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/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Cone Filter & Rejet problem /cgi-bin/YaBB.pl?num=1194205089 Message started by DavidD on 11/04/07 at 11:38:08 |
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Title: Cone Filter & Rejet problem Post by DavidD on 11/04/07 at 11:38:08 Hi All, I picked up an very used (but mostly running) '87 this past July, and have been gradually restoring it. When I got the bike, it didn't have the airbox or connector tubes, so I bought one of the metal-mesh cone filters and hooked it straight to the carb. Following Balderdash's suggestions found here http://suzukisavage.com/cgi-bin/YaBB.pl?board=RubberSideDown;action=display;num=1183926901, I stepped the pilot up to a .055 jet. When I put the carb back on the bike, I got no idle unless I had the choke pulled out to the first notch - pushing the choke all the way in would idle so low that the engine would nearly die. I drilled out the cap over the idle-mixture screw, but the screw was varnished in place, so had to drill it and use extractors, then replaced the screw, spring, washer and o-ring. (Does the O-ring go ON the screw, or just in-front of the screw in the hole? I put mine ON the screw.) With the new screw, I fired the engine back up, and tried adjusting it, but it seemed to make no difference at all when I'd tweak the mixture screw - from all the way in to 3 full turns out, the non-choked idle was still near stall. SO I removed the carb again, disassembled it (except for a few of the air jets), and blew an entire 12 ounce can of carb-cleaner through every orifice and hole I could find (including the airjets I'd left in). I put the carb back on yesterday, but the idle is still so low the engine dies, unless I use the choke. It runs pretty well on 1/2 choke... ;) Can anybody offer any suggestions? The Clymer says not to use wire to clean out the orifices, but I'm starting to wonder if maybe I've got a piece of brass or something (from all the drilling) stuck somewhere in the idle circuit that blowing-out won't remove. Thanks for any advice, Dave |
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Title: Re: Cone Filter & Rejet problem Post by barry68v10 on 11/04/07 at 11:45:44 This seems silly, but... Did you attempt to adjust the idle speed? If you tried, what were the results? How new is the gas in the tank? |
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Title: Re: Cone Filter & Rejet problem Post by LANCER on 11/04/07 at 12:57:26 I hate to say it but you need to take it apart again, including every single jet in the little thing. Get more carb juice and you can use tiny wire if you are careful to clean the passageways. I take small electrical wire, strip the insulation and unravel the strands of copper wire and use them to go through the passageways... GENTLY Every little hole needs to be open and clean. |
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Title: Re: Cone Filter & Rejet problem Post by Rockin_John on 11/04/07 at 13:26:44 Seeing nobody addressed the idle mix screw o-ring question: I also had to replace mine, but I replaced only the screw/needle. In this fiche: http://www.ronayers.com/fiche/300_0039/carburetor/carburetor.cfm?man=su&groupid=7070&parent=7050 It shows the o-ring under a washer with the spring on top of it (Items 43-47). I would assume that means it shouldn't be around the screw as you said you have it installed. |
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Title: Re: Cone Filter & Rejet problem Post by Reelthing on 11/04/07 at 13:28:38 If that '87 has the stock carb and it looks like it does that's a very big pilot jet. The carbs we a good bit different - might should go back to stock 47.5 jet http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1098869040 |
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Title: Re: Cone Filter & Rejet problem Post by Rockin_John on 11/04/07 at 13:34:36 Reelthing wrote:
Right-O... Even after installing a Dyna muffler on my 87, I realized it already had good sized jets in it. I put the new ones in, even though they were the same size, and closed it back up. The only adjustment necessary was on the idle mix and idle speed screws and it ran fine. At least the carb got cleaned and Stainless allen head capscrews installed out of the deal. Your main malfunction may be having that idle mix screw and o-ring in wrong... anyone else know different? |
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Title: Re: Cone Filter & Rejet problem Post by DavidD on 11/04/07 at 20:37:51 Thanks for the replies, folks. Barry: The idle speed screw is about midways. Idle was pretty decent before I started, maybe a tiny bit high for a single. I've tried a few more twists up, but it didn't seem to make much difference, the RPMs are still in the basement. I got the gas about 3 weeks ago (had to replace the petc0ck on the tank). And also have an inline filter as well. Rockin John - Thanks, that looks alot like the fiche at BikeBandit - and neither really shows where the o-ring is supposed to be when assembled. So your o-ring is sitting down in the carb when you take the mixture screw out? When I finally got mine out, the o-ring was down in the carb so had to get it out with a piece of wire. When I went to put the new one in, I just figured it went on the screw with the washer and spring - it seemed to fit OK, and I didn't know where else to put it other than leave it loose down in that circuit. Am I wrong about that? And John and Reelthing - should it at least idle with a too-big jet? I could understand if a too-small jet made the idle go so low, but I'd think a too-big one wouldn't drag it down to stalling. I've got a 47.5, so I may try it. Lancer - thanks, I was afraid somebody was gonna say that. heh. At least it's getting cold outside, so I don't feel like I'm missing out if I'm inside with a disassembled carb instead of out riding with cold fingers... I'll give the electrical wire a shot. Does anybody know where the idle circuit dumps into the airstream? Is it those three tiny holes right above the butterfly? I guess I'll need to feed the wire "backwards", right? Thanks again, Dave |
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Title: Re: Cone Filter & Rejet problem Post by Rockin_John on 11/04/07 at 22:54:31 Dave, I'll tell you all I know about the idle mix screw circuit assembly, but hopefully one of the other people can fill in any blanks. When I drilled out the cover plug over my screw, I bunged up the head of the soft brass screw with the drill bit. (I know several others here have done the same). Anyways, I ordered a new screw to put into mine when I was doing my other jetting, but it seems there is more than one type of screw for that same Mikuni, and Ron Ayer's sent me the wrong one. The one I pulled out was a complete needle point on the end, and the one they sent me was flat on the end with only about half of the end making a small needle point. (Wish I could find my picture I took of the two side by side, but that explanation is the best I can do.) Also, When I pulled the original plug and brass screw, no spring or o-ring came out. In the end, I simply filed a new slot in the top of the old screw/needle jet so I could easily adjust it with my little screwdriver, and that's how it is to this day. I can tell you that turning my screw in or out definitely makes a difference in the amount of backfire I get. I've reached a happy medium at about 2 turns out, and an idle speed of right under 1k. (Setting your idle down really slow where the bike sounds really cool, turns out to be a real problem to correct tuning.) Hope that helps, good luck. |
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Title: Re: Cone Filter & Rejet problem Post by smokin_blue on 11/05/07 at 02:40:42 DavidD wrote:
Dave, When cleaning your carb I am assuming you stripped it down? All the jets out type of thing? As for the pilot circuit. Make sure you take out the pilot jet and make sure that is clean. (always becareful with carb spray to keep it out of your eyes..nasty stuff) Then open the butterfly with one hand via the thottle linkage, insert spray can tube up the tube where the pilot jet was, then look in the engine side of the carb. Not spray! Alot of fluid will come back out the pilot tube but you should see some come up through the 3 holes. Depending on how the stream goes in that could be anything from a burble to 3 shots coming out the holes. Depending on the storage conditions, those little holes can be the down fall of a carb job. Lastly, if it idled before did you induce an air leak when you reassembled it? Was it in the manifold/rubber boot fully and the clamp tight? any signs of cracks in the rubber boot? That could destroy an idle also. Good luck |
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Title: Re: Cone Filter & Rejet problem Post by gj859 on 11/05/07 at 15:03:20 If it started acting up after you put on the inline filter, try it without the filter. |
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Title: Re: Cone Filter & Rejet problem Post by DavidD on 11/07/07 at 20:11:47 John - thanks for mentioning your different parts. I pulled my carb tonite and removed the mixture screw - the new one that BikeBandit sent is definitely different than the original one. The original was brass, the new one is steel (I guess). The original had 2 steps near the needle-end - the main shaft steps down to a smaller diameter that's about 3 mm long, then that steps down to the needle which is also about 3 mm long (all eyeballs, no ruler handy). The new one is a single step - main shaft down to a cone-needle. As well, the "needle" part of the new one is about 2 mm shorter than both steps on the original, and the point of the needle looks a bit smaller/pointy-er. Actually, from the end of the threads to the tip of the needle, the new one is about 2 mm shorter altogether, although the main shaft on both seems to be about the same length. Ron Ayers and Crotch Rocket both list the mixture screw, and the fiche pics LOOK like the two-stepped screw - not that I really trust any fiche to match reality. The part numbers are similar between the two sites, but not exact. Guess I'll order both, since they're only $4, and see which, if either, is the correct one. Blue - thanks for the tips. As far as I can tell, the boot is OK - doesn't look dry-rotted, isn't hard and brittle. GJ - it worked fine with the cone filter originally, the problem started after changing the jets. |
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Title: Re: Cone Filter & Rejet problem Post by gj859 on 11/08/07 at 02:41:54 When did You put on the fuel filter? |
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Title: Re: Cone Filter & Rejet problem Post by LANCER on 11/08/07 at 07:21:30 Old carburetors behave a lot like old mistresses ::) |
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Title: Re: Cone Filter & Rejet problem Post by DavidD on 11/08/07 at 16:08:55 John, Do you happen to still have the part #'s for the two screws you got from Ron Ayers? I think your "wrong" screw sounds like my "right" screw. Thanks, Dave |
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Title: Re: Cone Filter & Rejet problem Post by Dr_Jim on 11/08/07 at 20:55:07 - |
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Title: Re: Cone Filter & Rejet problem Post by Rockin_John on 11/08/07 at 21:59:26 DavidD wrote:
Dave, Sorry, I struck out altogether here. Can't find the picture of the two screws side by side; which I had posted in another thread here, but appear to have deleted from my website AND computer! So... I broke down and went out to the garage to dig through the 'leftover' parts boxes. I know I saved the one screw I ordered from them in the bag it came in; which would show the real Suzuki part number. But danged if I can find it anywhere! Even found a couple of shipping "bill of materials" from Ron Ayer's, neither of course included the screw/jet in question. Finally logged on to their site and searched my past orders and found their part #: 13279-47070 but it did not look like the one that came from my Mikuni: http://catoosatrading.com/images/cycles/87ls650_idlescrew.jpg That is a picture of the Ron Ayer's page for our LS-650PH model's version of the Mikuni (BG40 isn't it?) At the bottom is the silhouette of the actual screw I pulled out of my 87. It looks just like the screw in the picture to me, but the one they sent me from that part number did not. A warning here: you've already noticed that each dealer uses a slightly different parts numbering system, and not the factory numbers. Real convenient for cross referencing huh? While pulling my screw out, I discovered that it was only set at 1/2 - 3/4 turn out instead of the 2 turns I thought I'd left it at. And as I mentioned before, there was no spring under my screw from the factory. Unless the old man who had the bike before me replaced the screw without a spring; as I know that he had recently cleaned the tank and carb before I bought the 87, but I assumed he hadn't been into the idle screw circuit. I guess you can by the plug to replace over the screw so it doesn't show you've been in there tinkering. Oh, best I could see down in the hole with my magnifying glass, if there is a small o-ring and washer covering it down in there, I couldn't see it. I'm not inclined to go digging around down in there either, since the setup I've got works well. Anyways... just as you, I'd like to get this issue resolved once and for all: Which screw and associated assembly of parts are the correct ones for our 87 models? If I get time tomorrow, I may dig back into my parts boxes and see if I can find that elusive screw... but for now this is all I have... |
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Title: Re: Cone Filter & Rejet problem Post by DavidD on 11/09/07 at 08:27:03 I couldn't get a decent pic of my two screws, so I drew them (crudely) in MS Paint. http://www.nighthawk750.com/idle-screws2.jpg (wow, this site makes the image BIG) The top one is the original one I pulled out of the carb. The bottom one is the new one sent by BikeBandit. (the needle on the bottom one should be a little shorter than the the -- I'm no artist...) Before I go and spend another $15 on parts that may or may not be right, I'm gonna clean the carb again. BTW - I did notice that the fiche's at BikeBandit, Crotch Rocket, and Ron Ayers are different for the 87 carbs. BikeBandit and Ron Ayers show TWO air jets in the top (under the needle slide diaphram), Crotch Rocket only shows one. My carb only has one jet up there, and doesn't look like the one in Greg's fourth photo at http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1098869040 I only have the jet that he calls "unknown", I don't have a jet where he says his Pilot Air Jet is. I'm guessing Greg has a 95-or-newer? Maybe BikeBandit and Ron Ayers use the '95-up fiche for the older models too, and that throws the whole thing into fits... |
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Title: Re: Cone Filter & Rejet problem Post by toddlamp8 on 11/09/07 at 13:05:59 The bottom one looks like the "better" one to use. It appears to have more adjustability since the entire end is tapered. |
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Title: Re: Cone Filter & Rejet problem Post by Rockin_John on 11/10/07 at 22:51:51 Yes David, same with me: Your first picture looks like what is still in my carb, and the second "pointy" one looks like the one Ron Ayer's sent me. Until we can find who will send a correct mixture screw for an 87, or if there is any interchangeability, I'm with you on not wasting money. I'll continue to use the one I've cut the crappy slot into. |
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Title: Re: Cone Filter & Rejet problem Post by DavidD on 11/21/07 at 13:36:35 For the record: I ordered a new idle mixture screw from Crotch Rocket, and it matches the one that was in the bike - it's brass and has the stepped-down area on the end. Part # for the Idle Mixture Screw for an '87 : 13269-37400 Crotch Rocket's site says it "replaces" part # 13269-37410, and calls it various names - "screw pilot" on the site, "screw air" on the packing list - neither of which sound like much fun... :) Will be installing it this weekend to see what difference it makes. I took apart the carb last weekend and I swear it's clean now. I swear it. I took out all of the jets I could find, except that little tiny one under the choke diaphram (or whatever the diaphram is that's "behind" the choke) - it wouldn't budge and I couldn't find it on any of the fiches, so I decided it would have to do since bunging it would mean a replacement carb... |
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Title: Re: Cone Filter & Rejet problem Post by Rockin_John on 11/21/07 at 19:01:48 Thanks for the report back David. Now hopefully I can reliably order a new correct needle-screw for mine. It appears that at least one dealer has the correct part and knows the difference. Edit: I just went to crotchrocket.com and looked at the fiche for my 87 and 99 carbs, and the difference is shown. When you enlarge the pictures you can plainly see that the old style had the "step down" graduated screw; and the later models have a pointed screw... Now why couldn't Ron Ayer's figure that out and send me the right one in the first place? |
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Title: Re: Cone Filter & Rejet problem Post by DavidD on 11/23/07 at 09:56:20 I just installed the new screw and put the carb back on the bike. I'VE GOT IDLE AGAIN!!! Musta just been a clogged passageway in the carb somewheres. But I still don't get much difference from adjusting the screw. From all-the-way-in to 3 turns out, the idle sounds pretty much the same. It does sound a little better once I get it down to less than one turn out. I'm guessing the lack of tweakability is from the big 55 pilot jet I've still got in it. I'm gonna pull the carb and put the 47.5 jet back in to see if that makes a difference. Then I've got to figure out why the front brakes are dragging. Then I've got to figure out where the oil is leaking from the crankcase. Then I've got to figure out why I'm getting so much black smoke out the exhaust. Then why there's an oil leak near the exhaust manifold. And what's making the thunk-thunk-thunk noise from the drive sprocket area. And how I'm going to fix the crows-nest of wires under the gas tank. Perhaps even get the decomp solenoid working again. And then maybe one day I'll tackle the switch pods - right now the "horn" button now starts the engine...hehe. Somebody made some interesting wiring adaptations in the back hills of Kentucky... Yep. winter is gonna be busy... glad my Nighthawk is still in good shape. :) Thanks guys, for all of your help and suggestions. Maybe one day this bike will be road worthy again. |
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Title: Re: Cone Filter & Rejet problem Post by T-Mack1 on 11/23/07 at 14:46:19 I've been told to only change the pilot jet only if you can not get the idle to drop when turning out. In other words, a proper sized pilot jet should be able to be adjusted so that the idle drops on both the lean side and the rich side. Should check before changing it. 47.5...? ? ? Do you have a CA model? ? ? ?? . |
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Title: Re: Cone Filter & Rejet problem Post by DavidD on 02/17/08 at 09:46:37 I put the stock 47.5 jet in yesterday, but haven't had time to fine-tune the adjustment screw. But it was OK enough to test ride at about 1 1/2 turns out. But I've run into a bigger problem. If I'm going along at about 1/2 throttle and open the throttle all the way, the engine speeds up by a few hundred RPM but then starts sputtering like it's gonna stall. Any suggestions? My first guess was maybe the needle jet, since it was in really bad shape when I first started working on the carb, and I thought I had done a good job of cleaning its holes pretty well, but maybe I hadn't done it as well as I thought. I haven't modded the jet needle washer, but that's not to say the PO didn't. Or I wondered if maybe the slide diaphram had a leak or something and wasn't pulling the slide high enough. I dunno, I'm sorta just guessing at this point. Any suggestions are much appreciated. Thanks, Dave |
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