A little while ago, I changed the rear tire on my SS50 motorcycle and took some pictures.
It now has a 120cc motor, that promisses to be very powerfull, only I haven't really got it up and running yet because of bad weather and ignition problems that should be fixed now. Have been tinkering with the jetting on the CB750 carb, but today I found something in my local Honda moped shop that will change all that again:
Found this in a box of 2stroke carbs, an original cable operated 28mm carb, So as far as I know, this should be a rare CB750K0. Not 100% complete, but I have a lot of newer ones that I can steel some parts from. The other three weren't there sadly. But I just have to put this on my bike now, as I'm crazy about original rare Honda stuff.
How do you mount a big vintage carburetor to an SS50?
Step one; buy a big monkey manifold. Step two; cut it up, weld it back together and turn it on the lathe to fit an original Honda carb boot.
Step three; mount it and add CB750 carb modified to take a normal throttle cable.
Oh, step four; tidy it up, but I still have to do that to the whole 120cc motor. Everything will be glassbeadblasted to match.
And now just keeping my fingers crossed that I can get this carb to work. My dad has used them before on 125cc motors, so luckily I can peek at those for the jetting.
My SS50M motorcycle needed some new front fork, the Original shortened 25mm forks were just not strong enough for the heavy abuse with a 100+ cc motor and a stoppie producing front brake. So now some leftovers from the Race project, a set of 27mm forks with CY50 lowers, and for now the front fender of my RSC90 although that is rubbing against the tire.
When working on the forks, I discovered a leak in the CD50 fuel tank, so that was swapped for my old SS50Zk1 tank with modified flip up filler and a racing seat in matching colours, RC style.
tank and seat combo is for sale or trade, if anyone is interested.
Had a problem with my SS50 not running well, but it wasn't consistent, mainly in the higher revs but not always and not with a particular throttle position. Till at some point, I was looking down at the motor again, while riding, I figured out that it was my leg in front of the carburetor disturbing the airflow.... Solution: take of the cheap crappy long velocity stack, and make a nice shorter one, so I get more clearance to my leg.
turned from the top of some old gas bottle
no more ugly rubber ring holding the screen, but a nice internal "filter" to keep out bugs and rocks.
Just one quick picture I took of my own SS50 as it stands now (cooling off on the shoulder of the A2 after a slight case of overheating) My little Honda was slightly out of place between all the big bikes, but people seemed to love the little thing.
With the SS50 race project being for sale, the chance exists I could actually sell it to someone and I didn't really want to loose the Takegawa clutch that was on that motor. So I decided to switch it over to my 110cc engine.
Now the motor is rebuilt...again... with a 5speed gearbox, Takegawa clutch updated to 4 plates with some leftover china junk.
But that meant I had to start building a new engine for the racebike. SS50Z cases, 5speed gearbox (and a spare 4speed close ratio) clutch moved to the gearbox input shaft by using chinese parts combined with a little bit of Kitaco, 85cc piston (allowed by the SAM) on a 12v crankshaft. I have some plans for the head, but I'm not that far yet. yesterday I did start on something for the breather, made it out of a CL72 filler neck that will get a bung welded on the rear to attach a hose.
It looks way high now, but imagine an upswept exhaust running just underneath that.
No longer a mangled CB72 shifter, but homemade alloy. Also ran the rod over the top instead of the bottom, to get more clearance in all directions. Sort of CR93-ish.
Testride today went okay, the final transmission might be a bit high for this 110cc motor, with 16/33 sprockets. It does 100km/h in 3rd gear, but it doesn't really pickup in 4th unless I've got a tailwind.
New alloy rear fender with C110 taillight. And a homebuilt exhaust, 32mm pipe with megaphone muffler with internal silencer.
after I took this picture, I removed the front winkers, as the rear ones now no longer have a mount. Someday I'll put the winkers back on, maybe in a different position. For tomorrow I want to finish the new shifterpedal and if there is time left, try a big carb, If it works that would be nice for the caferacerdag Let's hope the newly rebuilt 110cc engine holds up, with a "normal" 4speed gearbox.
Okay, it took a while, but finaly some pictures. The brake pedal, with just enough room to have the kickstarter underneath, theoretically it is possible to start the engine, although with the high compression it is difficult. Need to find me some different kickstarter pedal some day.
Shifter pedal, will need to build something for this, I can't get enough angle underneath the footpeg, so I will probably make something more like a CR93 shifter.
The way it looks now:
I didn't feel like making another bracket for my low exhaust, so I put this thing on, that I once bought for the header, but didn't use. Kind of like the scrambler look so I'm thinking of putting on normal handle bars. Or just keep going with the cafe-racer look and fit a long tank and bumstop seat......I don't know yet. For now, the motor is out again, I made a mistake on the 4speed close ratio gearbox, and it is too close for street use, so I will probably put a "normal" 4 speed in this motor. Or maybe even a 5speed, as I think I've figured out what is wrong with the 5speed design.
For a long time I have been wondering what to do with my SS50 motorcycle, I planned on putting a long racetank on it, with a short bum-stop seat, but I wondered what that would ride like in combination with my rearsets and clip-on bars. Thus I quickly made some brackets to fit a cheap seat to my SS50, looks odd with the big space between the seat and tank, but it was just for testing. The tank that should go on there would fill the gap.
however, this rode like sh!t, I'm constantly resting on my arms..... My plans needed to be changed, so I tried some things when back in the workshop; normal handlebars...don't like the look, but then I would get a rideable bike. Normal footrests, too high, too far forward, but almost rideable. Conclusion: To build my bike with long tank and short seat, I need footpegs somewhere around the swingarm pivot. So I started building, to be continued.
I've changed my plans. I have an SS50 motorcycle (2 actually, but the second one isn't ready yet) and I collected a lot of original 50cc 5speed parts for them, like alloy cilinders and the heads with big fins and ports. But now I've ridden with a 50cc and a 70cc engine on public roads and I just can't keep up with modern traffic. So I've fallen off my beliefs and started with the bigbore stuff. But still not the kitakkiewakkie-craft, just cheap aftermarket stuff.
I've now built a 110cc SS50 engine using a 52mm stroker crank and a 52mm piston.
specs: - 52x52 110cc - Old Type 70cc head with big fins (NOS), ported - C70 camshaft - advancing flywheel, 6V ignition - 2plate clutch with alloy centre - 5speed gearbox with modified first gear - 20mm carb (until its broken in, then I might go bigger)
Today I built this engine under my SS50 motorcycle and took it for a testrun. Nice torque, lots of power, in fact, more than the clutch can handle. So at the end of the day I took the motor out again, will need stiffer clutch springs and also need to look at a small issue with the gearbox. But this promises much good things, I allready have plans for a 125cc 54x54 engine.
And another crazy idea, a very much cc old style C90 with the 6V engine. My S90 has shown these old things can be quick, now I'd like to use one of these old beasts to kick the crap out of some of those modern chinese 125cc+ bikes. With the parts Ralph has, we could get upto 180cc, or just 170cc with the cranck he would sell to me. but still that is more then the china-crap. Now just to find a C90 to start the project...... if someone in holland has something, you could let me know.
crappy sketch:
I won't be actively pursuing this project, as I still have a couple of other ones that are unfinished, but this would be a fun quick one.
I had some problems with the ignitioncoil I used on the S90, it was an old CB72 coil but when it was replaced with a different type, my S90 ran better.
I really did want an original CB72 coil, as they were used n RSC90's back in the 60's and it looks good, so I had to test the coils that we have.
My SS50 was the answer:
I found out which of the 5 coils were good and now have an original CB72 coil on my S90 again.
The plan: build a mechanical tacho and tach-drive onto an SS50 engine. terms: do not use kitaco or takegawa bolt on stuff.
I started with a tach drive from a CB175, turned something on the lathe and took the teeth off of an old camshaft sprocket, this should be soldered together with silver and mounted to the camshaft. should look like this when mounted: The housing was cut down to remove unnecessary material and to create a hole for the bolt to go through that will hold everything onto the cylinderhead. A brass plug will be put in there with threads to accept the bolt. One problem, on a CB175 this is on the right side of the camshaft, on the SS50 it will be on the left, so the tachocable will be turning the wrong way.
On the back of the Yamaha 600 guage unit (that I took the tach from for the RSC90) was an angle drive that I could use to reverse the rotation...
Some PVC tubing, a CB50 tach and one Yamaha drive later: Testrun if it all works...NO?... I looked at the angle drive the wrong way, so it doesn't actually reverse the rotation. I will have to make something else to fit onto the modified CB175 drive and use this tacho on another bike when it is finished. Will be painted black, alloy ring to be turned on the lathe and a piece of plexiglass to close it all up, after I've made a new face for it, probably upto 14000 RPM or a bit higher.
Today was Hondaday, the yearly gathering of the dutch honda moped club. In the morning the weather was almost clear, so I thought I'd give the SS50M a ride to completely break in its 70cc engine. I totally forgot to take pictures, but Ralph will probably put some up on his blog. Spoke with Ralph for a while about the C110 engine I am restoring for him and the S90 parts he borrowed me. Had a look around the lot, spoke to some other people too and then went home again. But only after I had the SS50/70 on the dyno. The Honda club had arranged a free dyno for everybody to try their bikes, so I couldn't pass that up. Graph seen here with some great pictures from Mischa who brought his 1970's polaroid camera. About 6.5 HP at the rear wheel, not bad for a 70cc with 20mm carb, with a top of 115km/h. The bike is now totally run in, so it's time to start looking at the 26mm carb that I would like to put on it.
