Do ya mean Intake Manifolds? the rubber boots that mount carbs to motor? If ya have them off and they are cracked through then they are junk-They cannot leak at all-If they are really hard and dry but have no cracks they can be saved- Ive done this quite a few times on different bikes with alot of success-....Go to a graphic arts/ printing supply store, such as Expedex, Arvey, Dixon, to name afew, and get a quart of what is called RUBBER REJUVENATOR, manufactured by Hurst or varn. Soak the rubber parts for a couple hours in the stuff. Keep an eye on them-= they may swell up a bit but thats o. k....After a couple hours, pull them out and heat them up with a heat gun or hair dryer- NOT a torch, as the stuff is pretty flamable. After they cool off, they will be a little softer. Repeat process two or 3 times, untill they are soft enough- Also, they install easier if ya heat them up right before ya put them on. I just got a used ignition switch from Caldwell Motor Toys,Russell, PA (814)757-4404 off a bike, It may still have decent manifolds-I have a friend here in Kansas city wh works in a bike shop and sez he can get decent used ones also-Hope this helps ya-contact me if i can help more. Have a day:)KB