John gs1000 are 2 valve engines. I have the 4 valve. 1983 was the last year for the gs1100 and the crank was welded from the factory and the big end or the crank is bigger. The eariler models had a small end on the crank and the stator would walk right off. A riding buddy had a 1981 and he had to weld the stator to the crank. I have never had the head off. It has 28k miles at a quarter mile at a time. Right now it has aftermarket 33mm smooth bore carbs with the fuel running thru a dual outlet race petcock. The pipe is an old rusted kerker race pipe (circa 1984) with a Alum canister. I have the street and competiton (too loud) baffle. Back when I was a young man (1984) I was National #2 for the season in PRO ET (I was bracket racing full drag bikes with slicks bars and air shifters vs. my street bike). I won three nationls in a row in the Dragbike AMA series. I had the longest winning streak in the history of the series with 16 rounds won. Eight rounds were won at a race in conjunction with cycle jam weekend at Pocono Internation Raceway (the 2 1/2 mile tri oval). We raced down the front straight a real big crowd. The dragbikes were at a real disatvantage. There was no rubber down like a regular drag strip. The made them burn out on a piece of steel and launched on reg. blacktop. The lights were these real old jobs that they used to have at a local track and I was right on. In the finals I raced a guy from York on a bar bike. I ran a 11.909 on a 11.90. He ran a 10.909 on a 10.90. There were no reaction timers or even mph numbers. Real hayseed seat of the pants drag racing. The next race was in syracuse, ny and I won that (4 rounds). Then I went to columbus oh and won that race. In the finals out of all those bar bikes it was two street bikes. Me on the GS and another kid on a kz1000. He was 2-3 tenths slower than me and he left first. I had a bad light and was trying to run him down and was getting nowhere fast at when at about a 1000ft he missed a shift and I slid right on by. Then the next and last race that year was in Maple Grove in reading pa. I red lighted first round to a fj1100 the was 2 tenths faster than me. So that was my 15 mins. of fame.