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SuzukiSavage.com
/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> New Rider, New Bike, Question /cgi-bin/YaBB.pl?num=1221698959 Message started by DrunkenDwarf on 09/17/08 at 17:49:19 |
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Title: New Rider, New Bike, Question Post by DrunkenDwarf on 09/17/08 at 17:49:19 I'm a brand new rider. Rode my first motorcycle at the MSF Beginner Course in July and now I'm the proud owner of a used 2007 S40. The previous owner put different jets in (0.055 pilot and 0.155 main), a HD Dyna exhaust on, and turned the idle screw way down. The reason I'm here is the infamous backfire (I've seen it called afterfire on some websites). Backfires happen. Quite often. Most of the time it's a solid pop, with the occasional vocal bang. The previous owner said it backfired LESS after he made the changes. WOW. I can't imagine what it sounded like previously. Back on topic, am I correct to assume that reducing the "white spacer" is probably a good way to reduce the backfiring? The previous owner said he didn't do that adjustment because he had read about some bad results. At what point should I consider the idle mixture screw a required adjustment? Thanks for your help. -Drunken Dwarf |
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Title: Re: New Rider, New Bike, Question Post by seviersavage on 09/17/08 at 18:08:30 on the idle screw clockwise is leaning it and counterclockwise is richening the mixture. I thought that the backfires were due to an overly lean mixture. Perhaps richening the idle mixture would help. Does the bike run well now? I suppose you could do the white spacer mod, I haven't rejetted but have half spacer and idle screw out 2 1/4 turns and no backfires. I'm running a dyna -muffler too. What kind of air filter are you using? I read that the air filter has the most affect on mixture, even more than exhaust. I'm sure others will chime in who know more than I. In the tech section are many how to's... plenty on carbs and tuning. Do a search on white spacer mod . Good luck, you can fix the backfires! At shutoff some people just pull out the enrichener as they shut it off and this will stop the backfire at shutdown. Seviersavage |
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Title: Re: New Rider, New Bike, Question Post by serowbot on 09/17/08 at 18:19:11 You can get "backfires", afterfires from being too rich also. And your jetting is on the rich end. Seviersavage is referring to the idle mix srew on the right side of the carb not the idle speed screw on the left, by the choke. Your idle mix screw may be blocked off by a brass plug, if so it must be drilled out to make adjustments. "Pop, blat, wooble-wooble, blat" type sounds are quite normal for a big thumper engine on deceleration. "Kaa-BANG!", gunshot type sounds are not good and you should try to reduce those. My jetting is 150#/50# and I have similar mods to you. I am at 2500ft elevation in a dry climate, and that makes a huge difference in jetting. What is your elevation and climate? Heat, humidity, and elevation will make you run rich. Dry, cool, sea level will make you lean. Feel free to ask for help, search past posts, and welcome , Serowbot |
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Title: Re: New Rider, New Bike, Question Post by verslagen1 on 09/17/08 at 19:13:55 Also check the header bolts when cold they should be 15-20 ftlbs |
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Title: Re: New Rider, New Bike, Question Post by DrunkenDwarf on 09/17/08 at 19:38:27 253621203F3234363D62530 wrote:
I guess I need to buy a torque wrench. :-[ -Dwarf |
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Title: Re: New Rider, New Bike, Question Post by DrunkenDwarf on 09/17/08 at 20:01:27 2731263B23363B20540 wrote:
The idle mixture screw has not been drilled out. It's mostly "pop, blat" type sounds with only the occasional "BANG". Perhaps it's normal. Would a recording be useful? Quote:
Elevation: 505 ft Climate: "humid continental climate zone" is the technical term. Not quite as bad as Seattle, but close. Rochester, NY to be specific. -Dwarf |
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Title: Re: New Rider, New Bike, Question Post by DrunkenDwarf on 09/17/08 at 20:16:51 6162777C717760657B7E7E7B737F61120 wrote:
It's a stock air filter, but the cover has been removed. Not the 'outside' cover, but the 'inside' one. I actually haven't taken it apart to look at it. I just know I've got the parts sitting on my desk. (I think it's proper name would be "Air Filter Access Cover" or "Air Filter Compartment Cover" or "Air Cleaner Case Cover"...it's the plastic one.) -Dwarf |
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Title: Re: New Rider, New Bike, Question Post by serowbot on 09/17/08 at 22:57:39 505ft is virtually sea level, jetting wise,..but the humidity will make you richer...I definitely wouldn't rush to go any richer. pay attention to the weather...if you get less popping, blatting,..on dryer days,..you are overall a little rich...If you get more in dry weather,... you are lean. I suspect your current jetting could be a bit rich. The spacer mod would richen your mid-throttle, but your main and pilot jets are on the large size. Does your gas mileage suck? Should be 50 to 60mpg. Since your "Bangs!" are not so much as just "pops and blats",...I wouldn't be too worried...You just want to fine tune. BTW, you are correct....technically, actual "backfires" are pops thru the carb... "Afterfires" are out of the exhaust,...but people generally,mistakenly, refer to exhaust pops, as backfires.... |
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Title: Re: New Rider, New Bike, Question Post by DrunkenDwarf on 09/21/08 at 08:06:45 3F2C3B3A25282E2C2778490 wrote:
Header Bolts = where the exhaust connects to the cylinder? I hope so, 'cause I just tightened them to 15ftlbs (+/- 4%). I got the brass plug out, managed to ding the lower lip of the fuel tank in the process. Where can I get paint? I haven't rode enough to get a gas mileage measurement. The previous owner said it got over 50mpg. I think I'm starting to understand this carburetor stuff. With a big main jet, I'm probably running a bit rich when I'm 1/2 to full throttle. With a big pilot jet, I'm probably running a bit rich when I'm idle to 1/4 throttle. The idle mixture screw could help me adjust the pilot system. Changing the spacer would make the it run richer 1/4 to 3/4 throttle. Which I may or may not want to do. How would I go about determining the correct course of action? Is it just a matter of preference if I don't have access to a dynamometer? -Drunken Dwarf |
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Title: Re: New Rider, New Bike, Question Post by verslagen1 on 09/21/08 at 08:38:24 262F2A23392E2A4B0 wrote:
Find yourself a long uphill grade, something you can do WOT for an extended period. If you can back off from WOT (about an 1/8 turn) and it sounds like it picks up, then the main is too small, go up a size. |
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Title: Re: New Rider, New Bike, Question Post by DrunkenDwarf on 09/21/08 at 17:33:26 667562637C7177757E21100 wrote:
OK. What if my main is already too big? What about 1/4 to 3/4 throttle? -Drunken Dwarf |
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Title: Re: New Rider, New Bike, Question Post by verslagen1 on 09/21/08 at 20:18:54 767F7A73697E7A1B0 wrote:
I don't know of a test for too big, only too small. Drop it down a size and test it. My guess is a 150 will do you fine. I don't know a fool proof test for the mid range. Get a stack of #4 washers that stack up to 0.1" and drop one out and test it out. If it accels smoothly, then try another. some have taken it out and it runs fine others say it needs the whole thing. I beleave it depends on the main so do it last. |
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Title: Re: New Rider, New Bike, Question Post by LANCER on 09/22/08 at 02:56:50 [quote ] I don't know of a test for too big, only too small. Drop it down a size and test it. My guess is a 150 will do you fine. I don't know a fool proof test for the mid range. .[/quote] In general, the following apply TOO RICH -engine noise dull/intermittent -condition grows worse when choke opeded -condition grows worse when engine gets hot -removing air cleaner will improve condition somewhat -exhaust gas heavy -fouled plug TOO LEAN -engine overheats -condition improves with choke opened -acceleration is poor -spark plug burned -engine surges, lacks power 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. |
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Title: Re: New Rider, New Bike, Question Post by justin_o_guy2 on 09/22/08 at 03:35:06 And dont set the idle speed low, trying to make it sound extra cool. It will hurt the cam bearings, |
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Title: Re: New Rider, New Bike, Question Post by mornhm on 09/22/08 at 05:45:35 Getting back to the original question. In many cases, the idle mix screw is all that needs adjusted to eliminate backfire so if that is the desired result it should be attempted before changing jets after adjusting the idle speed. (There's a reason it's a screw adjustment even if it's covered by a plug to make the environmental people happy.) There's also a reason the idle speed is on a thumbscrew. It's nice to have a tach to adjust by, but if the engine is running real slow and rough and even "loping" it probably needs adjusted. As far as rich or lean running conditions, Lancer has a nice summary there. Others have also put in valid points. In your case, you may want (different than need) larger jets because of the change in exhaust however you may not have the right sizes. |
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Title: Re: New Rider, New Bike, Question Post by DrunkenDwarf on 09/22/08 at 20:06:18 Thanks for all of your help. I'm going to try Lancer's idle adjustment and then leave it alone. One last question. The previous owner removed the "Air Cleaner Cap". Does it make a difference if it's on or off? I haven't found an air flow diagram. -Drunken Dwarf |
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Title: Re: New Rider, New Bike, Question Post by DrunkenDwarf on 09/25/08 at 15:36:04 Quick update. Made the idle mixture screw adjustment. Started 2 turns out. At 1 1/2 turns it started to slow. At 3 turns it started to slow. Set it at 2 1/4 turns. I'm not sure how to set the idle speed screw. I don't have a tach. Is there a way to do it 'by ear'? -Drunken Dwarf |
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Title: Re: New Rider, New Bike, Question Post by EssForty on 09/25/08 at 16:40:26 You'd need an mp3 of a Savage with an idle setting of 1000-1200 rpm's and a similar muffler. a way to play it in your garage (ipod maybe in one ear) and then you'd need to have the ear of a musician. I know there are some mp3 links on this site but not sure if they are calibrated to idle speed. |
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Title: Re: New Rider, New Bike, Question Post by DrunkenDwarf on 09/25/08 at 17:13:04 Would something like this be useful? http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95670 -Drunken Dwarf |
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Title: Re: New Rider, New Bike, Question Post by verslagen1 on 09/25/08 at 17:41:32 5E57525B415652330 wrote:
couldn't hurt, might pick up one myself, cheap enough. |
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Title: Re: New Rider, New Bike, Question Post by DrunkenDwarf on 09/26/08 at 06:19:55 I think I screwed up. The engine stalled 3 times riding into work this morning. All three times it was when I pulled the clutch in as I was coming to a stop. I turned up the idle speed a little and that seemed to fix it. Does that make sense? I guess I really need a tach. -Drunken Dwarf |
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Title: Re: New Rider, New Bike, Question Post by DrunkenDwarf on 09/26/08 at 15:54:21 Quick update - It seems like now I get a POP every time I close the throttle. That could be because I'm getting more comfortable and using the throttle more aggressively. Or I could be hallucinating. -Drunken Dwarf |
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Title: Re: New Rider, New Bike, Question Post by verslagen1 on 09/26/08 at 17:06:19 Tell your girlfriend to hold on tighter ;D or turn it alittle more to the left... :o |
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Title: Re: New Rider, New Bike, Question Post by T Mack 1 on 09/26/08 at 18:38:39 252C29203A2D29480 wrote:
turn the idle mix screw up 1/4 turn. Or optionally, turn up in 1/8 turn steps until pop is almost gone. It's a thumper so a little pop is normal. |
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