SuzukiSavage.com - Carb changes to make

NCSUindy09

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Carb changes to make
09/21/14 at 10:43:05

Hey guys. I think it's about time to rejet the carb and maybe take out the white spacer. I was wondering if anyone had a guess at which size jets I'll need and which ones to replace.

Here's my setup:
1986 with 18k miles
Stock muffler (With a couple small holes for sound)
Cone style air filter (lots of air)
Raptor Petcock
Idle mix screw is probably 3+ turns out
Stock Jets/carb
Stock everything else
315ft above sea level

Right now I get a ton of engine braking and some loud backfire on decel. The acceleration is pretty good. Warms up and idles well. I get occasional flooding but it's probably just from crap in the tank getting the float valve stuck. A few good whacks usually fixes that. I'll probably invest in a fuel filter soon.

I'm checking with some friends to try to find an audio/electronic tach to make things easier.

Yay turd polishing Grin

Thanks

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1986 Savage, 18k Miles. Cone air filter, drilled & wrapped exhaust. Stock carb and jets. Daily commute bike.

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Ed L.

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Re: Carb changes to make
Reply #1 - 09/21/14 at 10:59:37

Don't take out the entire white spacer, it will make the bike run too rich in the mid range. Get some small washers and use them to stack up to about half the white spacer height. That should be about right for your setup. Or you can shave the spacer down.
The main and pilot jet should be just about right and I wouldn't swap them out quite yet. I ran a 152.5 main with the stock pilot jet for years with no problem and my bike has open exhaust and intake.
Just upgraded to a stage 1 cam and did a 155 main and 50 pilot rejet for the new cam profile.
If you are going to change out a jet start with the main, all the pilot does is control the idle and very bottom end.
One change at a time is the best way to tune the carb.
Been polishing my turd for quite a few years now, fun isn't it? Wink

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Silver '02, clubman handle bars, Cobra headlight, Sportster muffler, K+N stock air filter, 152.5 main, Superbrace, oil cooler, 1/2 inch aluminium plate forward controls, spark advance, goes like stink

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verslagen1

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Re: Carb changes to make
Reply #2 - 09/21/14 at 11:05:27

Sounds to me like you don't need to change a thing.

Quote:

The acceleration is pretty good.

So you don't need to change the white spacer.

Quote:

Warms up and idles well.

Idle jet ok

'86 had a 155, and I don't hear you complaining about the top end.

Quote:

and some loud backfire on decel.

sounds like you need to clean the carb, and make sure to clean the TUV valve. This could be a consequence of the drilled out muf, but most will tell you is "don't snap shut the carb on decel and it won't do it" Hold it open a bit on decel.

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Versey's Place
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NCSUindy09 Junior Member Offline Rollin' Posts: 64	Re: Carb changes to make Reply #3 - 09/21/14 at 11:28:45 Cool, thanks. I've cleaned out the carb before as thoroughly as I could. I'm not sure what the TUV valve is though. I'll give it another good cleaning and maybe fiddle with the spacer next weekend. Thanks for the tips
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Serowbot YaBB Moderator ModSquad Offline OK.... so what's the speed of dark? Posts: 28367 Tucson Az Gender:	Re: Carb changes to make Reply #4 - 09/21/14 at 11:33:59 FYi.. the 86' don't even have a spacer... ...it's got a notched needle... ... It's a TEV valve... (throttle enrichment valve)... it get's pulled open at high vacuum decel to toss a little juice out the pipe, reducing afterfires.. Right-side.. near the vac line tap... 3 screw cover plate, I think... ... Number 12...
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Ed L. Serious Thumper Alliance Member Offline "We All go a Little Crazy Sometimes" Norman Bates Posts: 2808 Sunny Florida Gender:	Re: Carb changes to make Reply #5 - 09/21/14 at 11:37:33 Check for exhaust leaks, they can cause some real good pops out the pipe. The gasket that goes between the head and header pipe will get crushed flat after a few teardowns and give some good snap, crackles and pops. It's one of those things that might look good but leaks no matter how hard the bolts are tightened.
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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: Carb changes to make Reply #6 - 09/21/14 at 14:47:20 And you are better off needing to snug them every so often than stripping the threads trying to make sure they stay tight. Snug when the motor is cool.
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NCSUindy09

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Re: Carb changes to make
Reply #7 - 09/22/14 at 09:19:00

The backfire sounds like it's coming from the air filter rather than the muffler. After I put the air filter on I got a decent HP boost and a much meaner sound. Sound from the intake is much louder than the exhaust.

Also yeah I didn't know what that was (TEV valve) when I cleaned the carb so I left it alone. Gonna get that sucker this time.

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1986 Savage, 18k Miles. Cone air filter, drilled & wrapped exhaust. Stock carb and jets. Daily commute bike.

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49mack

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Re: Carb changes to make
Reply #8 - 09/24/14 at 08:09:16

NCSUindy09: poke around on this forum and find the thread on cutting a single coil off the TSU or anti-reversionary valve. That's on the right side of the carb held in place by 3 screws. This reduced a lot of backfire for me. While you're at it, replace those 3 screws with allen head cap screws (home Depot) and it will save you the hassle of future "screw-ups" when the Phillips head screws made of Silly Putty eventually strip. Look for zinc or plated screws. The black oxide w screws will eventually rust.

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justin_o_guy2 Serious Thumper Offline What happened? Posts: 55279 East Texas, 1/2 dallas/la.	Re: Carb changes to make Reply #9 - 09/24/14 at 09:09:33 I use Anti-seize on just about every bolt that screws into aluminum.. especially on the carb. The valve cover bolts,for sure..
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leconya YaBB Newbies Offline SuzukiSavage.com Rocks! Posts: 2	Re: Carb changes to make Reply #10 - 09/26/14 at 11:06:25 I have 05 S40. I backfire like crazy. Previous owner did drill out the bafflers. I don't mind the loud pipes but the backfireing is driving me crazing and scaring people on the streets. Help!
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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28755 L.A. California Gender:	Re: Carb changes to make Reply #11 - 09/26/14 at 12:38:20 leconya wrote on 09/26/14 at 11:06:25: I have 05 S40. I backfire like crazy. Previous owner did drill out the bafflers. I don't mind the loud pipes but the backfireing is driving me crazing and scaring people on the streets. Help! You need to rejet, see carb tuning in the tech section.
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justin_o_guy2

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Re: Carb changes to make
Reply #12 - 09/26/14 at 13:09:01

Even with all stock setup my 05 made too much racket on decel. I'm not sure now,because that was a long time ago,but I don't think I had found this place at the time. Now,knowing what I've learned here,I'm pretty sure that the header bolts or something needed attention. I'm pretty sure it was not doing that for the first few hundred miles. Anyway,I dropped the$$$$ for a Supertrap and the pack of extra disks,put in a fatter main, slimmed the white washer down and it ran really nice and sounded really sweet.. BUT,if I had it to do over again,I'd slap a Dyna on it and tune the carb to that. They are better looking than the Trapp, and cost a lot less AND the performance and sound are too close to be worth spending the money on.
Changes to the intake don't have near the impact on mixture inside the cylinder as changes in exhaust restrictions. The piston pumps that out,using a ring designed for pushing. Intake,OTOH,is a product of vacuum, which isn't as efficient as exhaust.

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