Make sure you have the proper key for your clutch that fits the grove in the clutch and crank shaft , it should have came with your clutch . Some people will use a washer in between the clutch and engine as a wear spacer . It should be the same size as the crank shaft and should fit snug on the crank shaft . The gear side should be to the inside , against the engine . Sometimes you need to install the chain on your clutch before you slip it onto the crank shaft , because of the chain guard not giving you enough room to do it after you install your clutch . Leave the chain off of the rear drive sprocket for now while installing your clutch . After you have the clutch on the engine , place the lock washer onto your bolt , then add the flat washer that goes against the clutch on it . Make sure the washer you are using doesn't contact any of the moving parts of the clutch , such as the weights on a disc clutch . Tighten the bolt onto the engine , but do not over tighten the bolt , because you can break the bolt off into the shaft . If you are using an electric impact , just hit it a couple of times , don't just hammer on it . After you have the clutch installed on the engine , place a gear set onto the axle and slid your engine until it is tight , which you will then see if you need to move your axle drive hub . Line the chain up using a straight edge to the best you can . If you are not using any type of chain tension device , slide your engine to loosen up the chain a little and give it a little slack 1/2 inch or so . Your axle should spin freely with little binding at this point . Make sure everything is on correctly , then you can start your engine to see if it is working properly , don't over rev your engine with no load on it on the stand . If you have a tach on your engine , you can put a tire on the axle and hold onto it , and bring you engine up slowly to see about where your clutch starts to engage . Clutch lock-up should be set according to your weight class , meaning a small child will not need as much stall speed on the clutch as say a larger adult . Ask your parts man on this item , or check around at your local track to see what is good for your class . Have fun !