a Yamaha Radian a while ago:

Different fork springs and rear shocks, a little modification to the back of the frame, different tank/seat/bars/lights, little refinishing- it was remarkably easy and fun to do, and I'd do it again.  I agree with everyone who says to focus on getting the bike running decently, then you can just focus on the fun modifications after that instead of fighting with it.  All in it was under $1k too, mostly because Radians are sort of hideous and therefore cheap.

Man, you guys are giving all sorts of reasonable responses. Thanks.

I mean, I know the proper thing to do is get it riding first but I totally want to rip into it. Ha. I guess getting it ridable will help keep it out of the garage.

In reply to ¯\_(ツ)_/¯ :

Like what you did with that............except for the tires, but I've neither liked nor understood that trend. Regardless you took an unloved Radian and made something fun.

In reply to Tom1200 :

We've got a lot of gravel roads around, but the tires were still the wrong choice.  I'd put something more pavement oriented on if I were to do it again.

As mentioned a few posts above an '80s superbike like is hard to beat imo.

 Much better rider comfort then a cafe build,and the point is to enjoy riding vs parking and looking at it:).

My virago project has the superbike vibe,won't sound as sexy or be very speedy but I won't see one just like it on every ride.;)