What cam is it?

[Rob Farmer]

I've been pulling my 78 R100RS engine apart today. There was a choice of cams for this year so I pulled the cam looking to see if it's a 308 or 336 item. There's no number stamped on it just 1250 249 in one place and 884 in another. Any idea what it is?

 

[(RIP) Proff]

70 bhp cam Rob, the engine was out of a full power R100 rs

 

[Rob Farmer]

Proff,

It's the engines from my 78 100RS not the engine in my GS.

 

[(RIP) Proff]

Has it got the 40mm exhausts?? if so it will be the same as the 100GS engine you have....
The only reason the GS has 38mm exhausts is to fit the GS exhaust system, I sold the [ engine in the GS ] heads to another mate

 

[Rob Farmer]

yes it's got the 40mm exhausts but they were offered with the standard or the sport cam in 78.

81 on bikes all have 38mm exhausts.