I've got a manual at home for an 18R-G that might have that info in it. The U just stands for the polution controls used so the rest should be the same. I'll have a look tonight to see if I can find anything
Errrr.... No it doesn't. It's a completely different head. The U means it's a yamaha head, nothing to do with the emissions control. From what I've been told(no exact specs), 18rg runs 9.7:1 compression, 18rgu runs 8.7:1. 18rg has smaller valves than the 18rgu, 18rg has better cam specs than the 18rgu. Ooh and most importantly the 18rgu makes less hp.
also there are a couple of different types of 18rgu with a few little changes (like double sprung valves, and I thing bigger valves in one of them too)
There will be someone on here with the correct specs (probably WITZL????)
Wed, 07 May 2003 00:12
