Ok I know that the roadrage b1 is for bigger engine builds and the b4 is for stockers. Is the header different on the b1 ?Or is it just the slip on that changes? I currently have the RR b4 and its not playing well with my 125+ hp build.

 

Both headpipes and mufflers change depending on the system you choose. Also, pay attention to the year range each system fits. Probably a good idea to call Bassani and ask them to explain the nuances of the systems.

For example, the B1 FLH-777 says it's for engines over 130 hp, while the B1 FLH-767 is for engines producing over 120 hp.

• 2-into-1 equal-length headers
• Stepped 1 3/4" to 1 7/8" into 2" headpipes
• Utilizes an advanced inner collector for maximum performance
• 4" Straight muffler

• 2-into-1 equal-length headers
• Stepped 1 3/4" to 1 7/8" to 2" headpipes
• Utilizes an advanced inner collector for maximum performance
• Megaphone muffler

The B4 FLH-747 also states it good for engines producing over 120 hp

• 2-into-1 equal-length headers
• Stepped 1-3/4" to 1-7/8" headpipes
• Utilizes an advanced inner collector for maximum performance
• Megaphone muffler

 

Thx for the reply. I did try to call them this morning but they were closed fridays. I have the b4 747 with the megaphone. I did see it was rated for 120 hp. I just didn't see any difference in the header portion.

 

Having a Matrix with all the exhaust systems for comparison on their web page might be a good idea

 

OP, what do you mean by "not playing well?"

 

well I did a FM 107 outlaw build. On my 15 rgs took the bike to get dyno tuned and the bike had some crazy reversion. It sputters at 2700 and very little at 4000 rpm. This was only happening when we got on the throttle hard for the dyno pulls. Well I pulled the 19" baffle out. And installed a smaller baffle in and the bike improves instantly. I think its choking the engine up . I triple checked my end at least the mechanical portion timing,compression, leaks.and push rods. All checked good.

 

your correct the the b1 and b4 are different headers and mufflers.. thanks

 

Do you have a copy of your dyno sheet? I ask because we built a 107" using a Bassani RR pipe and had a very large dip (valley) in the curve that the tuner was attributing to the pipe. I am curious to see your chart with your combo...

 

I think the higher output 107 (120 hp) dont do well with the b4 RR. My lesson. Now I gotta spend more money for a new pipe.