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the 78rebuild is going slowly. I have a crankcase with no mains or crank. I have been contemplating balancing the crank shaft and blueprinting the engine. I've never done that before. The other thought is to try to bring this back as near stock as possible. That would mean getting rid of the CC braced frame. I don't have the RS fairing either. Originally I was going to put a sport cam in the motor and some other performance goodies and use a s fairing. I now have a big appreciation for stock bikes left to perform the way they were intended, (improving the brakes is good though).

It's all out there on Ebay twist.

US Ebay seems to be rather expensive, but German Ebay can have some excellent deals........and most sellers will post internationally. Examples are RS fairing, minus screen, mirrors, dash, indicators, delivered to Aus for less than $200.
Same colour as my RS too!
A good crank should be easy enough to find, but get it from someone who really knows their stuff! Unground, undamaged, Std red bearings is the go.

And as far as performance of stock bikes is concerned, (/7's) especially post 81's, Nothing needs to be done in order to mess it up with full blown sports bikes. In the right place of course.

Good luck

twist wrote:the 78rebuild is going slowly. I have a crankcase with no mains or crank. I have been contemplating balancing the crank shaft and blueprinting the engine. I've never done that before. The other thought is to try to bring this back as near stock as possible. That would mean getting rid of the CC braced frame. I don't have the RS fairing either. Originally I was going to put a sport cam in the motor and some other performance goodies and use a s fairing. I now have a big appreciation for stock bikes left to perform the way they were intended, (improving the brakes is good though).

Good Dude you're stating to understand. Use the tool as designed and it won't break or spit you off. Improving brakes....priceless.

A well-set-up '78 R100s [stock] can kick some serious butt. ( I'm assuming it is an R100?)
We've discussed the brakes issue before.
Make it stock FIRST, and then see what you might want to change later. You could waste a lot of money fixing what ain't broke.
If you want rapid acceleration , consider some 38mm Mikunis instead of the 40mm Bings.

Jean wrote:A well-set-up '78 R100s [stock] can kick some serious butt. ( I'm assuming it is an R100?)
We've discussed the brakes issue before.
Make it stock FIRST, and then see what you might want to change later. You could waste a lot of money fixing what ain't broke.
If you want rapid acceleration , consider some 38mm Mikunis instead of the 40mm Bings.

the bike is a '78 R100RS Motor Sport. It came to me with a CC braced frame. Yes, 38mm mikuni's will give it great throttle response, so would DelOrto's. The mikuni's are easier to set up. Stock is kinda my direction on this. Brakes need to be made better and maybe electronic ignition. A 1984 or later transmission would give it the advantage of a lighter flywheel. Other than good shocks there's not much else I should do. But it's very tempting to tune it so it's a lot sportier. I have a blank canvas so to speak, I can do anything and do it from bottom up since it's already in parts.

What shocks are on it now? They might be already stiffer than the OEM ones. The RS faring is right heavy.
There will be more vibration with the lighter flywheel, I think, and that's been discussed in earlier posts, too.
Easy first thing for performance is an electronic ignition and some HOT coils. Probably the least expensive, to start.
I'd go for the Mikunis..as you said they are easier to set-up and parts are readily available. Dels are dear.
Do ONE thing at a time.

Jean wrote:What shocks are on it now? They might be already stiffer than the OEM ones. The RS faring is right heavy.
There will be more vibration with the lighter flywheel, I think, and that's been discussed in earlier posts, too.
Easy first thing for performance is an electronic ignition and some HOT coils. Probably the least expensive, to start.
I'd go for the Mikunis..as you said they are easier to set-up and parts are readily available. Dels are dear.
Do ONE thing at a time.

This bike is literally in a box! No fairing but the frame and block match. I have a late model swing arm from a twin shock model, so it's stronger than OEM unit for that year. I have a transmission but would opt for a late model for the clutch and better box. I have shocks but I'm thinking I will get works shocks. I have a set of Hagon, a set of Koni and a stock set. Right now I need to find a good crank, followers, lifters pistons, con rods and timing bits. A electronic ignition will be used. I have the stock cam but am considering a sport cam. A single row timing chain over the duel, (less reciprocating mass). So, at the moment I'm cleaning up the block and collecting all the bearings to get the crank in. I have no idea how to do that, I've never done that.

twist wrote:So, at the moment I'm cleaning up the block and collecting all the bearings to get the crank in. I have no idea how to do that, I've never done that.

Everything you've ever done, you had to do once for the first time. It's an adventure.

In the beginning, there was the block. An individual creation poured from the fires of hell.
And the man who created said block stood back and said, "shit hot man." (shitzen heib mann)

And the man said, "now to perfectly fit an individual crank to this block" (by means of firstly having said perfect crank)
"I need the perfect size thrust washers to give the perfect crank end play"

"Ah," said the man. "First I need to have correctly sized (to the perfect crank) bearings installed in the block and front carrier".

After having said correct bearings and thrust washers installed, the immaculate insertion was complete.

(Of course the connecting rod journals were measured to ensure the correct big end bearing size)

I would like to weigh in on the transmission subject.

My 1976 R90S transmission was rebuilt by Ted Porter with not a thing spared. Mucho Dinero. The clutch is new, the cable is new, etc. It has a lightened and balanced flywheel/clutch assembly. It is a frickin' tractor (no offense to tractors) transmission! It's not much of a problem if you're riding fast in the hills. Up, down, shifts at higher rpm are find and dandy. It's around town that it sounds like it's going to break the transmission housing. I remember the sound from when I was a young man and cops had those bikes. KLUNK! That's first gear. On and on, but I'll quit there.

My later model bikes with the newer trans/clutch carrier and clutch are, no kidding, the nicest motorcycle transmissions I have ever used. The 1999 R1100S I had for a while was about 80% as nice. Every time I ride either the older airhead or the newer bikes, I marvel that they have generally, the same transmission.

I'm saying the newer transmissions are sehr gut!

That said, I was under the impression that it is fairly involved to do the switch over to a modern transmission with an early engine.

Chuey