S&S 111 Dyno Chart Review

[j1mmyr1chter]

Red / Stench / anybody else with engine know how,

Heres my latest dyno chart (a little hard to see, but I think you guys will get the picture by the curves). I know it needs some work. So in case you guys dont know, my scoot has an S&S 111" that is pretty much 'crate' with crappy performing pipes (straight duals with fishtails lol). I havent done anything to the motor, its bone stock. I dont know the cam or anything like that because I dont have a build sheet or detailed specs on the motor. I am wondering if you guys see anything obvious here that I can do to get my low end performance up without sacrificing my balls to the wall high rpm torque (I tend to use it a lot ;-). I know, I know, my straight pipes with fishtails are killing me, but they look and sound kick a**. To me it looks like my mixture is totally hosed on the low end. What do I need to do? Any other ideas for getting the low end cleaned up without changing pipes? Let me know what else you need to know to help me out. Thanks guys!

[wolffman]

You can still get kick ass looks and sound out of a 2n1. You can probably even make ya one for ya fishtail too.

2n1 would be a bigger helper. Just sayn.

Did ya tweak the carb or anything at all???

[j1mmyr1chter]

Thanks Wolffman. Yeah I know everybody's gonna say "pipes", but I feel like there oughta be a few other things I can do to at least help the low end situation. I am not really that unhappy with the performance, but when puttin along in traffic, it would be nice if she would act a lil better. On the top end, its like a raped ape man, just want to clean up that low end. The carb was adjusted by the shop that did the Dyno. It just doesnt look right to me on the chart. The reference point vs where I am at on air/fuel looks wayyy off at the bottom end.

[wolffman]

The motor must have some high RPM cams like in the 3000+ range. KWIM

You could always have the heads re-dun buy that could shot ya self in the foot too.

I'd try to find a spec sheet for the motor to see what kinds internals it has before ya go changen stuff.
I know a lil but not alot LOL

You got any kinda baffel in them dur pipes???? No back pressure for da motor and make it sluggish at a low rpm too

[imrotton2]

that chart looks kinda weird!!! most tq and hp lines tend to cross at 5250rpms.... for a s&s 111" crate motor, its rather weak...jmo
should be getn around 1hp to 1 cu in.... tq around 13numbers higher than hp

[j1mmyr1chter]

Agreed Rotton. It pushes real hard way up in the rpm range, but sluggish at the bottom. I dunno if mixture could be a problem, but that air/fuel line doesn't look so good to me. Cleans up real nice up high, which helps me understand the great performance in high rpms, but wtf is goin on at the low end there?

[j1mmyr1chter]

@Wolffman, no baffles at all. 'Fence post' as my buddy likes to call straights.

reversion at low rpm , big valves, lots of cam, not enough compression, lack of tune. you cant tune it with those pipes, and if you could, it would do little good.

im guessin the 625 cam, its still pulling over @ 6k. inside the motor, its probably rich as heck. in the pipe, its probably lean because the air is running the wrong way. search for standoff!

does she go da-dit-dadda-dit, dadda, YANKKKKKKKK. when ya hit it ? LOL

wouldnt you really rather rip the tire off at 3000 rpm?

oh, hoping you didnt pay much for 15 runs and a dyno guy that beats your motor for no reason. why in the world would he start a pull that low?

[j1mmyr1chter]

There ya are Red! I was waitin on some abuse... I mean advice from ya lol. Naw, I highly doubt he ran it 15 times. Not sure why the run says #15. So, I hope you can forgive my ignorance here Red, but when you say 'tune it', are you talking mixture? Again, I fully realize (although maybe I don't fully understand the tech of it all) that my pipes are bad for performance on the low end. However, I KNOW you gotta know some things I could do to bring that curve up to more of a 'square wave' so I have better umph on the low end without changing them! Come on man, don't hold out on me! :-)

Cant see the rpm on the bottom. Does it get you to Dunkin Doughnuts ? If it does ,dont worry. If you love your pipes ,just put in a 'smaller cam'. Woods 6H would really wake up the bottom end. Speakin of 'bottom ends' .... never mind. Stench ps. you can try 'adding' some timing in the lower rpm's ,try add 2-3 degrees at a time ,up to 3500 rpm ,will pull more tq. but, if you start hearing funny noises, like a frog shooting 'pickles' ,stop,and back it off , -2 . Time to 'pinch one'.