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View Full Version : vmax, caps or no caps



ottawaair
03-22-2009, 06:16 PM
I have supertrapp slip-ons on my 97 vmax, they come new with 8 disks per side & closed end caps. Recently I was at test & tune w/ my bike running pretty fair, made about 8 passes. while letting bike cool down, I removed endcaps & all disks. Went back out & gained 4-5 tenths/second for about 8 more passes. Am i better off open or could i see even more power with disks back on & adding more disks???

jwells
03-23-2009, 08:26 AM
Typically, with more discs or none as you have found you may see a slight increase in top-end at the expense of a slight drop in the off-idle/bottom end. This is without any fuel changes. Doing wide open pulls such as you were doing would show this. On the street where you are not 'launching' the bike at half and above throttle settings you would probably notice a slight loss in the bottom.
Typically for the street, you are better off with the discs on and benefitting from the broader spread in power.

ottawaair
03-23-2009, 05:36 PM
Do you think 8 disks is enough for all around. Average cruising rpm is 4-5000, so downshift & go. Low rpm throttle roll on doesn't bother me. I just wonder if some backpressure is better than none??

jwells
03-24-2009, 07:43 AM
http://www.supertrapp.com/images/pdfs/003-0171.pdf

Here's a link to the specific instructions for the V-Max. Stock bike 6-8 discs is good. No more than 8 on a stock bike.
Ideal would be a jet kit and better air cleaner, then run more discs, up to 18-20 even.

ottawaair
03-25-2009, 09:44 PM
I got the instructions with the pipes & went with them. I have a K&N, stage one jet kit, 3,000 rpm v-boost, modded air box, Barnett clutch kit, & heavy right hand. These are not major mods but I was surprised to see 1/2 second gain on back to back runs by removing the disks & caps. Just tonight I put them back on but I drilled a 1-1/2" hole in the endcaps, just because the ends of the silencers are so ugly open.

hugger
03-30-2009, 10:09 AM
I have supertrapp slip-ons on my 97 vmax, they come new with 8 disks per side & closed end caps. Recently I was at test & tune w/ my bike running pretty fair, made about 8 passes. while letting bike cool down, I removed endcaps & all disks. Went back out & gained 4-5 tenths/second for about 8 more passes. Am i better off open or could i see even more power with disks back on & adding more disks???

Running the discs with the closed end cap is always better, so add a couple of discs and see what happens.