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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Mysterious rich running issue /cgi-bin/YaBB.pl?num=1721917881 Message started by lucme on 07/25/24 at 07:31:21 |
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Title: Mysterious rich running issue Post by lucme on 07/25/24 at 07:31:21 I'm new to posting here but have been reading up on as much as I can about these bikes for a few months. I have an '05 Boulevard S40 that had been parked for 5 years or so until I got my hands on it. I was able to get it running with a good carb clean and new jets, new air filter, oil change, new plug, and fresh gas. As well as some of the basic recommended mods from around here like a Raptor petcock. I've been through the carb fully twice. Once with some brushes and carb spray, and a random Amazon jet kit. This got it good enough to run but would bog out with more than 1/2-3/4 throttle, and it liked having the choke on all the time. But it was good enough to ride it to my shop space across town where I could dig into it further. So I went through it a second time, this time running the body through a buddy's ultrasonic cleaner. After that it was struggling to idle. I found that I had the larger pilot air jet and the main jet switched, and also opted to get an AllBallsRacing jet kit to replace the no-name Amazon kit. This is where my problems have really begun. Currently the bike will fire up from cold pretty easily, the idle is a little lope-y, but it seems fast enough to avoid the oil starvation issues of a slow idle. As it heats up, it begins to cough a little black smoke, and once it gets fully hot it will simply die from being too rich. It will stay running if you are on the throttle, but it spews black smoke, especially if you give it a good hard blip. The plug is always fouled with gas, black and damp. It is basically unrideable as anytime you have to stop and let it idle it tries to die out. This is all with the pilot screw all the way in. It only gets worse as I turn it out. I have verified all the jets are the correct sizes, in the correct places, save for the smaller-bodied pilot air jet under the needle diaphragm is a bit big. (I tossed the original jets the first time I replaced them. I know, I'm an idiot). I've checked the float/fuel level in the bowl and it appears to be within spec. I've done a valve adjustment. The spacer on the needle is stock, not cut down like is suggested for a lean throttle. It does have an exhaust leak in the muffler. The air box is clean, no blockage. I am going to try running it without the air filter to see if that improves things when I have time. It feels like I should be back at a basically stock carb now, so this constant super rich running issue is really confusing me. I feel like I've hit a wall on this project. I'm probably going to pick up a brand-used carb from a junkyard in the area if they've got one, if nothing else for spare parts. This is all the relevant info I can think of right now, if you need more, please let me know. I'd really appreciate any suggestions you have for me, as I really am not sure where to go from here. Thanks in advance! |
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Title: Re: Mysterious rich running issue Post by ThumperPaul on 07/25/24 at 14:49:06 Are you sure it's a rich carb condition and not oil getting past the piston rings and into the combustion chamber? When you installed the Raptor petcock valve, did you cap off the vacuum line that works with the stock petcock valve? Check your carb connection at the intake flange and make sure it's tight. An air leak there will cause all kinds of wierd issues with idle and power. It will also force you to use extra twist of the throttle (more fuel) to compensate for all the extra air coming in. It will be poorly atomized fuel and almost pour into the cylinder rather than being a fine mist. Hopefully others will chime in too. |
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Title: Re: Mysterious rich running issue Post by ohiomoto on 07/25/24 at 17:03:12 It's not mysterious at all. You know what one of the problems is...the junk set of jets. You said one of them is a tad large, but if the jet came out of one of those kits you don't know what size it is. You need a known good set of OEM spec jets. You could measure the jets you have, but the pin gauges needed to measure them would cost as much as OEM jets. And be sure to check the upper air jets if you changed them. People have mixed those up with the lower jets before. Are you missing washers under any of the jets? I don't know if your carb even had any. If you don't know, you'll need to do some research. And triple-check that float level. And don't forget to make sure the vacuum line is plugged like Paul said. And did you change the oil before you replaced the petcock? If you did you might want to be sure there is no gas in it. |
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Title: Re: Mysterious rich running issue Post by lucme on 07/26/24 at 06:19:53 Thanks for the replies, Paul and ohiomoto. I did plug the vacuum line when I installed the petock. Paul, what do you suggest to do if it is oil getting past the rings? I didn't suspect that since it only smokes black, not blue like is typical with oil burning. I will check the intake connections for leaks next time I'm working on it. ohiomoto, I agree that my jet situation is not ideal. Unfortunately, there is not a Suzuki dealer in my area, but I will pickup a used carb from a junkyard near me if they have one. I did have one of the upper jets mixed up with a lower at first, but that has been fixed. From all the diagrams and info I've come across, the only jet that has a washer is the main, and I have that washer. I will check the float level again when I check the intake. Thanks for the input. I'll get back with any results from doing those couple things, but that might not be for a few days. |
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Title: Re: Mysterious rich running issue Post by Dave on 07/26/24 at 11:13:34 I would not suspect the rings at this point.......it appears you have a carb issue and are just dumping too much fuel into the fuel/air mix. |
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Title: Re: Mysterious rich running issue Post by lucme on 07/26/24 at 12:16:45 Little update: Dave, that's what I was figuring as well. I just can't figure out the cause. I was able to poke at it a bit this morning. I made sure the intake connections were tight and flowed propane around them to see if it was leaking. It doesn't appear there are any leaks. I checked the float height again. I'm using the clear tubing method I saw suggested here since pulling the carb all the way out is more of a headache than I wanted to deal with today. The bowl level was a little low so I raised the float a bit to get it back up to where it should be. I changed the oil after I did the petcock. I gave it a sniff and it does smell slightly of gas currently. Would that indicate fuel leaking through the carb into the crankcase? If so, how do I go about finding/fixing the leak? Dave, seeing what I've already done, or starting from scratch, do you have any suggestions for tracking down the over fueling? I am definitely going to see if my local bike junkyard has a carb I can buy so at least I have a set of what should be stock jets etc. Also just so I'm sure, the plate that holds the needle in the slide has 2 holes (other than the screw holes) that line up with holes in the slide when flipped one way, but when flipped the other they cover the slide holes slightly. I've been under the assumption that they should line up. Is this correct? Or should I flip that plate so the holes are obscured? Again thanks for the input. |
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Title: Re: Mysterious rich running issue Post by Dave on 07/26/24 at 13:11:24 The holes in the bottom of the slide are what allow the vacuum in the venturi to get on top of the slide/diaphragm and raise the slide. When the vacuum is low the slide drops....when the vacuum is high the slide rises. If the float level is correct and the float bowl is not overflowing - then the chances of filling your crankcase and airbox with fuel is not going to be an issue. The other way the crankcase/airbox get filled with fuel is when the diaphragm in the stock vacuum operated petcock fails and allows fuel to flow down the vacuum line. If you have a smell in your oil currently, it is likely from the overly rich fuel/air mix. I suspect that you just don't have the jets in the proper place. I would start with a #150 main jet and a #50 or #52.5 pilot jet. Make sure the other jets are in their proper place. What is the condition of the diaphragm in the TEV (Throttle Enrichment Valve). Those get stiff and won't work as they age. I likely have a good stock carb....I will look and see what I have. |
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Title: Re: Mysterious rich running issue Post by lucme on 07/26/24 at 14:10:48 Thanks Dave. Would flipping the plate over to reduce vacuum be something to try? I have a 145 main, 52.5 pilot, 230 pilot air 1 up top, and the other pilot air is oversized. I'm going to get my hands on a correct size pilot air one way or another so I know its all correct. I'll take a look at the TEV diaphragm next time I can. Not till Sunday at best. |
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Title: Re: Mysterious rich running issue Post by Dave on 07/26/24 at 15:36:52 Those 2 holes in the slide need to be there....without them the slide will not ever rise, and you will never get above an idle speed. The size of the holes is also somewhat critical, as they determine how quickly the slide will respond to changes in the engine vacuum when you twist the throttle and open the butterfly. Smaller holes will give more time for slide to rise - larger holes will make it happen faster. Changing the size of the holes is risky - if the holes are too large the slide could rise too quickly and you will lose the "Constant Velocity" benefits. The slide could lift quickly and allow the vacuum to drop - which would then allow the slide to drop.....it could get into some weird oscillation. When I clean carbs, I never remove any of the jets in the carb inlet or the top where the diaphragm is located. I only remove the pilot and main jet - the air correction jets never seem to get corroded or plugged up. I never have to worry about getting them in the right place if I never take them out! |
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Title: Re: Mysterious rich running issue Post by DragBikeMike on 07/26/24 at 17:53:56 "a random Amazon jet kit" " also opted to get an AllBallsRacing jet kit to replace the no-name Amazon kit" When you started with these aftermarket jet kits you lost control of the problem. First, you didn't take note of exactly what was in the carb to begin with. Then you put in the generic Amazon jet kit but have no way of knowing what you actually installed. Then you installed another aftermarket kit of questionable pedigree. This old post provides very specific details on what to check for. It should give you a good idea of exactly how bad these aftermarket jet kits can be. They can really get you screwed up. http://suzukisavage.com/cgi-bin/YaBB.pl?num=1641171298 I suggest you break out the camera and provide us with some pictures. We have a better chance of evaluating what you have if we can see it. For starters, what color is your needle jet? Is it silver (i.e. stainless steel) or is it yellow (i.e. brass)? What color is your slide needle? Is it silver (i.e. anodized aluminum) or is it yellow (i.e. brass)? Does your idle mixture screw look like the long bogus screw discussed in the old post, or is it short like the OEM screw discussed in the post? "The plug is always fouled with gas, black and damp. It is basically unrideable as anytime you have to stop and let it idle it tries to die out. This is all with the pilot screw all the way in. It only gets worse as I turn it out." You can expect this when the bogus long screw is installed because the needle tip is grossly undersize. As such, it doesn't throttle fuel flow. It's essentially an on/off valve, two selections, full-on or full-off. "I will pickup a used carb from a junkyard near me if they have one." I would be careful with that. You stand a good chance of finding a carb full of these bogus parts. It would not surprise me if half the LS650s in a salvage yard ended up there as a result of someone installing one of these bogus carb kits. Once one of these rascals gets installed, I bet it is a complete nightmare trying to figure things out. I imagine some folks just plain give up and junk it. Review the old post and familiarize yourself with all the little details, then when you go to the salvage yard insist on disassembling before you purchase. Verify that the needle jet is silver and has OEM markings. Verify that the slide needle is silver and has OEM markings. I personally find Jets-R-us to be an excellent source for replacement jets. They stock genuine Mikuni jets, and they also have a line of non-genuine jets that are good quality and correctly sized. The non-genuine items are about half the price of the genuine items. They do flat-rate shipping and as I recall it's about $6 bucks. If you can get your hands on a Suzuki OEM needle jet and a Susuki OEM slide needle, then all you need are the correct size main jet, pilot jet, air bleed 1 & air bleed 2. I buy Suzuki OEM needle jets and OEM slide needles from Babbitts Suzuki Parts House. They have always come through for me. You should be able to get the other jets from Jets-R-Us. |
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Title: Re: Mysterious rich running issue Post by lucme on 07/30/24 at 06:15:22 Dave, thanks for the info on the slide. Mike, I think you're probably right about the jet kits. I'd like to basically start from scratch with good jets, and if you say Jets-R-Us is reliable I'll go through them. It looks like they don't list anything for our specific carb model, BS40 if I'm not mistake. So do you know if the jets in our carbs cross with to another more common model? Otherwise I'll pull them all out and take measurements of them to compare to the listed dimensions on the website. If you've got any suggestions for identifying the jets, or even just specifically which ones I need, I'd appreciate it. |
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Title: Re: Mysterious rich running issue Post by ThumperPaul on 07/30/24 at 06:32:34 Here’s a link to the jets for our carb. For the pilot jet, ours uses the first set listed (without emulsion holes). Although some people have experimented with the pilot jet that has the emulsion holes. Since you are already having problems, stick with “no holes”. I’d try 50/150 if you have a stock bike. If you have a freer flowing exhaust, maybe a 152.5 or 155 main (no bigger). To save on shipping costs and have some options handy, I’d get a 47.5 and 50 pilot jet and 147.5, 150, and 152.5 main jet. I didn’t check where you live and elevation. https://www.jetsrus.com/a_jets_by_carburetor_type/jets_mikuni_BS_series.htm |
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Title: Re: Mysterious rich running issue Post by DragBikeMike on 07/30/24 at 17:12:03 Lucme, the Mikuni jets for the stock carburetor are designated in millimeters. So, if the specified jet is a #145 the orifice is 1.45mm. The stock jetting for your 2005 carburetor is as follows: Main Jet: #145 = 1.45mm = .057" Pilot Jet: #52.5 = 0.525mm = .0207" Pilot Air Jet 1: #45 = 0.45mm = .0177" Pilot Air Jet 2: #230 = 2.30mm = .0906" The jets are expensive, and from what I understand you haven't modified your engine much, so I would stick with the stock jet sizes until you get the thing running correctly. You need to establish a baseline first. The only way to do that is get it back to the stock setup. If you have a free flowing airfilter and a less restrictive muffler, then maybe install a 147.5 or a 150 main jet, all the other jets should be stock size. It will run lean and hicup and take forever to warm up, but it will run. From that point you can make changes (never more than one thing at a time) and dial it in. These carbs really only need the slide needle raised up a bit and the mixture screw backed out a bit. Measuring the jets is tough unless you have pin gages. You can do some crude checks with numbered drills, but don't expect any real degree of accuracy. For the pilot jet, a #76 drill should just go in, and a #75 should not. For the main jet, a #54 drill should just go in, and a #53 should not. For PAJ #1, a #78 drill should just go in, and a #77 should not. For PAJ #2, a #43 drill should just go in, and a #42 should not. If you use numbered drills to check sizes, you do not want to insert the cutting edge of the drill bit, you insert the shank so as not to damage the jet. Use a light touch, never force the steel bit into the jet. If you have a miniature numbered drill set, it would be most beneficial to know what's in the carb now. It might help you to understand the problem better and also you could share that with us so we can learn too. You can purchase a miniature numbered drill set from any decent hobby shop. For PAJ #2 you can do a crude check with fractional drills (5/64" & 3/32"); close enough for diagnostics. Getting a set of correctly sized jets is the easy part of your problem. IMO, the lion's share of your issue stems from the slide needle, needle jet, and idle mixture screw. Those items are harder to come by. So, in an effort to get you on the road again, I humbly ask for your assistance. Again: What color is your needle jet? Is it silver indicating stainless steel, or is it yellow indicating brass? What color is your slide needle? Is it silver indicating anodized aluminum, or is it yellow indicating brass? Is your mixture screw long like the bogus screw identified in my old post, or is it short like the old post shows? Can you post some pictures so we can actually see what you are working with? |
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Title: Re: Mysterious rich running issue Post by DragBikeMike on 07/30/24 at 17:17:15 For the Jets-R-Us ordering data, you need the following type of Mikuni jets: For Main Jet & PAJ #2: "Large Round" N100.604 For PAJ #1: "Small Round" N102.221 For Pilot Jet: No emulsion holes N151.067 |
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Title: Re: Mysterious rich running issue Post by ohiomoto on 07/30/24 at 17:52:56 I told you it wasn't mysterious!! (It will be mysterious if the correct jets don't solve your problem but you have to start with a "known good" parts.) :) Jets R Us shafted me once. They made a mistake on my order and refused to send me the correct jet until I shipped the wrong jet back. The shipping was more than the cost of the jet. Pretty crappy since their policy is NO RETURNS because they claim they can't resell the jet since it could have been modified. They are a good source if they send you what you ordered. You can also go through Partzilla or some other reputable mail-order parts company. |
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Title: Re: Mysterious rich running issue Post by lucme on 07/30/24 at 19:04:32 Thanks for the Jets-R-Us info. I will try to get some pictures this week. What exactly do you want pictures of? I haven't had a chance to take a closer look at my idle screw, but I do know my needle jet is brass, and I have one brass slide needle with 3 adjustments for the e-clip and one silver slide needle with no adjustment. It looks like Partszilla like ohiomoto mentioned will sell the needle jet, slide needle, and idle screw but they're pretty pricey. I'm at about 900ft elevation so I figure going up in jet sizes probably isn't necessary right now, but since they're cheap I might just get a couple options like Paul suggested. I'll look into ordering those more this week as well. Would you consider a leaky muffler a "free flowing exhaust"? ;D |
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Title: Re: Mysterious rich running issue Post by Graybeard on 07/30/24 at 21:12:26 Would you consider a leaky muffler a "free flowing exhaust"? Grin As long as you call rust Weight Reduction, sure. |
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Title: Re: Mysterious rich running issue Post by ThumperPaul on 07/31/24 at 05:42:17 The exhaust leak is the air intake leak’s less ugly cousin. You should probably get that ironed out before tuning the carb. Tuning the carb to a leaky exhaust system adds an extra layer of fun. The different needles you have demonstrate the inconsistencies you’ll find in aftermarket generic kits. Did you save the original needle? Do you still have the white spacer that goes on the needle? Have you swapped out or shaved down the white spacer. I’d skip Partzilla for carb parts (more generic stuff I’m guessing). I haven’t looked recently, but JetsRUs should have the correct needle for the carb. I think they are like $20 each. They have an entire section on the website for needles. They are proud of those things. I’ve bought the cheap kits before and found some of the parts usable. I did compare the needle in one kit to an OEM needle and the needle taper was about the same (surprisingly). I obviously can’t speak to the needles you have in your hands. |
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Title: Re: Mysterious rich running issue Post by ohiomoto on 07/31/24 at 19:55:01 695548504D584F6D5C48513D0 wrote:
---------- Partszilla sells OEM parts, that's why they are so expensive! But I agree, Jetts R Us is a better place to purchase. Be sure to order exactly what you need because their return policy sucks and they might treat you like poo if they don't send you what you ordered. Since they screwed me over once, I just found another source: https://www.nichecycle.com/ncs/categories/carburetor.html LOL It feels good to get some revenge! ;D EDIT: I forgot about LANCER. I'm pretty sure he could source the OEM parts. |
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Title: Re: Mysterious rich running issue Post by DragBikeMike on 08/01/24 at 00:14:34 The only source for the needle jet, slide needle, and mixture screw will be OEM. They are special parts unique to the LS650. Sometimes ya just gotta bite the bullet. It's a good lesson. Never throw old carb parts out until you know for sure it runs correctly. In the case of the needle jet, it is made from stainless steel. I don't think you could ever wear it out. It's very expensive, so cleaning it up is the way to go. Lucme, pictures of your needle jet, slide needle, and mixture screw would be most helpful. If there are any markings on the needle jet and slide needle it would be great if you could focus on the markings. Some pictures of the carb interior, float bowl interior, enrichment plunger, carb exterior (right & left) and slide also will be helpful. Regarding the leaky muffler (I'm lovin that comment about weight reduction), is it a stock LS650 muffler? The stock muffler is very restrictive. Unless the rust holes are in the forward chamber, I doubt that there's been much change in flow. Pictures of the rust holes would be helpful. |
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Title: Re: Mysterious rich running issue Post by lucme on 08/01/24 at 08:24:07 I will take pictures tomorrow since I'll have plenty of time to mess with it. I have the original white spacer for the needle that came in the carb, unmodified by me. I also get paid tomorrow so I'll order up some jets, and I should probably fork over for the needle, needle jet, and mixture screw too. As for the muffler leak, it's underneath the outer sheetmetal heat shield/heat dispersion thing. It is an OEM muffler, has a Suzuki part number. I'll try to get a picture that shows where its coming from as best I can. If it were simply on the exterior or on the header pipe I could weld it myself, but its in a place I can't see, even with the muffler off. So if it ends up being a real issue, I'll have to buy a new one. Mike, I agree, this is definitely a good lesson in not throwing stuff away. I'm quite upset with myself that I did that, I ususally keep old parts off whatever I'm messing with. But nothing I can do about it now sadly. I'll be remembering this in the future though! |
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Title: Re: Mysterious rich running issue Post by ohiomoto on 08/01/24 at 17:10:41 Understand that we don't know if your issue is the jetting or something else. The point is that you wholesale replaced the parts with parts that might be suspect and you need a known good baseline. But you are in good hands. This forum has a strong record of helping people work through these issues. There are some incredibly knowledgeable people here. I'm just a POM (Plain Old Member). I just wanted to point out the problem with the jetting situation before you invested more time into this. :) |
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Title: Re: Mysterious rich running issue Post by DragBikeMike on 08/01/24 at 23:21:12 "I have the original white spacer for the needle that came in the carb, unmodified by me." Lucme, is that white spacer currently installed, or do you just have it stored in a safe place? The overly rich problems you are experiencing, are they with the white spacer installed, or with the white spacer removed? |
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Title: Re: Mysterious rich running issue Post by lucme on 08/02/24 at 14:55:33 The white spacer has been installed the whole time. EDIT the links did not work. what is the best way to insert images. I tried using the function above the text box and used flickr links EDIT 2 ok im just gonna use straight links so hopefully that works for you Here are the pictures: (hopefully these links work) https://flic.kr/p/2q7GJej exhaust leak is coming from inside the sheet with the holes. I can't get to it to find or repair it without cutting it apart. https://flic.kr/p/2q7PaQV My 2 slide needles. The silver one has 5C39 marking. The brass one does not. As you can see the white spacer is not so white anymore. I ordered a new needle and spacer just to be sure. https://flic.kr/p/2q7GJdn Mixture screws. The one on the left is from the AllBalls kit. Same issues happening with both. Ordered a new one, as well as the spring, washer, and o-ring. https://flic.kr/p/2q7Mpe4 Inside slide and diaphragm. That is how I have the holes lined up, which seems like its correct thanks to Dave's info. https://flic.kr/p/2q7PAmK Outside of slide. It's definitely seen some use but I didn't think it's too severe so I did not order a new one. https://flic.kr/p/2q7NFgj Top of carb with slide removed. Front of bike to the left. You can see the choke is pushed in. https://flic.kr/p/2q7GJ7v Inside bowl. https://flic.kr/p/2q7NFgp https://flic.kr/p/2q7PaFG https://flic.kr/p/2q7PaEj Some mediocre pics of bottom of carb. I didn't want to pull it all the way out since I can get at everything with it on the bike and it's a pain to put back on. https://flic.kr/p/2q7PaBJ https://flic.kr/p/2q7PAe5 Needle jet. No markings on it. It does have emulsion holes. I ordered a new one. https://flic.kr/p/2q7PaEp https://flic.kr/p/2q7NFbz Choke or TEV. It looks in good shape so I did not order a new one. https://flic.kr/p/2q7Mpfw https://flic.kr/p/2q7PArz Carb sides before I removed the throttle cable etc to remove the TEV. I do have the bowl vent tubes, I just removed them to take the slide out. The hose with the bolt stuck in the end is how I plugged the vacuum port for the stock petcock. The bolt is sealed with rubber sealant. I ordered all new main, pilot, air 1, and air 2 jets. I got a couple different sizes as well as OEM sized mains and pilots. If you want anymore info or pics let me know. Thanks everyone. |
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Title: Re: Mysterious rich running issue Post by DragBikeMike on 08/02/24 at 19:29:21 Thanks for all the superb pictures. Overall, your carb looks pretty good. The muffler will be tricky. That's the forward chamber that you show in your picture. A leak there will aggravate backfires and make the carb difficult to dial in to the gnat's @$$, but it will probably support getting the bike running and drivable without fouling plugs. It will sound bad (literally), but you should be able to get it running decent if the hole isn't too darned big. You will need to get a different muffler eventually. I think you already know that. The slide needle on the left side of your picture is correct. The 5C39 is the correct designation. The stack goes as follows: -Washer under C-clip -Spring under washer -Plastic spacer on top of C-clip Like this. |
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Title: Re: Mysterious rich running issue Post by DragBikeMike on 08/02/24 at 19:38:26 The mixture screw you show on the left side of your picture has the correct geometry. It is short like it should be, it has a straight unthreaded section for the o-ring/washer/spring, and the tapered section looks pretty close to the correct size. The picture you provided of the side of your carb shows the mix screw deep in the hole like it should be. I believe you said you ordered a new OEM mix screw, so when you get it do a comparison and let us know if the AllBalls part measures up. Where did the bogus screw come from? The stack you show is correct. Spring on first, then the washer, then the o-ring. |
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Title: Re: Mysterious rich running issue Post by DragBikeMike on 08/02/24 at 19:49:18 The retaining plate in the slide is installed correctly. Those teeny-weeny screws can be tricky. A magnetic screwdriver comes in handy. The slide condition is poor. All of the dry lubricant is worn away and there is a lot of scoring. If that thing is hanging up it will run very bad. I believe OhioMoto has experience with that. Maybe he can describe the symptoms. I would operate the thing with the air boot removed so you can watch the slide. Make sure it isn't hanging up when you run the engine. Best have a fire extinguisher right there when you do that, and do it outside, well away from any structure. Any sort of hicup or flashback could light the beast up. That slide should raise up as you open the throttle. Even though it's not directly connected to the throttle, the air flow through the venturi will cause the slide to move up as flow increases. You want to verify that it returns to the at-rest position when you close the throttle, and that it moves up in response to more throttle. You really need a new slide. |
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Title: Re: Mysterious rich running issue Post by lucme on 08/02/24 at 20:01:41 The bad screw was from the Amazon kit (shocking, i know) Its gonna take a little while for everything to get here but I'm going on vacation next week anyway. So I'll report back once parts have arrived and I've installed them. Looking at everything now, I suspect the needle jet is a culprit. It also came from the Amazon kit with the bad screw and unmarked needle. Mike, you clearly have more experience with these things than me so I'd like to take your word and get a brand new slide, however they're almost $200... So maybe I'll see if I can find a used carb with a decent looking slide. I'll look into that this weekend. |
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Title: Re: Mysterious rich running issue Post by DragBikeMike on 08/02/24 at 20:07:56 The top of the carb looks good. As you mentioned, the enricher looks like it is closed. The larger jet should be a #230, and the smaller jet should be a #45. I can see that the needle jet is brass. I don't care for that, but you said you have a new OEM item on the way so that problem will be corrected. Inside the bowl looks good; no sludge or slime, but I'm seeing some small black particles. Are those black particles loose or are they fixed to the interior of the bowl? The hole in the bottom of the bowl (upper left in the picture) is the supply for the enrichment circuit. Make sure that is not fouled with any of those black particles. The interior of the carb looks good. The brass rod sticking down is your enrichment jet. Make sure it is not plugged. I wouldn't try to remove it, just verify that it's not obstructed. Is there a washer on the main jet? Have you checked the floats for leaks? Sometimes they develop a leak and fill with gasoline. You can check them by shaking the brass float assembly. You will hear the gasoline sloshing around in there. You have to be careful when removing the float, if you don't support the aluminum post on the carb body while driving the pivot pin out, it's easy to break off the post. |
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Title: Re: Mysterious rich running issue Post by DragBikeMike on 08/02/24 at 20:30:39 The brass needle jet is questionable. Since it looks like they got the mixture screw geometry correct, I guess there's a chance that the needle jet is dimensionally OK, but the brass jet will wear out quickly since the slide needle is constantly buzzing away inside the jet. The needle jets typically come in .0002" increments (that's two ten-thousandths of an inch), so extremely small changes in the orifice diameter make a significant difference in fuel ratio. As previously mentioned, you ordered an OEM replacement so that issue should be resolved. The enrichment plunger looks OK. Verify that the rubber seat on the face of the plunger is in good condition, and that it makes up correctly with the metal seat in the carb body. Your approach to capping off the vacuum nipple on the carb body looks fine to me. Regarding the vent hoses, make sure they are unobstructed, and route them up into the hollow backbone of the frame. You need to verify that your main air bleed is unobstructed. If the main air bleed gets plugged with dirt, it will cause a rich condition. When the needle jet is removed, spray copious amounts of carb cleaner through the main air bleed and make sure the carb cleaner comes out from the needle jet bore in the carb body. This is the main air bleed. |
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Title: Re: Mysterious rich running issue Post by DragBikeMike on 08/02/24 at 20:42:31 Regarding the worn slide, I have never experienced that particular problem. I imagine it could result in grossly rich mixture under certain conditions. If the slide is hung up the slide needle position will not match the throttle plate position. The slide needle will be allowing way too much fuel into the air stream at small throttle plate openings. I suspect even idle would be affected. The needle jets come in .0002" increments so even the smallest variation can make a big difference. Your description of the problem points to the needle jet and slide needle combo, but if the worn slide is hanging up it would create the same sort of condition since the needle would be positioned way too high in the needle jet. Ohiomoto, was it you that had the worn-out slide problem? What were the symptoms? |
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Title: Re: Mysterious rich running issue Post by ThumperPaul on 08/03/24 at 05:40:07 DBM has done an incredible job as usual reviewing and assessing the photos. My hunch is a sticking slide is the main culprit. I’ve seen similar and probably got lucky not addressing it. You posted pics of the choke (fuel enrichment as some call it). The actual TEV is on the right side of the carb behind the 3 screws. See photo. As you can see, the screws can be easily stripped. A good JIS (Japanese Industry Standard) “screwdriver” and not a #2 Phillips screwdriver is strongly recommended. This is a “before photo”, and a popular change is to swap out for Allen head screws (I think M4x16 - double check me). There is a post somewhere with the size verified, but I can’t find it at the moment. People also ditch the float bowl and carb top (dome) screws in favor of Allen head screws. Here’s a link to all kinds of good discussion about the TEV. http://suzukisavage.com/cgi-bin/YaBB.pl?num=1342323516 |
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Title: Re: Mysterious rich running issue Post by Graybeard on 08/03/24 at 08:19:06 Your #2 Phillips can be a JIS . You only need to tell it it needs to learn to Identify as a JIS, then, once it's psychologically ready, after it's spent a week living as a JIS, you take it to the bench grinder and point its little pointy tip straight at that brutal spinning stone and grind it. Put a flat spot on it. Test it for proper fitment into the JIS screw. Keep going until the tip doesn't hold the X up from engaging with the head of the screw. Aftercare is really easy, a little oil before slipping it back in the drawer is all it needs. |
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Title: Re: Mysterious rich running issue Post by lucme on 08/03/24 at 13:41:04 Those particles are fixed, just some tiny pitting. The enrichment circuit is unobstructed. And the rubber on the end of the choke plunger looks good. The floats are not leaking, they are very light and do not make any noise when shaken. The main jet does have its washer, always has. If I remember correctly, the actual TEV (forgot about that) looked good when I pulled it apart the second time I had the carb out. I don't plan on modifying it until the bikes running properly if needed. I would pull it out again but I don't want to take my chances on those screws right now, even with my JIS driver. The main air bleed also appears to be free. I sprayed carb cleaner though it and it came out the needle jet passage. |
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Title: Re: Mysterious rich running issue Post by ohiomoto on 08/03/24 at 16:04:59 494F403C3E393D0D0 wrote:
--------------- Yeah, that was me. The slide looks similar to mine. It only caused extreme lean conditions for me. The first time the motor would make it to the mid-range with full throttle but could hardly pull 20 mph in any gear. I had just rejected the carb so I assumed I didn't seat the diaphragm properly. But it looked perfect when I assembled it and it looked the same when I pulled the carb to inspect it. I cleared the slide, put it back together and the bike ran perfectly. I believe the slide was moving but the vacuum couldn't fully open it. A few weeks later I lost all throttle control while shifting from 4th to 5th...chop the throttle, shift, crack the throttle, and nothing. The bike was still running but would only idle and I had to pull off the side of the road. I tapped the side of the carb with a rock and it came back to life. It ran perfectly fine the rest of the ride home. I'm pretty sure the slide was stuck closed in this case. I replaced the slide and haven't had to touch that carb since. It was about $120 from Partzilla but that must have been 5-6 years ago. I don't think it would cause an excessively rich condition unless it was stuck completely open with the throttle plate closed as DMB said. Pretty unlikely IMO, but I could be overlooking something. I would try to get it running with that slide before dumping $200. It will be interesting to see what happens with the new jetting. |
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Title: Re: Mysterious rich running issue Post by Graybeard on 08/03/24 at 16:40:30 I had just rejected the carb so I assumed I didn't seat the diaphragm properly It may have just been sad. |
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Title: Re: Mysterious rich running issue Post by ohiomoto on 08/03/24 at 16:52:55 It's nice to see the ghost of JOG is with us. ;) |
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Title: Re: Mysterious rich running issue Post by Graybeard on 08/03/24 at 18:33:29 With you from beyond. Some people would say Waaay beyond.. Meh,,so they don't get it. The science really is settled.. |
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Title: Re: Mysterious rich running issue Post by lucme on 08/13/24 at 06:58:36 Hey all, I'm back from vacation! Sorry for the radio silence. I got the Jets-R-Us order in while I was gone. I checked to make sure that what they sent matched what I ordered and it's all good. They were out of stock on the 52.5 pilot jet but I had ordered a 47.5 and 50 as well so hopefully that will work. It looks like the only next size up they have is a 60 so I'd have to find another supplier if I need larger than a 50. Unless I want to try one with the emuslsion holes. Otherwise, I've got a 145, 147.5, and 150 main and 230/45 pilot airs in their respective styles. The needle, needle jet, and mixture screw are still on the way from Partszilla, UPS says they should be here next Monday. I'm going to wait till that all arrives and then throw it together with stock jetting, save for obviously the pilot which I'll try the 50 first. Anyways, I'll probably be pretty quiet again until the Partszilla order comes in. Thanks again everyone! |
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Title: Re: Mysterious rich running issue Post by ThumperPaul on 08/13/24 at 15:06:00 Cool. The 50 pilot jet will be fine. You can adjust it with the air/fuel mix screw. It'll be fine. You can make any pilot jet 47.5 - 52.5 work. The 60 would be way too big. |
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Title: Re: Mysterious rich running issue Post by Dave on 08/14/24 at 04:10:10 467A677F6277604273677E120 wrote:
Cough/Gag/Belch/Blaaaaaaah! :-/ It would be similar to a wet gasoline vapor sauna!!!!!!! |
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Title: Re: Mysterious rich running issue Post by ThumperPaul on 08/14/24 at 04:22:30 Great sound effects, Dave! I think the 128 main jet in my PWK38 carb is giving me a case of the blaaaaahs at wide open throttle. It’s just not crisp and seems “thick”. Acceleration seems dull compared to acceleration while finessing the throttle in the midrange. Back to the 125 and see what happens. I’m very good at selecting a main jet that’s too big due to a terrible fear of running too lean at WOT. |
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Title: Re: Mysterious rich running issue Post by lucme on 08/27/24 at 05:18:22 Well guys you were right! All new good jets and the OEM needle, needle jet, and mix screw makes her run like a dream! Been out riding for a couple days and it feels great. Gonna mess with the mix screw a little more to see if I can cut down on the backfires a little but I'm not too worried about that. I really appreciate all the advice y'all gave me! |
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Title: Re: Mysterious rich running issue Post by ThumperPaul on 08/27/24 at 05:33:04 Cool! Good job! Glad you didn’t have to replace the slide. Expensive suckers! |
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Title: Re: Mysterious rich running issue Post by ohiomoto on 08/27/24 at 06:36:55 That's great news! Now leave that carburetor alone. ;) |
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