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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Backfireing /cgi-bin/YaBB.pl?num=1323846775 Message started by mmg123 on 12/13/11 at 23:12:55 |
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Title: Backfireing Post by mmg123 on 12/13/11 at 23:12:55 Hi, guys I have a suzuki savage LS650 i cured my backfireing with the white spacer mod. My friend has bought one same model but abit younger than mine, his backfires, i have done a full carb strip down cleaned and white spacer mod on his, but still have backfireing, and i mean big backfireing and loud explosions in the muffler when you open the throttle, it will tick over nicely but has soon has you open the throttle you get loads of backfireng period . Please can anybody advise what wrong. :( |
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Title: Re: Backfireing Post by justin_o_guy2 on 12/13/11 at 23:33:18 Look for a leaky exhaust, Be Gentle with the header to cylinder bolts. Tighten them when the engine is cold, |
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Title: Re: Backfireing Post by verslagen1 on 12/13/11 at 23:52:00 6262683E3D3C0F0 wrote:
This is unusual for us, backfiring when you open the throttle. You may have gone too far with the white spacer mod. I'd put it back to stock. And certainly, check the header and muffler for exhaust leaks. Is it a stock muff? what jets? mileage and year? |
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Title: Re: Backfireing Post by Routy on 12/14/11 at 06:00:40 If it is backfiring thru the exhaust when you open the throttle, it is "misfiring" ! I'd be looking for ignition misfiring or timing. If it was backfiring (sneezing) thru the intake, then I'd be looking at the carb, possibly late timing. |
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Title: Re: Backfireing Post by Arnold on 12/14/11 at 12:51:09 You have stock air filter and muffler? |
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Title: Re: Backfireing Post by mmg123 on 12/15/11 at 23:28:18 Thanks guys,I have checked the header and muffler for any leaks ,even took it off completely and re-sealed it. My friend has bought this bike like this backfireing, yes abit dumb but this is why he got it cheap. And yes its a new replacement header pipe and muffler stock. No difference with the white spacer mod. :'( |
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Title: Re: Backfireing Post by mmg123 on 12/15/11 at 23:30:36 252A302B37312220282631430 wrote:
ignition misfiring or timing. ??? Are these two seperate things ??? |
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Title: Re: Backfireing Post by mmg123 on 12/16/11 at 23:25:55 Ok, Guys i have checked the timeing all marks line up, I have noticed when i took the fuel tank off the petcock tap does not shut the fuel off ???? :-/ |
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Title: Re: Backfireing Post by justin_o_guy2 on 12/16/11 at 23:30:02 If you swing it so it points to the back of the bike, thats p[rime, & its gonna drain the tank, down is "on", but no fuel flows till theres vacuum from the carb to the petcock. Forward is reserve. Its "Off" unless its on prime, or unless the diaphragm is busted. |
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Title: Re: Backfireing Post by mmg123 on 12/17/11 at 22:19:33 So the petcock cant be the problem then :-/ |
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Title: Re: Backfireing Post by mmg123 on 12/17/11 at 23:26:04 Can the head gasket cause this problem ??????????? :-/ |
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Title: Re: Backfireing Post by justin_o_guy2 on 12/18/11 at 00:13:02 Id plug the vac line & run it on prime, |
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Title: Re: Backfireing Post by mmg123 on 12/18/11 at 20:48:46 Already plugged it, Also today done valve clearences, still backfireing, maybe person before has over tightened them and the problem is a bent valve. ???????????????? :-/ |
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Title: Re: Backfireing Post by verslagen1 on 12/18/11 at 21:09:02 You'd have to seriously over tighten to get a bent valve that way and it wouldn't run... period. Can you do a compression check? that would eliminate a problem with the valve (and rings too) mileage (or kilometerage) ? Do you know what jets you have? |
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Title: Re: Backfireing Post by mmg123 on 12/18/11 at 21:40:57 I dont know what the jet sizes are,( how would i find this out), i can borrow a compression test kit, can you please guide me has to ( what the compression should read). Thank you to all concernered for your help so far. 8-) 167000 miles |
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Title: Re: Backfireing Post by verslagen1 on 12/18/11 at 21:50:41 Clymer has it at 145 to 203 psi or 1000 to 1400 kPa 116 psi or 800 kPa is the service limit I hope you included tenths of a mile. Anyhow, I'd include a cam chain adjuster check... you're close to needing one and maybe the problem. This could bend the valves, but don't think it would run afterwards. |
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Title: Re: Backfireing Post by Serowbot on 12/19/11 at 07:47:42 Don't just run on prime,... Block the vacuum line as well... It could be fuel leaking down the vac line into the intake, causing the problem... Read here... http://suzukisavage.com/cgi-bin/YaBB.pl?num=1251932429/1 |
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Title: Re: Backfireing Post by mmg123 on 12/19/11 at 22:27:54 Thank you serowbot , these adjustment have been done till i get a new petcock on order , Doing a compression test today. |
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Title: Re: Backfireing Post by LANCER on 12/20/11 at 07:15:22 Backfiring through the exhaust is ALMOST ALWAYS because of an air leak in the exhaust system or a lean mixture in the pilot circuit of the carb. If the exhaust has no leaks then check the pilot jet size, pilot screw adjustment and ensure clean and free flowing passageways in the carb body. It just is. |
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Title: Re: Backfireing Post by mmg123 on 12/20/11 at 22:59:11 Thank you , Lancer I couldnt do compression test my friend had a tester but wrong fittment for plug hole. I will go with you lancer on this and double check carb for clear passage ways . |
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Title: Re: Backfireing Post by mmg123 on 05/11/12 at 19:05:47 This ia a old post but decided today to put the carb back togeather what has been sitting in a can of fuel all these months and i took the carb off my bike and tried this carb, guess what a little bit of popping in the exaust no backfireing at all, did some idle and air screw adjustment popping went, but when i took it on a test drive i could not get more than 50km out of it throttle wide open. :( |
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Title: Re: Backfireing Post by jamesjoshua on 05/12/12 at 16:59:59 u have that milage on a suzuki 650? :) |
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Title: Re: Backfireing Post by mmg123 on 05/12/12 at 21:55:27 It does the same on both bikes :-/ |
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Title: Re: Backfireing Post by Cavie on 05/13/12 at 04:30:39 167,000 miles????? Your joking right????? |
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Title: Re: Backfireing Post by LANCER on 05/13/12 at 05:11:49 Backfires Through Carburetor Common Causes: Ignition: The factory engine's ignition can contribute backfiring through the carburetor. Cam design: Long duration cams with early opening intake valves can contribute to backfiring. Intake manifold air leak: A lean condition due to an intake manifold air leak can cause backfiring. Carburetor jetting: An overly-lean low-speed circuit, non-functioning accelerator pump or clogged pilot jet can contribute to backfiring. Ignition: Under normal conditions dual fire ignitions present no problems. However, when combined with high performance long duration cams the stock ignition can cause premature ignition of an air/fuel mixture entering the rear cylinder. This, in turn, results in backfiring through the open intake valve into the intake system. One of the sparks starts combustion while the other is wasted which is not on its firing stroke. If that mixture is ignited by the wasted spark, then a backfire occurs as the burning mixture forces its way past the intake valve and out through the intake manifold and carburetor. Single fire ignitions can often eliminate carburetor backfiring since they do not produce a wasted spark. Cam design: The earlier the intake valve opens the more likely the dual fire ignition will ignite air/fuel mixture. High performance long duration cams open the intake valves earlier than the stock one. This is the main reason why modified engines tend to backfire through the carburetor more frequently than stock engines. Intake manifold air leak: A common and continuing problem with engines is air leaks around the junction of the manifold and the cylinder head. Carburetor/manifold leaks are much less common. An air leak can cause carburetor backfiring. Other symptoms of an air leak include a slow return to idle or an irregular idle. Carburetor jetting: Excessively lean carburetor settings can contribute to backfiring. If the mixture is too lean, it may burn very slowly and unevenly. This condition, in turn, may result in burning mixture remaining in the cylinder until the beginning of the next intake stroke when it can ignite the incomming air/fuel mixture. A too-small or partially blocked pilot jet can bring about this condition. A partial vacuum in the fuel tank can reduce fuel flow and bring about a lean condition. Gas cap that incorporate a one-way valve (for emission purposes) sometimes restricts air flow into the tank. This restriction can result in a partial vacuum and fuel flow restriction. |
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Title: Re: Backfireing Post by LANCER on 05/13/12 at 05:12:58 Backfires in Exhaust Note: It is normal for many high performance exhaust systems to moderately backfire or pop when the throttle is closed from mid-to-high rpm. In fact, one should expect a well-tuned high performance engine to "pop" and "crackle" when the throttle is closed at high rpm. The popping is a result of the air/fuel mixture becoming very lean when the throttle is closed and the engine is rotating well above idle speed. It is also necessary that the exhaust system have rather open mufflers. Why This (normally) Happens: 1) When the throttle valve is in the idle position, fuel does not flow out of the main system (needle, needle jet, main jet). Fuel is only delivered to the engine by the pilot (idle) system. 2) The combined effect of the closed throttle and elevated engine rpm is to create a fairly strong vacuum in the intake manifold. This vacuum, in turn, causes a high air flow rate through the small gap formed by the throttle valve and carburetor throat. 3) Under these conditions the pilot (idle) system cannot deliver enough fuel to create a normal, combustible air/fuel ratio. The mixture becomes too lean to burn reliably in the combustion chamber. It gets sent into the exhaust system unburned and collects there. 4) When the odd firing of the lean mixture does occur, it is sent, still burning, into the exhaust system where it sometimes ignites the raw mixture that has collected ---- the exhaust then pops or backfires. Other possible causes: Air Leaks: Any source of fresh air into the exhaust system can create or worsen the conditions that bring about exhaust backfiring. The most common entry point is the junction of the header pipes and mufflers. Even a small air leak can dramatically increase the intensity or likelihood of exhaust system backfiring. A high temperature silicone sealant, as can be found in many auto parts stores, may be used to seal the pipe/muffler junction. Lean Carburetion: While exhaust system popping may be considered normal, it is certainly made worse by an overly lean idle circuit. Be sure that your carburetor's pilot jet is the correct size and that the idle air mixture screw is correctly adjusted before looking for other causes of popping. Ignition: If exhaust system popping is very loud, irregular and accompanied by loss of power, then you should suspect that the ignition system is not performing as it should. If, for some reason, the ignition sometimes fires at the wrong time, then exhaust popping can become very energetic (loud). Look for failing high tension leads (plug wire), failing ignition coils and especially switches or connectors as possible causes. |
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Title: Re: Backfireing Post by Routy on 05/13/12 at 06:10:57 Its NOT the carb, because he switched carbs and its still a problem. There is a big difference tween backfiring on closed throttle than opening the throttle. Exhaust leakage is not causing backfiring on opening the throttle. The problem is ignition misfiring, or late ign timing.....or valves leaking, or valve timing. |
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Title: Re: Backfireing Post by mmg123 on 05/17/12 at 23:08:47 problem solved, After 3days of taking carb off and on checking and cleaning every time spotless I decided to poke fuse wire down the jets, guess what,the pilot jet was blocked and i mean blocked, you wouldnt beleive the crap that came out it was solid with the stuff. Happy days again all running perfect again Thank you guys for all your help and concern Best wishes to you all :) :) 8-) :) :) Thank you Thank you Thank you |
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Title: Re: Backfireing Post by LANCER on 05/18/12 at 02:55:18 75757F292A2B180 wrote:
Y E A ! ! :D |
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Title: Re: Backfireing Post by mmg123 on 05/23/12 at 23:01:43 Now this i dont beleive, Bike has run A1 for three days now, i dont get it its started bucking, jerking and runing rough ideling nuts :'( :-[ |
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Title: Re: Backfireing Post by justin_o_guy2 on 05/24/12 at 01:12:20 Drain the carb bowl & look for junk. IF ya find junk, put a filter inline. Mite be time to clear a jet again.. |
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Title: Re: Backfireing Post by Dave on 05/24/12 at 03:57:50 Sounds like you have dirt coming from somewhere that is plugging up the carb jets. This time.....clean the carb, tank, fuel lines, and petcock. |
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Title: Re: Backfireing Post by mmg123 on 05/24/12 at 10:11:01 Thanks , guys thats what i was thinking too , after talking to my pops he said the same, Gas tank, filter, clean all start again, will let you,s Know :-[ |
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Title: Re: Backfireing Post by mmg123 on 05/25/12 at 23:34:15 Ok cleaned the carb again used a full tin of carb cleaner , blown out with air line, done tank swill and petcock cleaned,installed new inline filter still the same, checked all timeing and electrical connections, :'( :( :'( |
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Title: Re: Backfireing Post by mmg123 on 05/27/12 at 22:37:59 Triple checked everything beats me :( |
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Title: Re: Backfireing Post by verslagen1 on 05/27/12 at 23:30:15 OK, let's start over again, we fixed the clogged jets. Is it still backfiring when you open the throttle? |
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Title: Re: Backfireing Post by mmg123 on 05/27/12 at 23:45:51 yip, and lacks power you can see down the jets if you hold them up to the light , they clear,also its not ideling proper it try to die on me i have to notch up the idle knob to keep it running |
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Title: Re: Backfireing Post by verslagen1 on 05/27/12 at 23:56:23 OK, do you remember what size jets they are? |
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Title: Re: Backfireing Post by mmg123 on 05/28/12 at 22:08:19 No, i am asumeing 155 maim 47.5 pilot 1986 model never been changed with original exaust fitted no mods at all same air box , i have also blown out the airbox and filter. |
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Title: Re: Backfireing Post by renegade1 on 05/28/12 at 22:14:52 im new at this guys so hopefully this isnt a completely rediculous question... what is a " white spacer mod" and what are the perks/disadvantages if any. |
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Title: Re: Backfireing Post by verslagen1 on 05/28/12 at 22:55:57 when there is a widely referred to mod, look it up in the tech section. there's a lot of info there... follow the links. ;D |
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Title: Re: Backfireing Post by mmg123 on 05/28/12 at 23:04:20 mine has had this done, i did it last year and it run well then with no backfiring or popping at all .Till now :( |
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Title: Re: Backfireing Post by mmg123 on 05/30/12 at 00:03:51 Had the throttle body out today flated and polished it with 1500 mircro flat, gave it a spray with carb cleaner before putting it back in still no diffrence :'( |
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Title: Re: Backfireing Post by mmg123 on 05/31/12 at 23:15:28 Can any kind person shed any light on this for me please, i m stuck and dont know what to do next. :'( |
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Title: Re: Backfireing Post by verslagen1 on 05/31/12 at 23:28:25 3A293E3F202D2B29227D4C0 wrote:
I didn't see an answer for this one... have you checked your cam chain? |
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Title: Re: Backfireing Post by mmg123 on 05/31/12 at 23:54:15 OK, Thank kindly for your reply, i will do the check and report back. :) |
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