What's up guys, quick question. I'm getting a cool head for my 87 250r, but I'm not sure about the dome size. I was hoping to stay with 91 octane, but I want to feel the difference so I'm willing to go 50/50 race/91. From talking to ESR and checking out this and other sites, I'm thinking 20 cc dome with a CR head gasket. Will there be a noticeable difference? It's got a trx6 pipe/silencer, mild port, c/f reeds and K&N filter w/o lid. I got a clymer manual and the install seems pretty basic, but are there any hidden tricks to it? Is there a brake-in period? Do they have a head stay? Going to pismo this weekend with some YFZ's and a couple of modded 400ex's so I'm looking for a little extra. And those cool heads look sweet!
87 R
83 R
81 200

 

i have a pro design cool head on mine(comes with a head stay) i got 2 domes to change in it. i have a 19cc race dome, and a 21cc normal dome. i can change those out for whichever type of racing i will be doing. i would use the 19cc race dome on race fuel for mx or TT, but for Flattrack i use the 21cc dome, on regular fuel b/c it doesn't rev out so fast, allowing me to get a overall faster top speed. i've never tried a 20cc dome, but if i were you i would just go with a 21cc dome to get away with running normal fuel, i wouldn't push it down to a 20cc dome, b/c that would be getting the compression up a little high for normal 91 octane! hope this helps!