SuzukiSavage.com - jetting help

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Re: jetting help
Reply #30 - 04/15/09 at 19:42:40

Well I am at a lose. Spent yet another whole night messing with this thing. Found a combo that works well but can't possibly be right.

Needle: Spring, Washer, Clip, 2.4mm White Spacer
Main Jet: #155, one (OEM?) brass washer
Pilot: #52.5
Mixture Screw: 1.5 Turns out

Seems the main is the issue. If I put anything but the 155 in at mid - full throttle the bike seizes up, sputters, and jerks. To tired to give this anymore thought tonight. Will see how it rides in to work tomorrow. Before this setup I couldnt even hit 50. I took it out an hour ago with the above mentioned setup and hit 50+ no problems.

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1988 LS650 - Candy Apple Red w/ Ghost Flames, Harley muffler, S40 seat, white spacer Mod, #55 pilot, #155 main.

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Re: jetting help
Reply #31 - 04/16/09 at 11:30:56

Well this carb is truely messed up. Still runs like poo, guess I didnt push it hard enough last night.

Looking at this picture:

I am missing the part "I don't know" and its not mentioned in the suzuki fiche so I cant order it Sad

The main I pulled out of this carb was a 132.5 according to Suzuki the OEM main was a 155 (no wonder the bike likes that better).

ARGH!!

Anyone know what "I don't Know" is and where I can get one?

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1988 LS650 - Candy Apple Red w/ Ghost Flames, Harley muffler, S40 seat, white spacer Mod, #55 pilot, #155 main.

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NewThumperGuy Full Member Offline Lets Ride!!!! Posts: 119 Sarnia, Ontario, Canada Gender:	Re: jetting help Reply #32 - 04/17/09 at 16:29:30 Man, that carb shines. Mine doesn't look like that!
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Re: jetting help
Reply #33 - 04/28/09 at 05:03:45

Well that was a waste of time on money Tongue

I dont have two jet on the top of an 88 carb Sad

I have a pilot air jet where the pic shows "I don't know" and just a hole where it is marked "Pilot air jet" which goes down to the second diaphragm thing.

Behind the second little diaphragm was another jet which I pulled out and cleaned and then put back in.

Sooo I re-cleaned everything. Put it back together.

STOCK (From: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1098869040):
===============
Main Jet: #155
Main Air Jet: 0.6mm
Jet Needle: 5c17
Needle Jet: X-6
Throttle Valve: #125
Pilot Jet: #47.5
Stater Jet: #22.5
Pilot Screw: 3 Turns Out
Pilot Airjet 1: #67.5
Pilot Air Jet 2: 2.0mm
===============

My Settings:
===============
Main Jet: #155
Main Air Jet: 0.6mm (I assume, could not find this jet)
Jet Needle: 5c17 (Spring, Washer, Clip, 2.4mm White Spacer)
Needle Jet: X-6 (assume, did not change)
Throttle Valve: #125 (assume, could not find)
Pilot Jet: #52.5 (From Lancer Kit)
Stater Jet: #22.5 (Assume could not find)
Pilot Screw: 1 Turn Out (To start testing)
Pilot Airjet 1: #67.5 (New from Ron Ayers)
Pilot Air Jet 2: 2.0mm (Assume, could not find)
===============

I think I may go grab a cone air filter instead of putting the air box back in. I am up in the air on it. Not sure if I want to loose my side covers or mess with moving the battery box back but I REALLY hate how cramped the spacing is in there for everything.

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1988 LS650 - Candy Apple Red w/ Ghost Flames, Harley muffler, S40 seat, white spacer Mod, #55 pilot, #155 main.

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Reelthing

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Re: jetting help
Reply #34 - 04/28/09 at 06:54:07

That pilot jet may workout for you - but that's 2 sizes up for a 86-88 with a stock mainjet - the old rule-of-thumb for the relationship between the two for a starting point was for each 2-3 sizes up on the mainjet you go up 1 on the pilotjet - if such an old outdated rule holds true in this case you would need a 165 to a 170 mainjet to match that pilotjet - which of course is too much fuel unless some pretty radical mods had been done to the air flow.

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Re: jetting help
Reply #35 - 04/28/09 at 07:35:35

Reelthing wrote on 04/28/09 at 06:54:07:

That pilot jet may workout for you - but that's 2 sizes up for a 86-88 with a stock mainjet - the old rule-of-thumb for the relationship between the two for a starting point was for each 2-3 sizes up on the mainjet you go up 1 on the pilotjet - if such an old outdated rule holds true in this case you would need a 165 to a 170 mainjet to match that pilotjet - which of course is too much fuel unless some pretty radical mods had been done to the air flow.

Hmmmm I dont think I have anything smaller for the pilot than the 52.5 Sad

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1988 LS650 - Candy Apple Red w/ Ghost Flames, Harley muffler, S40 seat, white spacer Mod, #55 pilot, #155 main.

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Re: jetting help
Reply #36 - 05/02/09 at 16:56:40

OK here is where I am at.

I completely disassembled and re-cleaned the carb. I re-assembled with the following specs:

My Settings:
===============
Main Jet: #155
Main Air Jet: 0.6mm (I assume, could not find this jet)
Jet Needle: 5c17 (Spring, Washer, Clip, 2.4mm White Spacer)
Needle Jet: X-6 (assume, did not change)
Throttle Valve: #125 (assume, could not find)
Pilot Jet: #52.5 (From Lancer Kit)
Stater Jet: #22.5 (Assume could not find)
Pilot Screw: 1.5 Turns Out (To start testing)
Pilot Airjet 1: #67.5 (New from Ron Ayers)
Pilot Air Jet 2: 2.0mm (Assume, could not find)
===============

I also went with a Raptor Petcock and an Emgo 12-55754 air filter (Which I WAY overpaid for!). I also still have the harley muffler with no baffle.

No more hesitation or power issues. I took her out tonight and really ripped on her and she ran very powerful. There is still some popping now but not nearly as bad as originally.

I am going to run it for a few days and see whats up. I am sure the mixture screw will need some tweaking. I am still thinking about going with a 160 main and 4 washers in place of the 2.4mm white spacer to try and squash the last of the popping. Whats everyone's thoughts on that?

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1988 LS650 - Candy Apple Red w/ Ghost Flames, Harley muffler, S40 seat, white spacer Mod, #55 pilot, #155 main.

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verslagen1 YaBB Moderator ModSquad Offline Where there's a will, I want to be in it. Posts: 28768 L.A. California Gender:	Re: jetting help Reply #37 - 05/02/09 at 17:04:41 go up an 1/8 to 1/4 turn on the idle and recheck for popping. Some is ok You want to minimise the shut off pop. When I get others, I look for leaks.
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diamond jim

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Re: jetting help
Reply #38 - 05/02/09 at 17:07:34

Are you certain the little bit of popping left is not due to some exhaust leaks. Even the smallest leaks will cause some minor backfiring. And I don't know if you can get it to where you never have a mild backfire every once in a while. If I were you, I'd loosen the header bolts, header heat shield and the muffler mounting bolt til you've got just a little bit of play in the whole exhaust. Then snug up the header bolts. Gently move the exhaust a little more and check the header bolts again. The goal here is to have the best exhaust gasket seal you can get. Then tighten up the heat shield then the muffler mount. Also check to see if you can improve the muffler to header seal. Sometimes it is difficult to get a perfect HD muffler seal outside of a quality weld job. At this point I think it would be better for you to do those things to eliminate potential exhaust leaks than to increase the main jet to a 160 and change the spacer thickness. Do the idle mixture screw changes as well like Verslagen said. If you adjust it just right it makes a big difference.

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Mortation Full Member Offline Posts: 205	Re: jetting help Reply #39 - 05/02/09 at 18:25:02 verslagen1 wrote on 05/02/09 at 17:04:41: go up an 1/8 to 1/4 turn on the idle and recheck for popping. Some is ok You want to minimise the shut off pop. When I get others, I look for leaks. I get a burble on shot off not a pop. Like a poof lol.
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Re: jetting help
Reply #40 - 05/02/09 at 18:27:24

diamond jim wrote on 05/02/09 at 17:07:34:

Are you certain the little bit of popping left is not due to some exhaust leaks. Even the smallest leaks will cause some minor backfiring. And I don't know if you can get it to where you never have a mild backfire every once in a while. If I were you, I'd loosen the header bolts, header heat shield and the muffler mounting bolt til you've got just a little bit of play in the whole exhaust. Then snug up the header bolts. Gently move the exhaust a little more and check the header bolts again. The goal here is to have the best exhaust gasket seal you can get. Then tighten up the heat shield then the muffler mount. Also check to see if you can improve the muffler to header seal. Sometimes it is difficult to get a perfect HD muffler seal outside of a quality weld job. At this point I think it would be better for you to do those things to eliminate potential exhaust leaks than to increase the main jet to a 160 and change the spacer thickness. Do the idle mixture screw changes as well like Verslagen said. If you adjust it just right it makes a big difference.

I already re-did the exhaust. I replaced the header with a shinyer new to me header. The header is sealed up good. The harley muffler was a PITA the PO did not even close to have a seal. So I drove the reducer deeper into the muffler to seal that end then clamped it. On the other end where the reducer connected to the header there was some play no doubt due to the metric/standard size difference. So I wrapped the base of the header with muffler tape then slid it on and clamped it to seal that up.

Maybe I will pope it off and see if there is a gap now that it has hardened. Thanks guys.

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1988 LS650 - Candy Apple Red w/ Ghost Flames, Harley muffler, S40 seat, white spacer Mod, #55 pilot, #155 main.

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diamond jim Serious Thumper Offline Posts: 1425 North Alabama Gender:	Re: jetting help Reply #41 - 05/02/09 at 18:33:18 Then the pilot jet and air mixture screw setting are indeed your likely suspects for the popping.
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odvelasc

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Re: jetting help
Reply #42 - 05/02/09 at 18:41:34

Mortation wrote on 05/02/09 at 18:25:02:

verslagen1 wrote on 05/02/09 at 17:04:41:

go up an 1/8 to 1/4 turn on the idle and recheck for popping.

Some is ok Smiley

You want to minimise the shut off pop.

When I get others, I look for leaks.

I get a burble on shot off not a pop. Like a poof lol.

I get decent poof on mine as well. Almost a pop-poof lol. I have a small leak where my exhaust connects to my header. When I shift between 2nd and 3rd I get a pop, pop and I love it lol, but I have to fix the leak. I know I have it because I used aluminum tape to cover up the mess I made sealing up the exhaust and it now has some black soot around where it leaks.

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diamond jim

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Re: jetting help
Reply #43 - 06/04/09 at 10:39:39

Hypothesis- I think the common spacer mod- thinning the spacer or replacing the spacer with a couple of washers- still leaves a too lean midrange that we often compensate for by over-jetting the main and sometimes the pilot.

Background- I've been running a 55 pilot w/ bleed holes, 1 turn out, 2 washers and 155 main. It's has a nice,smooth acceleration. However, gas mileage stinks so I've been wondering if I'm running too rich across all jettings. Today, I put in the 145 main and went for a ride. I had a very significant flat spot in the midrange with power returning on the high end but not quite as much as with the 155 main. Then I removed one washer and went for a ride again. Still a midrange flat spot but not quite as bad. Put in the 152.5 main and the flat spot was reduced to a barely noticeable spot and high end performance improved. Installed the 155 again and midrange was restored with a nice linear acceleration but high end no better than with the 152.5 main. So I discovered that 2 washers, and to a lesser extent 1 washer, is too lean for good midrange and that the overly rich pilot and main jet was hiding this fact. Here's my thoughts:

This is what I feel is an illustration of ideal jetting. The jets are even and overlap evenly with no significant overly rich or lean spots.

In comparison, this is stock. The pilot jet (with the factory idle mixture screw setting) and needle spacer make for a too lean condition but the main jet really is not all that bad especially with the stock airbox and stock muffler or unmodded HD muffler.

Doing the idle mixture screw mod and thinning the spacer to 2-3 washers fattens up the idle and midrrange areas and improves performance.

Going to a 55 pilot jet fattens up the idle circuit even more. So does going to a larger main jet. The result is increased overlap on both ends and starts to compensate for midrange leanness of 2 washers.

Going up another on the main increases the overlap and reduces the gap between pilot and main providing even more compensation for lean midrange. Performance improves but at the expense of running overly rich in the pilot and main.

So I'm thinking the most ideal baseline carb setup is:

Pilot: 52.5 (2-3 turns out) with airbox
55 without bleed holes (1 turn out) with pod filter

Spacer: no spacer (regardless of intake)

Main: 145-152.5 (depending on intake and exhaust)

Just my thoughts on the issue.

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Re: jetting help
Reply #44 - 06/04/09 at 12:40:54

Quote:

Going to a 55 pilot jet fattens up the idle circuit even more. So does going to a larger main jet. The result is increased overlap on both ends and starts to compensate for midrange leanness of 2 washers.

So what you're saying is, the carb chart that shows what component affects what range.. is only a rough guide. It says the main only comes into play at the top 1/4 throttle, which you've shown is bunk when you're dealing with the larger jets. They not only richen their respective range, but bleed into the adjacent range more, and even main-to-idle circuit if the main is large enough. Shocked

Cool, I'm going to try to get into my carb today and remove the spacer, clean the (stock) main jet and tune the idle screw, with dyna muffler installed if I get that far.. never had any luck fine-tuning the idle mixture by the idle speed method, will listen for pops instead.

Thanks!

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