Spanking the Cow- The continuing saga of an R100GSPD at the Races

[gsd4me]

Originally Posted by Rucksta

I believe I could have picked up Rays 860 motor complete for under 5.

Pity it`s already sold. It sat around for ages now people want it.

[Rucksta]

Originally Posted by GSD4ME

Pity it`s already sold. It sat around for ages now people want it.

I didn't really want it but was very interested in the technology and mods he did.
Sort of hoped he was going to do a full on dirt bike with it and come an play on the side of the volcano ocassionally

[RealOldDualSportGuy]

Any suggestion as to tires for the Sand Blast rally?

Stage Hand has us "hooked" on rallying in the sand come spring.

Any and all assistance/input is appreciated.

Regards

Blame It on Stage Hand

[Stagehand]

Tom!

I was just thinking about you, today.

I recommend D606's. They're DOT, (which is technically required byt he rules ) and they have good sand bite (when they're new) and they're relatively cheep and they are made in a 17 and an 18".

My personal preference.

[AntonLargiader]

Originally Posted by Stagehand

SInce the short width of the R65 stems from the short con-rods, and one is required to shave the cylinder bases down anyway, is it feasible to simply put short con-rods in an R100?

A bit (4.5mm?) of the narrowness also comes from the shorter stroke. For a high-RPM motor I suspect short rods with regular stroke is a bad idea. The narrow race motors of the '70s used extreme pin location in the piston. On some (or all) you had to remove the rings to get the pin out. There is one such motor about 100 miles away; I should go check it out.

I think the mix 'n' match logic goes like this: if you want the shorter rods you need the shorter stroke. Once you have the heads closer to the crank you might as well use the R65 block for better pushrod angle. Therefore, use the whole R65 bottom end. The problem with that (in the old days at least) has been the lack of cam selection, and I think some vintage racers are using the R65 setup in R100 blocks and just accepting the funky lifter angle.

[RGregor]

Originally Posted by AntonLargiader

The narrow race motors of the '70s used extreme pin location in the piston.

They also used 125mm rods (Butler & Smith and Helmut Daehne for example). That's minus 10mm each side.
Gives about the same rod-length ratio like in the oilheads.
I would think the 118mm rods of the small blocks would be a bit too extreme in combination with the long stroke.

Originally Posted by AntonLargiader

The problem with that (in the old days at least) has been the lack of cam selection, and I think some vintage racers are using the R65 setup in R100 blocks and just accepting the funky lifter angle.

In the meantime Schleicher offer a variety of cams (from 320° to 344°) for the small blocks.

[Owly]

I read that Helmut Daehne's bike with the shorter barrels, the engine was taken off the production line and where the push rod tubes go into the block, that the block had to be machined to allow for a steeper angle on the shorter push rods.

But i am no expert engine builder.. Just a reader

[Stagehand]

Here I am wondering if its more manly to build a damn bike and race it and knowing me that is a dodgey prospect, the build part) rather than just get a hold of one any way I can. And go race it. Especially listening to you guys talk tech, god I am forty years old there isnt enough time in the day to take in all this info, I should have started back when I was just a kid, instead of this whateverthehellitisIdo, The race, I now realize is all about the suspension. Tied with reliability.
Good old reliable R100? or hotted up 650 with shaved private parts and an unfamiliar cam stuck in its hoo ha.

Ooo but the little hottie is tempting. Should I waste my time building it? Or have somebody build most of hte damn thing and I just put my resources into fixing what i break out in the bush?

[igormortis]

Well, I guess you've worked on Rider for a bit. Now do Chassis. When you can't go any faster, build a stonking Engine.

[Rucksta]

Rolling Chassis aint that hard.
Running gear and adding the elusive lightness is the hard part.

Weight loss from the motor is minor compared to other areas of fat.
Engine weight loss is an expensive chase usaully combined with increasing the performance.

Like you said. You have enough power already.

P.S. Forty is young but it doesn't last much longer

[Prutser]

Originally Posted by Stagehand

Here I am wondering if its more manly to build a damn bike and race it and knowing me that is a dodgey prospect, the build part) rather than just get a hold of one any way I can. And go race it. Especially listening to you guys talk tech, god I am forty years old there isnt enough time in the day to take in all this info, I should have started back when I was just a kid, instead of this whateverthehellitisIdo, The race, I now realize is all about the suspension. Tied with reliability.
Good old reliable R100? or hotted up 650 with shaved private parts and an unfamiliar cam stuck in its hoo ha.

Ooo but the little hottie is tempting. Should I waste my time building it? Or have somebody build most of hte damn thing and I just put my resources into fixing what i break out in the bush?

On a picture that was put on airheadsdown under fb. (on the MX track)You really tried to snap the bottom shock mount.
How much problems do you have with the suspension ?
The travel in Paul's bike must have been great. But would you mind to have your bike that tall when doing single tracks with technical sections ?

[hardwaregrrl]

I know where you can get a bike that's halfway there!

[Rapid Dog]

Originally Posted by hardwaregrrl

I know where you can get a bike that's halfway there!

[Stagehand]

Originally Posted by Rapid Dog

Lol! I know that bike!

[hardwaregrrl]

Originally Posted by Rapid Dog

nathan mende has it. Has had it for almost a year. Rebuilt the trans, the carbs, and a new clutch. After all of that, he's asking 4500 I think. That's why it hasn't moved, but it is a damn blast to ride! I want the bike, but can in no way afford it right now. If anyone is interested let me know. I've tried to sell it for him, just not here for fear of being flamed. And I will say, I've tried to convince him to let me race it at Sandblast.......but he wasn't going for that one.