OK, I have a new mod that I have to tell you all about. I put a Hinson timing advancer in my quad, and holy cow, all I can say is awesome. It is like I have two different motors now.
My main type of riding is motocross, and for that, I like to have tons of bottom end power. I set the advancer so that the spark occurred on the upstroke of the piston. This added even more grunt to an already very potent motor. This last weekend, I raced at a speedway, where we went most of the way around a 1/4 mile dirt oval, and then did a few small jumps in the infield, and then went back out on to the oval. In the first race, I was the slowest guy on the oval, so I changed the timing back to top dead center, and that helped for the second race. I was much faster than the first race in the second race. So then I figured, if that was better, maybe setting it so that the spark occurred on the downstroke would be even better. Well it was. In the main, I was smoking fast on the oval. There was a guy at the track that was racing pro, and his bike broke, so we let him race another bike in the intermediate class (that is what I was in). He was riding the bike that won the pro class. He got the holeshot on the start, and I was right on his butt for the first 8 laps. He is a much better rider than me, so I could not get by, but let me tell you, I was pushing him around the track, and he was holding me up. I might have beat him, but I spun out on the oval with only four laps to go, and I ended up fourth.

In short, the timing advancer took my bike from all bottom and no top, to not much bottom, and tons of top power, and the whole change only took me about 5 minutes.

 

On the cr250 head gasket I ran these in all three 250r's that I owned and had many riding buddies that ran this same setup and had no problems. I recommend running straight race gas below 3000ft. in elevation and a 50/50 mix of race and premium above this elevation. At 5000ft. you should be running around 175psi compression and at sea level it will be running around 195 psi.. When I was going to Dumont dunes a few years ago I called Allen Knowles of CT racing and these were his recomendations on fuel as I remember them. Dirt Wheels, years ago, recomended going with two base gaskets and the cr head gasket which also changes the port timing and would bump the compression back down a bit, not sure how much though. Running a good synthetic or caster (bean) oil is a must with these high comp. ratios. Av gas is crap fuel for an altenative to the expensive race gas (race gas blended for atv's and motorcycles, av gas for air planes) and trying it will cost more than it's worth. Hope this helps

 

I forgot my picks on pipes, my favorite was a hand rolled fmf torque pipe and second and the only one that can probably be bought is a CT ntl midrange. The worst was a pipe bought for duning, a paul turner high rev, my fmf hand rolled would out perform this thing on bottom, mid and top, the fmf would walk away from this supposed high rev pipe. Have rode R's with paul turner mid range pipes and they were good pipes, but the high rev was not a performer. All pipes discussed were run with the cr head gasket.

 

unless you are running in non-dusty/muddy conditions keep the lid and run a two stage foam filter. also take a stock trx head gasket, drill out the rivets and just run either the top or the bottom shim.

 

I think the first mods to get for a bone stock 250R would first be a k&n or uni air filter, tires and wheels if they are worn, chain and sprockets if they are old, and if the piston and rings are stock change them out. A pipe and silencer, ram or rad valve (or at least reeds), and cool head or power head would definetly give your R some more pep, but if you're looking for some real hard hitting power, get your motor ported or get a big bore kit. Then get some aftermarket shocks, longer a-arms, longer axle, and if you want your quad easier to throw around and less prone to spin outs, get a -1" swingarm. I have had my 250R for about 6 months and because I race mx, I bought the suspension, a-arms, axle, swingarm, nerf bars, ac bumper, etc. first. The only other mods I have are a uni air filter, chain and sprockets, case saver (gotta have it), and an FMF pipe and silencer. Even if i'm close to last out of the hole I catch up on the turns and doubles others cannot do.