SuzukiSavage.com - Carb jetting

justin_o_guy

Ex Member

Carb jetting
07/13/07 at 12:42:25

I went out & ran for top end. Got to 88 or maybe 89, went home, let it cool, dropped the main to a 150 from the 152.5. Went & ran it again. Made every bit as good a run, maybe one MPH better. Still not backfiring & grumbling on decel. Once in a while a small pop if I let the throttle slap shut just right. Does this mean I could drop the main another step & see what it does? I am really surprised that the MPG is as low, mid 40's, as it is. Also, considering I have a Supertrapp with 14 baffles & a K&N drop in, snorkel removed & the inner wall of the header removed, seems this thing would be very lean. I have even replaced the white spacer, as well as possible. The slide seems to be free &^ I have been very careful to avoid gooing it up. Since the girl is running it, I am trying to detune it & get the MPG up & still give her a decent ride.

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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 29042 L.A. California Gender:	Re: Carb jetting Reply #1 - 07/13/07 at 14:12:37 On a supertrapp, disks don't equal baffles. The more disks you have the 'holes' you have for the exhaust to escape. So more disks equal less backpressure.
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LANCER

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Re: Carb jetting
Reply #2 - 07/13/07 at 14:26:36

verslagen1 wrote on 12/31/69 at 16:00:07:

On a supertrapp, disks don't equal baffles.

The more disks you have the 'holes' you have for the exhaust to escape. So more disks equal less backpressure.

YEP
.........................

KEEP IN MIND THAT THE BACKFIRING ISSUE IS A FUNCTION OF THE PILOT SYSTEM JETTING, NOT THE MAIN JET

.....................
IS YOUR SUPERTRAPP A MUFFLER+DISC'S OR JUST A CAN WITH DISC'S?
WHEN I WAS RUNNING MY SUPERTRAPP I HAD TO UNLOAD THE DISC'S AND JUST GO WITH THE OPEN MUFFLER, OTHERWISE IT WAS TOO RESTRICTIVE.
THE MUFFLER I RUN NOW HAS A 2" OPEN CENTER WITH DUAL SPIRAL BAFFLING AROUND THE OUTSIDE. IT CREATES BACKPRESSURE WHEN GOING SLOW AND FUNCTIONS LIKE AN OPEN PIPE WHEN WIDE OPEN.

IF YOU HAVE THE MUFFLER VERSION, THEN TAKE OFF THE DISC'S AND GIVE IT TRY.

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justin_o_guy Ex Member	Re: Carb jetting Reply #3 - 07/13/07 at 19:39:01 Are you sure you read my post? I appreciate your knowledge, but I am not sure you are understanding what I am asking.
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Reelthing Serious Thumper Alliance Member Offline Fish or ride that is the question Posts: 5397 Houston,Tx Gender:	Re: Carb jetting Reply #4 - 07/13/07 at 20:22:08 the fuel mileage on yours has always been a bit low - of course a different wrist is on the throttle now and it'still under 40? how many turns out on the mixture are you? I might drop down another - have you had a chance to eyeball any of the new sparkplugs in throttle chop fashion?
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justin_o_guy

Ex Member

Re: Carb jetting
Reply #5 - 07/13/07 at 21:33:46

I am just not comfortable at wide open for more than a few seconds. As soon as it stops accelerating, I am ready to let off. Amazing what differences a guy notices at 52 versus 26. I am half as stupid & twice as old. Gee, at this rate, if I make it to 104 I will be all the way up to moron! I was looking at those plugs just a day or so ago. Tell me again how to do it? The least amount of wide open time in high gear you can recommend is what I want.

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Reelthing Serious Thumper Alliance Member Offline Fish or ride that is the question Posts: 5397 Houston,Tx Gender:	Re: Carb jetting Reply #6 - 07/13/07 at 21:39:35 could do it in 4th I guess - at least a mile - brand new plug - WOT - pull in the clutch and kill it -
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Reelthing

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Re: Carb jetting
Reply #7 - 07/13/07 at 21:56:38

you know - but if you really too big on the main you can usually feel it - you can hold WOT for a bit and slightly roll back just a liittle and you feel the bike pickup speed with less throttle

you can get a good idea on the midrange the same way - but a tach helps - new plug hold the engine at around 3500rpm in 5th for a couple miles and kill it

use to be a good link around here on the "plug chop method" but I didn't find it just now

here's vroom's his is a little less violent

http://suzukisavage.com/cgi-bin/YaBB.pl?board=RubberSideDown;action=display;n...

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LANCER

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Re: Carb jetting
Reply #8 - 07/13/07 at 21:58:50

I read... you commented about lack of backfire except a little pop, and then asked if you should drop the main a size, and I was just offering that it is the pilot system that is primarily responsible for the backfiring issue so changing the main jet does not affect that.
Also, with your top speed under 90 I am suspecting that your small main jet and the Supertrapp baffles are restricting your top end.
With the low and midrange tuned well you can still get good milage and have good top end.

I was getting 48 mpg avg, with the lower 40's when running really hard.

I am hearing that your general focus is on efficient running and improving mpg. Did I hear you correctly?

By the way, what pilot jet is in it and how many turns out?

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justin_o_guy

Ex Member

Re: Carb jetting
Reply #9 - 07/13/07 at 23:05:01

I think the 150 gave me a slight gain over the 152.5. I had a 155 in it & it sooted the brake quite a bit. It was still sooty with the 152.5, just not as bad.I don't know how the 150 is gonna act regarding the soot issue. I just want to lean the carb out till it's actually lean & then , put a stock air cleaner in it, first, then if still too lean, maybe add the snorkel? Or remove a disk or 2? I am just not sure exactly how to decide when its jetted right. I am thinking Reelthings suggestion to stick plugs in & run it Wide Open & chop the throttle may be the only way I will ever figure it out without adding a sensor to the header.
I was under the impression that it would snarl & grumble on decel once it was jetted right. That went away so long ago I dont remember what I did. I THink it was when I put the TRapp on it & went to a bigger jet, but, I cant say for sure. If it wont run 90 that's okay. I just want it to be fun for the girl & she has only been riding for 500 miles or so. She doesnt need so much speed. I dont mind her having acceleration, that's fun & as safe as anything we can do.

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LANCER Serious Thumper Alliance Member Offline Savage Beast Performance Parts Posts: 10875 Oklahoma Gender:	Re: Carb jetting Reply #10 - 07/14/07 at 14:16:43 A well tuned bike with a performance muffler will produce the snarling grumble you mentioned. So what pilot jet are you running and how many turns out? Is your white spacer stock or filed?
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justin_o_guy Ex Member	Re: Carb jetting Reply #11 - 07/14/07 at 14:46:14 Stock pilot is 52.5, screw is out very close to, but just shy of 2 turns. The white spacer WAS filed down. I put stuff back with it( a couple of small washers) so that it is within a hundredth of an inch or so of stock, on the thin side, not thicker than stock. Thank you guys for your time.
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LANCER

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Re: Carb jetting
Reply #12 - 07/14/07 at 16:20:43

justin_o_guy wrote on 12/31/69 at 16:00:07:

Stock pilot is 52.5, screw is out very close to, but just shy of 2 turns. The white spacer WAS filed down. I put stuff back with it( a couple of small washers) so that it is within a hundredth of an inch or so of stock, on the thin side, not thicker than stock.
Thank you guys for your time.

OK, stock pilot and near stock needle setting, with a 150 main. All in all, not a typical rich setup. But you are still getting rich indications on the plug. You have a supertrapp with a bunch of disc's on it ... 14 discs?
I am still thinking you should try the the supertrapp muffler without any discs, for an open muffler...that will lean it out.

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justin_o_guy Ex Member	Re: Carb jetting Reply #13 - 07/14/07 at 21:35:43 I think I will run a new plug & do what Reelthing suggested before I mess with the mixture any more. I wouldnt want to melt something down. My girl would just shoot me if I messed her ride up. I wouldnt blame her, either.
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