I don't know how anyone might be seeing over 7990 rpms since theres a hard rev limiter there. Meaning you can sweep thru it. D&D twins are nice and no matter how bad your clutching is they will still have more power and track speed. It is worth the time and effort to dial them in, not perfect but good to keep your rpms in a 3-400 rpm range. You have to go light on the heels. Use atleast the 060 or the XS-817 belt. AS the XS will drop rpms big. 250-500 in some cases, very durable. stock secondary spring works very well with many helix'. 85 grams IS silly heavy. But some roll that way. hahaha. Might wanna double check and spec the primary and its parts.....3 or 4 arm??? Jaws are very good, I have never had a bad set. I did however have 1 or 2 sets that mysteriously just made 5-8HP more than advertised and all the rest. Volume tested them and checked measurements, but without cutting them up no way of telling why?????? Greg has a very nice program to assist in developing the pipes to match the engine. With the lower operating rpms you can afford to go abit higher in helix without loosing any grip. Past 7800 and then it starts to show. The big 1000 can pull big helix , but only if thats your kinda riding. 46-40 full progressive 44-36, 42-38 seem popular. Seen a few 50/42-38,48/40-38. Straight 50 or 48 just for the quick snap up to higher trackspeed, but once past 20 mph it will never be in the 50 anymore. Atleast thats the way it was told to me. I like the heavier mid weighted arms since thats where i ride the most and it gives a good upshift and grip. Seems you have to have a finish rate of atleast 310 or 330 to get real good backshift during a climb with the heavy arms. Other thing that seems to work well is to lower the belt rediculously low in the secondary with stock helix. Just as long as it doesn't hurt the start, and it seems to XTEND belt life big. over 900 miles on 1 belt, but almost no stucks too or atleast no bad ones. Anyone try the speedwerx twins, I never read anything about them, never tried them myself but I seen they made real good power at elevation 8-9k test. On the D&D's make sure you have good back pressure, that is important. i think at 10-11k its 3/4-7/8 open on the barker. Watch for it to goo stupid lean if your way off , with not enuff BP. And if power seems to drop too quick during a climb or not what they should then your pipes could be stacking. Short test runs and you'll be safe for testing.
