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/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Surging at 20-25 kph / 12-15 mph in first gear /cgi-bin/YaBB.pl?num=1309237160 Message started by BillF6531 on 06/27/11 at 21:59:19 |
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Title: Surging at 20-25 kph / 12-15 mph in first gear Post by BillF6531 on 06/27/11 at 21:59:19 Background: I bought a 2007 S40 a few days ago. It has 131 kilometres on it. Apparently the woman scared herself and it got parked in the garage until her husband decided to sell it. I've put fresh fuel in it and a large dose of carb cleaner, and driven it about 100 kilometres - just breaking it in. It idles smoothly and has lots of torque and top end, although I haven't hit the highway, yet. Problem: It surges when held at a steady speed, as noted in the caption, doesn't back-fire, and gives a quiet puff at shutdown. Is this a dirty / gummed up carb, or a lean mid-range, or will it heal itself with more mileage? I'm at 3500 feet. Suggestions from the experts are welcome. Solution: I removed and disassembled the carb. It was spotless inside - no sign of any varnish, and no jet orifice plugged. I was going to do the white plastic washer mod, but was unable to find anything with the correct diameter. I reassembled everything, drilled and removed the brass plug covering the idle mixture screw, and in so doing, found my problem. The screw was tight. I turned it out three turns. A quick drive to try and duplicate the problem, and 90% of it is gone. While I was at it, I installed a fuel filter, and checked the plug - a nice tan colour. Update: I did the .06" white spacer mod, thanks to Serowbot who was generous and mailed one to me when I couldn't find one locally. The mod resolved all the just-off-idle hesitation and the low-throttle / low-speed surging caused by the lean air-fuel mixture. The bike now accelerates smoothly from idle to any rpm. This is definitely the solution to poor low-rpm performance. |
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Title: Re: Surging at 20-25 kph / 12-15 mph in first gear Post by Serowbot on 06/27/11 at 23:30:58 Sounds like something is plugged up... You can keep running the cleaner through, and hope it clears... In the meantime, you're running lean, ... or go ahead and clean the carb... I buy bikes that have been sitting, and bring them back to life regularly... And going through the carbs is a given... I'd strip it and clean it... but, if that's intimidating, you can keep trying the cleaner... It may work things loose after a few tankfuls... ... a couple of teaspoons of Marvel's Mystery oil in the tank might free up the needle jet slide if it's gotten sticky, too... PS.. that oil has been sitting in the crankcase a long time as well... It builds up water condensation over time,... I'd change that, too.. if you haven't already... Don't use synth oil, 'cause your engine's not broke in yet... Plain old 10W-40 for the first 800 miles... ... and don't do steady cruising too much,... piston rings like lots of easy, acceleration and deceleration during break in... PSS,... the stock jetting might be just about right for a stock bike at 3500ft... it's a little lean at sea level... ;)... Gee... did that sound like a lecture?... Sorry, don't know why it came out like that... maybe I'm tired... :-?... Anyway,...welcome to the site, and ride safe... ;)... |
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Title: Re: Surging at 20-25 kph / 12-15 mph in first gear Post by BillF6531 on 06/28/11 at 08:48:36 Yes, oil change, check the air filter and box, drain the carb and tank, inflate the tires to the proper values, check the torque on all the major bolts, etc., ... all done. Many thanks for the advice. :) |
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Title: Re: Surging at 20-25 kph / 12-15 mph in first gear Post by Bubba on 06/28/11 at 15:02:12 I'd give the white spacer mod a try. Instead of shaving it down use a small #4 nylon spacer from the hardware store. That way you can go back if you need to. Be careful of those screws...they can strip pretty easy but if they do and you still get them out replace them with the little screws they use to hold hard drives in PC's. http://suzukisavage.com/cgi-bin/YaBB.pl?num=1104205157/28#28 |
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Title: Re: Surging at 20-25 kph / 12-15 mph in first gear Post by Trippah on 06/28/11 at 15:57:36 On this bike, ist gear is just to get it moving; I would probably have shifted by 15 mph....2nd gear is for putting around. :D and welcome....enjoy the ride. |
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Title: Re: Surging at 20-25 kph / 12-15 mph in first gear Post by Routy on 06/29/11 at 06:51:47 Try the cleaner,...If it doesn't help, go to plan "B" ! Plan "B".......... It sounds exactly like the problem my '07 had when I bought it w/ 3500 miles on it, and it hadn't been setting long at all. It idled and run perfectly,....except under light load.....low rpm, in any lower gear, it would just kinda lope along (surging badly) If I left the choke on 1 click, it would run fine. After reading the info here, it sounded like a "white spacer" problem to me,......and thats exactly what it was. I trimmed it to 1/2 size, and got lucky,....runs perfect, and requires less choke now when cold, a big improvement also. Try the choke,.....even tho it is designed for a cold engine, it make a great pc of test equipment ! |
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Title: Re: Surging at 20-25 kph / 12-15 mph in first gear Post by BillF6531 on 06/29/11 at 16:17:54 1B3035351F6F6C6A68590 wrote:
Solution: I removed and disassembled the carb. It was spotless inside - no sign of any varnish, and no jet orifice plugged. I was going to do the white plastic washer mod, but was unable to find anything with the correct diameter. Not much selection of odd parts in Canada, and I tried three large hardware places. I reassembled everything, drilled and removed the brass plug covering the idle mixture screw, and in so doing, found my problem. The screw was tight. I turned it out three turns. A quick drive to try and duplicate the problem, and 90% of it is gone. While I was at it, I installed a fuel filter, and checked the plug - a nice tan colour. If anyone has a spare white spacer in the correct diameter, and would be interested in mailing it to me, I'll buy you a beer. Thanks, everyone, for your helpful advice. Best regards, Bill |
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Title: Re: Surging at 20-25 kph / 12-15 mph in first gear Post by Serowbot on 06/29/11 at 16:52:10 6D46434369191A1C1E2F0 wrote:
Does that take a regular stamp?... To go to Canada I mean... PM me your address... ;)... |
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Title: Re: Surging at 20-25 kph / 12-15 mph in first gear Post by Howitzer on 06/29/11 at 20:45:18 200B0E0E2454575153620 wrote:
Solution: I removed and disassembled the carb. It was spotless inside - no sign of any varnish, and no jet orifice plugged. I was going to do the white plastic washer mod, but was unable to find anything with the correct diameter. Not much selection of odd parts in Canada, and I tried three large hardware places. I reassembled everything, drilled and removed the brass plug covering the idle mixture screw, and in so doing, found my problem. The screw was tight. I turned it out three turns. A quick drive to try and duplicate the problem, and 90% of it is gone. While I was at it, I installed a fuel filter, and checked the plug - a nice tan colour. If anyone has a spare white spacer in the correct diameter, and would be interested in mailing it to me, I'll buy you a beer. Thanks, everyone, for your helpful advice. Best regards, Bill [/quote] Nice job solving your problem. |
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Title: Re: Surging at 20-25 kph / 12-15 mph in first gear Post by BillF6531 on 07/09/11 at 14:13:15 Update: I did the .06" white spacer mod, thanks to Serowbot who was generous and mailed one to me when I couldn't find one locally. The mod resolved all the just-off-idle hesitation and the low-throttle / low-speed surging caused by the lean air-fuel mixture. The bike now accelerates smoothly from idle to any rpm. This is definitely the solution to poor low-rpm performance. And Routy is correct. Pulling out the choke one notch will prove that this is the solution, since it causes a richer afr. |
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Title: Re: Surging at 20-25 kph / 12-15 mph in first gear Post by Serowbot on 07/09/11 at 14:40:04 That's great!... Ride safe, Serow ;)... |
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Title: Re: Surging at 20-25 kph / 12-15 mph in first gear Post by Routy on 07/10/11 at 06:52:37 Quote: Solution: I removed and disassembled the carb. It was spotless inside - no sign of any varnish, and no jet orifice plugged. ------------------------------------------------------------------------------- You gotta be kidding ! A spotless carb,....that has been setting around w/ Gasahol in it ?? Go tell that to someone who will listen ! I, for one, WILL, and believe it ! But isn't it wonderful that we'll always have the Gasahol around to blame every little fuel problem onto,.......when all else fails ! >:( |
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Title: Re: Surging at 20-25 kph / 12-15 mph in first gear Post by jdeluca on 07/10/11 at 07:10:51 Quote:
I don't know if this is a gasahol argument or not...It's a 2007 with less than 500 km on it that after it sat he ran carb cleaner through it before he opened it up, any varnish or other gasahol residue would have been washed away...Also, he lives in Alberta, Canada, do they use ethanol "enhanced" gasoline up there as well? |
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Title: Re: Surging at 20-25 kph / 12-15 mph in first gear Post by BillF6531 on 07/10/11 at 09:15:35 We do have some stations selling fuel with 10% ethanol blend, but I have no way of knowing what was in there while it was stored for 4 years. That said, it was truly spotless inside. And just to add some fuel to the pure vs. ethanol argument, my 2003 Corvette doesn't run the same - and I do the tuning - using ethanol, even when tuned to the proper afr value for stoich. And fuel economy is definitely less. However my lawn mower and snow blower don't seem to care. ;D |
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