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/cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Carb Confusion /cgi-bin/YaBB.pl?num=1280361248 Message started by DrunkenDwarf on 07/28/10 at 16:54:08 |
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Title: Carb Confusion Post by DrunkenDwarf on 07/28/10 at 16:54:08 Previous owner had put a 55 pilot in, I finally (2 years later) got around to moving it to a smaller jet. So, I went from a 55 w/ bleed to a 52.5 w/ bleed and the air screw still wants to be 1 turn out. I can turn it all the way in and the engine slows, but doesn't die. Still pops on shifts, still a WUMP at shutdown. I did tighten the header bolts, but haven't smoke tested it. I don't get it. It's as if I've got the exact same jet in there. :o Today was particularly warm, perhaps that's having an impact. -D. Dwarf |
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Title: Re: Carb Confusion Post by LANCER on 07/28/10 at 16:58:58 232A2F263C2B2F4E0 wrote:
when carb does not respond as it should dispite jet changes = blockages inside passages |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 07/28/10 at 17:20:09 Ugh. When I dropped the bowl there was a small collection of fine grit. There's no build up that I can tell. Oh well. I guess I'll have to strip it at the end of the season. Thanks for the suggestion. Any idea where a blockage might be that would cause that symptom? Could be the air bleed jet (where ever that is)? Over all it runs pretty well. (Then again, I don't have anything to compare it to.) The spark plug base was a little sooty (see below) and I suspected it was a little on the rich side, that's why I went down a jet size. -D. Dwarf http://lh5.ggpht.com/_gpMEVRBlMes/TFDI3cuLxKI/AAAAAAAABFw/Zbi2aEI8MRQ/s800/plug%20crop.JPG |
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Title: Re: Carb Confusion Post by verslagen1 on 07/28/10 at 17:27:51 it still gets hot enough to burn all deposits off, so I'd say your main is a tad lean (not knowing how long you spend at full speed) and your idle/choke is rich. |
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Title: Re: Carb Confusion Post by Serowbot on 07/28/10 at 17:28:09 The plug looks okay to me... Pops on decel, and wump on shutoff are normal for a big thumper... as long as the big gunshot "Kerpow's!" are rare, I wouldn't worry... You could try a 52.5 without the bleeds if you want... You should notice a little boost is MPG's with the smaller pilot... (Goodie, goodie!)... Mine doesn't die when I shut the pilot out full either,... there are small idle ports still active when you close the pilot completely, so it is possible... Other Savages I'm worked on do die when you close off the pilot... Some do,.. some don't... No worries there... |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 07/28/10 at 18:26:57 53405756494442404B14250 wrote:
Which is why I went down a size on the pilot. I don't spend much time at full throttle. I hit 80 in forth gear a day or two ago, but I generally ride in the 40-60 mph range. I really should grow a set and do a WOT plug chop. :-/ 5345524F57424F54200 wrote:
I'm trying to reduce the pops when I shift. It's pretty consistent. The really weird thing is when the engine is warming up and I still have the choke out, it never pops on a shift. But as soon as I put the choke in, even if the engine isn't warm, pop! [edit]One more comment. I'm running 1.5mm spacer because it does this weird surging at 35mph in 3rd gear. It still happens when then engine isn't fully warmed up. I guess it's "lean hunting"? My commute is only 10 miles (20 minutes) so I spend most of my time riding an engine that isn't fully warmed up.[/edit] -D. Dwarf |
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Title: Re: Carb Confusion Post by Serowbot on 07/28/10 at 20:14:01 A good indicator of overall jetting is the weather...if popping/backfiring increases on humid days, or at higher elevation, that indicates rich....less popping at those times indicates lean. To test the main, accelerate from 30 or 40 mph, in 4th or 5th gear at full throttle for several seconds, then reduce throttle by about 1/8,...if power increases for a second, you are lean on the main jet. Go up one jet size and test again. |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 07/29/10 at 07:09:02 1305120F17020F14600 wrote:
I've noticed no correlation between weather and backfiring. It could be because of my proximity to Lake Ontario, it's always humid. 1305120F17020F14600 wrote:
I've tried this several times last summer, with jets 145, 150, 152.5 and 155. I'll see if I can find my posts from that time period and link to them. I've never noticed any change when backing off the throttle. I don't know if I'm doing it wrong (not waiting long enough, waiting too long, backing off to far, not backing off far enough, whatever) or if there's no response or if I'm incompetent. -D. Dwarf |
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Title: Re: Carb Confusion Post by ralfyguy on 07/29/10 at 08:34:58 Your bike behaves exactly like mine. 145 main and 52.5 pilot. It is just like you rode my bike and wrote about it. Even the plug looks the same. Amazing! I tried a 55 pilot with bleed holes before and it was way too rich. The screw all the way turned in then didn't cut it. I also put a 150 main in and I had surging problems and sooting at full throttle. I tried pulling the choke just a little while riding. That makes all the pops and bangs go away, but accelerating is feeling to rich with ucking and surging. So I assume that is just the way the bike is. I got about the same thickness spacer in there. Drunken Dwarf can you try something for me? With the engine warmed up and idling, squeeze the vacuum hose off with your fingers on the u-bend and tell me if the idle seems to rise a bit, and when you let go seems to go back down. |
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Title: Re: Carb Confusion Post by Serowbot on 07/29/10 at 08:49:31 7F6C616B746A78740D0 wrote:
...sounds like you got a leaky petcock diaphragm.... |
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Title: Re: Carb Confusion Post by bill67 on 07/29/10 at 09:35:00 I think if you let of the throttle slower its backfires less. |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 07/29/10 at 12:24:25 73606D6778667478010 wrote:
I'll try to remember to do that tonight. I've got a spring around the vacuum hose, so we'll see how well I'm able to pinch it off. -D. Dwarf |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 07/29/10 at 18:29:38 45565B514E50424E370 wrote:
That's exactly what happened. Quite noticeably, in fact. I wish all carburetor testing was that obvious. I had the hose off the carb last weekend and didn't notice any gas. I guess I should try disconnecting the vacuum hose and running on prime. As soon as I get new brake pads. >:( -D. Dwarf |
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Title: Re: Carb Confusion Post by ralfyguy on 07/29/10 at 18:40:35 It is not said that both of our petcock diaphragms are bad. Maybe this is just the way it is. BTW mine is a '06 S40 with 12,500 miles on it. I was thinking about getting a new petcock, because the lever only turns with brutal force. I disassembled it last weekend, cleaned what wasn't really dirty, lubed everything that moves on it and put it back together with no real improvement. I didn't notice any gas or gas smell either with the hose off. One of these days the lever is gonna break off. Are they all turning that hard? It worsens significantly when the temperature rises above 90F. In the morning around 70F it isn't that bad. Does yours turn that hard? Oh and for the record: My pilot jet is a stock 52.5 without bleed holes. And the pilot screw is 2 1/4 turns out. This seems to be the sweet spot on mine. I tried more and less and it wasn't quiet right. I always come back to 2 1/4 turns out. However in winter I set it to 2 1/2 turns, as it then runs as smooth as in summer. Where did you get the 52.5 pilot WITH bleed holes from? Does that mean it may run a bit richer than the same size without holes? I wish I had one to try, as the 55 jet I have is too much. |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 07/29/10 at 18:44:08 6A79747E617F6D61180 wrote:
Yes it does. ;D -D. Dwarf |
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Title: Re: Carb Confusion Post by ralfyguy on 07/29/10 at 18:48:24 I added some stuff to my previous post. :) |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 07/29/10 at 21:15:45 62717C7669776569100 wrote:
Lancer, I think. Does anyone have any suggestions on what I can use to temporarily block the vacuum port on the carb? I've got plenty of golf tees to use on the vacuum hose. -D. Dwarf |
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Title: Re: Carb Confusion Post by Serowbot on 07/29/10 at 22:25:40 if you have another bit of hose,... use that and stick a golf tee in there too... |
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Title: Re: Carb Confusion Post by LANCER on 07/30/10 at 02:12:55 I get the little rubber caps at the auto parts store |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 07/30/10 at 05:54:48 6771667B63767B60140 wrote:
I don't. 767B74797F68282D1A0 wrote:
What's the ID of the hose/cap I should be looking for? -D. Dwarf |
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Title: Re: Carb Confusion Post by Bubba on 07/30/10 at 07:21:25 Put a screw in mine then capped it with a rubber tip thing from a dish rack |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 07/30/10 at 07:34:41 According to this: http://suzukisavage.com/cgi-bin/YaBB.pl?num=1117481092/1#1 It's 3/16". I'm surprised it's not 5mm. (or maybe it is) -D. Dwarf |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 08/01/10 at 13:05:37 2E3D303A253B29255C0 wrote:
I performed this test again with the petcock in the ON and RES position and got the same results. I then setup the petcock up as describe in the thread Test your Petcock (http://suzukisavage.com/cgi-bin/YaBB.pl?num=1251932429). The engine idled at faster rate then usual. Very similar to having the vacuum line pinched. With the test setup I bottomed out the idle mixture screw without the engine stalling. So this points to either a leaky vacuum hose or petcock diaphragm. Does anyone have a suggestion (or bet) on which one it is? After the engine cools I'll install a new vacuum hose (got some 3/16 inside, 3/8 outside diameter fuel hose from Lowe's) and try again. -D. Dwarf |
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Title: Re: Carb Confusion Post by Serowbot on 08/01/10 at 13:30:02 Give a suck on the vacuum line,... if you get gas,(don't swallow)... the diaphragm is leaky and you need a new petcock,... if you don't get any gas, you need a new hose... |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 08/03/10 at 18:26:47 5640574A52474A51250 wrote:
I didn't get a mouthful of gas (no liquid), but I did get the taste of gas. -D. Dwarf |
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Title: Re: Carb Confusion Post by ralfyguy on 08/03/10 at 19:53:08 The hose is connected to the carb and there's gasoline not far away from the nipple. I did that on mine and I got the same sensation. There's a vacuum created and when the engine stops, the vaccum breaks and a tad of gasoline vapor is sucked backwards into the hose to equalize the atmospheric pressure. I would consider that normal. I even make a bet that everyone on here with the stock setup that would try that is gonna get the same sensation. |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 08/03/10 at 20:16:21 687B767C637D6F631A0 wrote:
Cool. I'll replace the vacuum hose and see how it goes. I tried to do it earlier, but I couldn't get the new hose on the petcock while the tank was still on. A couple questions about the vacuum hose. My replacement is thicker than the old one and the spring won't fit on it - any issue with it being against the cooling fins? Also, due to the thickness of the replacement I may not be able to route it above the carb. Does the length matter? -D. Dwarf |
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Title: Re: Carb Confusion Post by ralfyguy on 08/04/10 at 04:32:50 Did you get 3/16" ID? Sounds like it's bigger. It shouldn't touch the cooling fins. It's gonna melt. I got 3/16" fuel hose at O'Reilly's for about a Dollar for 3 foot. |
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Title: Re: Carb Confusion Post by Routy on 08/04/10 at 05:23:36 There can be an outside diameter difference between fuel hose and vacuum hose. Why not use vacuum hose ! |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 08/04/10 at 06:24:05 5E4D404A554B59552C0 wrote:
525D475C404655575F5146340 wrote:
I got 3/16" ID and 3/8" OD fuel hose from Lowe's. It was the only thing they had in 3/16" ID that wasn't vinyl or poly. I didn't see anything at AutoZone, I'll try Advanced Auto. -D. Dwarf |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 08/08/10 at 11:38:32 1107100D15000D16620 wrote:
Installed new hose, tried the suck test. No gas. However, it still exhibits the same behavior that ralfyguy demonstrated. A pinched vacuum hose results in a higher RPM than a free one. :-/ Can someone else try this? I'd prefer to have more than 2 data points before blaming both our petcocks. 7C6A7D60786D607B0F0 wrote:
Tried this again today. I don't have throttle positions marked currently, so I had to guess on the 1/8. 30mph in 4th gear. Man the engine was at a low RPM. I'm usually shifting from 2 to 3 at this point. Slammed open the throttle, engine sounds like a jack hammer. Wait a few seconds (about 10 mph faster) and closed the throttle slightly. The engine sounds got "smoother", there wasn't an obvious change in acceleration. -D. Dwarf |
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Title: Re: Carb Confusion Post by justin_o_guy2 on 08/08/10 at 12:23:03 30 mph in 4th & slappin WFO isnt okay, IMO,, 40 mph, maybe, but 30 is gonna lug thecrap outta the thing. You could accelerate gently from there, butWFO dont seem okay. Id have top go try it, & mines shut down rightnow. |
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Title: Re: Carb Confusion Post by Routy on 08/09/10 at 05:29:19 Agreed, I would never go WOT at 30-40 in 4th or 5th. And you don't have to. Start at 60 in 5th, go WOT 10 seconds max, then quickly back of to 1/2 throttle. If its running rich at all, there will be a very noticeable stumble for a second before leveling out. |
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Title: Re: Carb Confusion Post by bill67 on 08/09/10 at 05:38:42 I go wot at 40mph in 5th a lot thats what I like to do,It really pulls strong.It pulls strong at 35 but I think thats a little low rpm for the engine. |
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Title: Re: Carb Confusion Post by ralfyguy on 08/09/10 at 07:07:59 292227277D7C4B0 wrote:
I kinda ride the same way. If I'm not in a hurry. But it does pull strong from 40mph in 5th. In fact it pulls from 40-70 in under 10 seconds. That's what I like about the bike. Torque! Displacement not spoilers! :D |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 08/09/10 at 15:40:15 It seems I got some bad advice. Oh well. -D. Dwarf |
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Title: Re: Carb Confusion Post by Routy on 08/09/10 at 17:34:47 Well no kidding Bill,....what ever brought you to that conclusion ? It couldn't have been because its trying to hammer the crankshaft out of it.... now could it ? Ride anyway you want, its your lower end thats being hammered ! Good thing they are tough, huh ? 3C37323268695E0 wrote:
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Title: Re: Carb Confusion Post by Jay on 08/11/10 at 20:03:13 OK, I have a question. Warning: I'm dumber than a box of rocks on carbs. An earlier post said if it pops more in humid weather, it's running rich. Everytime it clouds up that's what mine does. It also does a bit of a stumble at stop lights, but never dies on me. I'm in Fort Worth, Texas, no idea my elevation; no previous owner, my carb and bike are stock, except for the idle screw adjust, and my pipes are turning a nice golden hue. I've been frusrtated with my mpg (it steadily dropped after breakin from 55 to about 48mpg where it's rested ever since.) Anything I should be concerned about? |
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Title: Re: Carb Confusion Post by LANCER on 08/12/10 at 02:16:17 4A43464F554246270 wrote:
you're still having the same issue with it ? |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 08/12/10 at 09:16:40 535E515C5A4D0D083F0 wrote:
you're still having the same issue with it ?[/quote] I haven't been able to ride much recently - failed inspection - no front brakes left. Getting pads today (FA106), I'll do the job over the weekend. I replaced the vacuum hose but it still does that weird RPM pick up with the vacuum hose pinched. I have no good explanation. Either the petcock has a slight leak and I must not suck hard enough. :o Or...??? re: spark plug http://www.4secondsflat.com/Spark_plug_reading.html Mine looks pretty close to example #2 on this page, which supports verslagen1 suggestions in post #3. A leaky petcock could be a contributing factor. So yes, nothings change and I'm still learning. -D. Dwarf |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 08/18/10 at 09:36:02 On the road again! Yay for new brakes. So much quieter. Back to the issues at hand. Actually, I need to gather some data and I'll probably make a new thread. Talked to an old shovelhead mechanic. He thought it was an intake leak. He could be right. I did use an impact driver on the screws on the top of the carb - without removing the carb. Dumb, I know. Anyway, no one else is willing to pinch their vacuum tube? :( -D. Dwarf |
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Title: Re: Carb Confusion Post by ralfyguy on 08/18/10 at 10:37:17 333A3F362C3B3F5E0 wrote:
I'm curious about that too. I wanna know if this is normal |
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Title: Re: Carb Confusion Post by Routy on 08/19/10 at 05:34:36 I did it for someone some time back. There was no change at all. Of course it is not normal !,....how could it be normal unless there was a vacuum leak ? Think ! :o 22313C3629372529500 wrote:
I'm curious about that too. I wanna know if this is normal[/quote] |
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Title: Re: Carb Confusion Post by DrunkenDwarf on 08/19/10 at 06:40:12 212E342F333526242C2235470 wrote:
Vacuum leak? Intake leak? Petcock leak? All three? :o Guess I've got some leak hunting ahead of me. -D. Dwarf |
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