Most of the time the oil leakage around the head gasket joint is because the barrel spigot is too tall, and prevents the head from seating down on the head gasket sufficiently to seal the oil around the pushrod tunnels.In cases like that, no amount of re-torquing will fix the leak. However, a little measuring of the gasket gap between the head and barrel, and a gasket that is .010" thicker than the gap, will fix it. Or, if you turn down the spigot enough so that the gasket gap is .010" thinner than the gasket you plan to use, then it will seal.As for the porting, the port is already big enough for 6000 rpm, and all the gains for that port will be in the valve seat, unless you go to bigger valves and know how to re-shape the bowl properly to get gains from it.Take it from a guy who has a LOT of Bullet cylinder head work under his belt.And if you plan to ever have it ported professionally, like by us, then leave it alone until you want to send it in, because sometimes we can't get the best results if metal is removed where it wasn't supposed to be removed.This port retains the 32mm entry, but has 1.84" intake valve with narrower stem, with re-shaped bowl and special 5-angle valve job done on a Serdi machine, with custom guides, and will receive a custom hand-matched and flowed inlet manifold stub pinned on those pin-holes you see in the photo.
Checking the mating of the spigot to the mating surface on the head is essential. Ace has gone over this many times before. If you do a forum search on this site or Tom's (Ace) site you will find the info needed to properly check and mate the surfaces. Most mating surfaces are suspect on newly assembled iron barrel motors from the RE factory. The spigot top should be parallel to the machined surface on the barrel top. Many times it isn't. The spigot and head should be lapped. Ultimately you want a perfect seal mating barrel spigot to head and parallel surfaces barrel to head for the best gasket seal. I would say that a complete blueprinting of an iron barreled Bullet motor would be a must when finally deciding to do a complete tear down. From the factory the varied tolerances and poor metallurgy make engine survival a real crapshoot. There are a few who have a jillion miles on their Bullets. The word few is the real problem because it should really be the opposite when talking longevity of a product that has been in production as long as the Bullet has been. If you love your Bullet as much as most of us do you will one day have to pony up the cash and time to make it right. Thanks to Tom and Chumma's meticulously thought out parts testing and rebuilding process a new foundation has been laid to build a practically bulletproof Bullet iron barrel motor. For many this may not be monetarily feasible but could be a basis to use when rebuildling to stock specifications. Thankfully Tom and Chumma have really gone to great lengths to offer a kit for every level of price point and performance along with the knowledge and support to help everyone along through their build. This shows great dedication and discipline between the two which can be attributed to their love of these motorcycles and they're passion for innovation. I am looking forward to what they have in the works for this new year.
BTW, my spigot does not contact the head, and the gasket holds the tremendous compression quite nicely.
If that is the case, wouldn't the characteristics of your combustion chamber change if the spigot does not contact the recessed surface. That can't be right or good in my opinion.
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