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III b.  Internal Engine Modifications 

14.b. In addition, for those with an unending appetite for performance mods, custom cams and pistons are available. Check out the TECH TIP below on piston replacement, and browse the VROC Archives for recent posting on these topics. 

TECH TIP: At 29K miles I replaced all eight valves on my Vulcan. In reality, only the intake valves were damaged but I had a full valve job done while the engine was out for new pistons.  I have also added the Stevens Motorsports www.stevensmotorsportsomaha.com piston kit (Weisco 10.5:1 pistons www.wiseco.com, rings and wrist pins) and I had the head ported/polished and put in new valves.  You might want to modify the right up to state:  I am using ignition curve 10 with my Dyna 2000 ignition module and the rev limited set on 6000 rpm. This curve combined with 93 octane gas cures pinging. The bike pings badly on curves 1-5 which are the range of curves recommended for a fairly stock bike. The higher compression pistons need some retarding of the spark curve which is available in curves 6-10. I arrived on curve 10 after extensive trial and error. 

The reason that the valves pit is that  carbon deposits build up on the intakes and when early detonation (pinging) occurs, the carbon burns on the valves and leaves small nicks. When the intake valves have too many of these nicks, they do not seat properly. The cost of eight genuine Kawasaki valves was $120 for four new intake valves, $156 for four new exhaust valves, $64 for new valve seat, and $38 for new head gaskets. Since  the engine has to be removed to perform a valve job and the parts are costly, a valve job on a BUBF is something to be taken seriously. 

James, the mechanic at Extreme Powersports is a certified Kawasaki mechanic and was head wrench at Universal Kawasaki for many years. He bought their dyno and set up his own shop geared towards performance mods. He did the work on my bike and noted that  all Vulcans he disassembled with about 30k miles had pitted intake valves. The pinging can be reduced by using a higher octane gas. I previously used 87 octane and occasionally got a very slight rattling noise (it is the pinging) on  acceleration. With the addition of high compression pistons, I definitely am using 93 octane. It may also be prudent to use a fuel additive on a periodic basis, which is formulated to remove deposits on valves. Fellow VROCers recommended Yamaha Ring Free and Sea Foam. Sea Foam is available in most auto parts stores. I also had carbon on my piston tops and am going to use a deposit remover in the future. Hope my experience saves someone a few bucks in the future. My BUBF is now running much stronger than it had as a result of the recent modifications. Wiredgeorge, V2420, lesho@bigfoot.com, TX

14.c. I heard of claims that a compatible dual carburetor replacement kits for the BUBF is available.  The cost is somewhere above $400.00.  I believe Carburetor Parts Warehouse (http://www.carbparts.com) sells the carbs.

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