Anyone have any suggestions on what I can use to plug the crossover pipe on a Forty Eight? I just installed Bassani Firepower slip ons and love them. Looking for something that I can use to plug the two opening on the crossover. Would a heat resistant high temp silicone plug suffice? I want it to be something that I can remove later if need be. Thanks for the input.

 

I don't think high temp. silicone will work. The temp. of the exhaust pipe is higher while running the bike at anything over idle speed shortly after warmup. The high temp. silicone will resist temps up to about 446°F. Your exhaust pipe will run about 375°F to 395°F after starting and idling for about 2 or 3 min. After going on a run of more than about 25 min. the temp. of your pipes will reach up to and over 490°F.

The material they use for the head to exhaust port on the bike is a spun wire mesh because they can not use anything like silicone at those temps. Plugs for car exhaust are typically made of cast iron that you insert into the opening and clamp the pipe onto.

What type of cross over are you talking about. Older Sportsters had a big chrome crossover that matched the exhaust pipes themselves and crossed over about the level of the bottom of the cylinders. Newer (i.e. about 2004-2008) used a black tube that attached to the bottom of the frame and connected right in front of each of the mufflers and was also used as part of the support/mounting of the exhaust.

I'm thinking maybe you can find some copper plumbing caps, cut some slits in the open end of each cap and use a pipe clamp to compress them on the open ends of the pipes if you don't have the latter type of crossovers. If you are looking for something to use to plug instead of cap, maybe you can just pack/stuff them with the same glass they use in for wrapping around baffles. You can buy large amounts of the stuff for a reasonable price.

 

Thanks for the response DOMAPOI.

I have the newer crossover pipe that is attached at the bottom and serves as a mount as well. I was looking last night and came across the steel knockout caps that are used for electrical boxes. They come in all sizes and are easily removed. Thinking of swinging by Home Depot and taking a look. Was gonna use some hi temp black exhaust paint on them. What do you think?

 

The paint should work, if you can find a plug that fits. The crossover won't get all that hot when not being used.

 

Why plug them if you're not using them? Can you just take the crossover out, and mount your pipes without it?

I've got the old style, so not familiar with crossover/pipe mount assembly.

John

 

What is the reason for wanting to block it? Certainly will not help your performance.

 

The crossover is actually the mounting point for the muffler and is located below the pipes. The slip ons that I installed do not utilize the crossover pipe so I have two open ports on the crossover. I want to cap them off in order to keep crap from collecting inside.

 

Without the crossover functioning, you may get reversion waves in your individual pipes. That will lower your midrange torque, so your perfomance may actually be worse than before.

John

 

That is almost certain to happen. But, not too many people on here seem interested in performance anymore.

 

Temps aren't an issue on the crossover. I put a set of slipons on my '05 and they came with a set of plastic caps for the crossover and they have held up perfect for the past 6 years. Plus they come off easy when I have to switch back to stock for a day to be able to pass inspection every 2 years. The only purpose they serve is to keep water and junk from getting in.