News:

This forum is run by RPM and donations from members.

It is the donations of the members that help offset the operating cost of the forum. The secondary benefit of being a contributing member is the ability to save big during RPM Holiday sales. For more information please check out this link: Membership has its privileges 

Thank you for your support of the all mighty FJ.

Main Menu

Supertrapp tuning disc question!

Started by Tor-King, April 06, 2017, 10:03:50 PM

Previous topic - Next topic

Tor-King

Hi all.

I have a 2 into 2 Supertrapp exhaust on my 3CV.  I do not require it to be overly tuned for high end performance/horsepower but need a starting point as to the number of tuning discs I require.  Currently there are 5 discs on each side...  It is not overly loud but would like to know if this number is creating too much back pressure or rich condition?? I acquired the bike last year and this is how it was set up. Can anyone who has this exhaust give me some guidance?

Thanks!
Dean
1993 Yamaha FJ1200
1988 Yamaha FJ1200
1986 Yamaha FJ1200
1984 Honda Nighthawk S 750
1972 Yamaha XS-2
1972 Honda CT70
1974 Honda CT70
1992 Yamaha DT50 MX
2012 Honda CBR250R
2008 Honda CBR125R

Tor-King

Oh, and the jetting is 110 mains and 42.5 pilots with 2 1/2 turns out on the mixture screws...  The airbox is factory.
Thanks,
Dean
1993 Yamaha FJ1200
1988 Yamaha FJ1200
1986 Yamaha FJ1200
1984 Honda Nighthawk S 750
1972 Yamaha XS-2
1972 Honda CT70
1974 Honda CT70
1992 Yamaha DT50 MX
2012 Honda CBR250R
2008 Honda CBR125R

FJmonkey

The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

FJ1100mjk

Quote from: Tor-King on April 06, 2017, 10:03:50 PM
Hi all.

I have a 2 into 2 Supertrapp exhaust on my 3CV.  I do not require it to be overly tuned for high end performance/horsepower but need a starting point as to the number of tuning discs I require.  Currently there are 5 discs on each side...  It is not overly loud but would like to know if this number is creating too much back pressure or rich condition?? I acquired the bike last year and this is how it was set up. Can anyone who has this exhaust give me some guidance?

Thanks!
Dean

From another source, an '86 with a similar system as yours:

I have the stock airbox with a Yoshimura exhaust system and I run:
#42.5 pilot jets
#117.5 main jets
Stock needle shimmed .035"

************************************************

I have an '87, that has a 4-1 SuperTrapp on it with six or seven discs on its can. It has size 40 pilot jets, 112.5 standard mains, and standard air jets. I can't recall how many turns out the pilot air screws are. It has always run fine, and I have put some good miles on it.
Platinum Zircon-encrusted Gold Member

Iron Balls #00002175
www.ironballs.com


yamaha fj rider

I had a Supertrap 4 into 1, it had 12 disks. I used a Factory Pro jet kit.

Kurt
93 FJ1200
FJ 09
YZ250X I still love 2 strokes
Tenere 700
FJR1300ES